20S miLLKTIN :U, ITNITKI» HTATKS NATIONAI. Ml'SKl'M. 



Tiny will 1»L! rcforml to latiT in lliis iiiticU'. Mfuiiwliili^ I (U'scillij ;., 

 typii'al sin'ciineii of the form Viiidi'.sccii.s. 



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2 \ I 4 



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rill. 5'J. Dininietllliin nriili'KCi'ii:i rlriilcg'rnii. No. I«lfi3. Aiki'll, S. ('.; jj. 



TlK'oiitliru' of till! Iiciul si'oii from above is an oval, wliirli conliiutts 

 anteriorly and posteriorly, and is not distinj;iiislied from tlic neck liy 

 tlie abrnpt contraction of the latter. The back is r(»ol'sha[»ed, and I lie 

 section of the body a vertical oval. The leiijjth from the axilla to llie 

 end of tho muzzle is Just a little less than the di.staii(!e between the ax- 

 ila and the "roin. The tail is niiich compresseil tliroii<;h(int, and is as 

 Ion;; as the head and body (vent iiududed). 



The muzzle, viewed from above, is triii.cateromided, and it projeitts 

 a little beyond tho month. The two ridj^es o»' the top of tl.i^ head in- 

 close a long lenticular open {jroove which is closed in front on the muz- 

 zle, bur open behind on the occiput. (Jii their external sides is a 

 shallow jjroove. There is a distinct but obtuse eant'nis lostralis, and 

 the lorea' region is slightly concave. Thi^ protlle i-i slightly dt'c rved 

 at the muzzle. The eye is rather large; is length exceeds a litlle the 

 length from its anterior canthns to tlii' end of the muzzle, and is a. 

 little less than the interorbit 1 'vidth. The nostrils are close together, 

 and look upwards as well as outwards. The distance between them 

 enters the interorbital space two and a half times. The eyes do not. 

 project ujiwards, so that the eyelids avi' nearly plane with the front. 

 The lower Jaw is only partly overlapped by the posterior paitof the 

 upper lip, and there is no distinct lower lip or groove. On the side of 

 the head posterior to the eye is a straight row of four jiits, the tiist of 

 which is near the eye and the last is in the position of the first branchial 

 lissnre. Those pits are shojtly linear and curved, as tlmugh made by 

 the pressure of an instrument with a short curved edge. The tlistancis 

 between them are equal to each other and to half the diameter of tin's 

 eye. At the position of the posterior iiit are traces of three branchial 

 lissiires in three vertical short rows of minute pits; but these are not 

 always present. The (theek-pits, moreover, are fre(iiiently wanting. I 

 give the results of the examination of seventy individuals of the forms 

 \'iiidescous and Miniatus: 



riyidvbceiis. I 



fossil' prt'st'iit y8 ' Fosnic pri'HCMit 



M'uiialiiK, 



10 



l-'oSSill WiUltillLC 



1 



dssM' waiitini; 



The pits are g<'iierally syninietri(!al, but in :; Miniatus there is but one 

 pore on one side, and in a Virid(!scens there are no pores on one side 

 and three on the other. 



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