Boone, Critstacea, Cruise of "Alva" 1931 223 



174, 254, 262, surface (Chevreux) ; off Canary Islands, 250 

 fathoms (Boone). 



Material examined : Two specimens, taken in 250 fathoms, 

 off Fuerte Ventura, Canary Islands, Atlantic Ocean. Port Cabras, 

 bearing 270 true 7 miles distant, by the yacht "Alva." 



Technical description : The larger of the two "Alva" speci- 

 mens is 25 millimeters long diameter, in the curved position char- 

 acteristic of this genus. The head is typically large, covered on 

 either side by the large eyes, which are separated dorsally by a 

 narrow median strip ; anteriorly the head is produced to a promi- 

 nent median frontal "angle" or node, as in Dr. Stebbing's male 

 specimen. 



The upper antennae have the distal peduncular joint reduced, 

 the flagellum with the proximal portion very long; the brush on 

 the convex side faintly developed, the opposite margin with many 

 longer setae; the second article small, but distinctly articulated; 

 the third article is minute, conic, tapered. 



The inferior antennae have the basal article, with the gland 

 cone incompletely coalesced with the wall of the head ; the third 

 peduncular joint is long, slender, curved, distally dilated; the 

 fourth joint is similar, slightly longer ; the fifth joint is narrower, 

 about as long as the third article ; the flagellum has the first article 

 shorter than the fifth, slenderer, reflexed upon itself; the distal 

 article about two-fifths of the length of the preceding joint, curved, 

 tapered distally. 



The mandibles, first maxillae and maxillipeds are identical 

 with those described and figured by Dr. Stebbing. 



The first gnathopoda have the sideplates as figured (pi. 66) , 

 decidedly produced forv/ard, with the upper front margin folded 

 and the front apex rounded; the first joint is sinuous, deeply 

 channelled anteriorly in both the proximal and distal ends and 

 posteriorly forming a small "elbow" just below the sideplate; 

 the wrist is large with the front apex much produced and finely 

 serrate, with the chela-forming portion armed with seven primary 

 teeth on the front margin and armed with eight primary teeth on 

 the hinder margin, in addition to the apex and several secondary 

 denticles ; the distal half of the hind margin of the hand has eight 

 teeth; the finger is about two-fifths of the length of the hand, 

 slender, acuminate. 



