Chap. I. 



UROGENITAL ORGANS. 



289 



means of which the young, like young Birds, break through the hard shell. Dr. 

 Weinland tells me, that in a beautiful serie.s of specimens of Crocodiles in the 

 Museum of Berlin, the snout of the embryo about hatching is sufliciently hard 

 to break the egg, and that there is no such tubercle upon it; neither is there 

 a tooth in the intermaxillary bone for this purpose. 



The cloaca is very large in both sexes; it opens on both sides into a large 

 pouch, (sacci anales,) tlie function of which is not yet fully ascertained ; it may 

 stand in connection witli the reception of water into the cloaca, mentioned above. 

 The cloaca is exceedingly long in Trionyx. In female Turtles, we see in the 

 bottom of the cloaca a longitudinal furrow, with thick, rounded walls, running out 

 generally into fringed appendages behind. This serves as a vagina in the act 

 of copulation. Interiorly Ave find, in the cloaca, first, the opening for the urine, 

 then behind and outside of it, on each side, that for the oviduct. 



The copulation is generally said to take place only once in a year; but my 

 observations have satisfied me, that, at least in some species, it takes place twice 

 every year, namely, in the spring and in the autumn. 



It is, perhaps, the proper place to mention here some glands in Turtles which 

 open outward and secrete a strong, odoriferous oil. These glands seem to have 

 a more immediate reference to the relations of the animal to its fellow-beings 

 than to its own individual organism. We find such glands in the lower jaw in 

 Testudo, in the neck and shoulder region in sea Turtles, while in the family of the 

 Cinosternoidai there are two larger glands on each side under the carapace, near 

 the bridge which unites the carapace and plastron, the excretory ducts of which 



the year 1841, p. 329 and foil.) The operation of the 

 tooth itself in the living animal has been observed 

 in young Snakes, while hatching, by Dr. Wein- 

 land, (see Wurttembergische naturwissenschaftichc 

 Jahreshefte, XII., for the year 1856, p. 90 and foil.,) 

 so that there can be no doubt alwut the function of 

 this strange tooth, which is fixed in the intermaxil- 

 lary bone, where afterwards, at least in most Snakes, 

 no tooth at all is to be found. Nor can there 

 be any question of its being common to all Snakes 

 and Lizards, when hatching, for after Miillcr had 

 already found it in very difTercnf families, it lias 

 been traced by Dr. Weinland in all the German 

 Snakes and Lizards. Now neither J. ISIiillcr nor 

 Dr. Weinland could find this tooth in the young 

 Crocodiles when hatching. This is remarkable, 

 because it strangely coincides with the suggestion of 



37 



Stannius, (see above, p. 288, note,) to unite the 

 Snakes and Lizards on one side, and the Turtles 

 and Crocodiles on the other side, into two large 

 groups ; the first of which have such an egg-tooth, 

 whilst the latter have none. But, as far as the 

 Turtles and Crocodiles are concerned, this resem- 

 blance is evidently only negative, and cannot, there- 

 fore, prove any affmity ; while the fact, that the 

 cgg-looth is common to the Lizards and Sn.akes, is 

 another striking instance of their close affinity, and 

 of the correctness of the views of Stannius, who 

 proposes to unite them into one group, in opposition 

 to Turtles and Crocodiles, as Merrem has already 

 done. Thus, the Reptiles would really form only 

 three large groups, one comprehending the Lizards 

 and Snakes, another the Crocodiles, and a third 

 the Turtles. 



