300 SUMMARY OF CURRENT RESEARCHES RELATING TO 



Epidermal Organs in Lizards.* — F. Folg has made a comparative 

 histological examination of the femoral, pre-anal or inguinal, and anal 

 organs in Laccrta, Agama, and other lizards. These organs all show 

 a more or less marked agreement with the epidermis, and are not of a 

 glandular nature. 



Reptilian Lower Jaw.f — J. S. Kingsley discusses the composition 

 of the lower-jaw in reptilian types. A good deal of confusion has 

 arisen, since Cuvier recognised at most six component bones (1836). In 

 an embryo of the lizard Sceloporiis, in which the centres of ossification 

 have appeared, reconstruction from serial sections shows the following 

 elements : most posteriorly a long and slender dermarticular, the arti- 

 cular, the angular, the splenial, the coronoid, the dentary, and the 

 surangular. The only difference between Cuvier's account and that 

 given by Kingsley is the recognition of the dermarticular as a distinct 

 element. In the lizard it afterwards fuses with the articular, but in 

 some reptiles it is distinct throughout life. Its characteristics are its 

 position on the posterior inner side of Meckel's cartilage, its inferior 

 margin being overlapped by the angular and its anterior end, which lies 

 ventral to the coronoid, by the splenial element. 



Classification of Birds.}— R. W. Shufeldt gives his classification of 

 the higher groups down to and including the families of birds. The 

 divisions employed are Order, Super-sub-order, Sub-order, Family. Xo 

 details are given, but the paper discusses in a general way the value of 

 various criteria in classification. 



Rudimentary Upper Canines in Elk.§ — E. Lonnberg describes in 

 an old male of Alces alces a pair of rudimentary canine teeth, which 

 were imbedded in the firm connective tissue of the soft palate, and not 

 implanted in alveoli. They were quite short, without fang, and in shape 

 resembled the crown ends of the " hooks " of red deer. 



Perineal Sac in Cavia cobaya.]] — S. Grosz describes in both sexes 

 a perineal sac, into which two sebaceous glandular bodies open. These 

 glands are markedly developed in the male, less so in the female. The 

 author is of opinion that this apparatus is related to the sexual function, 

 and effects attraction between the sexes. 



Arboreal Ancestry of Mammalia.^ — W, D. Matthew discusses the 

 probable origin of the mammalia, postulating a common ancestral group 

 from which all known mammals, excepting the Prototheria, are de- 

 scended. The evidence for such a group is the close uniformity of 

 these mammalia in general structure, in spite of their wide divergence 

 in adaptive specialisation, and the invariable approximation towards a 

 central type of each race whose development is known from palaeontology. 

 He enumerates with considerable detail the characters of this primitive 



* Arbeit. Zoo). Inst. Wien. xv. Heft 2 (1004) pp. 7-3G (3 pla.). 

 t Amer. Nat., xxxix. (1905) pp. 59-64 (8 figs.). 

 t Op. cit., xxxviii. (1904) pp. 833-57. 

 § Zool. Anzeig., xxviii. (1905) pp. 448-9. 

 || Zeitsclir. wiss. Zool., lxxviii. (1904) pp. 261-7. 

 ^ Amer. Nat, xxxviii. (1904) pp. 811-18. 



