10 KEY. T. E. E. STEBBIXG ON THE 



nie a drawing, correspond in general shape and proportions with those of Urothoe hrevi- 

 cornis, Sp. Bate ; but the peduncle of the first pair shows a series of twenty-four spines, 

 and the outer ramus has four spines, the outer ramus of the second pair carrying three 

 spines. Urothoe brevicornis, moreover, is not less, but more, bulky than Urothoe 

 elegans, 



I have been most kindly assisted with specimens for this paper by M. E. Chevreux, 

 D. Robertson, Esq., and the Rev. Canon Norman. Dr. Norman had already taken 

 up the subject himself, but as soon as he heard that my work was further advanced 

 than his own he at once, more siio, placed at my disposal both his preliminary notes 

 and his collection of species from numerous localities. 



Ueothoe ierostratus, Dana. 



1853. Urothoe irrosiratus, Dana, United-States Explor. Exped. vol. xiii. pt. 2, p. 922, pi. 62. 



figs. 6 a-/. 

 1862. „ „ Spence Bate, Brit. Mus. Catal. Ampli. Crust, p. 117, pi. xx. figs. 3, 3 c. 



1876. „ „ Boeck, De Skand. og Arkt. Amph. p. 225. 



This, which has become the type species of this genus, was only partially figured by 

 Dana, under the impression that this and his Urothoe rostrcitus might be male and 

 female of one species. His description of Urothoe irrostratus is : — •' Near the rostratus. 

 Front not rostrate. Flagellum of the superior antennoe six- or seven-jointed, shorter 

 than the base ; appendage very short, two- or three-jointed. Tarsi of feet of fourth and 

 fifth pairs nodulose along inner side, this side somewhat arcuate." Spence Bate inter- 

 prets the tarsi to mean the carpus ; but in the special figures which Dana devotes to the 

 extremities of the fourth and fifth pairs of feet, the carpus is not included, while the 

 finger shows a nodulose convex inner margin in accordance with the description of the 

 so-called tarsi. It is unfortunate that Dana gives neither figure nor description of the 

 sixth and seventh pairs of feet (the fourth and fifth pereeopods). In his notes on the 

 genus he says " the six posterior legs [third, fourth, and fifth pairs of peraeopods] are 

 broad lamellar, especially the first, third, and fourth joints." But just as he evidently 

 inferred without examination that the maxillipeds of Urothoe irrostratus were similar 

 to those of Urothoe rostratus, so he may have inferred without observation that the 

 fourth and fifth peraeopods would be alike in the two species. In the European species 

 the expression " broad lamellar " would not be especially appropriate to the third and 

 fourth joints of the last two pairs of peraeopods. 



Dana figures the lower antennae with a long, slender flagellum carrying calceoli, so 

 that there can be no doubt that his specimen was a male. The three joints of the 

 peduncle of the upper antennre are figured as nearly equal in length. 



The exact relationship of this species to its kindred in Europe cannot well be 

 determined until fresh specimens have been obtained from the Sooloo Sea. Should 

 there prove to be any very striking diversity in regard to the fourth and fifth peraeopods, 



