Boone, Echinodermata, Cruises of "Ara" and "Alva" 183 



teriorly. The mouth is definitely ventral, bordered by a conspicu- 

 ous papillose collar. There are 24 to 26 closely crowded, widely 

 peltate tentacles, with the crests arranged in two approximately 

 concentric series, the ampullae long. The peristome is wide, con- 

 spicuous. The pedicels are restricted to the flattish ventral sur- 

 face and are packed closely together without definite arrangement. 

 The dorsal papillae are irregularly distributed and of about the 

 same size as the pedicels, but much less numerous. They are more 

 crowded and larger along the lateral margins of the dorsum, adja- 

 cent to the pedicels and also near the anus. The peristome is tough, 

 leathery, with two types of deposits in the dorsum, namely longer 

 and shorter rods which have their ends dichotomous or spinose 

 and their lateral walls with small spinose or blunted processes. 

 Scattered among these are many small multibranched rosettes. 

 On the ventral peristome the deposits are very characteristic, form- 

 ing several layers. They consist of numerous small, oval grains 

 and of larger simple rods with the ends roughened. The rosettes 

 are sparsely represented in the ventral peristome. The calcareous 

 ring is heavy. The radialia and interradialia are of nearly the 

 same size. There are two Polian vesicles present and two to three 

 madreporic bodies ; these lie to the left of the dorsal mesentery, 

 free in the body cavity. Cuvierian organs are present. The right 

 respiratory tree is twice as long as the left one, reaching to the 

 calcareous ring. The left tree is more thickly branched. 



References : Holothuria mauritiana, QuoY and Gaimard, Voy- 

 age de Astrolabe Zoologie, Zoophytes, T. IV, 1833, p. 138. — 

 Brandt, J, F., Prodrom. Descript. Anim. ab H. Mertensio 

 Observ., 1835, p. 54. 



Mulleria mauritiana, Semper, C, Reisen im Arch, der Philippinen 

 Wissensch. Resul. I, Holothurien, 1868, p. 76. — Theel, H., 

 Rept. H. M. S. "Challenger" Zool., Holothuroidea, pt. II, 1885, 

 vol. XIV, p. 201.— Lampert, K., Die Seewalzen, 1885, p. 98; 

 Zool. Jahrb. Bd. IV, 18 — , p. 83 (with synonymy). — Sluiter, 

 Ph., Siboga-Expeditie Holothurien Monogr. XLIV, Livr. I, 

 1901, p. 24. 



Actinopyga mauritiana, Bell, F. J., Sci. Trans. Royal Dublin 

 Soc, ser. II, vol. Ill, 1887, p. 653, pi. 39, fig. 1.— Fisher, W. 



