Daris R. Swindler

THE DENTITION OF THE MINK (MUSTELA VISON)

Sixty-five specimens of mink (Mustela vison), ranging in age from fetuses to adults, were examined and the morphologic features of the dentition were described. The dental formula for the deciduous teeth is: DI, 3/3; DC, 1/1; DP, 3/3 = 28. Deciduous teeth erupt between the 16th and 49th day after birth. The range in eruption of the permanent teeth is from 44 to 71 days. Calcification of the permanent teeth commences at about the time of birth and all the permanent teeth show evidence of calcification by 30 days post-partum. The paracone is the first maxillary cusp to form and the protoconid is the first to develop in the mandible. Sixteen known-age (from 28 days to 51/2 years) mink skulls were examined and used in describing the deciduous and permanent dentition. The time and sequence of eruption of the deciduous and permanent teeth was determined by daily examination of 29 live mink kits. These animals were observed from birth until all the permanent teeth had erupted. The teeth were considered to be erupted when the tip of the crown had pierced the gingiva. To ascertain the order of cusp formation and calcification of the permanent teeth, 20 mink (ranging from 43 days gestation to 3 months of age) were collected from commercial mink ranches. After preserving the specimens in 10% formalin, the teeth and tooth buds were dissected from the jaws, stained in alizarin red-S, and cleared in 2% potassium hydroxide. The nomenclature of the Trituberculate Theory (Osborn, 1907) was followed through- out the investigation.

Calcification of the Deciduous Molars in Baboons (Papio anubis) and Other Primates

Molar tooth buds of known aged baboon fetuses were removed and stained in alizarin red S. The sequences of cusp calcification and coalescences were studied in the deciduous molars. The cusp calcification sequence was similar in the baboon, rhesus monkey, and man; the coalescence pattern of the baboon and rhesus monkey differed from that of man.

The comparative gross anatomy of the arteria cerebri media in the green monkey (Cercopithecus aethiops) and olive monkey (Papio anubis)

The gross anatomy of the arteria cerebri media inCercopithecus aethiops andPapio anubis was studied and compared statistically. Several features appeared to be species characteristic. InCercopithecus aethiops the first branch, r. striati, arose directly from the main artery, however, inPapio anubis, r. striati arose from r. orbitales the second major branch. InCercopithecus aethiops, r. orbitales and r. frontales arose by a common trunk from the a. cerebri media and inPapio anubis these two branches had separate origins. In both species r. temporales arose from two trunks, on either side of the a. sulcus centralis. Each trunk of r. temporales divided into two or three branches inCercopithecus aethiops and three or four branches inPapio anubis. The last portion of the a. cerebri media, r. parietales, divided into two trunks inCercopithecus aethiops and continued as a single trunk inPapio anubis. In the former, r. parietales sent one or two branches to the sulcus intraparietalis and sulcus lunatus while sending one branch to the gyrus postcentralis. In the latter, r. parietales sent two or three branches to the sulcus intraparietalis, three or four to the sulcus lunatus and one to the gyrus postcentralis.