EUSIRIDAE 



i93 



Description. Close to crassi, Stebb. All side-plates considerably shallower than their 

 segments; 1-4 longer than deep; 1 subquadrangular, not projecting below inferior 

 margin of head, scarcely produced forwards, but antero-inferior angle quadrate. All 

 peraeon segments rounded dorsally. Postero-inferior angle of pleon segment 3 quadrate, 

 margin entire. Telson cleft for a little more than half its length, apices acute. 



Antenna 1, accessory flagellum obsolete. Lower margin of flagellum of antenna 1, 

 and upper margin of flagellum and 5th peduncular joint of antenna 2 calceoliferous. 

 Mandible with 2nd palpal joint very broad. 



Fig. 117. Eusiroides stenopkura, n.sp. a. Head, peraeon segments 1 and 2, with side-plates; the dotted line 

 indicates the extent of the reddish pigment, b. Side-plate 4. c. Mandible, d. Maxilla 1, with spine from outer 

 lobe further enlarged, e. 2nd joint of peraeopod 5 with hind margin further enlarged. /. Telson. 



Gnathopods 1 and 2, palm of hand evenly convex as in crassi, defined by one spine 

 proximally. Peraeopods 3-5, 2nd joint with hind margin entire, or, in peraeopod 5, 

 very feebly indented. 



Otherwise resembling crassi. 



Remarks. These specimens certainly represent a distinct species; the shallow side- 

 plates separate it from all the others. 



The faceted eyes are reniform and, as preserved, reddish ; but lying within the cuticle 

 and occupying nearly the whole of the side of the head is a round patch of reddish pig- 

 ment, dorsally almost contiguous with its fellow. Compare Strauss' figures of the form 

 he calls Rhachotropis diploops, n.sp., captured by the ' Valdivia' at St. 54 in the Atlantic 

 (i° 51' N, o° 31' E). Strauss (1909, p. 38, pi. iv, figs. 24, 25) gives no description, except 

 of the eye, by which the species can be identified and Schellenberg (1926 b) makes no 

 mention of it. Strauss' fig. 24 would fit the present specimens as regards the rostrum 

 (for this reason his specimen was certainly not a Rhachotropis), the mandibular palp, and 

 the antennae, but not the 1st side-plate. The anterior margin of the latter is just indicated 

 by Strauss and shows a rounded antero-inferior angle projecting considerably below the 



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