1^ 



' VI 



218 mjLLETTN :?l, UNITKD STATES NATIONAL MUSKUM. 



Tlie bnuicliial fissiuv. is sitiiatiMl iieiiily as far posteiior to the caii- 

 tliius oris as the latter is posterior to tlie end of the lower jaw. It is in 

 the anterior part of a fossa, and is bordered anteriorly and posteriorly 

 hy a narrow free nienibranons lamina. A short distanec beiiind and be- 

 low this is situated the anterior limb. The len«ilh of the linib is eqnal 

 to the intero(!nlar space; in some spetinensa little less. The hnnierns 

 nuikes an anj^ie with tiio rest of the Imib, but the foot is eontinnons 

 witli the cubitns; it is divided into either two or three toes. The jjos- 

 terior limb is huj^er than the anterior, nieasnrinj;- nearly half as lonjj 

 aijitin. Its jjosterior bonier orijfinates a very short distancj'; in front of 

 the anterioi'extremity of the vent. It is compressed, and }?ently enrved 

 inwards at the knee Joint. It is <lirecte«l posteriorly, not quite reach- 

 in}; the i)()steri()r extremity of the vent. It is divided into two or tliret^ 

 di}>its. The vent is a lon.uitudinal slit, with a jirominent margin. Its 

 internal face is densely i)appilloso within the marj-inal border. 



Measiirrmnils nf So. (>;!()(>. 



31. 



'l"(.(iil Iciifith f^Hi 



L(Mi<;tli(il'tiiil l-'-.i 



J^i'iij^tli to ciintliiis oris 017 



Lei)<;tli to ln'ainlii;il lissiire 077 



Lcnjjth to I'oriOiiiiU OHi) 



Li'iifitli of torn limit 0175 



Leii<;tli ot'liind liiiil) (»'-»l 



Wiillh l.ct\V(!(Mi nostrils ()(H 



Width hc.twccii cy.'s OlS 



Width ofh(';id at can thus oris til.') 



In specimens in alcohol the color is a dark slaty brown above ami 

 slate colored below. Its (tolors in life are said by Dr. Ilolbrook to be 

 the same. 



I have united int(> a sin<>le sj»ecies the Amphhtmu mcnnn and A. iriilac- 

 ti/la ill the above account. The dest^iption was made from a specimen 

 (No. (I.'KIO) in which there, are two toes on the anterior and three toes 

 on the pD-teiior limb. In two specimens of the National collvction on 

 the toes are .'5-1 ami 2-1 in front. In the niimeron.i spe<!iiin'iis (No. 

 70i;>) from Mississippi the toes are variable also. Mr. ifyder* has 

 l>ointed out that one specimen displays the di<;its H ij ; a second H il ; ii 

 third I in front ; others have the characters of the .Means type, H r;, and 

 others the Tridactyle <;haracler, ij ji. All areyonii;;' and from the same 

 locality. ]\Ir. Ilyder concludes from these facts that the two sii|»itos<'d 

 jjenera must be united. In this 1 aj;roe with him ; and after a study of 

 the specimens in tln^ National Miiseiiin and in my own collection, I be- 

 lieve that the two species on which these supposed j^enera rest are not 

 distiiijjiiisiiabl(\ I find no characters ])e(;uliar to any set of individuals. 



Development. — I'rof. O. P. Hay has observed the habit of this spe- 



* I'lmced. I'liiia. Ac!. 187!», i,. 14. 



