REPORT ON THE HOLOTHURIOIDEA. 107 



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

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



Among the specimens, which have been dredged at the above-mentioned station only 

 a single one is completely extended and presents the shape and dimensions which are 

 noted in the diagnosis ; all the other individuals are more or less contracted, consequently 

 the form of their body deviates in some degree from that above described. The ventral 

 surface is nearly flat or slightly convex, and more or less Uke a sole, while the dorsal 

 one is strongly convex ; forwards, but especially backwards, the body is depressed, its 

 hindmost extremity being thus almost flat. The mouth is completely ventral, while 

 the anal aperture is dorsal, situated close above and in front of the hindmost pedicels. 

 The fifteen tentacles are capable of being entirely drawn within the body, and their 

 discoidal end is provided with about twelve small, retractile, cligitiform processes which 

 are arranged round its edge. The minute cylindrical pedicels of the odd ambulacrum, 

 from fifty to sixty in number in the largest specimen, are not to be found in the foremost 

 part of the ventral surface. The numerous pedicels round the more or less considerable 

 brim of the body are of a conical form, retractile, and mostly visible as small tubercles ; 

 they are much larger than those belonging to the odd ambulacrum. The very thin 

 hindmost portion of the body presents almost the aspect of a fin, on account of the 

 small pedicels round its edge and their wide canals, which communicate with the 

 lateral ambulacra and penetrate it. Immediately behind the ventral tentacles some 

 small papilla-like projections are to be observed, which are indistinctly disposed in a 

 transverse row. The back is provided with minute conical processes, from eight to 

 ten in number, which are scattered along each of its ambulacra, and are often scarcely 

 distinguishable. 



The body -wall is thin and soft, and contains scattered cruciform calcareous deposits, 

 the arms of which seem to be more or less spinose, and attain a length of about 0'5 mm. 

 (PL XXXVI. fig. 26). Unfortunately, the calcareous substances are mostly dissolved, 

 consequently the true shape of the deposit is scarcely discernible. Here and there some 

 minute round or elliptical grains are to be found within the integument, but their 

 presence ought probably to be ascribed to some foreign matters (PL XXXVI. fig. 27). 



The calcareous ring is almost totally dissolved, wherefore it has not been possible to 

 examine it. The Polian vesicle is cylindrical, and measures from 35 to 40 mm. The 

 madi-eporic canal opens exteriorly, partly by a single pore (PL XXXVIII. fig. 2), partly 

 by several (PL XXXVIII. figs. 1 and 3), which are thus crowded on the obtuse top of a 

 small papilla, situated somewhat in front of the genital pore ; when there is only one 

 pore, this seems to be placed side by side with the genital aperture. The madreporic 

 canal is strengthened by a great number of more or less regular and spinose cruciform 

 deposits (PL XXXVIII. fig. 4) resembling those of the perisoma. The reproductive - 

 organ (PL XLVI. figs. 9-10) consists of two fascicles about 70 mm. long, and its common 



