OPHIURIDiE, CEINOIDiE. 
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Ophiomusium jjulchellum, sp. n., and OpTiiacantha cJielys^ sp. n., dredged 
off Madeira, in 1675 fathoms, in Wyvillo Thomson’s, “ The Atlantic,” 
ii. p. 63, the last-named species on Corallium\ Ophinglypha hullata, id, 
1. c. pp. 400-402 (2650 fathoms. Gulf Stream, but universally distributed 
in the Atlantic and Southern Sea). Ophiacantha vivipara is refigured, 
1. c. ii. p. 242. 
The genital slits of the Ophiuridce do not lead into the general cavity of 
the body, but into genital pouches, or special cavities into which the 
true orifices of the sexual glands are placed ; Ludwig (14, 5). 
On the schizogony and reconstruction of Asteridm and Ophiuridm 
{Ophiastis), the detailed investigations of Simroth (21) are to be con- 
sulted ; the division is not accidental, and is repeated several times ; in 
the work of reconstruction, a prominent part is taken by the so-termed 
aquiferous system. Considerations and remarks of a more general cha- 
racter, or the comparative morphology of the five principal types of 
EcMnodermata, based upon the author’s investigations of the anatomy of 
Ophiastis, and the development of its constituent parts during the re- 
generative process, are adduced. 
Crinoid.®. 
The admirable researches of Ludwig (14, 1 & 2) have apparently 
almost exhausted the subject of the anatomy of Crinoids (especially 
Comatula ov Antedon)^ in such a manner that most of the more important 
disputable points discussed by late observers may be regarded as defini- 
tively settled, and comparatively little remains still as dubious. A. radial 
nerve underlies, as in the A the epithelium of the ambulacral 
furrows of the disk, arms, and pinnulai, uniting with its follows to form a 
circum-oral ring. Between the radial nerve and the radial (ambulacral) 
aquiferous tube, a radial sanguiniferous vessel is situated, forming like- 
wise an oral ring, lying close to the nerve ring, and to the ring-shaped 
central portion of the aquiferous system ; this ring-shaped blood-vessel 
is provided with appendages, communicating by their ramifications with 
the vascular plexus of the visceral cavity. In like manner, the ambulacral 
ring-tube is provided with numerous tubular prolongations, “stone canals,” 
suspended in the body cavity and communicating through their terminal 
apertures with the lacunar system. Numerous pores, widening into small 
fimbriating cavities, and arranged rather regularly in the inter-radial and 
inter-palmar areas of the perisome (rarely also continued on the proximal 
part of the arms), lead the sea- water into the body-cavity, and play the 
part of the “ madreporites ” in other Echinodermata. (In Rhizocrinus, the 
number of madreporic pores and stone-canals is reduced to a single one 
in each of the 5-7 divisions of the disk.) The relatively large ventral 
and dorsal canals, or tubiform cavities, of the arms (sometimes sub- 
divided by septa, often communicating largely with each other ; in Rhizo- 
crinus reduced to a single one in the distal portion of the arms) are only 
prolongations of the body-cavity, originating the first from the axial, the 
second from the circum- visceral part of the body-cavity. The genital 
canal, situated in the septum between the “ dorsal ” and “ ventral ” canal, 
