^*'lH-ji" ] FKOCEEDIxXGS OF THE NATIONAL MUSEUM. 461 



of a closely fitting? interclavicular bone which bounds the recurved 

 inferior extremity of the clavicle on each side. The anterior face 

 of the clavicle is ex[)anded inwards below, so as to be wider than the 

 external face, and its inner edge is in contact with the corresiK)ndin<; 

 edge of the opposite clavicle, so as to inclose a short tube with the in- 

 terclavicles. The scab's of the inferior row di tier from the others in 

 having only half the diameters of the otiiers, so that two scales are 

 articulated to the inferior edge of each scale of the next to the bottom 

 row. Each of these narrow vertical scales of the inferior row sends up 

 an acute process which fits a corresponding pit in the scale of the row 

 above it. This character resembles what is seen in the genus Ijenedenia 

 Traquair in a general way. There are two such rows of scales in the 

 type of that genus, />. deiuriisis Traqu., and L can not make out from 

 Traipuiir's figure and description whether they are longitudinally 

 fissured or not. The figure iei)resents vertical grooves, which may be 

 sutures. The decision of this point must depend on further exam- 

 ination. I place this species i)rovisionally in the genus Platysomus, 

 but I do not find this character to be described in other species of the 

 genus, according to the descriptions of authors. 



The scale-series tend slightly backward from the vertical below, with- 

 out distinct curvature. The scales on the sides in front are about five 

 times as dee{) as long, and they graduate in size to the lowest undi- 

 vided row, where they are about twice as deep as long. The small 

 scales of the inferior row are twice as deep as long, and their <lei)th is 

 about half that of the scales of next series above them. The sculpture 

 of the scales consists of narrow vertical ridges, which are curved 

 slightly ba(;kwards below. About ten may be counted crossing a trans- 

 verse line oil each scale. Each of the narrow scales of the infi^rior row 

 possesses a median angular keel which extends from the anterior edge 

 downwards and backwards, but which does not reach the posterior 

 edge of the scale. The external face of the clavicle is vertically striate 

 like the scales, and horizontally striate on the recurved i)ortion. The 

 interclavicle has more distant hAigitudinal ridges, and one ridge on 

 each side of the low median keel is broken up into enamel tubeicles. 



The body is acute below. This is always the case, whether the frag- 

 ments are compressed or not. 



Me<i8iircmentD. 



-Mm. 

 Dianu'ters of autt'rior uuHliaii .scalt.' : 



Anteroposterior 2 



Vortical 10 



Diaiiicters of low est normal scale : 



Anleroposttrior :$ 



Vortical 4 



Depth of scale of inferior Itorder (specimen No. 2) 2.5 



Length of inttnclavicle (specimen No. :>) 10 



Width of interclavicle in front (No. 3) S 



Diameter of interclavicular tube, transverse (No. ;?) 7 



