59 



Museum, and I find that all of them must be referred to 

 U. nitidus var. concolor. 



The Helga has taken this species on two occasions. 

 Helga. 



S. R. 223.— 12 V '05. 53° 7' N., 14° 50' W., 410-500 fms., 

 coral. Trawl. — One, 17 mm. 

 S. R. 327.-8 V '06. 51° 43' 30"-51° 38' N., 12° 15'- 

 12° 18' W., 550-800 fms., ooze. Trawl.— Three. 



Vertical Distribution. — The species appears to occur most 

 frequently in depths of 300-700 fathoms, but it has been taken 

 in 160 fathoms on the one hand and 766 fathoms on the other. 



Uroptychus nitidus, var. concolor (Milne-Edwards). 

 PL VIII, figs. 5-10, PI. IX, fig. 1. 



Diptychus nitidus, var. concolor. Milne-Edwards and Bouvier, 

 1894 (b). 



Uroptychus nitidus, var. concolor, CauUery, 1896. 



Diptychus nitidus, var. concolor, Milne -EdAvards and Bouvier, 

 1899. 



Diptychus nitidus, var. concolor, Milne-Edwards and Bouvier, 

 1900. 



In general appearance this species resembles U . rubrovittatus , 

 but is distinguishable by well-marked characteristics. 



The surface of the carapace and abdomen is quite smooth 

 and glistening; it is sparsely punctate, but this can be seen only 

 when the specimens are dry. The carapace is narrower than 

 in the last species, and is devoid of hairs. The cervical groove 

 is barely distinguishable. The lateral margins are slightly 

 granular, with here and there a denticule. The antero-lateral 

 spine curves slightly more inwards than in U. rubrovittatus. 

 The tooth above the base of the antenna is blunt. The rostrum 

 is narrower and rather longer than in U. rubrovittatus, and its 

 margins are quite entire ; it is quite free from setae. The basal 

 part of the rostrum curves downwards, and the tip is elevated, 

 so that when seen in profile it has quite a different appearance 

 from that of the last species (PI. VIII., figs. 2, 5.). 



The abdomen resembles that of U. rubrovittatus, but is free 

 from setae. 



The eyes are large and oVal ; they reach beyond the middle 

 of the rostrum, and almost to the end of the antennal peduncle. 

 The stalks are slightly swollen just below the cornea, which is 

 of an orange yellow colour (in spirit). 



The antennules much resemble those of U. rubrovittatus. The 

 curved process springing from the basal peduncular joint bears 

 two large sharp teeth. The upper flagellum has fourteen joints, 

 and the lower only four. 



