138 



COPEPODA 



thoracic tergites are completely fused. The right lateral corner of the thorax (PI. V fig. i a) is fairly 

 regularly rounded and somewhat shorter than the left one, which is triangularly produced and some- 

 times shows trace of bifurcation (fig. i b). 



The abdomen is about one fourth of the anterior division; the genital somite is a little deeper 

 than wide and long; on the right side it has a strong, fairly long spine, directed upwards and back- 

 wards (fig. I a; te.xt-fig. 37 b); in the middle it is strongly produced, and has on the right side of the 

 vulva a strong spine directed backwards. Along the hinder margin of the third somite ventrally short 

 triangular teeth are found; they seem to be wanting in the other somites. The caudal rami are distinctly 

 wider than long; the terminal setae are at least as long as the abdomen, and the Si is one third as 

 long as St. 2. 



The antennulae extend almost to the end of the fourth abdominal somite. The Re of the 

 antennae is 17 as long as the Ri. The iiiaxillulae have in Le the S i — 3 of moderate length, the S 4 

 somewhat longer and the S 5 — 9 much longer, but of almost equal length; the Re has, as in the two 

 preceding species, the median setae distinctly shorter than the others, but not in so marked a degree. 

 The maxillipcds, in which the comparative length between Basp. i cv; 2, Basp. 3 and Ri is as 30 — 52 — 13, 

 have the setae of Ri even better developed than in the preceding species, so far resembling the 

 corresponding limbs of Euchcete. The mandibulac and maxillae are scarcely different from those of 

 U. major. 



The first pair of legs has the articulation between Re 1 and II almost obsolete; the Se Re II 

 extends distinctly beyond the middle of Re III, but scarcely to the end of it. The secotid pair of legs 

 has a fairly well developed accessory tooth in Se Ri I (text-fig. 37 c), and the St. has 45 — 50 serrations. 

 The Se of Ri I in the fourth pair of legs has a distinct pointed accessory tooth, even better developed 

 than the more rounded one in pes III; the inner margin of Basp. II is somewhat undulated, and 

 has on the posterior surface, in a similar position as in the preceding species, five short spines (text- 

 fig. 37 d). The glandular pores are as in the other species. 



The anterior coecal sac seems to be wanting. The lateral outline of the labrum is not quite 

 like that of the two preceding species; the anterior elevation, which on each side possesses about 

 two groups of long .slender hairs, forms an obtuse angle with the labrum proper; this is on each side 

 in front beset with a small number (about 50) of short hairs. 



The oral surface of the labrtim is like that of U. major (fig. 2 b PI. V), but shows similarity to 

 that of Ch. Streetsii by a larger number of setae; the lateral group of setae, f. inst, consists of 30—40 

 short spines, and the first group of the longitudinal series has two instead of a single row. The la- 

 mina labialis and the area in front of it are scarcely different from those of the preceding species. The 

 series of hairs behind and upon the labial lobes is rather characteristic as shown in fig. i c (PI. V). The 

 series I consists of a single oblique row laterally placed; the series II is represented by a large median 

 and posterior group of short hairs; the series III seems to be represented by a fairly big group in the 

 middle, almost fused with the corresponding portion of the opposite side, by a more lateral group partly 

 fused with the fourth group and by two oblique rows on the labial lobe; the series IV consists of a 

 median group fused with the third and fifth series, and of a rather short row on the labial lobe; the 

 fifth series consists of a median group and a lateral row. 



