48 MARINE INVERTEBRATA OF GRAND JIANAN. 



borrowed shells by additions to its aperture. From what I have seen in such species 

 of CorajJiickr as have fallen under my observation, I am inclined to think that 

 most of the members of that family form more or less permanent tubes under cer- 

 tain circumstances. The Unciola, when kept in captivity, will frequently retire to 

 some corner and collect the sand around it by some glutinous substance, so as to 

 form a cavity, in which it will often remain for some time ; but it may easily be 

 made to leave it, and will make another if it be destroyed. On the other hand, 

 some of the other individuals in the same jar will make no tubes ; and often at low 

 water it may be seen swimming about perfectly free. The same is true of some of 

 the other species of the family here mentioned, and of many species whose habits 

 I had opportunities of observing in the Harbor of Charleston, S. C, in the winter 

 of 1851-2. 



It will be seen from this and the succeeding descriptions, that the female of 

 Ctrapus has uniarticulate fingers on the second pair of legs, and Kroyer mentions 

 - an instance of a male Podocerus having bi-articulate fingers. It might be concluded 

 from this that the genera should be united. But there are Podoceri in which both 

 males and females have uniarticulate fingers ; to these the genus should perhaps 

 be restricted, while Kroyer's species will come under Cerapus. Dana gives, in a 

 diagnosis of Cerapus, " Styli caudales otii biramei, ramis subrequis, longiusculis" 

 (Amer. Journ. Sci., 2d ser., xiv. 309). In the Cerapi herein described, however, the 

 posterior pair of these caudal appendages consists of two thick simple stylets, at 

 the extremities of which are articulated one or two short spines, curved upward. 



Cerapus fucicola, St,, n. s., Fig. 34. Male, slender, smooth above, with the 

 breadth and height about equal. Epimera, small but conspicuous, proportioiuiUy 

 larger than in G. rithflcovjiis. Inferior antenna? stout, strongly subpediform, with 

 their terminal articles constituting about one-fourth their length. Superior antennte 

 of about two-thirds the length of the inferior ones. First pair of legs very small, 

 subchelate. Second pair with long curved basal articles; the fourth or antepenulti- 

 mate short; the penultimate elongated, very thick, curved, thickly hirsute along the 

 inner edge with short pinnate hairs, and with a stout curved finger of less than half 

 its length. Third and fourth pairs with long narrow basal articles; last three pairs 

 with broad ones. Caudal stylets of the last pair short, the peduncle constituting 

 nearly their whole length, with two very short curved processes at the extremity of 

 each. Female, difiering from the male in having its superior antennfe of nearly 

 the same length with the inferior ones, and in its small, slender, simply subchelate 

 feet of the second pair, which have no pinnate hairs. The color varies from light 

 olive or gi'eenish, to bright crimson. Eyes usually white. The articles of the 

 antennae are sometimes alternately red and white. Length of a large male, 0.36 

 inch. Proportions : breadth, .22 ; length of inferior antennae, .61 ; of a leg of the 

 2d pair, .59 ; of a leg of the 6th pair, .46. The figure represents the caudal stylets. 

 It inhabits slender tubes, which are found in considerable numbers on large alga3 

 in the laminarian zone. In this species, the hand is formed of the penultimate 

 article of the second pair of legs, the preceding article being very short ; so that it 

 cannot strictly remain in the genus. But it is so closely allied in general appeai'- 

 ance,. habit, and details to the preceding species, that it cannot with propriety be 

 separated. 



