13 



rounded at the tip, curved slightly inward and twisted a very little, 

 tending to bring the outer surface uppermost. 



Right clasp : Main body like that of the opposite side. Blade sim- 

 ilar in size, length, form and c:irection to the left cla^p, but not so 

 broad at the base, equally rounded at the tip and armed apically 

 with a very few minute, inconspicuous spinules; basal process reduced 

 to a slight pointed triangular tooth, connected with the blade by a 

 slight ridge. Lobe very large and broad, reaching downward beyond 

 the base of the blade, fully half as long as it, rounded at tip, directed 

 backward and a little upward, gibbous, curved inward a little more 

 than the blade, the tip bent suddenly upon itself and directed straight 

 forward; the bent apex and incurved lower edge armed, the former 

 with a (ew very long, the latter with more frequent shorter, minute 

 spinules. 



New England. 



GROUP II. 



Upper organ: crest scarcely elevated, with slight, horizontal, lat- 

 eral expansions ; terminal hooks consolidated, stout; tooth very large. 

 Clasp: appendages well armed, very small when compared to main 

 body. 

 Nisoniades loelus Lintner mss. Fig. 3. 



Upper organ : Main body short, pretty high, not very slender. 

 Dorsal crest consisting of a pair of very small, horizontal, lateral 

 alations, the posterior angle of each rounded, the anterior produced 

 laterally as a bluntly pointed triangle. Hooks forming a single, stout, 

 slightly curving, pointed beak, directed backward, bearing beneath, 

 just beyond the middle, an appressed, dentiform, backward curving 

 appendage, which is provided, on the outer edges of its apex, with a 

 pair of short, stout, divaricate thorns; on either side of the extreme 

 base of the hook, its upper surface expands laterally to a very slight 

 degree ; and from the extreme base of its lower outer surface, an 

 appressed, conical tooth projects downward and slightly outward. 

 Arms broad at base, narrowing rapidly, directed downward and at 

 the bottom bent at nearly right angles backward; they then curve 

 backward, inward and upward, broadening slightly until they meet 

 at some distance below the hook, bearing on the whole of the outer 

 lower surface of the curving portion, the inferior armature of rather 

 distant, comparatively large, short, blunt spines, largest at the most 

 post'. i'i,;r point. 



