152 Mr. A. Alcock on 



Family Pediculati. 



Malthopsis, Alcock. 



Malthopsis lutea, Alcock. 



Matthopsis lutea, Alcock, Ann. & Ma?. Nat. Hist., July 1891, p. 26, 

 pi. viii. fig3. 2,2 a; and Journ. As. Soc. Bengal, pt. 2, 1896, p. 319. 



In the description of this species it is stated that the curious 

 striated tubercles that take the place of scales are small, 

 distant, and sunken on the ventral surface of the body. As 

 a matter of fact, in several individuals lately dredged in the 

 Andaman Sea at 185 and 405 fath., these plates in the middle 

 line of the thorax and belly are particularly large and are in 

 close contact. 



Family Cataphracti. 

 Peristethus, Kaup. 



Peristethus investigator is, sp. n. 



Peristethus Murray i, Alcock (nee Giintber), Ann. & Mag. Nat. Hist., 

 July 1891, p. 28. 



D. IjtO. A. 21. L. lat. (from occiput) 35-36. L. tr. 4. 



Head, measured from tip of preorbital process to hinder 

 angle of operculum, 2| in the total, greatest body-height a 

 little less than 6^ in the total, without the caudal; greatest 

 breadth of head equal to the length of the combined snout 

 (including jirocesses) and eye. 



Preopercular processes short, broadly triangular, their length 

 is not quite a third the distance between their tip and the eye. 

 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 

 otily there are three small inconspicuous tubercles, disposed in 

 a triangle, on the forehead. 



Interorbital space concave, less than the major diameter of 

 the eye, which is not quite half the length of the snout (pro- 

 cesses included). 



The large labial tentacles, when laid back, reach beyond 

 the base of the preopercular spine. 



All the shields of the body carry a stout recurved spine — 

 eight rows in all. 



The anterior ventral plates are irregular in shape, their 



