SCHIZOPODA. 23 



thoracic limbs. Whereas, however, in Scolophthahnus the rostrum is prominent and 

 the eyes are modified into sharp spiniform organs, Hansenomysis has the rostrum 

 obsolete and the eyes more or less leaflike. 



Males of this genus have not yet been noted, but specimens of that sex of the 

 northern species, H. fyllse (Hansen, 1887), have come into my hands. Detailed 

 examination and description are reserved for a future occasion, but it may be 

 mentioned here that, besides having the pleopods biramous, males also have the basal 

 portion of the inner flagellum of the antennule considerably thickened and adorned 

 with rings of setfe. 



Hansenomysis Antarctica. 

 (PI. v.. Figs. 1-19.) 

 Hansenomysis antarctka, Holt and Tattersall, 190() (1). 



Locality of capture. — Off Coulman Island, 100 fathoms, two specimens, females, 

 20 mm. 



Form (Fig. l) compact, rather slender, tapering considerably towards the 

 posterior end. 



Carapace (Figs. 1 and 3) short, sub-membranous, leaving the last two thoracic 

 segments completely exposed, and part of a third visible behind its posterior 

 emargination ; anterior border produced, but very slightly, into a broadly and evenly- 

 rounded but somewhat strongly upturned rostrum ; antero-lateral angles evenly 

 rounded and extending forwards as much as the rostrum ; cervical sulcus well marked 

 and rather deep, the posterior margin bounded by a conspicuous and rather sharp ridge 

 formed by the carapace. Behind the cervical sulcus is a shield-shaped dorsal area, 

 indicating the attachment of the carapace to the thorax, behind, and on either side of 

 which the wings of the carapace are free. A slight ridge runs from the antcro-Iateral 

 angles, first downwards and then posteriorly, to meet the cervical sulcus, while a 

 shallow groove runs forwai'd on each side from the dorsal shield-shaped area, thus 

 marking off" a hepatic area, on which is a prominent f or war dly -directed spine with a 

 broad base. A shallow depression follows the base of the rostrum, and merges on 

 either side into the groove formed by the ridge from the antero-lateral angles. A 

 small blunt and rounded spine is present on the gastric area. 



Pleon (Fig. l) 9 mm. in length, a little longer than the thorax, which measures 8 mm. 

 from the eyes to the posterior margin of the last free segment ; segments cylindrical, 

 postero-lateral inferior margins not at all produced as epimera ; first segment arcuate 

 in dorsal contour, its anterior margin slightly raised above the level of that of the last 

 thoracic segment, its posterior margin broadly produced, so as to partly cover the 

 second segment, the whole forming a sort of " cap " over the junction of the thorax and 

 pleon ; second to fifth segments sub-equal in length and succeedingly narrower ; sixth 

 segment narrower than any of the preceding ones, and nearly twice as long. 



a 2 



