Lyell J. Thomas

Environmental relations and life history of the tapeworm Bothriocephalus rarus Thomas.

The description and distribution of the tapeworm Bothriocephalus rarus has been dealt with in another paper (Thomas, 1937), in which attention is directed to the known range of this parasite which up to the present time has been reported nowhere else but in the small intestine of the vermilion-spotted newts of Sedge Pool, Douglas Lake, Cheboygan County, Michigan; Seatons Lake, Uniontown, Pennsylvania; and an unknown locality in northern South Carolina. The tapeworm is uusual in that, to the writers knowledge, it is the second adult pseudophyllidean tapeworm reported for amphibia and the only one thus far described for the genus Bothriocephalus that does not necessarily have a second intermediate host and that has formed bothria in the procercoid stage. These last features are a departure from the classic study by Rosen and Janici (I917-I8) on the life history of Diphyllobothrium latum and the studies of Li (I929) on Diphyllobothrium decipiens and D. erinacei. It is also different from the life cycle of Bothriocephalus cuspidatus as given by Essex (I928). It, in fact, approaches in some respects the development of Cyathocephalus truncatus Pallas as described by Wisniewski (I932a and b). The data assembled here are the culmination of experiments made and notes taken during the summers I927 to 1933 at the University of Michigan Biological Station.

The life cycle of Diphyllobothrium oblongatum Thomas, a tapeworm of gulls.

This investigation deals primarily with the life cycle of a pseudophyllidean tapeworm infecting young gulls from Lake Michigan. It also examines the possibility of using larval characters as well as adult characters in establishing species. It is the writers opinion that this is important at the present time when there is a tendency among taxonomists to use only adult characters in establishing species of the genus Diphyllobothrium with a resulting confusion of species.

Cercaría sphaerula n. sp. from Helisoma trivolvis infecting cyclops.

A larval trematode of the family Hemiuridae was observed by the writer and a student, Arthur Dean Johnson, while at the University of Michigan Biological Station the summer of 1932. As it is one of the few cystophorous cercaria in this group described from freshwater snails of North America and as notes on the life history were obtained which may shed some light on infestations in marine as well as freshwater forms this preliminary report is given.

A New Disease of Moose. II

Thomas and Cahn 1 described a new disease of moose (Alces americana americana) in northern Minnesota. The symptoms of the disease were described, with the associated blood picture. Transplanting ticks (Dermacentor albipictis) from an infected moose to guinea pigs and rabbits produced a disease showing identical symptoms, with the same associated blood picture as in the moose. Profound cellular changes in the blood elements and the presence of bacteria were mentioned. The organism was isolated. The cellular changes will be discussed in the final report; the present paper deals with the isolated organism. The first recognized bacteria-like organism was found in smears of the intestinal contents of ticks engorged with the blood of diseased moose. With a modified Wright stain these organisms showed a capsulated coccoid bacterium. This intestinal content was cultured on dextrose agar, and the organism isolated. A saline suspension of this pure culture was inoculated intravenously into guinea pigs and rabbits, and all of the experimental animals died within 28 hours, exhibiting symptoms similar to those shown by guinea pigs and rabbits infected through the medium of the tick itself. The organism has been repeatedly recovered from the liver, spleen, lungs, heart, kidney, brain, bone marrow and urinary bladder of inoculated and infected animals. This organism has also been inoculated into a bull, a chicken, a ram and a 4-day-old lamb. The chicken and the lamb died with symptoms exactly like those obtained in the guinea pigs and rabbits. In the case of the bull, 5 cc. of the culture was given intravenously. Within one hour after the injection very definite disturbances were noted, including a marked physical depression, listless drooping, labored respiration followed by lung hemorrhages, coughing and bloating.