58 THE VOYAGE OF H.M.S. CHALLENGER. 



genera as Salmacis, Temnopleurus and their allies, especially of such forms as Tngono- 

 cidaris, where the number of anal plates is usually four, and compare it with the growth 

 of the anal system of Salenia. I have, fortunately, a number of very young Salenice 

 dredged in the last " Blake " expedition, and hope in my Eeport on the Echini of the 

 cruise to return to this subject again. 



In none of the specimens of Podocidans sctdpta thus far examined (20 + ) have I found 

 more than four anal plates. 



All the specimens of Parasalenia examined (9 + ) have four anal plates. Among the 

 smaller specimens of CcBlopleurus maillardi collected by the Challenger at Amboyna, of 

 the thirteen specimens examined all had four anal plates. The same was found to be the 

 case in the four large specimens from the Straits of Basilan. 



Of the " Blake " specimens of Coelopleurus floridaniis I have examined four collected 

 at Barbados and fifteen at Montserrat ; they all had only four anal plates. 



Arbacia dufresnii. 



Echinus Dufresnii, BL, 1825, Diet. Sc. Nat. 0. 

 Arbacia Dufres^iii, Gray, 1835, Proc. Zool. Soc. London. 



Nightingale Island ; 100 to 150 fathoms. 



Station 308. January 5, 1876. Lat. 50° 10' S., long. 74° 42' W.; 175 fathoms; mud. 

 Station 304. December 31, 1875. Lat. 46° 53' S., long 75° 11' W.; 45 fathoms; 

 sand. 



Arbacia nigra. 



Echinus niger, Molin, 1782, Chili (nou Rumph). 



Arbacia nigra, A. Agassiz, 186-3, Bull. Miis. Comi^. ZooL, vol. 1. p. 20. 



Gray (1835) did not mention Eckimis nigra in his list of species belonging to 

 Arbacia, though it was evident he intended to do so.^ In making out my chronological 

 lists (Revision of the Echini), though the species Echinus nigra does not appear till 

 1863 under the name of Arbacia 7iigra, it having then been credited to Gray by mistake, 

 it was accidentally omitted from the list of species, appearing under a new name in 

 A. Agassiz, 1863, Bull. Mus. Comp. Zool., consec[uently Gray is quoted under Arbaoia 

 nigra by mistake (Revision of the Echini, p. 401). 



Valparaiso shore. November 1875. 



Arbacia lyustidosa. 



Cidaris pvstulosa, Leske, 1778, Klein Add. 



Arbacia ptishdosa, Gray, 1835, Proc. Zool. Soc. London. 



St Vincent, Cape Verde Islands. 



1 A. Agassiz, 1863, Bull. Mus. Comp. Zool., vol. i. 



