NOTES ON EOHINODERM MOBPHOfiOGY. 597 



Notes on Echinoderm Morphology, No. VI. On 

 the Anatomical Relations of the Vascular 

 System. 



By 



p. Herbert Carpenter, M.jt.., 



Assistant Master at Eton College. 



I DREW attention in my last note^ to the striking variations 

 in the results of observations upon the vascular system of the 

 Echinoderms, vv^hieh have been made by different Continental 

 naturalists. The leading member of the French School, Pro- 

 fessor E. Perrier, asserts positively that the so-called " heart " 

 of the Echinozoa is an excretory gland, which communicates 

 with the exterior through the madreporite, and is entirely free 

 at its inner end, no vessel proceeding from it to join an oral 

 ring; in fact, it is not a part of the blood- vascular system at 

 all. Professor Perrier had arrived at this conclusion as the 

 result of his own observations upon Urchins and Starfishes, 

 together with those of Apostolides upon the Ophiurids. He 

 totally denies the existence of the radial blood-vessels described 

 by Ludwig in the Asterids ; and as regards the Urchins he, like 

 Hoffmann, is able to find but one vascular ring around the 

 mouth. This is described as connected with the water-tube 

 (stone-canal) and the radial vessels supplying the tentacles, and 

 also as the ring in which the ventral or internal marginal vessel 

 of the intestine originates. *' U y a done bien reellement com- 

 munication entre I'appareil vasculaire intestinal et le pretendu 

 appareil aquifere."- 



' This Journal, vol. xxii, pp. 371—380, October, 1882. 

 - ' Sur I'appareil circulatoire des Oursins," ' Coniptes rendus,' lS7'i, t. 79, 

 pp. 1128—1132. 



VOL. XXUI. NEW SER. R R 



