ZOOLOGY. dbl 



seu uud Ordiiungen des Tliierreichs," lias been contiuued and a 

 number of parts issued during tlie past two years. Trouessart's cata- 

 logue of all the living and extinct species lias also been continued in the 

 " Itevue et JMagasin de Zoologie." The most important of the many 

 memoirs on special groups is Allen's on the Pinnipeds of North America, 

 which contains besides a revision of those of other parts. The teeth 

 have been examined partly as to their mechanical and partly as to their 

 taxonomic relations, by Heusel and IJyder. 



The placenta? of Edentates of the families of DasypodidiB and Bra- 

 dypodidiB have been examined by Milne Edwards and Joly, — the former 

 by Edwards and the latter by Joly. 



O has made a special investigation of the muscle of the eye in 



the apes and monkeys. The foramina of the base of the skull have been 

 again investigated with reference to systematic values by Cope for the 

 ^Ehiroid Carnivores and by Wiugie for the Insectivores. 



THE PEOCtENITORS OF MAMMALS. 



The parents of mammals have been chiefly sought for in recent times 

 among the early reptiles, and it has been supposed that they were 

 descended from forms closely related to the Dinosaurians of the Jurassic 

 and Cretaceous epochs. In a recent memoir on the characteristics of 

 the pelvis iu the mammals, Professor Huxley has challenged this view,* 

 and has expressed his belief that " it appears to be useless to attempt 

 to seek among any known Sauropsida for the kind of pelvis which 

 analogy leads us to expect among those vertebrated animals which 

 immediately i)recede the lowest known Mammalia; for, if we i^roloug 

 the series of observed modifications of the i)elvis in this group back- 

 wards, the 'Promammalia' antecedent to the Monotremes may be 

 expected to have the iliac and obturator axes perpendicular to the 

 sacral axis, and the iliopectineal axis i)arallel with it; something, in 

 short, between the pelvis of the Ornithorhynchus and that of a laud 

 tortoise; and provided, like the former, with large epipubes intermediate 

 in character between those of the lower mammals and those of croco- 

 diles." As this condition is not fulfilled in the lieptiles. Professor 

 Huxley thinks that the original mammals have descended from an 

 entirely different stock. He asserts that in such a pelvis as the sala- 

 mander, for example, " we have an adequate representation of the type 

 from which all the dilferent modifications which we find in the higher 

 vertebrata may have taken their origin." He therefore deduces the 

 conclusion that mammals have been derived from the Ami^hibiaus 

 through "some unknown 'promammalian' group, and not from any 

 known forms of Sauropsida." In corroboration of this view he adduces 

 the two condyles of the occipital of the skull in which the mammals are 



* Hnxley (T. H. ). On the Characters of the Pelvis iu the Mammalia and the Conclu- 

 sions respecting the Origin of Mammals which may be based on them. Froc. Boyal 

 Society, vol. xxviii, pp. 395-405, ])\. 8. 



