$54 Analytical Notices of Books, 



structure consists, first of the well-known claw, placed near and 

 on each side of the anus, and articulated with a small bone, which 

 occupies its cayity, and is regarded as the phalanx of a toe ; this 

 phalanx is connected with a strong bone concealed beneath the 

 skin, to which Dr. Mayer assigns the name of os metatarsi; and 

 this again is articulated with the longest and principal bone of the 

 limb, called by the authour os cruris seu tibia, which has also at 

 its under and outer extremity two apophyses, considered as ana- 

 logous to the ossa tarsi. The muscles appropriated to these bones 

 consist of an extensor longus pedis, an extensor brevis, a Jiexor 

 pedis, the strongest of the whole, an abductor and an adductor y 

 which with their attachments and actions are all minutely de- 

 scribed. Of Eri/x, Pi/thon, and Clothonia, the authour has been 

 unable to procure specimens for examination ; but he quotes the 

 authority of Oppel, Daudin, Cuvier, and Schneider, for their 

 possessing claws near the anus, and hence he considers himself 

 justified in attributing to them a similar internal structure to that 

 of Boa, With regard to these organs in the genus Tortrix of 

 Oppel (Ilijsia of Hemprich) he enters into more detail, having 

 examined four different species of the genus, which forms the 

 passage from the Phcenopoda to the Cryptopoda, its claws being 

 buried in a cavity near the anus, which has only a very fine open- 

 ing in the skin, through which they can be protruded and re- 

 tracted at pleasure. The bones and muscles are perfectly similar 

 to those of Boa, except that they are comparatively smaller and 

 Ijess distinct. 



In the succeeding family, the Cryptopoda, these rudiments, 

 which have no external claws, gradually degenerate into small 

 and simple slips of bone, occupying the same situation as in the 

 more perfect genera, beneath the Musculus transversalis, and 

 between it and the peritonaum. In the last family they are 

 completely lost. But our limits warn us not to pursue this subject 

 further. We must, however, observe, that in treating of Caciliay 

 Dr. Mayer expresses his dissent from all the naturalists who have 

 hitherto written on that obscure genus, with respect to what 

 have been considered as its most essential characters. The 

 wrinkles on the skin, for instance, which have been so much in- 



