REPORT ON THE HOLOTHURIOIDEA. 57 



lying canals, the mouth has the aspect of being situated unusually far, about 30 nun., 

 from the anterior extremity of the body. At first sight one is almost tempted to think 

 that the mouth is situated near the middle of the ventral surface, but on making a closer 

 examination of that part of the body which lies in front of the mouth, one becomes con- 

 vinced that the whole of this part is constituted by an extension of the dorsal perisoma 

 forming the above-mentioned brim, and that, consecmently, the mouth is really placed 

 on the anterior part of the ventral surface. The peritoneal cavity is thus not prolonged 

 much in front of the mouth. The large, wide canals, penetrating the brim side by side, 

 are in connection with the dorsal ambulacra ; some of them on each side communicate 

 possibly with the ventral lateral ambulacra, but I am not certain as to this. The canals 

 taper towards their caecal ends, and the rather large spaces between them are occupied by 

 the connective tissue of the brim. Each of the canals enters one of the more or less 

 considerable processes which are to be observed round the margin of the brim. Almost at 

 the middle of the dorsal surface two pairs of small papilla-like projections can be dis- 

 tinguished ; possibly there may have been several others. The tentacles are torn off 

 except in one individual, where I found them to amount to twenty; they seem to be of 

 unecmal size ; on account of their macerated condition it is not possible to give 

 a description of their true aspect. As the pedicels are mostly torn off their number is 

 unknown. I feel certain that they are present on the posterior end of the body, but must 

 leave it undecided whether they are also to be found along the sides of the ventral sur- 

 face, though I have thought I could detect some traces of them there. The integument 

 being very flexible is in an extreme degree of dissolution, so that no calcareous bodies 

 can be distinguished. 



Achlyonice, Theel. 

 Achlyonice, Theel, Preliminary Report on the Holothuridte of H.M.S. Challenger, p. 13. 

 Body oval or ovate, about twice as long as broad. Tentacles eleven or twelve. The 

 dorsal surface with some processes anteriorly. The ventral surface with pedicels all 

 round its sides. Integument with calcareous deposits composed of three-armed bodies, 

 sometimes along with unbranched spicula and small wheels. 



Achlyonice 'paradoxa, Thdel (PI. V. figs. 1-2). 



Achlyonice ecalcarea, Theel, Preliminary Report on the Holothurklse, p. 13. 

 Body ovate, widening behind, about twice as long as broad. Mouth anterior, sub- 

 ventral. Anus posterior, dorsal. Tentacles twelve, of equal size ; their terminal part very 

 large, discoidal, with small retractile processes. Pedicels twenty-seven, disposed along the 

 sides and round the posterior part of the ventral surface. The dorsal surface with about 



(ZOOL. CHALL. EXP. PART XIII. — 1881.) N 8 



