REPORT ON THE HOLOTHURIOIDEA. 23 



directions from a common centre. The reproductive organs consist of two wide, short 

 tubes bearing small bundles of caeca ; they open into a single common duct having its 

 orifice immediately in front of the tentacles in the downwardly directed part of the 

 dorsal surface. Both of the tubes of the organ contain numerous calcareous deposits 

 in the form of spicula. I have not been able to examine the madreporic canal. The 

 alimentary canal is of a violet colour. 



The individual obtained from Station 157 shows several peculiarities which I 

 shall now point out. The size itself is considerable in comparison with that of the 

 above-described specimens, the length amounting to 55 or 60 mm. and the breadth to 

 about 25 mm. The body is of almost equal breadth throughout, with its posterior end 

 abruptly rounded, thus differing very considerably from the oval form peculiar to the 

 preceding. The dorsal surface also projects considerably in front of the mouth, which 

 thus becomes thoroughly ventral, and is situated about 10 or 12 mm. behind the trans- 

 versely truncated anterior end of the body. The processes which constitute the first 

 pairs are 22 mm. long, and the posterior ones a little shorter. The pedicels are eighteen 

 in all, nine arranged along each side of the posterior half of the ventral surface. On 

 comparing the individuals from Station 146 it becomes evident that the anterior half of 

 the body is always wanting in pedicels, while the number of the pedicels on the posterior 

 half may vary a little. The calcareous deposits within the integument are very 

 crowded and rather small, their arms attaining only to about - l mm. in length ; for the 

 rest, the size varies a little in the same animal, the deposits being considerably larger in 

 some parts of the body than in others. This variation in size is also accompanied by a 

 rather considerable alteration in the appearance of the calcareous deposits. I have 

 here been able to examine the calcareous ring more closely than in the above described 

 individual ; each of its five pieces or spicula, separated one from another, consists of a 

 short central part, which gives off, in opposite directions, about eight long rods, the ends 

 of which seem to be a little flattened, broad, and as if they were dichotomously branched. 

 Supposing the ends of the rods to be united one with another by a line, it seems that 

 such a line should then describe a semi-circle. The madreporic canal pierces the body- 

 wall and thus brings the ambulacral system into connection with the surrounding medium ; 

 its pore is situated nearer the tentacles than I have observed in any other form described 

 here. The madreporic canal seems to be destitute of calcareous deposits in its wall, 

 which is most singular, as the reproductive organ, except the narrow efferent duct, is 

 provided with numerous, crowded, rather straight, and slightly spinose spicula. The 

 reproductive organ ought properly to be considered as a single fascicle composed of two 

 bundles ; its long common efferent duct bears several small bundles. This duct has 

 the peculiarity of being divided, a little before reaching the body-wall, into two diverging 

 canals, which open far apart from one another, one on each side of the pore of the madre- 

 poric canal. 



