15 



features of this; aiii'iial. iti an elaborate treatise on llerpetology, in 

 Brewster's Encyclopaedia, these plates serve as the basis ol' scientific 

 classification : " Crocodilus Mississippiensis : Muzzle broad and flat- 

 tened : four carinated scales disposed in a square upon the neck." This 

 is the entire description, and is again repeated, and applied to the Alli- 

 gator. 



I will here give an account of one of these plates, taken from the 

 middle of the body. It is of a medium size, much smaller and more re- 

 gular than those of the neck, though larger than some others which be- 

 loncr to the inferior rows alonsr the sides. It was taken fi'om a skin 

 which had been dried for many years. A maceration of six weeks 

 caused all the soft tissues to separate. The plate proved white and 

 heavy ; smooth internally, though apparently marked with the cutaneous 

 fibres — perforated with a few minute holes admitting a bristle only ; 

 the general configuration (seen from within), sOjUare ; each border about 

 two inches long ; having rough, suture like margins, from one to three 

 lines thick. The exterior surface is so curiously figured, and withal so 

 irregular as to dety description. The plate rises gradually on three 

 sides ; abruptly on the fuiirlh, forming a carinated ridge, being in the 

 central portion nearly one inch high, having about 75 blind holes or de- 

 pressions sinking from one to three lines into the bone, some of which 

 are laro-e enouijh to receive half of a small pea : others look like shallow 

 sockets from which teeth have been extracted. On the smnmit of the ca- 

 rinated ridge are innumerahle small holes, not half as large as a hair. — 

 This plate was dried in the sun, and after fourteen months, it weighed 

 686 grains (Apoth. v/eight). Its specific gravity was ascertained, most 

 carefully, by Mr. Curtius,'*' (apothecary.) and myself, and was found to 

 be 2.057. 



The skin from which this plate was taken, presented ten larger, with 

 some smaller ones on the neck ; the first row on the trunk, nearest the 

 spine, amounted to 18 ; the second to 15 ; the third to 11 ; the fourth 

 to 6. In another alligator, about 11 feet long, I counted on the right 

 side: first rov/, 17; second 17; third 8; left side, first row 17; second 

 and third rows, irregular in arrangement, situation, size and number. 

 In another, upon which 1 experimented, the first row gave 15 ; the se- 

 cond 15 ; the third 18 ; the fourth 8. M. Geoffrey St. Hiiaire's plate, 

 so far as I can determine, gives for one side : first row, 12 ; second, 

 third, fourth and fifth, each 16 ; the sixth, 6 ; with five larger and som.e 

 smaller on each side of the neck. (PI. 2. Croc, viilg. Hist, Nat.) Are 

 not the number of plates in some degree proportioned to the age of the 

 animal, as the number of rattles are in the rattle snake {croiolus hor- 

 ridiis) '] 



The skin of the alligator, denuded of its cuticle, is white, and, except- 

 ing' that portion protected by plates, is so penetrable, that I have found 

 no difficulty in dividing it in the living state, and, that too, with the com- 

 mon lancet, the edge of which was not injured or blunted by the opera- 



* This yoimg gentleman, (vvhose knowledge is not restricted to the com- 

 pounding of drugs, but embraces a large portion of the physical sciences.) 

 adopted a very simple and satisfactory m.ethod of expelling the air from this 

 most porous of bones, in order to give its specific gravity Avith accuracy. 



