208 BULLETIN 34, UNITED STATES NATIONAL MUyiCUM. 



Tliey will be referred to later in this article. IMcauwliile I describe 

 t;^pical specimen of the form Yiridescens. 



2 1/4 



3 5 



Fig. 52. Dicmyctylusviridescensviridescens. No. 14163, Aiken, S. C; } f. 



The outline of the head seen from above is an oval, which contracts 

 anteriorly and posteriorly, and is not distinguished from the neck l>y 

 tlie abrupt contraction of the latter. The back is roof-shaped, anil the 

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

 end of the muzzle is just a little less than the distance between the ax- 

 il'a and the groin. The tail is ranch compressed throughout, and is as 

 long as the head and body (vent included). 



The muzzle, viewed from above, is truncate-rounded, and it projects 

 a little beyond the mouth. The two ridges of the top of the head in- 

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

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

 shallow groove. There is a distinct but obtuse canthus rostralis, and 

 the lorea' region is slightly concave. The profile is slightly dec rved 

 at the muzzle. The eye is rather large; i's length exceeds a little the 

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

 little less than the interorbit 1 width. 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 upwards, so that the eyelids are nearly plane with the front. 

 The lower jaw is only partly overlapped by the posterior pait of 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 pits, the fir.^t of 

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

 fissure. These pits are shortly linear and curved, as though made by 

 the pressnre of an instrument with a short curved edge. The distances 

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

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

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

 nlways present. The cheek-pits, moreover, are frequently wanting. I 

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

 Viridescens and Miniatus : 



Firidcsceiis. 



Fossa} present 28 



FosssB wautiiiii; 5 



Miniatus. 



Fosste present 10 



FossEB wanting *25 



The pits are generally symmetrical, but in a Miniatus there is but one 

 pore on one side, and in a Viridescens there are no pores on one side 

 and three on the other. 



