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TlIF, IIATHACIIIA OP NORTH AMKRIC'A. 



227 



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In ijonenil form llils iiniiniil is quite, I'loiif^uti', ;iii(l tlic t.iii is coiisid- 

 enibly shorter tliiin tlic body, inoasiiriii};- one half of the h.-ngth of the 

 head and body together. The head is a h)nger or shorter oval in out- 

 line, and the end of the ninzzle is rounded, truncate, and projects be- 

 yond the lower Jaw to a moderate degree. In prolile it is depressed, and 

 the line of the front gradually descends from behind. The fore limb is 

 short, measuring Just half the distance between its anterior base and 

 the end of the muzzle. 



The eyes are very small, ami are covered by a thin epidermis or 

 cornea. They are situated just one-third the distance between the end 

 of the muzzle and the base of the anterior external branchin. The 

 ui>per lip is pcndidous at the sides of thi; mouth, overlap])ing the lower 

 lip. The latter is free and pendulous at the sides, and is bounded be- 

 low at the base by a deep groove, which mayor may not be continuous 

 round the entire chin. Thus it is comi)lete in seven specimens and in- 

 complete in eighteen. liotii conditions are seen in specimens from the 

 same locality, as, for instance, those from Kiceborongh, (ra., and ^lata- 

 moros, in Tamanlipas, The external nares are well separated from 

 each other, and are short transverse slits. 



The superior horny sheath is quite short, covering only the prcmax- 

 illarybone. It has a sharp edge, and is black in <!olor. The lower 

 sheath is much longer, covering the entire edge of the dentary bone. 

 It is also sliari) edged and black. The tooth patches vary in propor- 

 tions in dilferent individuals. Tiiey are distinct from each other, but 

 are in contact anterioi ly ami diverge i)osteriorly. The teeth are small 

 and acute, ami are arranged in numerous transverse rows in each patch. 

 In adult individuals the patehes have an oval outline, but their width 

 varies, and in some others and in immature examples they are more or 

 It ss linear. Thus in one specimen from Matamoros the vomerine teeth 

 arc reduced t(. a line on each side, the two forming a A. In one from 

 (Icorgia the same arrangement occurs, but in a second from the same 

 locality, and in every other respect similar to it, the teeth are in a wide 

 patch. In two others the patch is intermediate in characters. The 

 surface of the tongue is smooth, not displaying plica' or large pappilhe. 

 It occui)ies nearly the entire tloor of the mouth. The interrial nostrils 

 are eaitha hole at the exterior side of the parasphenoid patches of teeth, 

 at tiie point marking the posterior third of their length. 



The fingers are moderately elongate, and are perfectly free from 

 dermal web or border. Tiieir lengths are in order, commencing with 

 the sliortest, 5-l*-4-.'{. The third and fourth are sometimes of equal 

 length. 



The brancliia', when fully developed, form a bipinnate frame-work, 

 to which tlie ultimate librilla' are attached : timt is, the primary stem 

 sends a row of secondary branches downwards on each side, and these 

 again ternary braiuihes on each side. To the under side of these the 

 fibrillar are attached. Tiiey are (juite short. Tiie entire brantdiia is 

 short and not produced at the extremity, as is the case with Nccfiwiis 



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