7 



>/' 



IIIK IIATKACIIIA Ol' NOU'i'll AMKKICA. 



G3 



AMIJLYSTOMA (.'OrKANTM I lay. 

 l'i(i(!t)o«liii|;s U, S, Natioiuil Musoiiiii, lri."*r), \i. 'M*, I'l. xi\'. 



The lu';i(l is lar^'f, somewhat wider than tlie body, and Ualdiiu'd; the 

 body short, and tiio tail h)ii^ and coiiipitissed. Tiiesi^in is tor tiic most 

 part smooth, bnt rvcrywiit'iv, as seen nnch-r a Kmis, is pitted with the 

 openin};s of the entaneous follicles. Of tliese, there area fewenlargeil 

 ones in a band snrronndin;;: tiie orbit and extending; forward to tlu; 

 iKKstril. Others are fonnd alK)ve the angle of the Jaw, and a few still 

 lariier ones on the posterior border of the i arotoid n'gion. The promi- 

 nent keel and the whole tip of the tail aie so riehly provided with 

 eidarjjed pores as to present a Ki'iiniilated appearan(;e. 



The width of the head is somewhat greater than that of the body. It 

 is possible that the breadth and llatness of the head havi^ been exag- 

 gcu'ated somewhat l>y the injnries that it has recu-ived; but this can Ix' 

 trne only to a very slight (vxtent. The breadth is abont the same at the 

 angle of the Jaw and the corner of the month. From the former point 

 the head tapers backward, the ontline being coiutave to its posteiior 

 border, where it is snddenly constricted into the necik. From the cor- 

 ners of the month tlie head tapers forward to nearly opi>osite the nostrils, 

 beyond which it is rapidly rounded to form the snont. The width of 

 the head is a little less than the distance from the snout to the gnlar 

 fold, and is (contained in tlu' distanei^ from the snont to the groin .5.0 

 times. Tlie distance to the gnlar fold iscontained in the distance to the 

 groin 3.1i tinu's. The depth of the head, on a line Joining the angles 

 of the Jaws, is a little less than one half its width. The gnlar fold does 

 not overlap, as it tloes in some s[n'cies. It may have done so in lile, 

 bnt manipnialion of the skin fails to restore an ()verlai)ping fold. Tlu; 

 npperjaw projects beyond the lower. Fyes of moderate size. Externiil 

 naies small; their distance apart somewhat less than the width of the 

 interorbital space. 



The tongne is not notably dill'erent from that of .1. fitfriiium. The 

 teeth are arranged in four series, which together form an inverteil V? 

 the angle of which is very obtnse. The limbs of the V? 'i'"* •'^^•^"' ^^''•''' tlie 

 nnaided eye, ai>pear nearly straight, and are .seen to extend beyond the 

 internal nares along their external lissnre. Examination with a lens 

 pnnes that the inner seriesare each slightly /-^/shaped, ami .so disposed 

 as to make the angle of the V r«)iinded oil". Th(M>nter series on each side 

 is nearly as long as the corresponding inner series ; is plaiidy .separated 

 from it, and nearly straight or slightly concave on the pt)sterior side. 

 Inner nares more; distant than the exterinil. The body is sonn;what 

 dei>re.s,sed, but has not the swollen ai)pearan(!e |)resented by A.opacnm. 

 The distance from tlM^snontto the axilla isjnstetinal to that from the 

 axilla to th(> groin. There are eleven well-marked costal grooves. Then^ 

 is a median fnrr<»w, not deep bnt distinct, beginning on the occipnt 

 ami riinnwigalitii ^ (hv^ b.ick, di'i-pening o.i the sacral ri'gion, and emling 

 over the middle of the vent, at the comnn'ncement of the caudal crest. 



4: 



\ 



