THE OSTEACODA. 251 



hluntly. The general type is that of Stage I., but shorter and plumper. Antenna i. 

 with an armature of about 8 or 9 pairs of spines, the distal four or five pairs close 

 together, the remaining pairs set at increasing distances from one another. Antenna ii. 

 as in Stage I., but with no basal bristles. 



Female (Mean, 0-79). -Sliell much less elongate, the height to the length about as 

 1 to l-f. or 1-5 ; tlic greatest height behind the middle of the length. Erontal organ 

 less spinous, but otherwise this and the antennce resemble those of Stage I. 



Stage III. 



Male (Mean, 0'61). — Shell much as in Stage II. but shorter; the height to the 

 length about as 1 to 1-4 ; both posterior and ventral borders very sharply convex, the 

 greatest height about the middle of the length. Frontal organ resembling that of 

 the female at Stage II., with a very few spines on the ventral border. Antenna i. 

 with the principal bristle of female character. Antenna ii. without hook -joint, other- 

 wise resembling that of the later stage. 



Female (Mean, 0-61). — Shell of about the same proportion of height to length as in 

 the later Stage II., but more semicircular, owing to the greater rounding of the postero- 

 ventral angle. The opening of the left asymmetrical gland further back in the length. 

 Frontal organ blunt, spineless, straighter. 



Stage IV. 



Male (Mean, 0-41). — Shell projecting less behind a perpendicular from the posterior 

 end of the dorsal border; opening of left asymmetrical gland far back. Frontal 

 organ spineless, unsegmented, but much as in Stage III. 



Female (Mean, 0-40). — Shell much as in Stage III. Frontal organ straight and 

 unditTerentiated. Antenna ii. without central bristles. 



CoNcncECLv spixifera. Clans. 

 (Plate 24. figs. 225-235.) 



Three stages Averc represented, of which only one showed male secondary sexual 

 characters. The oldest captured is therefore considered to bo Stage II. 



Stage II. 



Female (Mean, 2-12). — Shell with marked shoulder-ridge; the posterior border of 

 the left sliell is nearly at right angles to the dorsal border (except for the sligJitly 

 truncated postero-dorsal angle) ; on the riglit shell, a slight convexity under the spines 

 precedes the gently curved posterior border, The opening of the right asymmetrical 

 gland is approximately at the postero-ventral angle ; is is not prominent beyond the 

 shell-outline. Tlie ventral border gently convex ; the highest point of the sliell is at 

 about the middle of the shell-length. A group of (generally four) large granular gland- 

 cells is almost always to be found near the antero-vcntral angle. Frontal organ and 

 Antenna i. as figured by Miiller (ix. 14, 15) except that the dorsal bristle of antenna i. 

 was observed to reach nearly to the end of the frontal organ. Antenna ii. with two 



SECOND series. — ZOOLOGY, VOL. X. 43 



