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nn.LKTiN :ii, i-nmti:i> statks national museum. 



Tiipc />.— Piiliitiiio scrips fonniii;: n pMiiiltnlicjnvli iVoriKdM' cxtrcmiry 

 to the olhcr, ('xt(•ll<lill^' in iMlvaiic' ni the iiiiics. Tiim' s|MTimciis, 

 two of thciiior riill iHil not laru'i' ^^'Z''; '""' "• ••"' »''>i""'>' Inll.v .U.iil.le 

 tlif siz.' of otlifis from tJH' saiiM' lofiilii.v (Hm' IMiitlf Vallf.v), wliidi mv 

 ivf.'iT.Ml to tvprs (' and 15. vvitii larval ton^iiic ami luaiu'liial stumps. 

 TIk'oiIi.ts (HMiO), with larval toii^iiic l.iit the hraiicliia- iihsoilu-d. 



Ilt'ivma.v ln' iiiciitiniifd a ri'inarkaltic spt'ciiiifii (.5!>Sl'), wliicli is in all 

 otlit'i ri'spt'cts fiiilv <lt'VfI(»pt'tl. wlicrc tlic larval aicli of ti'i'tli remains, 

 bnt has ht'coiiM" opt-n anil sli;;htly tiansvt'isc, cxti'mliii'; Itnt lilllc be- 

 yond the anlcrior mar;;iii of tin- narcs. It is iiiti'iinrdiatf iK'twccii 

 tvpt's 1) and A. and is tht-n'snlt of a retardation in development of tlM> 

 larval anh, \\liiie type i> is proil'iced Itya retardation h\ the presci Na- 

 tion of the oblitpie lateral series of the larva at the expense «)f the arch. 



I add lieie a description of the var. ohseninm {AinhlyHtoiiid ohsritrinn 

 Haird, Proceeds. Acad. I'liila.,. IS(i!», p. 1!L'). 



The head is very l»road and the ;;ape nniisnally lar},'e. The internal 

 nostrils are veiy huj^i', their width half the diameter of tlioeye; the 

 distance between their inner borders is the same as that lu'tween the 

 oilier. The ton^Mie is Ia!j;e, broader than lony', its width about two 

 thirds that of the iipiicrjaw. 



The palatine teeth are in I iiir series, eolleelively foiinin;'' a broad in- 

 verted V; the an;;les anterior, and would beqiiit<' sharp but that there 

 is an iiileriiiption aloii;: the median line. The blanches reach as far 

 forward as tlieanteriorl»oidcr of (lie inner nostrils. 'J'liey are decidedly 

 concave aiitero-e.xicrnally. The ten iiiiiei anterior sections of the pal- 

 atine scries are each about twice the lcii;;th of the external ones; they 

 fall short of the inner border of the inner nares by nearly a diameter of 

 the latter, which space separates them from the outer section, which, 

 iiiiiijcdiatcly lichiiid the inner nares, are about as loii^ as the latter are 

 wide, and do not pass exterior to their outer border. 



There are twelve costal furrows. The tail is compressed, Init not 

 hijih. 



The C!»1(U' ai)pears to have been of a uniform brown above and on tlio 

 sides, brownish yellow beneath. On the sides daiker vertical blotelies 

 can be detected in the sinjile specimen before me. Similarly indistinct 

 markiiij^s are visible on the tail. 



The \ery convey, frontal re;;inii and the concave interrupted .m lies of 

 teeth alone distinjiuish this variety from the .1. t'Kjrininn of the West. 



It dillers from -I. //7/»H»«n»f the Kast in much larjier inner nares 

 and more widely .separated nostrils, tiie inner borders of the two beinj^ 

 at about the .same distance, instead of liavin;; the latter more approxi- 

 mated. The toii;jiie is wider, as well as the liea I. The teeth are more 

 V-slnipetl and roach farther forward. The outline of the limits of the V 

 is concave antero externally and is interrupted by spaces equal to the 

 wide nostrils, the outer section not extending' itcyoiid the nostrils. 



The specimen which lepie.sents this variety is Irom l-ort Des.Moiue.s, 

 Iowa (No. auOi.) 



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