G Messrs. E. W. L. Holt and W. M. Tattersall on 



Fam. Petalophtlialmidae *. 



Genus IIansknomysis^ Stebbing (1893). 

 Synou. Arctovu/sis, Hansen (1887), yiec Czeniinvsky (1888). 



The type of the fjcnns and of //. fyl/ce, the type species, 

 was a solitary specimen without eyes, and Hansen was 

 unable to decide whether these organs were naturally absent 

 or had been torn out. In the specimens referred below to 

 Hansenomysis the eye-apparatus is perfect and does not 

 look as if it could be very easily detached. Pending the 

 capture of further specimens of H.fylla the generic import- 

 ance of the eyes remains doubtful. 



Hansenomysis antarctica, sp. n. 



Form slender, tapering considerably towards the posterior 

 end. Caraj ace submembrauaeeous, very short, leaving the 

 last two thoracic segments quite exposed and free ; produced 

 in front into a broadly rounded but rather strongly upturned 

 rostrum, antero-lateral corners broadly rounded and produced 

 almost as much as the rostrum ; a small median tooth is 

 present just behind the rostrum and a larger lateral tooth on 

 each side some little way behind the median tooth ; cervical 

 sulcus well marked. Segments of the jAeon cylindrical ; 

 postcro-inferior corners not at all produced ; first segment 

 arcuate in dorsal contour, its anterior margin raised slightly 

 above the level of that of the last thoracic segment, its 

 posterior margin broadly produced so as to partly cover the 

 second segment ; sixth segment not quite twice as long as 

 the fifth. Eyes united together, forming a flattened pad, 

 the anterior end of which is produced in front of the carapace 

 into two short, thin, subtriangular, slightly diverging lappets 

 not extending to the middle of the basal joint of the anten- 

 nulur peduncle. Antennular iieduncle short, extending rather 

 more than halfway along the autennal scale, the three joints 

 subequal in length and rather broad ; second and third joints 

 with their inner margins densely armed Avith setse ; basal 

 joint with a single seta on its inner distal corner, and a more 

 or less continuous submarginal row of setse across the dorsal 

 region ; below and slightly external to the eye-lappets is a 

 slight semicircular ridge, marked by pigment, apparently 



• "We have defined this family in 'Fisheiies, Ireland, Sci. Invest.,' 

 1904, v., now in the press. It comprises the genera Petalophthalmus, 

 Hansenomysis, Scolophthalmt'.s, and Ceratonijjsis. 



