1 



so 



half as broad as the main body, directed upward and curved some- 

 what inward, particularly at the tip ; the basal half tapers but slightly; 

 the apical half tapers strongly to a fine point, is bent slightly down- 

 ward, twisted so as to bring the outer surface uppermost, leaving the 

 posterior inner termination of the basal half protruding inward as a 

 blunt, rounded, gibbous denticle; the apex is hooked slightly inward 

 and armed with very minute dcnticulations; basal process sessile, 

 consisting anteriorly of a triangular, pointed, spinous, depressed 

 piece, directed inward and forward, and curving slightly upward; 

 and posteriorly of a basal, unarmed, long and slender, compressed 

 but very gibbous, dactyloid plate, directed backward, and curving 

 strongly upward, terminating in a rounded apex. Lobe arising from 

 the upper, hind angle of the main body, directed backward and up- 

 ward and curved quite strongly and regularly inward, consisting of a 

 compressed, pretty long and broad plate of uniform width, more than 

 twice as long as broad, with a rounded apex, and having its lower 

 margin broadly and slightly excised. 



Right clasj) : Main body differing extraordinarily from that of the 

 opposite side, being very slender, the base of the blade marked on 

 the lower edge by a greatly produced, pointed, triangular denticle, 

 more prominent than in any species examined by us, and directed 

 downward. Blade long, broad, compressed, directed a little upward, 

 curving a little inward; the basal three fourths of nearly equal width, 

 tapering slightly; gibbous and twisted so as to bring the greater por- 

 tion of the outer surface uppermost; the apical fourth is quite differ- 

 ent, being only half as broad as the basal three fourths, on account 

 of the abi'upt excision of the lower half, causing the basal portion to 

 terminate with a sharp lower angle, which, with the apical half of 

 this portion of the lower edge, is bent inwards; the terminal fourth 

 is scarcely half as broad as the basal portion, broadens slightly 

 toward the apex, and is squarely docked at tip, the inner angle pro- 

 duced slightly as a minute, pointed denticle ; basal process wanting. 

 Lobe unusually developed, forming a long, compressed dactyl, sub- 

 parallel to the blade, its outer surface a little twisted so as to face 

 somewhat downward and curved strongly inward, especially near the 

 tip; it is of nearly uniform width, its upper edge slightly swollen 

 opposite the outer half of the larger portion of the blade, and has ita 

 tip produced along its lower edge only, tapering rapidly as if by an 

 oblique excision, and ending in a roundly pointed tip, the whole of 



