2 



53 



i5 th — 24" 1 segments. The 25 th — 43 ld segments are not furnished with these spines, but their 

 armature consists of 6 — 8 bristles situated near the extremity of each segment and giving the 

 extremity of this ramus the appearance, more or less, of an antenna. 



The 4 th — 6 th cirri have long rami of nearly equal size, of numerous but not elongate 

 segments. In the specimen that was examined the number of segments was 30 and 37 in the 

 4 th cirrus, 38 and 40 in the 5 th , and 39 and 41 segments in the 6 th cirrus. The segments 

 are almost without exception furnished with two pairs of very long, stiff, needle-like spines 

 along their inner face, at the base and between which two or three very short bristles are 

 regularly inserted. 



The .penis is very short, distinctly ringed, considerably broader near the basis, with 

 the terminal part cylindrical, recurved and rounded at the extremity. Delicate hairs are scattered 

 over its surface ; they form a dense group of minute bristles near the extremity. 



The specimen that served for the above description was taken at : 



Stat. 262. December 18, 1899. Lat. 5°S3'.8S., Long. i32°48'.8E. Depth 560 m. Bottom: solid 

 bluish grey mud. 



The specimen was found attached to a piece of grey granitic stone; a small specimen 

 of Verruca capsula was found attached to the surface of one of the parietes (the left-hand 

 carino-lateral compartment). 



General Rem ark s. This species, though in several respects approaching the new 

 species H. veltttiuiim, is easily distinguished from that and other species of the genus observed 

 in the Malay Archipelago and elsewhere by the thickness and bareness of its shell, and the 

 shape and colour of the opercular valves. 



Genus Tetraclita Schumacher 



The species of this genus inhabit the tropical and warmer temperate seas, and are 

 found attached to tidal rocks, shells, pieces of stone, wood, etc. They live only in shallow 

 water : dredging in deeper water has never yielded any form belonging to this genus. 



The eight species of this genus which Gruvel enumerates in his "Monographie" (1905) 

 are exactly the same as those of Darwin's Monograph (1854). Nor has our knowledge regarding 

 the distribution of these species been greatly enlarged since Darwin's work appeared, although, 

 on several occasions, one or more species were collected by different naturalists. 



Also in the Malay Archipelago and adjacent waters various species have since been 

 met with; I give here a list which, though perhaps not quite complete, may fairly well sum- 

 marize our knowledge at the present time. 



Tetraclita porosa (Gmel.), according to Weltner 1 , was collected at different places in 

 the Indo-Polynesian Region, the Berlin Museum has specimens from Singapore, Amboina, 

 Zamboanga, Borneo, etc. 



Weltner, W. Verzeichnis der recenten Cirripedienarten. Arch. f. Naturgesch. Jahrgang 1897. Bd. I. S. 227 — 2S0. 



125 



