NOTES ON ECHINODERM MORPHOLOGY. 139 
Notes on Echinoderm Morphology, No. IX. On 
the Vascular System of the Urchins. 
By 
P. Herbert Carpenter, D.Sc., 
Assistant Master at Eton College. 
EIGHTEEN months ago I published a note in this Journal,! 
which contained a partial analysis of the excellent memoir by 
Koehler upon the minute anatomy of the Echinoidea.? I was 
led more particularly to discuss those of his observations which 
dealt with the vascular system, and their bearing upon the 
two theories as to its anatomical relations which are current 
among morphologists. Many of these observations go far to 
support the views of Ludwig respecting the general morphology 
of the Echinoderm vascular system; while others seem as 
decidedly opposed to them, and in favour of Perrier’s theory 
as to the fundamental unity of the double vascular system of 
an Echinoderm, and the communication of the so-called 
“heart” with the exterior through the pores of the 
madreporite. 
At the same time I ventured to notice what appeared to me 
to be certain weak points in Koehler’s chain of evidence— 
points which it was desirable to have thoroughly established, 
as being those on which the theory of Perrier and Koehler 
mainly rested. 
If the French zoologists are in the right we must either 
1 “ Notes on Echinoderm Morphology, No. VI. On the Anatomical Re- 
lations of the Vascular System,” ‘ Quart. Journ. Mier. Sci.,’ vol. xxiii, 1883, 
pp- 597—616. 
2 * Recherches sur les Hchinides des Cotes de Provence,” ‘ Ann. du Mus. 
d’ Hist. Nat.de Marseille, Zoologie,’ Mémoire No. 3, pp. 1—167, pl.i—vii, 1883, 
