STICHOPUS. 51 



Stichopus natans. 



Holothuria natans, M. Sars, Vid.-Sclsk. Fork. 1867 (1868) p. 20. 

 Sticb opus natans, G. O. Sars, Vid.-Selsk. Fork. 1871 (1872), p. 30; M. 

 Sars, Faun. lift. Norveg. iii. (1877) p. 58, pi. vii. figs. 18-41. 



Mr. Sladen (Proc. Eoy. Ir. Acad. i. (1891) p. 702) reports that this species 

 was taken from 750 fms., in lat. 50° 1' N., long. 11° 50' W. It is, of course, 

 quite possible, but the' condition of the specimen, as seen by me in June 1892, 

 is such that, considering how much the species is said by Sars to resemble 

 H. trcmula, I cannot on its evidence alone admit the species into our list. So 

 far as I can form a judgment from the specimen, I am inclined to doubt very 

 strongly its being an example of S. natans. 



Stichopus tizardi. 



Stichopus (?) tizardi, Theel, Proc. Roy. Soc. Ed. xi. (1882) p. 696 ; id. ChaU. 

 Rep. Hoi. (1885) p. 193. 



Of this species, which can hardly be said to be satisfactorily known, 

 Dr. Theel remarks in his ' Challenger' Eeport : — 



" When I first described this species I had only some fragments at my dis- 

 posal. Lately I have received some new specimens dredged at about the same 

 locality, but unfortunately even these are very deformed and macerated, con- 

 sequently their true shape is difficult to state. The following may complete 

 the former description. Body elongate, equally rounded at each extremity, 

 flattened. Mouth ventral, with twenty yellow tentacles. Anus subdorsal. 

 Dorsal surface with conical processes, few in number, of unequal size, the 

 largest measuring 5 to 10 mm. in length ; those processes which attain a greater 

 size are thinly placed on or in the neighbourhood of the two dorsal ambulacra, 

 while the smaller are to be found partly in very limited numbers scattered 

 among the larger, partly more crowded, forming a simple row along the sides 

 of the body and round its anterior extremity. The pedicels probably form a 

 double row along each lateral ventral ambulacrum; but on the odd ambu- 

 lacrum, marked out by a deep furrow, I could not convince myself of the 

 presence of any such appendages. The calcareous ring is very reduced, in the 

 larger specimens absent. Two genital bundles, one on each side of the dorsal 

 mesentery. A single Polian vesicle and madreporic canal. Body-wall thick, 

 strengthened by Q-shaped bodies and tables. In some parts of the body the 

 spines grow much larger and possess much more numerous transverse beams; 

 in others all the tables become very robust, with a greater number of holes 

 in the highly dilated ends of the arms, and with the spire more irregulailv 

 developed and highly spinous. As a rule, the four rods which constitute the 

 spire are almost parallel and provided with spines. The dorsal processes carry 

 numerous spinous rods and tables with very long spires." 



Enown only from the Faeroe Channel. 



a-c. Faeroe Channel, 516 fms. ' Triton ' Exp. 



d-f. Faeroe Channel, 570 fms. ' Triton' Exp. 



I have nothing to add to Dr. Theel's account ; his label bears the words 

 " var. mollis" but the species is so imperfectly known that special varieties are 

 hardly to be distinguished. 



£2 



