Marietta Voge

THE SIZE ATTAINED BY HYMENOLEPIS DIMINUTA IN DIFFERENT HOST SPECIES

It might be surmised that the size attained by a tapeworm in a particular vertebrate host will be related to the size and species of the host animals. However, little quantitative data to support this view are actually available. Larsh (1946) showed that Hymenolepis nana attained a greater length in the hamster than in the mouse; in these experiments absolute comparisons are still open to the criticism that the two groups of hosts harbored quite different numbers of worms. Beck (1951) has demonstrated the usefulness of singly-established worms in the study of the biological relationships of Hymenolepis diminuta. In the present experiments individual hosts of several species were infected with single cysticercoids of H. diminuta, and an evaluation was made of the size attained in these various hosts. Volume of tapeworm tissue was used as the unit of measure of size attained. MATERIALS AND METHODS The tapeworm eggs for all experiments were obtained from the droppings of one rat infected with H. diminuta of the Rice Institute strain. Cysticercoids were obtained by feeding eggs to laboratory-reared Tenebrio molitor. In each series of host animals of the same species the cysticercoids used for infection were obtained from one beetle. Each host was lightly anesthetized with ether and a single cysticercoid was administered per ora with a pipette. All hosts were autopsied twenty days after infection. (The senior author has found the pre-patent period of H. diminuta to be 19 to 21 days in the hosts used in the present work.) The worms were washed in several changes of Tyrodes solution and blotted carefully on filter paper. Volume of worm tissue was determined by adding each worm to a 5.00 ml. burette, graduated to 0.01 ml., partially filled with Tyrodes solution. The difference in readings before and after addition of each worm was recorded as tissue volume. Tyrodes solution was used because it has been previously shown that the wet weight of H. diminuta does not change in this medium (Chandler, Read, and Nicholas, 1950). Duplicate determinations with the individual worms of one series of ten worms yielded a maximum error of 0.04 ml. No other measurements of worm size were made. EXPERIMENTS In a preliminary experiment twelve gray mice, Mus musculus, were given single cysticercoids. At autopsy twenty days later only one host was found to be harboring a worm. In a second experiment thirty-six albino mice, 60 to 73 days old, were used. Half of this group were males and half females. Six males and six females were given cysticercoids. The remaining twenty-four mice were given 0.05 ml. of 10% tincture of opium intraperitoneally; thirty minutes later each of these mice was given a cysticercoid. At autopsy the mice not treated with opium were free of worms while every individual in the treated group harbored a single

Occurrence and Distribution of Hymenolepidid Cestodes in Shrews

A survey of the literature dealing with cestodes of shrews reveals the increasing interest of contemporary parasitologists in this poorly known group of symbionts. In the United States approximately 18 species have been described from shrews in the last 15 years. These reports deal almost exclusively with morphology of the cestodes; however, information on distribution, host specificity, rate and intensity of infection, is either fragmentary or not available in published form. Examination of autopsy data from a relatively large number of shrews, collected primarily by Rausch, enabled us to obtain some information on the subjects listed above. During the study of our material, it also became desirable to compare some of the data from our shrews with those obtained from shrews elsewhere and to extend this comparison to other vertebrate groups, specifically with reference to infection with hymenolepidid cestodes. The present study is based on an examination of 452 shrews belonging to 11 species collected during the last 10 years in the United States and in Alaska. Numbers and kinds of cestodes found in each shrew were recorded; all the material ob

A new anoplocephalid cestode, Andrya neotomae, from the wood rat Neotoma fuscipes.

Thirteen cestodes, which I am describing as Andrya neotomae n. sp., were collected on June 23, 1941, from the small intestine of a male Neotoma fuscipes caught at the Hastings Natural History Reservation, Monterey Co., California. The worms were fixed in formalin and stained with Ranviers picro-carmine, Grenachers borax carmine, or Ehrlichs haematoxylin. The author is indebted to Dr. Harold Kirby for helpful suggestions in the preparation of this paper, and to Dr. Jean M. Linsdale for lending the material from which this study was made.

Notes on four hymenolepidid cestodes from shrews.

ALICATA, J. E. 1937 Larval development of the spirurid nematode, Physaloptera turgida, in the cockroach, Blatella germanica. Rabot. Gelmint. (Skrjabin), pp. 11-14. DITMARS, R. L. 1946 Reptiles of the World, Doubleday and Co., Inc., Garden City, N. Y. GUNTHER, A. C. L. G. 1902 Reptilia, Batrachia Biologia Centrali-Americana pp. I-XX, 301-325. London. Published for the editors of R. H. Porter, 10 Chandos St. Cavendish Square, W., and Dulau and Co., Soho Square W. HARWOOD, P. D. 1932 The helminths parasitic in the Amphibia and Reptilia of Houston, Texas and vicinity. Proc. U. S. Nat. Mus. 81 Art. 17, pp. 1-71. HOBMAIER, M. 1941 Extramammalian phase of Physaloptera maxillaris Molin, 1860 (Nematoda). J. Parasit. 27: 233-235. ORTLEPP, R. J. 1922 The nematode genus Physaloptera Rud. Proc. Zool. Soc. London, pp. 999-1107. PETRI, L. H. 1950 Life cycle of Physaloptera rara Hall and Wigdor, 1918 (Nematoda: Spiruroidea) with the cockroach, Blatella germanica, serving as the intermediate host. Tr. Kansas Acad. Sc. 53: 331-337. and AMEEL, D. J. 1950 Studies on the life cycle of Physaloptera rara Hall and Wigdor, 1918 and Physaloptera praeputialis Linstow, 1889. J. Parasit. 36: (6 Sect. 2): 40. SCHELL, S. 1952 Studies on the life cycle of Physaloptera hispida Schell (Nematoda: Spiruroidea) A parasite of the cotton rat (Sigmodon hispidus littoralis Chapman). J. Parasit. 38: 462-472.

