10 A. O. WALKEU. 



AVALDECKIA OBESA. (PI. 2, fig. 4.) 



WaMerkia ol)esa, Ckevreux. Expn. Antarctique Fran9aise (1906), p. 13. 

 Churrntia obesa, Chevreux, Bull. Soc. Zool. de France, Vol. XXX. (1906), p. 163. 



W.Q., 17 May, 1902, two ; 4 Oct., 1902, off Castle Rock (107), 3 ; 27 Aug., 1902, 

 two (one adult male) ; 5 March, 1903 (159), one large, one young ; 10 March, 1903 

 (160), one large. 



Female, length 18 mm. 



Body tumid : First four side plates at least twice as deep as the segments, the 

 fourth wider at the lower margin than deep, and greatly extended behind to the hind 

 margin of the side plate of the third perseopod ; this is large, convex, and subquadrate, 

 widest below, angles rounded. The posterior angle of the first pleon segment is 

 rounded ; that of the second acute ; the third has the hind margin elevated dorsally in 

 a blunt tooth, the posterior angle upturned and sub-acute, the hind margin of the 

 epimere hollowed out just above it, and thence convex. The first segment of the urus 

 is carinate, the hind margin dorsally elevated in a recurved point. 



Head scarcely produced in front, a little longer than the first segment, speckled 

 with red ; ocular lobe produced to an acute point reaching to the end of the first joint 

 of the upper antenme. Eyes large, dark, elongate-reuiform. 



Upper iinteimse a little longer than the head, reaching the middle of the flagellum 

 of the lower ; first joint as long as the flagellum, second very short, third almost 

 covered by the second ; flagellum twelve-jointed, the first joint longer than the next 

 two, setose ; appendage seven-jointed, reaching beyond the middle of the flagellum. 



Lower anteiinse : The first joint the shortest, the second the longest, curved and 

 widening distally, the second and third together subequal to the twelve-jointed 

 flagellum. In the male this reaches to the urus. 



Mandibles : Palp robust ; first joint about half as long as the second, which is 

 rather longer than the third, the anterior margin of which is convex for one-third its 

 length, then straight and fringed with set*. 



First inaxlllse as in So&tnies vahlii (Kroyer), except the inner plate, which has 

 four or five unequal plumose setae. 



Episto-ine with both lobes rounded. 



Miixillipeds with the inner plates squarely truncate, with rather long setse on the 

 ends and inner margins. 



First ynatliopods : Side plates more than twice as deep as wide, oblong, with the 

 front margin obtusely angulated near the insertion of the first joint, angles rounded. 

 First joint wide, and as long as the remainder ; wrist shorter than the hand and wider 

 than its base. The hand is simple (not subchelate), tapering to the base of the strong 

 curved dactylus, and setose on the hind and distal half of the front margins. 



Second i/uiif/iopods : .First joint fully as long as the remaining joints together; 

 wrist longer and rather narrower than the hand, the hind margin of which is a little 

 produced ; dactylus distinct. 



