4 AKT. S. 1. IK EDA : THREE NEW AND 



Internal Characters.— The general internal anatomy of the 

 female seems to agree nearly with that of Bonellia viridis, except 

 in a few, not unimportant points. 



The alimentary canal, throughout its convoluted course, is 

 kept in position by numerous delicate muscle- threads originating 

 from the body- wall. 



The posterior end of the œsophagus is embraced by the 

 heart, a broad vascular sinus of a triangular shape with the apex 

 directed forewards. From the basal angles of the heart, there 

 arise two moderately long vessels (commissures), which eventually 

 join the ventral vessel running over the nerve-cord. That junction 

 takes place somewhat behind the external aperture of the oviduct. 



The oviduct (segmental organ) is single and unpaired, that 

 of the right side being absent. The portion of the organ adjoining 

 tlie external aperture is for a short distance thin and duct-like, 

 the wall of tlie part being highly muscular ; the rest of the organ 

 is thin-walled, swollen and sac-like, extending behind nearly to 

 the anterior border of the middle third of the body proper. 

 The internal opening into the body-cavity is represented by a 

 small, but very distinct, ciliated funnel, which is borne on the 

 anterior end of the swollen oviduct, closely behind the point of 

 its passage into the duct-like portion. The sac-like oviduct is 

 found to be filled with eggs and presents a pale yellowish color. 

 The ovary is represented by a long cellular band developed along 

 the dorsal median line of the ventral blood-vessel. 



The anal glands are relatively short, but bulky on account of 

 the repeated branching of the main canal. The ultimate branchlets 

 are beset with numerous ciliated funnels, each of which appears to 

 be borne on a short thick stalk (fig. 7, PL II.). The free end of 

 the main canal is lixed to the body-wall by a fine muscle-thread. 



