igS Records of the Indian Museum. [Vol. VI, 



chamber lined with smooth chitin and covered externally by cir- 

 cular muscles (pi. xiii, figs. lO, ii), and (ii) of strong cilia round 

 the cardiac orifice of the stomach as well as the pyloric. The 

 spherical chamber is separated from the cardia by a cylindrical 

 glandular tract and opens almost directly into the main chamber 

 of the stomach, from which it is only separated by a ring bearing 

 stout and very active cilia. 



So far as is known, resting buds are not formed in this famih^ 



The family is only known from Central Africa and Eastern 



Asia and only two genera can be recognized, namely Arachnoidea 



Moore, and Hislopia Carter; they may be distinguished as 



follows : — 



1. Zooecia provided with an upright orificial 



tubule, separated from one another b}"^ 



stolon-like processes . . . . Arachnoidea. 



2. Orifice little raised above the dorsal sur- 



face of the zooecia, which arise directly 



one from another . . . . Hislopia. 



Genus i^RACHNOiDEA, Moore. 



Syn. Arachnoidia, Moore; Arachnidium, Loppens {nee Hincks). 



The zoarium consists of flattened zooecia of irregular outline 

 joined together in the typical cruciform manner by slender and 

 elongate basal tubules. Each zooecium is provided on the dorsal 

 surface with a relatively long but slender orificial tubule which 

 projects almost vertically upright. The polypide has 8 tentacles. 

 It possesses in its alimentary canal an almost spherical, strongly 

 muscular chamber lined with chitin and similar in structure to 

 that possessed by Hislopia which is described below. The collar 

 is supported by chaetae. 



Arachnoidea ray-lankesteri , Moore. 



Rousselet, P.Z.S., 1907 (i), p. 255, pi, xiv, figs. 5, 6. 



This, the only species, has the character of the genus, but 

 its anatomy is imperfectly known and none of the specimens now 

 in India or Europe appear to be in a sufficiently good state 

 of preservation for its further elucidation. 



A. ray-lankesteri is only known from Lake Tanganyika in 

 Central Africa. 



Genus Hislopia, Carter, 

 Syn, Norodonia , Jullien; Echinella, KorotnefT, 



Hislopia differs from Arachnoidea mainly in two characters, 

 [i) the fact that zooecia arise directly one from another without 

 the intervention of basal tubules, and {ii) the absence of an 

 orificial tubule, the orifice being raised above the dorsal surface 

 merely on a slight eminence. The form of the zooecia is also more 

 regular and each is surrounded by a thickened margin. The 



