4i8 STALK-EYED CRUSTACEA 



II. Abdonioi folded on itself: — 



6. Ptychogaster, 



Ptycliogaster ... A. Milne Edwards, FIcnderson, 



Bouvier. 

 Cliirostyhis .... Ortmann. 

 Gastroptychus . . . Caullery. 



Rostrum slender and spiniform, usually upturned. 

 Carapace narrow and somewhat ovate in shape, with its 

 surface glabrous and usually spinose. First pair of legs 

 and walking legs slender and greatly elongated ; the basal 

 joints of the latter not hid by the sides of the carapace. 

 Eye-stalks with the cornea dilated. Antennal peduncle 

 slender without basal scale ; the flagellum short. Ex- 

 ternal maxillipedes narrow ; the terminal joints elongated. 

 Abdomen folded on itself; the telson (which is transversely 

 segmented) and the last pair of appendages bent under the 

 preceding segments, and applied to the thoracic sterna ; 

 males with the first two pairs of appendages (genital) well 

 developed, those of the third, fourth, and fifth segments 

 rudimentary. Eggs few in number and of large size. 



Range. — Deep sea, 



I. Ptychogaster spinifer. 



Ptycliogaster sphnfer . A, Milne Edwards, A. Milne 



Edwards and Bouvier, 



The carapace is long, curved transversely, flat from 

 before backwards, contracted in front and covered with 

 small spines. There is a row of larger spines in the 

 middle line ; there are four gastric and four cardiac 

 spines. On each side on the branchial region on the 

 sutures there is a range of spines. The rostrum is in 