Hymenolepis parvissima n. sp., a minute cestode from the shrew Sorex bendirei bendirei (Merriam) in California.

Diagnosis: Strobila total length 0.467-0.850 in mature specimens, average 0.644; strobila greatest width 0.153-0.204; proglottid number 7-10, most frequent number 8. Scolex with well developed rostellum bearing 10 hooks. Scolex diameter range 0.090-0.150, average 0.109; sucker diameter range 40-60 x 48-74 It, average 51 x60 i; rostellum diameter range 50-72x60-90 ?, average 61 x 75 !~; hook length 20-24 f. Genital pores unilateral, situated in anterior fourth of lateral margin of segment. Testes in a straight line, diameter range 20-40 x28-48 R, average 28 x 35 It. Cirrus spinose; cirrus pouch length 60-86 ,I. Vagina with seminal receptacle about as wide as cirrus pouch. Ovary bipartite, situated in anterior half of proglottid. Uterus saclike. Eggs mostly spherical (30-40 l~ in diameter), occasionally ovoid (30 x44 li) in outline; onchosphere diameter 18-26 t. Type host: Sorex bendirei bendirei (Merriam). Habitat: Small intestine. Type locality: Humboldt Co., California. Type slide: U. S. National Museum, Helminthological Collection.

Observations on Shipleya inermis Fuhrmann, 1908 (Cestoda: Acoleidae).

Shipleya inermis, described by Fuhrmann (1908) and redescribed by Baer (1940), is known from only few specimens. The first and only North American record of this species was published by Webster (1951), who reported the finding of 2 specimens in dowitchers. Examination of a large number of cestodes from dowitchers collected by one of us (Rausch), and of cestodes from the Helminthological Collection of the United States National Museum yielded specimens which are without doubt Shipleya inermis. However, some of our observations which are reported here do not agree with Baers description. In particular, we are unable to agree with Baer (1940) that individuals of S. inermis are hermaphroditic. We are grateful to Mr. Allen McIntosh, Zoological Division, Beltsville, Maryland, for the loan of cestodes from dowitchers; and to Dr. F. N. Hamerstrom, Plainfield, Wisconsin, who collected the dowitcher from Iowa.

A description of Parafimbriaria websteri n. g., n. sp., a cestode from grebes, and notes on three species of Hymenolepis.

Study of cestodes collected from the grebe, Colymbus nigricollis, taken at Guardian Angel Island, Gulf of California, and Salton Sea, Imperial County, California, during 1953, revealed that 3 species of hymenolepidid cestodes were represented. One of these, a member of the subfamily FIMBRIARIINAE, is considered to represent a new genus. The remaining material from the grebes is referred to 2 previously known species, Hymenolepis furcigera (Krabbe, 1869) and H. podicipina Szymanski, 1905. Notes are presented on this latter material and on a third species, Hymenolepis recurvirostrae (Krabbe, 1869), collected from Recurvirostra americana, taken at Newport Bay, California. Worms were studied as whole mounts fixed in Bouins fluid and stained with

Ariolimax columbianus, an intermediate host for Brachylaemus virginiana (Dickerson) (Trematoda: Digenea) in California.

On March 3, 1951 a young male opossum was captured in Tilden Park, Contra Costa Co., California. The animal had a droopy, sickly appearance and was killed and examined for parasites. Several hundred small flukes, later identified as Brachylaemus virginiana (Dickerson), were found in the small intestine. Several months previously one of us had found metacercariae in the kidney of Ariolimax columbianus. This slug is commonly found in the Pacific Coast region and is restricted to this area. Comparison of the metacercariae with the flukes obtained from the opossum, as well as examination of pertinent literature (Dickerson 1930, Krull 1935), indicated clearly that the larvae from the slugs were metacercariae of Brachylaemus virginiana. Of 97 Ariolimax columbianus collected on the Mills College Campus, Alameda Co., California, 94 harbored this metacercaria in the kidneys. There were approximately two dozen larvae per kidney, while specimens with as few as one or two and others with as many as 50 or more were observed. In addition, 6 out of 8 Ariolimax columbianus from Berkeley, Alameda Co., California were infected. Seven A. californicus brachycephalus from San Mateo Co., California were found to be negative. Although the digestive, hermaphroditic and albumen glands were examined in several specimens of A. columbianus, no sporocysts or cercariae were found. Krull (1936) listed 1 slug and 5 snail intermediate hosts for Brachylaemus virginiana. We therefore examined a number of common gastropods, in order to determine possible additional hosts for the larval stages of this fluke. Of 20 Milax gagates, 10 Limax marginatus, 1 Limax flavus, 20 Deroceras reticulatum and 6 Helminthoglypta arrosa holderiana not a single one was infected. All these gastropods were collected on the Mills College Campus between February and May 1951 in the same habitat with Ariolimax. Three Helminthoglypta nickliniana from Tilden Park, Contra Costa Co., California, were also negative. Since the slug Deroceras laeve is a host for the metacercaria (Krull, 1936) one would expect that D. reticulatum might also be suitable. This was not so, however, and it was somewhat surprising to find the metacercariae only in Ariolimax. It may be that the food habits of the above mentioned gastropods are in part responsible for this situation. Ariolimax columbianus has been observed to congregate around and feed on feces in nature. None of the other species listed has been observed to do so. In relation to the opossum in California, we should like to stress that this animal was introduced into the state, the earliest record being sometime after 1880 (Grinnell, Dixon and Linsdale, 1937); subsequently it was introduced repeatedly around