118 GENUS DICHELASPIS. 



Size. — Small, with a capitulum scarcely exceeding a 

 quarter of a inch in length. 



Filamentary Appendages. — None. There are two small 

 ovigerous fraena, which, in D. Warwickii, had the glands 

 collected in seven or eight little groups on their margins. 



Mouth. — Labrum highly bulla te, with small teeth on 

 the crest ; palpi small, not thickly covered with spines. 

 Mandibles narrow, with three or four teeth. Maxillae 

 small, with a notch beneath the two or three great upper 

 spines ; lower part bearing only a few pair of spines, 

 generally not projecting, but in D. orthogonia largely 

 projecting. Outer maxillae, with their inner edges con- 

 tinuously covered with bristles. 



Cirri. — First pair short, situated rather far from the 

 second pair; second pair with the anterior ramus not 

 thicker than the posterior ramus, and hardly more thickly 

 clothed with spines than it, excepting sometimes the few 

 basal segments. All the five posterior pair of cirri re- 

 semble each other more closely than is usual. In 

 D. Lowei, the segments of the posterior cirri bear the 

 unusual number of eight pair of main spines. 



Caudal Jppendages.— -Uni-articulate, spinose ; in D. 

 pellucida they are twice as long as the pedicels of the 

 sixth cirrus, but I could not perceive in them any distinct 

 articulations. 



Distribution. — Attached to crabs at Madeira, and off Borneo; to sea- 

 snakes in the Indian Ocean. The individuals of all the species appear to be 

 rare. 



General Remarks. — Foui of the five species, forming 

 this genus, though certainly distinct, are closely allied. I 

 have already shown, that although the characters separating 

 Lepas, Paecilasma, and Dichelaspis are not very im- 

 portant, yet if they be neglected these three natural little 

 groups must be confounded together. Dichelaspis is 

 much more closely united to Paecilasma than to Lepas, 

 and, as far as the more important characters of the 

 animal's body are concerned, there is no important dif- 



