ANATOMY, PHYSIOLOGY, ETC. 
Ech, 11 
(ventral) surface, or at least large portions of it, and are analogous to 
the “ madreporites of other Echinoderms. In Antedon, the “ pinnulas 
orales are without tentacles, nerves, and norve-vessols (but not without 
the aquatic vessel) ; in Actinometra, large portions of the arms, or whole 
arms (of the aboral side) are equally deficient, though with great indi- 
vidual variation. Special ‘^sense-organs ” [?] are limited to the terminal 
pinnulae of these non-tentacular arms (3). As to the string-shaped organ 
in the axis of the arm-skeleton, opinions are much divided ; the experi- 
ments of Carpenter (4), and its nerve-like ramifications beyond the 
limits of the calcareous segments, strongly advocate its nervous cha- 
racter and high importance for the movements of the sea-lily. Below 
the first bifurcation of the arms, there are five such strings, arising from 
ten, which again are produced by the bifurcation of five basal chords 
emanating from the nbrillated envelope of the 6-chambered organ, or 
“ heart,” situated in the centro-dorsal piece of Antedon\ the axis of this 
organ is formed by several vessels, w^hich, upwards, are apparently con- 
tinued in the perivisceral vascular plexus of the body-cavity ; dorsally, 
the five peripheral vessels open in the five chambers of the heart, 
while the axial vessels are continued into the central vessels of the axial 
chords of the older dorsal cirri, and — in stalked Crinoids— into those of 
the stem ; those of the younger (outer) cirri spring immediately from the 
chambers of the heart. Whether vessels are continued from these into the 
interior of the lower portion, at least, of the brachial central chords, is 
still a matter of doubt ; on this, and on other questions of detail, there is 
apparently some difference in the short summaries hitherto published 
of the greater number of these delicate and difficult investigations. It is not 
always possible to identify the parts and organs described by the authors, 
or to reconcile the results arrived at. According to Teusciier, who 
regards the “coeliac ” and “ subtentacular ” canals as vessels, the upper 
one is continued below the ambulacra to the mouth, where it forms a 
ring-shaped vessel; the lower one forms a ring around the upper portion 
of the heart. He also describes the intestine as provided with numerous 
branched coeca, and the spongeous vascular tissue filling up the interspaces 
between the convolutions of the intestine as separated from the true 
body-cavity, and from the “ coeliac ” and “ subtentacular ” vessels, while 
these parts are regarded and described by others as parts of a common 
lacunose system. According to Carpenter (4), the coeliac vessels act 
as the venous, the subtentacular as the arterial portions of the circula- 
tory system. The subtentacular canals are continued into the axial 
canal of the visceral cavity, and the genital strings, are probably in like 
manner connected with the axial pedicle, and thus with the axial organ 
of the stem in pedunculate Crinoids. 
Genera and Species. 
HOLOTHURIlDiE. 
Cuvieria porifera, sp. n., Studer (19) p. 452 (Kerguelen, 63 fathoms). 
Trachythyone^ g. n., Studer. “ Corpus fusiforme, undique papillis 
1876. [yol. xii[.] j 3 
