96 THE ECHINODERMATA. <§, 97. 



§ 97. 



In the Crinoidea, these organs, in the form of tubes, are situated urrder- 

 the soft perisoma of the pinnulae, and probably are without proper excre- 

 toi-y ducts. '^' 



In the Ophiuridae, they consist of lobular, pedunculated sacs, which are 

 suspended in pairs in the inter-radial spaces of the disc. 



These ten organs are usually deeply fissured, and the lobules thus formed 

 appear as so many proper sacs attached to the peduncle. <-> These last are 

 sometimes subdivided also.® 



Sometimes each organ, divided in its whole length into lobules, is turned 

 in the shape of a ram's horn.'** The peduncle of these organs is directed 

 towards the mouth, but it is yet uncertain whether their contents escape 

 this way or fall into the cavity of the body. In the first case, the pedun- 

 cle would be the excretory duct ;'^* and in the second, the eggs and sperm 

 would escape through the respiratory openings.'^' 



In the Asteroidae these organs consist of varicose lobular sacs, situated 

 in the angles of the inter-radial spaces.'"' In those species which are without 

 an anus, there are no proper genital openings ; '''' these openings are also 

 wanting in those Asteroidae which have an anus.'^' In these last, the sperm 

 and very small eggs pass into the cavity of the body, and probably have 

 their escape through the respiratory openings.'^"' 



But in some species,'"' there are upon the back and near each angle of 

 the inter-radial spaces two small approximated plates, perforated by small 

 openings [Laminae cribrosae). These are the simple openings of these 

 organs, which here consist of multi-ramose sacs, situated all along each side 

 of the inter-radial septa, to the common duct which opens through one of the 

 plates. 



The number of these genital sacs varies widely in the different genera 

 of the Asteroidae. In many, a single trunk of them hangs on each side of 

 the inter-radial septa ;''-* in others, there is a whole row of them;"''' and in 

 others still, there are two rows attached to the dorsal surface of the cavity 

 of the body, and extending into the rays.'^'" 



In the Echinoi'dea, these organs descend along the internal surface of 



1 The development of the genital organs of 8 As in Astropecten and Luidia. 

 Comatula was first observed by Dujardin, who 9 As in Ophidiaster. 



asserts that the red vesicles situated on both sides 10 According to Sars, the ventral surface of the- 



of the tentacular furrows secrete, during the epoch disc and arms of the female Echinaster xanguin- 



of rut, a very beautifully red liquid (L'Instit. No. o/entiis and Asteracanthiun Miilleri have at cer- 



119, p. 268, or H'^ieg'mann^s Arch. 1836, II. p. tain times a kind of incubating cavity, in which the 



207). Thompson has seen the eggs of Comatula eggs remain during their development. He thinks, 



escape in clusters through the openings of the pin- they get there from the cavity of the body, through 



nulae (Edinb. New Philos. Jour. No. XX. p. 295, particular openings upon the ventral surface of this 



or Froriep''s neue Not. No. 1057, 1836, p. 4, fig. last ; see Wiegmann's Arch. 1844, I. p. 169, Taf. 



8) ; while, according to Müller, they escape by YI. fig. 1, 2. 



rupture (.\bhandl. d. Berl. Akad. 1841, p. 234, Taf. The genital parts of Echinaster snnguinolentu» 



V. tig. 17, 18). have been described with mm;h detail by SarSy 



2 Ophioderma longirauda, and Ophiolepis Faun, littoi«. Norveg. p. 48. 



scolopendrica ; see Rathki, Forie.p^s neue Not. H Asteracanthion ruhev/t, a,r\(i Solaster pap~ 



No. 269, p. 65 ; and, Neueste Schrift, d. Natur- pnsim ; see Müller and Trosckely loc. cit. Taf. 



forsch GeselUch. in Danzig. 111. lift. IV. 1842, p. XII. fig. 2-4. 



116, Taf. ri. fig. 3, 4. 1-' Kr.hinaster, Astrogonium, Asteriscus, and 



3 Ophiocoma nigra; see Rathk^, Danzig. Ctenoaiscn.^. 



Schrift. &c. loc. cit. Taf. II. fig. 5-7. '"^ Astropecten, Oreaster, and Culcita ; sea 



4 Ophinthrix frngilis. Tiedemann, loc. cit. p. 61, Taf. VIII. L. L. 



ß Rnthki, loc. cit. 1-1 Archaste.r, Chaetaster, Luidia and Ophidic 



ß Müller and Troschel, loc. cit. p. 133. aster ; see Müller and Trusc/iel, loo. cit. TaC 



7 Müller and Troschel have very interesting XII. fig. 5. 

 details upon the various arrangements of the geni- 

 tal organs uf the Asteroidae (loc. cit. p. Hi}. 



