REPORT ON THE HOLOTHURIOIDEA. 9 



Station 216.— Lat. 2° 56' N., long. 134° 11' E. Depth, 2000 fins. Globigerina ooze. 



Dei ma fastosum, Thdel. 



Station 232.— Lat. 35° 11' N., long. 139° 28' E. Depth, 345 fms. Sandy mud. 



Lcetmogone wyville-thomsoni, The'el (?). 



Station 235.— Lat. 34° 7' N., long. 138° 0' E. Depth, 5G5 fms. Mud. 



Lcetmogone spongiosa, Thdel. 



It is evident that some of the Elasipoda, living together in great multitudes, pass 

 along the bottom of the sea ; this seems especially to be the case with Lcetmogone 

 wyville-thomsoni and L. violacea, Oneirophanta mutabilis, several species of the genus 

 Benthodytes, Kolga nana, Scotoplanes globosa, &c, of which great numbers have some- 

 times been dredged at the same station. But numerous different species were also 

 found together; thus, no less than ten forms were obtained from Station 157, five from 

 Station 158, six from Station 160, six from Station 298, &c. The nature of the bottom 

 of the sea is doubtless of great importance in regulating the distribution of the abyssal 

 Holothurioidea, and they are found most numerous, and in greatest abundance, on a 

 bottom of red clay, globigerina ooze, or diatom ooze. 



DESCRIPTION OF THE SPECIES. 



Order ELASIPODA. 



Body bilateral, more or less distinctly symmetrical. The lateral ambulacra of the 

 ventral surface, with larger and smaller mostly non-retractile pedicels, disposed in a 

 single row, or rarely in two rows, and sometimes with another series of elongated 

 conical, commonly non-retractile processes placed externally and above the pedicels; 

 pedicels of the lateral ambulacra symmetrically arranged, being more or less distinctly 

 opposed across the ventral surface. The odd ambulacrum naked, or with a few minute 

 pedicels, or with a double row of such. The dorsal surface provided with very long, 

 elongated conical, non-retractile processes, often disposed in one or more rows along- 

 each of its ambulacra, or with only a few rudimentary ones in its anterior part ; or with a 

 single, very large, broad, and more or less flattened, branched or unbranched appendage, 

 crossing the odd interambulacrum, and some minute processes. Integument with plates, 

 wheels, and branched or simple spicula ; ambulacral vessels five ; polian vesicle single, 

 rarely two ; madreporic canal single, dorsal, either intimately united to the perisoma in 



(ZOOL. CHALL. EXP. — PART XIII. 1881.) N 2 



