138 



small, scarcely half as long as the 1st; last ])air well-developed, with both 

 rami foliaceous and setons on both edges, more richly so in the male, onter 

 ramus with a distinct, though rather small terminal joint. Telson of moderate 

 size, scale-like, and cleft nearly to the base. 



Bemarks. — As already observed by Sp. Bate, this genus exhibits an 

 unmistakable resemblance to the preceding genus both as to habits, and in its 

 general appearance, and also a slight similarity to some of the Phox( cephalid.?, 

 especially the genus Paraphoxus. may be found. Boeck was thereby led to 

 refer both these genera to the latter family, though in my opinion their 

 anatomical structure seems to bring them much nearer to the Pontoporeiidse. 

 The genus here spoken of would seem to comprise a rather great number of 

 nearly allied* species. Sp. Bate described, in his well known work, 4 British 

 species as U. Bairdii, marina, hrevicornis and elegans ; but as the distinction of 

 these species, to a great extent, was founded on merely sexual characteristics, 

 their validity has been questioned by most subsequent authors. Quite recently, 

 however, the Rev. Mr. Stebbing has redescribed the 3 latter species in both 

 sexes, and found some minor differences between them, apparently of specific 

 value. The 4th species of Sp. Bate, U. Bairdii, which was regarded by 

 Boeck as a synonym to his U. norvegica, is, according to the Rev. Mr. Stebbing, 

 only a young male of U. marina. Besides these, a well-marked Mediterranean 

 species, U. piiJcJiella Costa, is knfiwn, and the author has added a new species, 

 U. nhhreviata, from the Norwegian North Atlantic Expedition. The species on 

 which Dana founded his genus, U. irrostrata, is still very imperfectly examined, 

 as is also the case with some other species referred Ijy several authors to 

 tlie same genus. Tlie very anomalous form de.scribed by the Rev. Mr. Stebbing 

 from the Challenger Expedition as U. Jachneessa, was sul)se(|nently referred 

 by that author to a particular genus Urolhoides. 



10. Urothoe norvegica, Boeck. 



(PI. 47). 

 Urothoe norvegica, Boeck, Forhamll. ved de Skand. Natnrf. Mode 1800, [>. (i47. 



Body of female extremely tumid and i)ulpy, nearly depressed and 

 scarcely attenuated anteriorly, back broadly vaulted; that of male somewhat 

 less tumid, with the metasome comparatively more powerfully developed. 

 Cephalon exceeding in length the first 3 segments of mesosome combined, 

 rostral ])rojection very slight, lateral corners in female nearly obsolete, in 

 male more distinct and almost right-angled. The 2 anterior pairs of coxal 

 plates rather narrow, setons at the truncated tij); 3rd paii' considerably larger; 

 4th pair the largest, obliquely truncated distally, and exhibiting in the middle 



