no. 2073. HOLOTHURIANS FROM NORTHWEST PACIFIC— OHSHIMA. 227 



wrinkled, only very slightly rough to the touch. Tentacles 20. 

 Numerous minute pedicels scattered all over the body without any 

 zonal arrangement; they are largest on the ventrolateral ambulacra, 

 being about 0.8 mm. long. Ventrum apparently naked, but the 

 presence of scattered, rudimentary pedicels is indicated by small end- 

 plates. Deposits in the form of tables quite richly present all over 

 (pi. 8, figs. 4a, b). Disk is triangular with rounded angles, with a 

 central hole and six peripheral ones. These latter are most com- 

 monly of different sizes, being alternately larger and smaller. Over 

 the central hole is a triradiate arch, each arm of which gives rise to a 

 pillar, united with its fellows by a cross-beam (fig. 4a). In dorsum, 

 disks of tables measure 66/* in mean diameter, ranging 45-88/*, peri- 

 pheral holes 5-8 in number, and height of spire 40-50/*. Those of 

 ventrum are a little smaller, mean diameter of disks 54/*, range 41- 

 65/*, number of peripheral holes 6-10, height of spire 30-40/*. In 

 pedicels disk of tables is smaller, only 17-33/* in diameter, peripheral 

 holes being absent; spire 43-53/* high, pillars not connected by cross- 

 beams; no supporting rods, but the end-plate well developed with a 

 large central hole. Rods in tentacles slender and bent, with nu- 

 merous spines, often branched. Calcareous ring well developed. 

 Polian vesicle single, stone-canal ending in a large ellipsoidal madre- 

 porite, which does not lie in dorsal body-wall. Genital tubes twice 

 dichotomously divided, forming a tuft on the left side of dorsal 

 mesentery. 



It seems to me highly probable that in Perrier's genus Zygothuria, 

 there may be indications of the presence of ventral pedicels, as in the 

 present species. M. multipes Ludwig and M. incerta Koehler and 

 Vaney differ from this species in details of deposits. The present 

 species also closely resembles M. abbreviata Koehler and Vaney, which 

 is somewhat imperfectly known. 



Habitat. — Off Kii, Honshu. 



Type.— Cut. No. 34146, U.S.N.M. 



Genus PSEUDOSTICHOPUS Th6el. 



12. PSEUDOSTICHOPUS TRACHUS Sluiter. 



Pseudostichopus trachus Sluiter, Tijdschr. Ned. Dierk. Ver., Dl. 7, Afl. 1, 1901, 

 pp. 15-16; Siboga Holothurien, 1901, pp. 52-53, pi. 5, fig. 1; pi. 8, fig. 8.— 

 Mitsukuri, Actinopodous Holothurioidea, 1912, pp. 3-9, pi. 1, figs. 1-5, 

 text-fig. 1. 



Station 4968. One specimen. 



Station 5055. Five specimens. 



Station 5060. One specimen. 



Station 5092. Fifty specimens. 



Station 5093. One specimen. 



Station 5094. Seven specimens. 



Of these 65 specimens the largest measures only 70 mm. in length. 

 In these specimens as well as in those examined by Professor Mit- 



