﻿224 



The Philippine Journal of Science 



1914 



places. The interocular canals internal to the ring canal are 

 broader than the ocular canals, and show a sinuslike broadening 

 where they join the ring canal. Beyond the ring canal the 

 interocular canals are small and are closely surrounded by the 

 network of anastomosing canals, while the ocular canals maintain 

 a uniform size to the margin and have on either side just 

 outside the ring canal a small area free from the anastomosing 

 canals. 



The arm disk is 50 mm. in diameter, swollen in the zone 

 of origin of the arms, and thin in the center of the disk. The sub- 

 genital ostia are 18 mm. in width and 4 mm. high, with a 

 concave upper and swollen convex lower lip. The interostial 



pillars are 9 mm. wide. The 

 subgenital porticus is unitary 

 and square. Each gonad lies in 

 a complex series of folds in the 

 floor of the stomach. The folds 

 are longest in the center and 

 shortest at the ends, where at 

 the level of the center of the 

 interostial pillars the gonads are 

 separated from one another by 

 a very short space. Thus the 

 outer edges of the gonads out- 

 line a square area, the corners 

 of which coincide with the cen- 

 ters of the interostial pillars. 

 The bases of the pillars are 

 rounded, and the edge of the 

 portion of the arm disk between 

 them is straight, so the arm disk 

 may be considered 8-sided — 

 rounded and straight faces alternating with one another — or 

 more exactly 4-sided, each corner being rounded. The outline 

 of the stomach is square, but the invaginated gonads have so 

 encroached on it as to leave only a narrow cruciform cavity 

 whose outer ends are joined by a marginal sinus from which 

 the radial canals originate. 



The arms are about equally spaced. The two arms on a 

 common interostial pillar are widely separated, so that the base 

 of each arm lies over the outer one-third of a gonad. The 

 arm disk at the base is a little wider than the bell radius, 

 while at the point of origin of the arms it is only five-ninths 

 as wide as the bell radius. The arms are 50 mm. long from 



Fig. 12. Lobonemoides gracilis, a dia- 

 grammatic representation of a quadrant 

 of the bell from the subumbrellar side, 

 showing the subgenital ostium, canals, 

 etc. X 1. 



