CYCLOPOIDEA. |205 



nearly in contact at their posterior extremities. Along the venter 

 there is sometimes a keel-like projection, which is quite prominent be- 

 tween the natatory legs of the two sides, and into which the pigment 

 projects, reaching in certain species nearly to the posterior extremity 

 of the cephalothorax. 



There is a clear open space between the lenses and the conspicilla 

 (or cornea-lenses). 



The minute eyes between the prolate lenses were seen, but were 

 not clearly made out. In one species a very minute fibre, supposed 

 to be nervous, was traced to the conspicilla j they have no large nerve 

 like the true ophthalmic nerve. 



The anterior antennce are short, and consist of three to seven joints; 

 they are not geniculately flexed as in the Antariee. They are irregu- 

 larly furnished with setae, which are sometimes as long as the an- 

 tenna, or a little longer. It is common to find the antepenult joint 

 larger than the preceding or following. 



The posterior antennce have a two-jointed base and a two-jointed 

 finger. The second joint is long and stout, with the posterior margin 

 naked and nearly straight ; it has the front margin naked, but has 

 often an acute tooth at the inner apex. The sides are furnished with 

 one or more stout setae, which are long, and are either naked or 

 sparsely spinulous. The naked setae appear to be situated more ante- 

 riorly than the spinulous ; and when one kind exists alone, as is fre- 

 quently the case, it probably arises from the obsolescence of the other 

 kind, and not from the naked setae of one species being spinulous in 

 another. This however requires confirmation. Most of the Corycaei 

 have one naked seta, arising from near the base of the second joint, 

 on the outer side, and one within ; both extending often beyond the 

 apex of this joint, either curving or straight. 



The third joint is short, and forms the basal part of the finger; it 

 bears one or more short setae, which are sometimes stout and longer 

 than the joint, but usually quite short. The fourth joint is a kind of 

 claw when short, or a slender corneous finger when long. In the 

 latter case, it is at times longer than the second joint of the antenna. 

 In two or three species there was an appearance that was taken at 

 the time for another articulation, like the first one of the claw (see 

 fig. 8 a, PL 86). This occurs only where the finger was short, and it 

 is important that the point should be corroborated, before it is accepted 

 as a fact. 



302 



