REPORT ON THE ECHINOIDEA. 113 



true position. It has not, like the recent species of the old genus Psaimnechinus, the 

 actinostome covered with plates ; there are but ten large plates round the actinal opening ; 

 the madreporic body is slightly developed. 



The spines are white and of a yellowish-orange at the base, short, slightly flattened, 

 and deeply grooved (PL VI. " fig. 17). The primary tubercles are of the same size in both 

 areas, forming a very marked vertical row in the ambulacral area ; the secondaries are 

 larger in the interamlsulacral spaces, they form indistinct horizontal rows near the 

 ambitus (PI. VI.* fig. 15). The genital plates are thickly covered by secondaries ; the 

 anal system is covered by comparatively few plates (PI. VI.* fig. 16). The genital open- 

 ings are small and sharply cut. This is evidently a young specimen. The colour in 

 alcohol is yellowish-orange with whitish primary spines. 



Station 173. July 24, 1874. Lat. 19° 10' S.,long. 179° 40' E.; 315 to 310 fathoms ; 

 coral. 



Salmacis. 



Salmacis, Agassiz, 1841, Val., Anat. Genre Echiaus. 



Salmacis hicolor. 



Salmacis hicolor, Agassiz, 1841, VaL, Anat. Gen. Ecli. 

 Samboangan; 10 fathoms. 



Salmacis dussumieri. 



Salmacis Ditssumieri, Agassiz, 1846, C. R. Ann. Sc. Xat., vol. vi. 

 Station 212. January 30, 1875. Lat. 6° 55' N., long. 122° 15' E. ; 10, 14, and 

 20 fathoms ; sand. 



Amboyna; 100 fathoms. 



Salmacis glohator. 



Salmacis glohator, Agassiz, 1846, C. R. Ann. Sc. Nat., vol. vi. 

 Station 186. September 8, 1874. Lat. 10° 30' S., long. 142° 18' E. ; 8 fathoms; 

 coral sand. 



Salmacis rarispina. 



Salmacis rarispinus, Agassiz, 1846, C. R. Ann. Sc. Nat., vol. vi. 

 Station 186. September 8, 1874. Lat. 10° 30' S., long. 142° 18' E. ; 8 fathoms; 

 coral sand. 



Station 188. September 10, 1874. Lat. 9° 59' S., long. 139° 42' E. ; 28 fathoms; 



mud. 



Station 203. October 31, 1874. Lat. 11° 7' N., long. 123° 7' E. ; 12 to 20 fathoms ; 



mud. 



(ZOOL. CHALL. EXP. — PART IX. — 1881.) I 15 



