echhtobeemata. 147 



Holothurians it is especially necessary to remember the words of 

 Fabricius, " Tn spiritu vini mire deformatur, ita ut non pro eadem 

 habeatur '■"*. The remarkable spicules are, however, an exact copy 

 of those figured by Semper ; and there seems to be no good reason for 

 erecting on it a new species. 

 Port Jackson, 0-5 fms. 



3. Cucumaria semperi. (Plate IX. fig. A.) 



Body elongated, 5-Bided ; suckers regularly arranged in two rows, 

 except at the two ends of the body ; the suckers darker than the 

 other parts, being almost black ; the rest of the body of a mulatto 

 tint (in spirit), or slate-grey, or whitish. Body widest in the middle. 

 Length 36, 25 millim. ; greatest breadth 10, 8-5 mUlim. 



Retractors inserted at a little more than one third of the whole 

 length from the anterior end ; Polian vesicle large ; calcareous ring 

 long, and composed of a number of pieces, as in C. conjungens or 

 G. citrea. Genital tubes delicate, about 6 millim. long, attached to 

 the mesentery at about the middle of the body. 



The supporting-rods in the suckers are not unlike folding eye- 

 glasses in form, and are somewhat similar to those of Ocnus pygmceus; 

 the plates in the integument are spherical, the framework very deli- 

 cate and consisting, as seen in a surface view, of a central bar con- 

 nected at either end with the peripheral encircling piece by two 

 bars making an acute angle with one another. They are present 

 in great numbers. 



Port Denison ; Torres Straits. 



4. Ocnus, sp. 



A single specimen of what is apparently an undescribed species 

 is in the collection ; but its form is so characteristic that I have not 

 thoiight it right to injure it in any way. It is distinguished exter- 

 nally by the soft interspaces in the integument, the greyish-white 

 colour, and the elongated narrow form of the body. 



Port Darwin, 12 fms. 



5. Colochirns tabercnlosns. (Plate IX. fig. B.) 

 Colochirus anceps, Semper, Hoi pp. 67, 239, ibiqiee citata. 



There is a very large series of this species, and the specimens 

 dififer very considerably among themselves, not only in appearance 

 but in the extent to which the colouring-matter has been dissolved 

 out ; only one retains any indication of the red pigment. The 

 variations exhibited by the specimens as they have come to the 

 Museum (some being quite white, others slate-grey, and others 



* Fauna Groenl. p. 354. 



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