Again, the rudimentary scute lies in the dermis as in a sort of pocket, the superficial and deep walls of which separate from it with great ease; and in good thin sections made through the dermis and scute, there seems to be no direct connexion between the substance of the scute above and below, and the connective tissue with which it is in contact. Nor could I satisfy myself that the margins of the scute were continuous with the surrounding bundles of connective tissue. However, the specimen had been a very long time in spirit; and I am unwilling to lay too much stress upon these observations, which tend to negative the supposition that the scute proceeds from the direct calcification of the connective tissue of the dermis.
On the other hand, I must remark that horizontal sections of the scutes have presented oblique parallel fissures, sometimes crossing one another, which might readily be supposed to correspond with the lines of separation of ossified bundles of connective tissue.
Note.—During a recent visit to Paris, my friend Mr. Busk was kind enough to examine the specimens of recent Crocodilia in the Museum of the Jardin des Plantes, with reference to certain points to which I requested his attention. Mr. Busk informs me that there is no doubt about the transverse direction of the premaxillo-maxillary suture in Crocodilus rhombifer; and his statements lead me to entertain no question that C. bombifrons is a synonym of C. palustris.
In the typical specimens of C. marginatus and C. suchus of Geoffroy St.-Hilaire, the premaxillo-maxillary suture extends back to the level of the seventh tooth.
Mr. Busk has furthermore pointed out to me the existence of another American species of Crocodile—C. Morelettii, which has been described by M. Auguste Duméril in his "Description des Reptiles nouveaux ou imparfaitement connus," &c., 'Archives du Muséum,' t. vi. 1852.
This species inhabits lake Flores, in Yucatan; and it is said by M. Duméril to approach C. Americanus, from which it differs in the proportions of the skull and in the characters of the dermal armour.
June 21st, 1859.