70 



are nearly twice as long as broad and nearly twice as long as the posterior 

 ventral plates. 



Colours in spirit: flesh-colour, rather dusky dorsally ; distal half of pec- 

 torals and edges of vertical fins blackish. 



Length nearly six inches. 



Andaman Sea, 185 fathoms, 



Keffd. JNos. -;-, -r-. 



51. JPeristethium investigatoi'is, Alcock. 



Peristethvs invcHigntoris, Alcock, Ann. Mag. Nat. Hist., August 1898, p. 152: Illustrations of the Zoologt 



OF TSE iNVKSTIGATOB, FiSHES, PL. XXV. FIGS. 1. I'l. 



B. 7. D. VII. 20. A. 21. L. lat. 35-36. 



The length of the broad triangular preorbital processes is equal to consider- 

 ably less than half the distance between their base and the anterior border of the 

 orbit. 



Preopercular ridge trenchant, ending in a sharp spine, which is about two- 

 thirds as long as the eye. 



A spine at the posterior angle of the orbit, one on either side of the occiput, 

 one on either post-temporal region, one at the upper angle of the operculum ; 

 in young specimens onli/ there are three small inconspicuous tubercles, disposed 

 in a triangle, on the forehead. 



Interorbital space concave, less than the major diameter of the eye. 



The large labial tentacles, when laid back, reach far behind the posterior 

 border of the orbit. 



All the shields of the body carry a stout recurved spine — eight rows in all. 



The anterior ventral plates are irregular in shape, their greatest length, 

 measured diagonally, is nearly twice their breadth, and is half again as much as 

 the greatest length of the posterior ventral plates. 



Colours in life : adults red, young dusky violet ; pectorals, first dorsal, and 

 distal half of labial tentacles black, second dorsal with a black edge. 



The largest specimen is a little over 6 inches long. 



Andaman Sea, 188 to 220 and 405 fathoms : off Travancore coast, 224 to 

 284 fathoms. 



u J AT -i.-ynnn lorvoo 121 140 529 530 



Regd. Nos. 13037, 13038, —, — , — , — , 



This species appears to be near P. platycephalum Goode and Bean, from 

 Barbados. 



