104 THE VOYAGE OF H.M.S. CHALLENGEE. 



dredged during the Challenger expedition, the breadth must have been much greater. 

 When fully extended the body appears to be rather depressed, and its broad surrounding 

 brim very thin, especially towards its edge. Here and there a tentacle is found slightly 

 smaller than the others ; the terminal part itself as well as its processes are covered with 

 some minute prominences. The pedicels of the odd ambulacrum, about sixty in number, 

 are minute and closely crowded together. The brim, which in some more extended 

 individuals is even as broad as the body itself, is penetrated by a great number of closely- 

 lying canals, which connect the ambulacral system with the minute conical pedicels 

 round the edge. Those canals are plainly visible through the integument in consecpience 

 of their walls being of a dark purple colour. The dorsal processes (PL XLIV. fig. 8) 

 are very minute and completely retractde ; their number does not seem to exceed eight 

 along each ambulacrum. When the body is contracted the thick dorsal perisoma forms 

 large rounded lobes separated from one another by funnel-shaped hollows at the bottom 

 of which the processes are to be found. 



The calcareous deposits (PL XXXV. fig. 4) of the integument are rather scattered 

 and consist of more or less curved unbranched and spinose spicula. The tentacles, pro- 

 cesses, and pedicels contain also spicula of about the same shape. 



The polian vesicle attains a length of from 20 to 25 mm. The madreporic canal opens 

 externally immediately in front of the genital aperture ; its walls are strengthened by a 

 calcareous network, and by spicula (PL XXXVIII. fig. 5). The very narrow part of that 

 canal which pierces the body-wall is destitute of deposits excepting its uppermost part close 

 to the " pore," which is surrounded by a minute network. The cloaca is of considerable 

 size. The calcareous ring seems to consist of a very fragile irregular network, the true 

 form of which I have not been able to study. The reproductive organ consists of two 

 small, thin fascicles, each composed of a few larger and smaller sometimes rather long 

 caeca ; the organ opens from 10 to 15 mm. behind the anterior extremity of the body. 



Benthodytes sanguinolenta, n. sp. (PL XXIIL). 



Body elongated, more or less cylindrical, six to seven times longer than broad. 

 Tentacles eighteen, with their dilated terminal part provided with small retractile digitiform 

 processes round its edge. The dorsal surface with a great many very minute, completely 

 retractile processes, scattered over the lateral interambulacra ; the odd interambulacrum 

 naked or with a few such processes. Integument thin and pliable ; its calcareous deposits 

 dissolved. 



Colour in alcohol red, inclining to violet ; the back lighter excepting its processes, 

 which are of a darker colour. Length of the largest specimen, about 340 mm. Breadth, 

 about 50 mm. 



Habitat.— Station 298. November 17, 1875. Lat. 34° 7' S., long 73° 56' W. 

 Depth, 2225 fathoms; bottom temperature, 1"3° C. ; grey mud. Three specimens. 



