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



The spines are arranged in longitudinal rows, five of which are visible from one 

 aspect. The number of spines in each row varies considerably ; they are, however, 

 usually distant, but here and there two spines may be quite close together. The spines 

 form short laterally compressed cones with a sharp apex ; they are placed at right angles 

 to the axis, and are usually about as high as broad (PI. VIII. fig. 5). 



In the terminal portion of each branch, the sclerenchyma is thin and membranous, 

 the spines are very far apart, and the whole axis for several inches collapses when dry. 



The whole corallum, with the exception of the basal portion of the stalk, is densely 

 covered with zooids. There is no interval between adjoining zooids either as regards 

 the members of a group (triplet) or the adjacent members of successive groups. There 

 are usually six zooids to a centimetre on the branches, but in parts where the gonozooids 

 become much distended with the reproductive elements they may be a little more 

 distant (five to a centimetre). Height of zooid, excluding tentacles, about 2 mm. ; breadth 

 across base of tentacles 3 mm. ; length of tentacles 4 to 7 mm. These measurements are 

 only approximate, as in spirit specimens the amount of contraction varies a little in 

 different portions of the colony. There appears, however, no difference in the size of the 

 zooids which may not be attributed to unequal contraction or to a variable development 

 of the reproductive elements (PI. VIII. fig. 3). 



The gonozooids seen from above are oval in outline, the greatest diameter, i.e., in 

 the sagittal axis, being 2 "5 to 3 mm. Each gonozooid has a more or less well-marked 

 depression in the transverse axis corresponding to the position of the mesentery. 



The gastrozooids are similar in outline to the gonozooids. The mouth, which is 

 usually rounded in outline, is situated on a cylindrical prominence placed between the 

 pair of tentacles. Ova were found in various stages of development in all the gono- 

 zooids examined microscopically, so that it seems probable that the species is dioecious. 



Habitat— Station 323; February 28, 1876; lat. 35° 39' S., long. 50° 47' W., off 

 Monte Video ; depth, 1900 fathoms ; bottom, blue mud. 



Schizopathes affinis, n. sp. (PI. IX. figs. 1-6). 



Branched portion of the corallum flattened, triangular ; branches lateral, alternate ; 

 the lower ones very long, the others rapidly becoming shorter towards the apex of the 

 stem. Spines crowded, conical, and very short, arranged in imperfect verticils or some- 

 times with a slight indication of a spiral arrangement. 



The base is free and flattened as in Schizopathes crassa, but the extremity is more 

 hooked. The middle of each flattened surface bears three or four longitudinal furrows 

 bordered by rows of short sharp serrations (PL IX. figs. 5, 6). The total length of the 

 stem is about 31 cm., the length from the lowest branch to the point of the hooked base 

 about 12 cm. The stem is somewhat flattened to near its apex; the lower portion is black, 



