Prof. AUiiian on Chelura terebrans. 363 



posed of seven distinct segments with the epimerse distinct and 

 moderately developed. First two pairs of thoracic feet didac- 

 tyle, five remaining pairs terminated by a small unopposable 

 claw. First three segments of abdomen each bearing a pair of 

 biramous natatory feet ; remainder of abdomen consisting of 

 one very large trunk supporting anteriorly a pair of large 

 foliaceous lobed appendages and a pair of cylindrical false feet, 

 and terminated posteriorly by two lamellar leaping organs 

 and an intermediate leaf-like lobe*. 



Species unica, C. terebrans^, Phil. PI. XIII. fig. 1. 



Hab. In timber taken from the sea at Trieste, Philippi. In 

 excavations formed in the timber-piles of the jetty in Kingstown 

 Harbour near Dublin, M. B. Mullins, Esq., and R. Ball, Esq. 



The largest specimens of C. terebrans measure about half an 

 inch in length, including the caudal appendages and antennse. 

 The head is large, and presents when viewed from above a tole- 

 rably regular pentagon with one angle directed forwards between 

 the eyes (fig. 2). These last are borne upon the two latero-ante- 

 rior angles, which are prominent, and almost suggest the first 

 sketch of the ocular peduncles of the podophthalmic Crustacea. 



There are two pairs of antennse ; the superior (fig. 1 and 

 fig. 2^) originate at the level of the eyes and on their internal 

 side. They consist of a peduncular portion which is composed 

 of three hirsute articulations, the last of which supports two rami 

 of very unequal development {, one being as long as the peduncle 

 and composed of six hirsute articulations, the other consisting of 

 a single slender articulation terminated by two or three rudi- 

 mental ones with a few long hairs and not reaching beyond the 

 first joint of the longer ramus. The last two articulations of the 

 longer ramus are very minute. The inferior antennse (fig. 1) arc 

 considerably larger than the superior; they originate just below 



* Philippi gives no detached summary of the generic characters ; the 

 above, which were drawn out from an examination of the Irish specimens, 

 are therefore retained. 



f It has been already mentioned that a slight discrepancy exists between 

 Philippi's description and that here given. This however has been supposed 

 to be referable to a source different from a real distinction between the ani- 

 mals described. It is yet possible however that the Adriatic and Irish spe- 

 cies may not be the same. The discrepancy alluded to will be chiefly found 

 in the form of the superior antennae and of the terminal portion of the last 

 three pairs of feet. Though it may therefore perhaps be deemed advisable 

 to retain provisionally for the Irish animal the specific name " destructor " 

 applied to it in my original paper, subject to rejection or confirmation ac- 

 cording as an actual comparison of specimens may decide, I have neverthe- 

 less in the present memoir preferred considering the Irish as identical with 

 the Adriatic species. 



X This condition of the superior antennse is not described by Philippi. 



JJ6* 



