FOSSIL AND KECENT LAGOMOEPHA. 486 



numerous juvenile dentitions wliicli were at the author's disposal might have shown him 

 that the separation of the two lobes is characteristic of young stages in the inferior 

 cheek-teeth of Lepns generally. 



The Bony Palate in the LAgomorphine Skull. 



The greatly reduced hony palate is considered to be one of the characteristic features 

 in the skull of Lagomorpha. At first sight the only difference in this respect between 

 Leporidae and Lagomyid* appears to be that in the latter family the palatal bridge is 

 shorter than in Leporidte. On investigating the matter more closely, however, it may 

 be seen that in Leporidte the bony palate is shortest in the genus Lepus s. str., viz. in 

 those forms which are most sj)ecialized for running and leaping ; and that the 

 shortness is principally due to a reduction in length of the os palatinum. In Lagomyidse, 

 on the contrary (PI. 39. figs. 34, 36, "jj"), the latter bone is comparatively elongate, 

 while the part of the bony palate formed by the maxiliaries (m) is greatly reduced, so 

 that in some cases the latter do not even join in the laiddle line antei'iorly, the middle of 

 the anterior margin of the palatal bridge being formed by the palatine bones. As seen 

 from the figiu'cs, Prolagus (fig. 36) is in this respect scarcely different from Lagomys 

 (fig. 34). 



It might, a priori, be expected that this speci?lization of the Lagomorpha will be 

 reduced to a minimum, in other words that the bony palate will be longest, in the oldest 

 members of the group, and this is in fact so. Cojie describes this part of the skull 

 of Palceolagus as follows : — " The palatine bones are flat and occupy more than half the 

 palate between the molars. Their common suture is at least as long as that of the 

 maxillaries, and extends as far forward as the posterior border of the second molar. Prom 

 this point the anterior suture extends to the posterior border of the third molar. The 

 palatal notch is rectangalar, and is not wider than the palatine bone on each side of it." * 



some phylogunetic speculation has been based thereon. The author avails himself of these two types, the 

 tritubercular and the diprotodont, in tracing two primitive types in the teeth of one species, Lepus sa.catilis ; the 

 anterior upper cheek-tooth is referred to the tritubercular type ; the conformation of the two anterior lower teeth, 

 on the other hand, " decidedly suggests the molars of Kangaroos and Wombats, and makes it probable that the 

 ancestors of the Lagomorpha were llarsupials, holding ahout the middle between Phascohjnii/s and Lagorchestes" 

 (p. 545). By the cheek-teeth of its ripe embryo, the Wild Rahbit is far removed from Lepus curop<ms (p. 553) ; and 

 the cheek-teeth of the latter were evolved from the tritubercular type (p. 551). The rabbit's skull approaches the 

 Marsupial type (p. 551). The author seems to be unaware of the existence of deciduous cheek-teeth in the Leporidae. 

 On p. 549, the anterior of the upper cheek-teeth is twice termed p. 1. Supposing that we have really to do with 

 a premolar, the anterior premolar in the upper series would be p. 3, according to Hensel's mode of writing, adopted 

 by the present writer, or p. 2, according to the usual custom, hut under no circumstances p. 1. Considering, 

 however, that the two teeth referred to by Prof. Xoack belong, the one to a mature, the other to an unripe embryo 

 of L, europa'us, in which species the tooth-change takes place only some time after birth, the alleged p. 1 is in 

 reality a d. 3 (d. 2 of authors). On pp. 544 and 545 the remarkable circumstance is noted that in the half-grown 

 L. saxatilh the second and third anterior upper cheek-teeth are more retarded in their development than the same 

 teeth in embryos of L. europceus. The very oljvious explanation is that those of the former sjiecies are premolars, 

 those of the latter deciduous teeth. 



* E. D. Cope, 'The Vertebrata of the Tertiary Formations of the West," i. p. 875 (lS7(i) pi. Ixvi. figs. 1, 4 

 0883). 



