OKNERAL NOTES. 
511 
1.^, Perrier, E. Sur I’appareil circiilatoire ties Oursiiis. C. R. Ixxix. 
pp. 1128-1132 ; abstr., R. Z. (3) ii. pp. Ixv.-lxvi. 
14. Schmidt, F. Miscellanea silurica. II. Ueber einige neue und 
ivenig bekannte baltisch-silurische Petrefacfcen. Mem. Petersb. (7) 
xxi. No. . 11, 48 pp. 4 pis. 
15. Semper, C. Kurze anatomische Bemerkungen iiber Comatula. 
Arb. Inst. Wiirzb. i. pp. 259-263. Translated with an addendum by 
W. B. Carpenter, in Ann. N. H. (4) xvi. pp. 202-209. 
Embryology, Anatomy, 
The larger portion of the concluding part of Agassiz’s “ Revision ” 
(1) is devoted to the anatomy and embryology of the Echinidfv, the 
former of which subjects would have been more complete, had not the 
auth6r’s notes and drawings been destroyed in a conflagration. An 
analysis would be out of place here. 
Per PIER has studied the circulatory system of Echinus (13), arriving 
;it results, which are in several important points contradictory to 
those attained by other anatomists. The presumed “ heart ” is, according 
to him, only a gland. The vertical vessel (“sand canal”), which abuts 
on the “ madreporic body,” opens at the other extremity in the circular 
vessel of the “ lantern,” which is the only vascular circle that Perrier 
was capable of discovering ; the five vessels which spring from this circle, 
are continued in the five ambulacral vessels, which give off branches for 
the ten great buccal tentacles, but terminate “ en cul de sac” behind the 
“ocular” plates ; there is however in this place neither eye or tentacle, 
as has been supposed, nor any communication with the exterior. There 
is no anal vascular ring. The internal intestinal vessel springs directly 
from the vascular ring of the lantern, in a place opposite to the 
“ sand canal ; ” its branches form the capillaries of the intestine and 
mesentery, which are again in direct communication with the external 
intestinal vessel ; there are other anastomosing vessels combining the two 
principal vessels of the intestine, but apparently no direct communication 
between the external intestinal vessel and the vascular circle, 
IIoi-'EMANN confirms (7) in several important points the surprising re- 
sults arrived at by G reeee. The five nervous bands, occupying the whole 
length of the bottom of the ambulacral furrows, outside the ambulacral 
skeleton, are subdivided each into three longitudinal cavities, which belong 
to the vascular system ; the walls are continued in the suckers (ambulacral 
feet), the external layer of which is formed of the same fibrillated, gang- 
lionate substance as the bands themselves ; the pentagonal central portion 
of the nervous system, from which the five ambulacral bands spring, 
covers the double pentagonal oral vascular rings, which also lie on the 
outside of the buccal membrane ; the lymphatic oral ring gives off five 
ambulacral stems, which lie above the nervous bands, but below the ambu- 
lacral skeleton, and communicate with the suckers ; the true vascular oral 
ring gives off three branches for each arm, but these branches are the 
true cavities of the nervous bands ; the anal vascular circle communicates 
with the oral circle by means of the tube enclosing the “ stone canal,” 
