a neto PcJtnicuhile (Wrripedt'. 445 



above liaU' tlieir length ; tlicy curl closely round the mouth- 

 or^raius, the functions of which they may be presunicil to 

 assist ; each ramus has seven segments, all of them furnished 

 with numerous spines and all of tliem stout except the terminal 

 one. The remaining pairs have rami of from twelve to 

 fourteen segments, each segment carrying from eight to 

 thirteen pairs of smooth spines, of which tlie distal are very 

 long, the proximal very short ; there is also a small group of 

 spines at the apex of the outer margin of each segment. In 

 all the pairs the jieduncle is armed with many spines. 



The caudal appenda(jes are slender, shorter than the 

 peduncles of the sixth pair of cirri, tipped with a group of 

 spines, two of which are considerably longer than the ap- 

 ])endages themselves. The penis is about equal in length to 

 any one of the last five pairs of cirri ; near the base it forms 

 an abrupt crook ; its breadth is considerably diminisiied near 

 to the blunt apex, which is very hairy, small hairs or setules 

 being more sparsely distributed over the whole length. The 

 rings, which Darwin regards as equivalent to segments, are 

 extremely numerous. 



Size. — The length of the species is about a quarter of an 

 inch, of which the peduncle occupies the larger half. 



The name is given in compliment to W. R. Forrest, Esq., 

 from whom I received the specimens. In sending me a small 

 collection of animals from the West Indies Mr. Forrest 

 says: — ''May I call your attention to the growth (?) on a 

 small piece of membrane, the cuticular lining of branchio- 

 stegite of a crayfish? " This growth proved to be a consider- 

 able number of specimens of the little cirripede here described, 

 with the body projected from the capitulum, as shown in the 

 figure. There was, however, one little group of three in 

 which the body was Avithin the capitulum. These were not 

 situated, like the other specimens, either on the membrane or 

 the podobranchia, but on the calcified joint which sup])orts 

 the branchia, and in these three the terga and scuta are not 

 quite in conformity with those of the other specimens. In one 

 of the three (fig. A, p. 446) tiie basal and median segments of 

 the scutum are represented by the two acute horns of a single 

 piece, and in a second (fig. B) the two segments are solidly 

 combined below. The terga of these specimens are almost 

 oblong, with a very slight excavation facing tlie apex of the 

 occludent segment of the scutum. The third specimen, as 

 far as could be seen without dislodging it, showed agreement 

 rather with these two than with the rest. Darwin has noticed 

 that the valves o( JJichelasjjis ]Va)' wick it are variable in shape, 

 and probably that is the case with the present species. Even 



