188 PROCEEDINGS OP THE ACADEMY OP 



shield. Anterior in contact with a very large anterior marginal, making to- 

 gether eleven vertebrals in an interrupted series. 



' This interesting genus is nearest to Chelydra, though widely different ; its 

 general appearance and interrupted vertebral series approximate it to the Cino- 

 sternidse, especially Aroniochelys and Staurotypus s a 1 v i n i i,* Gray. Indeed 

 it only differs from the latter species in the immobility of the anterior lobe of 

 the sternum, and absence of inguinal and axillary plates, as well $s the 

 presence of the mesosternal bone, if the latter belong truly to the Cinosterni- 

 dsef. Claudius must be placed on the confines of the Emydidse in this direc- 

 tion, as Chelopus marks the extreme in the other. 



Character specijicus. Marginal scales all very narrow, especially anteriorly; 

 four lateral grooved ; nuchal very small, transverse. Anterior vertebral longest, 

 broad as long, posteriorly rounded, acuminate, in contact with second marginal. 

 Third and fourth vertebrals broader than long ; last narrowed above. Anterior 

 costal li the length of the third. Epidermoid layer rather thin, concentrically 

 ridged anteriorly and externally on the plates ; a median and lateral keel on 

 each side, all quite weak. Sternum rounded in front, acute behind, equal 

 portions before and behind the abdomino preanal suture. Abdominal three- 

 fifths of pectoro-gular plate. Above blackish brown, the plates paler medially, 

 below yellow, unspotted. 



The head is disproportionately large, and of an elongate form, with narrow 

 postorbital arches ; baove plane, covered with a soft skin, except an oval 

 plate of horn on the top of the nose. Maxillary sheath hooked in front, and 

 with a sharp tooth below the anterior margin of each orbit ; edges sharp. 

 Mandible with a remarkably long symphyseal hook, which is received into a 

 correspondingly deep premaxillary pit. A pair of barbels ; skin of neck with- 

 out warts or appendages. Toes and claws rather slender, very fully webbed ; 

 tbe forearm with three anterior curved corneous ridges, and the heel with 

 four series. Tail (of 9 ) very short, without terminal claw, and with a double 

 dorsal row of skin warts. 



Color blackish plumbeous, the inferior surfaces paler. 



Called Talmame by the natives. Museum Smithsonian, 6518. 



" Talmame lives in swamps, and digs itself in to a depth of two and three 

 feet ; eats small fish, crustaceans, snails, etc. Animal food I have found also 

 in the stomach of Chiquihuau, (entire ampullarias,) Huau and Pochitoque." 



ritaurotypus triporcatus, Wagl. 



Called by the natives Huau. 



Travellers relate that the alligator is often killed by a turtle, which he 

 swallows alive, and which devours the intestines to get out. Heller (Reisen 

 iu Mexico, p. 313) says that he has seen a living turtle " of the genus Cynixis" 

 within a fresh-killed alligator. Waldeck, whose imaginatory power exceeds 

 far his observatory, says (in Voyage pittoresque) that he has found in every 

 killed alligator's stomach a living " Ticotea or potohitoque, which is the same 

 known in Egypt, (thirse,) and also the Testudo triunguis of Torskal." (!) 



I have it from a number of different and reliable persons that they have 

 witnessed the fact ; either found a living Huau in the body of a dead alligator, 

 who was supposed to have run on shore and died, or even seen the Huau just 

 breaking out of the dead body of the alligator ; but never any other kind of 

 turtles ; only the Huau. 



Huau has two very distinct voices ; one imitated in the name, a strong 

 expiration in the given vowels, not intoned with the larynx, but only with the 

 fauces and mouth, and a squeak, like that of dry carriage wheels or of a 

 large door. The first seems an expression of anger, when teased ; the second 

 perhaps a call, as I heard them often when at night ; once alone in a corner 

 of my house ; never when male and female were near each other. 



* Proe. Zool. Sob., Lond., 18t 4, 127. 



fVid. Le Conto's system, Pr. A. N. S., 1854, 1S2. 



["Oct. 



