I 29 

 •j. Lucicutia pera nov. sp. Plate XL, figs. i — 9. 



Female — length 4 mm. 



Seen from above, the body appears elongate and narrowly ovate. The cephalic segment 

 is moderately wide. It is very flatly rounded in front, and is without lateral processes. The 

 posterio-lateral angles of the last thoracic segment are very narrowly rounded. Viewed from the 

 side, the distal end of the last thoracic segment is rather broadly rounded, then emarginate as 

 it joins the dorsal line (Plate XL, fig. 3). The rostral filaments are long and slender. 



The abdomen is composed of four segments. The combined length of the abdomen and 

 furca is equal to two-thirds of the total length of the cephalothorax, from the frontal margin 

 to the end of the last thoracic segment. The genital segment is as long as the combined length 

 of the second and third segments. It is quite asymmetrical when viewed from above. The distal 

 portion of the right side is considerably wider than the base of the second abdominal segment. 

 It has therefore a well defined projection (Plate XL. fig. 1). Seen from the side, the dorsal 

 surface of the segment is greatly inflated at its posterior end, and forms a well marked protuberance. 

 The ventral surface is much swollen near the middle (Plate XL, fig. 3). The ventral swelling 

 may be due to the presence of a spermatophore, however, as shewn in the illustration. The 

 second and fourth segments are of nearly equal length. The third segment is shorter than the 

 second and fourth segments. The furcal joints are nearly five times longer than broad. Each 

 furcal joint is distinctly shorter than the combined length of the third and fourth abdominal 

 segments. The furcal joints are furnished with two outer edge setae. 



The antennules are composed of twenty-five joints and extend to about the middle of the 

 furca. The last joint is equal to one-half of the length of the second last joint. 



The antennae, mandibles, maxillae and maxillipedes are similar to those of Lucicutia philyra. 



The exopodites and endopodites of the five pairs of feet are three-jointed. The inner 

 distal spine on the second joint of the exopodite of the fifth pair is very stout. lts length is 

 contained one and two-third times in the length of the third joint. The terminal spine on the 

 third joint of the exopodite of the fifth pair is very short. lts length is contained fully three 

 times in the length of the joint (Plate XL, fig. 9). 



Male unknown. 



This species comes very near Lucicutia lucida Farran (1908), but differs from it in the 

 asymmetrical genital segment when seen from above. The terminal spine on the exopodite of 

 the fifth pair of feet is shorter than in Farran's species. 



Occurrence. — One specimen was obtained from the plankton collected with the 

 Hensen vertical net at each of the following stations. 



Stat. 128 (700 metres to surface). — Stat. 276 (750 metres to surface). 



The genital segment was identical in each specimen. 



129 



SIBOC.A-EXI'EDITIE XXIX cl. 



17 



