28 DE. p. H. CARPENTER OK CERTAIN POINTS 



the osculum, oi* nearly so*. This is well shown in Aristocystis 

 (PI. I. figs. 12, 13) and Glyptosplicera (fig. 15), both of which, and 

 perhaps also Fijrocystis (figs. 10, 11), had a fourth opening {d) 

 in the same interradius, which must, I think, he regarded as ex- 

 cretory in function. 



The small second opening (c) in the anal interradius CD has been 

 generally considered, of late years, as a genital pore ; but the 

 condition of Aristocystis shows the probability of its fusion with 

 the anus (PI. I. figs. 12, 13). Hence in Echinoencrinus and its 

 six allies f (which have no second opening in the anal interradius) 

 the oviducts and rectum may have had a common oscular opening, 

 as supposed for Agelacrinus and Caryocrinus. But if so, what was 

 the third opening, that in interradius DE, of these types ? If 

 genital, its position outside the anal interradius is somewhat 

 anomalous ; and I cannot help suspecting that it may be an ex- 

 cretory pore. The researches of the Sarasms seem to indicate 

 that the problematical ovoid gland of Astlienosoma is really a 

 kidney which opens externally through the madreporite J ; and 

 they point out that Prouho's description of the ovoid gland and 

 its connections in Dorocidaris § is capable of a similar interpre- 

 tation ; though Cuenot's studies of the Asterids and Ophiurids 

 have led him to regard this organ as essentially a lymphatic gland 

 which produces the amoebocytes of the coelom and vascular 

 system \\. Kowalevsky ^, on the other hand, concludes from his 

 experiments that it is an excretory organ ; and I am inclined to 

 think that there is much to be said for this view of its function, 



* Aristocystis, Caryoct/stis, Beutocystis, Echinosplicera, Glyiytos'plKBra, Mega- 

 cystis, Orocystis, Proteocystis, Pyrocystis, Protocrinus, Sphwronis. This third 

 opening is possibly also present in AUocystis, Miller, and Trochocystis, Barrande, 

 though its position is not easy to determine from the published figures of these 

 types. That of Eucystis seems to be in interradius EC, 



t Apiocystis, Callocystis, Cystoblastus, Cryptocriiius, Echinoencriims, Glypto- 

 cystis, Sjphcsrocystis, and possibly Lepadocrimis. 



\ " Ueber die Anatomic der Echinothuriden und die Phylogenie der Eehino- 

 dermen, " Ergebnisse Nat. Forsch. Ceylon, 1888, Ed. i. Heft 3, pp. 105-114. 



§ "Recherches sur le Borociclaris pafillata, et quelques autres Echinides de 

 la Mediterranee," Arch, de Zool. Exp. et Gen. 2'' ser. vol. v. 1888, pp. 114-119 

 (of separate copy). 



II " Etudes anatomiques et morphologiques sur les Ophiures," ibid. vol. vi. 

 1888, pp. 50, 66. See postscript, infra, p. 45. 



^ " Ein Beitrag zur Kenntnis der Excretionsorgane (Schluss)," Biol. Centralbl. 

 '1889, Ed. ix. pp. 73, 74. 



