146 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 



bloods vessels of Ludwig and other authors (PL XXXIX, 

 fig. 2). 



Perrier and Poirier (7), followed by Cuenot, deny the 

 existence of these radial haemal strands; but the latter 

 author admits that there is what he calls a "glandular" 

 tract in the vertical septum, and figures one of the lacunar 

 spaces. At regular intervals strands which appear in 

 sections as oblique septa, and were described as such by 

 Cuenot, pass from the radial haemal strands to supply the 

 tube-feet. The radial peribaemal canals are continuous, 

 through the medium of lateral extensions passing between 

 the tube-feet, with a system of lacunar spaces everywhere 

 present in tlie body wall. I have already more than once 

 referred to the existence of coagulum in the hsemal system. 

 It is present at all points in larger or small quantities, 

 the tubules of the central plexus frequently being much 

 distended with it. AVhether the fluid which gives rise to 

 it merits the term blood or not may be open to question, 

 but I am satisfied that it is a nutrient fluid, derived from 

 the gut, and conveyed by the gastric haemal strands to the 

 central plexus, and from thence along the genital and 

 radial strands. That such is its course is demonstrated by 

 a series of sections cut from a young specimen of Aster ias 

 ruhens, for which I am indebted to the kindness of Mr. 

 W. Garstang. Into the stomach of the specimen in ques- 

 tion, a number of very small cyst-like bodies, about g^th 

 of an inch in diameter, and of a dark green colour, had 

 found their way. Many of these had been ruptured, 

 setting free large numbers of still smaller spore-like bodies, 

 of which hundreds are now to be seen lodged between the 

 bases of the epithelium cells lining the stomach, in the 

 tubules of the gastric haemal strands, and of the central 

 plexus. Cuenot maintains that the true blood-fluid circu- 

 lates in the perihaemal canals, but the very large number 



