96 



THE ECHINODERMATA. 



S^97. 



§ 9T. 



In the Crinoi'dea, these organs, in the form of tubes, are situated under 

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

 tory 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 Asteroldae these organs consist of varicose lobular sacs, situated 

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

 an anu'?, there are no proper genital openings ; ® these openings are also 

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

 and very ."-inall eggs pass into the cavity of the body, and probably have 

 their escape through the respiratory openings. ^^"^ 



But in florae species, ^^^ there are upon the back and near each angle of 

 the i]iter-radial spaces two small approximated plates, perforated by small 

 openings {Laminae crihrosae). 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 

 Comatula was first observed by Dujardin, who 

 asserts that the red vesicles situated on both sides 

 of the tentacular furrows secrete, during the epoch 

 of rut, a very beautifully red liquid (L'Instit. No. 

 119, p. 268, or fViegmann's Arch. 1836, II. p. 

 207). Thompson has seen the eggs of Comatula 

 escape in clusters through the openings of the pin- 

 nulae (Ediub. New Pliilos. Jour. No. XX. p. 295, 

 or Froriep''s neue Not. No. 1057, 1836, p. 4, fig. 

 8) ; while, according to Rlu/ler, tliey escape by 

 rupture (Abhandl. d. Berl. Aliad. 1811, p. 234, Taf. 

 V. fig. 17, 18). 



2 Ophioderma longicauda, and Ophio/epis 

 gcolopendrica ; see Rntltki, Foriep''s neue Not. 

 No. 269, p. 6o ; and, Neueste Sclu-ift. d. Natur- 

 forsch. Gesellsoh. in Danzig. III. Hft. IV. 1842, p. 

 116, Taf. II. fig. 3, 4. 



3 Ophiocoma nis^ra; see Rathki, Danzig. 

 Schrift. &c. loc. cit. Taf. II. fig. 5-7. 



4 Ophinthrix fragilis. 

 fi Rathki, be. cit. 



6 Midler and Trosc/iel, loc. cit. p. 133. 



7 Mailer and Troschel have very interesting 

 details upon the various arrangements of the geni- 

 tal organs of the Asteroidae (loc. cit. p. 132). 



8 As in Astropecten and Luidia. 



9 As in Ophidiaster. 



10 According to Sars, the ventral surface of the 

 disc and arms of the female Echinaster xanguin- 

 olentus and Asteracanthion Mulleri have at cer- 

 tain times a kind of incubating cavity, in wliich the 

 eggs remain during their development. He thinks 

 they get there from the cavity of tlie body, through 

 particular openings upon the ventral surface of this 

 last ; see Wiegniann^s Arch. 1844, I. p. 169, Taf. 

 VI. fig. 1, 2. 



The genital parts oi Echinaster sanguinolentus 

 have been described with much detail by Sars, 

 Faun, littor. Norveg. p. 43. 



11 Asteracanthion rubens, and Solaster pap- 

 posus ; see Muller and Troschel, loc. cit. Taf. 

 XII. fig. 2-4. 



12 Echinaster, Astrogonium, Asteriscus, and 

 Cte.nodiscus. 



13 Astropecten, Oreaster, and Culcita ; see 

 Tiedemann, loc. cit. p. 61, Taf. VIII. L. L. 



14 Archaster, Chaetaster, Luidia and Ophidi- 

 aster ; see Muller and Troschel, loc. cit. Taf. 

 XII. fig. 5. 



