320 DISCOVERY REPORTS 



outer side of this prominence is the long narrow eye, which is devoid of pigment. 

 Vanhoffen (p. 518) does not mention the eyes in his description; but he illustrates them 

 (fig. 51 a), using cross-hatching which, however, may be intended to represent optical 

 units and not pigment. 



Either the absence or the reduction in the amount of pigment, or the absence or the 

 reduction in the size of the eyes, seems to be a characteristic of the deep-sea forms, for 

 the colour of the eyes of S. bromleyana, Suhm, is whitish yellow, and that of S. neaera, 

 Beddard, is bluish black owing to the comparatively small amount of pigment, whilst in 

 S. gracilis, Beddard, the eyes are small and inconspicuous and in S. antarctica, Beddard, 

 they are absent. 



On the inner side of each eye prominence is a small backwardly projecting spine ; the 

 rest of the area between the eyes is raised and divided posteriorly into a median and two 

 lateral parts, the latter of which have their posterior margins toothed ; the posterior 

 margin of the median part is straight. The lateral portion of the cephalosome, on either 

 side, is divided by a transverse groove which extends from the posterior angle of the eye 

 to the lateral margin. 



The coxal plates are curved and sickle-shaped; the articular processes which unite 

 together the succeeding plates are placed at some distance from the junction between 

 the terga and the plates ; those of the first three free somites are separated from them by 

 sutures. The coxal plates of the seventh thoracic somite extend backwards to about the 

 base of the spine of the terminal segment. The pleural plates of the second and third 

 abdominal segments are of approximately equal length and do not reach quite as far as 

 the base of the uropoda. 



The terminal segment is considerably longer than broad ; it is broadest at the level of 

 the bases of the uropoda, from which point it gradually narrows to form a long spiniform 

 process, the lateral margins of which are deeply serrated. A longitudinal median toothed 

 keel runs from near the anterior margin to the end of the terminal process, and between 

 the anterior end of the keel and the anterior margin are two small, backwardly directed, 

 rounded spines, situated one on either side of the median line. Between these spines and 

 the median keel, on either side, is an oblique transverse ridge which extends to the base 

 of the uropod and terminates in a small spine. The uropoda are comparatively small. 

 Unfortunately in the type specimen one is missing and the other incomplete ; the proto- 

 podite is only slightly produced on its inner side. 



Remarks. Vanhoffen gives no description of the mouth-parts and appendages of this 

 species. I append a few notes, which are necessarily brief as my observations have had 

 to be restricted to those made on the entire specimen. 



The antennule is not much shorter than the antenna. The first joint of the peduncle 

 is almost triangular in shape ; the second is 7 mm. long ; the third is shorter than the 

 second, measuring 5-5 mm., and the fourth is 3-5 mm. in length. Dorsal grooves are 

 present on the second and third joints. The flagellum measures 18 mm. in length and 

 consists of thirty-three joints. 



The antenna consists of a peduncle of five joints, the first two of which are short; 



