114 THE VOYAGE OF H.M.S. CHALLENGER. 



male ; they have besides iu both sexes two large spiniferous seta;, originating from the base of the 

 last joint. In the mandibles and maxillae I have not seen anything remarkable; the maxillipedcs 

 however, are very large (fig. 2, mxp.), and terminated by three claws. In Corycazus germanus there 

 is only one recurved nail. The four pairs of thoracal feet are no doubt powerful natatory organs, 

 as they are, especially in the male, very broad and covered with long hairs. The fifth pair, a rudi- 

 ment of which is to be found in Corycceus germa/nus, could not be observed here. 



The thorax ends in the female with a very sharp and slender spine, which is not so strongly 

 developed in the male. The abdomen is reduced in Corycceus to two joints, which in our case are 

 even not clearly to be distinguished, though I think that in the female the first abdominal segment 

 ends behiud the genital opening (fig. 1, sp.), but in the male is inseparably connected with the last 

 one. The furca is terminated by two large and two small spines. As can be seeu from our 

 pictures, the shape of the abdominal segment is very different in both sexes ; in the female it is swollen 

 up nearly ^rpiare, and has some small spines on the angle, which is formed at its inferior frontal side. 

 In the specimen I have drawn, some nval spermatozoa were attached to the vulva (fig. 1, s?J.). In the 

 male this abdominal segment is very differeut; it is more in continuance with the thoracal part of the 

 body, and has no prominent angle at its underside. I could not find the genital opening in the male, 

 which in the female is at the upper surface of the segment. 



From the species hitherto known, Corycceus megalops differs especially by the pectoral process, 

 "by the want of the last and fifth pairs of thoracal feet, and by the union of the two abdominal seg- 

 ments. It will always be a curious fact that in this species the outlines of the cephalothorax have 

 given way so far as to form a long process to receive the immensely increased eyes. Length of female, 

 O'SVo mm., width 0-350 mm. 



The species was in considerable quantity in the surface-water for two days, but since that time 

 has never been seen again. 



3. Corycceus limbatus, n. sp. (PI. XLIX. figs. 18-22). 



Length, 1-1 6th of an inch (1 "55 mm.). Body slender; posterior thoracic spines 

 moderately long, reaching to about the middle of the first abdominal segment, which 

 is about three times as long as the second ; caudal stylets slender, about eight times 

 as long as broad, not divergent. Anterior antennae short ; posterior slender, the terminal 

 claw in the male (fig. 19) long, slender, and falcate; inner margin of the second joint 

 bordered with a pellucid and very finely pectinated lamina, which is best developed on 

 the distal half; posterior foot-jaw (fig. 20) rather small, with a fiexuous terminal claw. 

 The marginal spines of the swimming feet (fig. 21) are lancet-shaped, wdth delicately 

 pectinated margins, and the usually vacant interspinous spaces are occupied by supple- 

 mentary spines (a, a), which, however, are not free, but anchylosed by the inner edge 

 with the limb. Eyes contiguous, situated immediately on the front of the head. 



This species was noticed only in one gathering from the tropical Atlantic, in bit. 

 12° 16' S., long 13° 44' W. Only one or two specimens were seen, but the characters are 

 amply sufficient to distinguish them from any described form. 



