21 



GROUP V. 



Upper organ: crest slightly elevated, and bearing a backward- 

 facing, bristly shield, expanding above; hooks separate, moderately 

 stout; tooth of moderate size. Clasps: basal process of left blade 

 triangular, hind angle greatly produced; right lobe consisting of a 

 long curving finger, directed backward. 

 Nisoniades Ennius nov. sp. Fig. 9. 



Upper organ : Main body rather long and not high, nor greatly 

 curved ; posterior part of upper surface much elevated and bearing, 

 near the extremity, a crest in the form of an appressed plate, facing 

 backward and very slightly upward, narrow at base, rapidly and 

 greatly expanding above, the outer angles sharp, the upper border 

 arched, and bearing an extensive armature of slender clustered 

 spinules, curving forward; anterior to it the upper surface has a dis- 

 tinct median furrow. Hooks very short and stout, compressed, 

 bluntly pointed, divaricate, pretty widely distant at base, and bearing 

 at their junction a pretty broad, very short and small, bilobed, ap- 

 pressed tooth. Arms of nearly uniform size, curving in all their 

 course, having at first a general downward direction, then bent in a 

 sharp, angular curve at less than a right angle, beyond which the 

 limb is directed upward, backward and inward, and bears at the 

 united tips the inferior armature, which is a very large and broad belt 

 of raised points. The crest and arms are somewhat asymmetrical. 



Left clasp : Main body pretty broad, irregularly gibbous, increasing 

 rapidly in width from the base backward, the terminal 'edge squarely 

 docked between the lobe and blade. Blade very long and slender, 

 the outer surface facing upward and outward, curving slightly inward 

 and upward, the upper edge with a median, broad, slight denticle, 

 the apex rounded, its inner angle produced to a sharp point, bent 

 inward and a little downward, armed with minute spinules ; basal 

 process subtriangular, attached by a narrow neck, one apex, with the 

 smaller half, directed backward, its tip pointed and bent a little 

 inward; the other apex, with the larger half, directed upward and a 

 little forward, bent also strongly inward, and at the same time twisted 

 so as to make the outer surface face a little backward; this part of 

 the surface is armed with minute .«pinules and the tip is rounded. 

 Lobe widely distant from the basal process of blade, quadrate in 

 shape, nearly twice as broad as long, a little broadest at apex, di- 

 rected backward and a little upward, curved also somewhat inward 



