GENEEA UEOTHOB AND UEOTHOIDES. 2l 



nine on the outer margin, two at the apex, and fourteen on the inner margin. In 

 another specimen, also a male, and from the same locality, there were only fifteen seta; 

 on the outer and seven on the inner margin of the outer ramus, while in this specimen 

 the second joint was more elongate than in the other. Very little constancy is to be 

 expected in the number of these ornaments, which undoubtedly varies with the age of 

 the animal, as well as probably between individuals of the same age. 



Telson. Cleft nearly to the base on the upper side and quite to the base on the under 

 side, the cleft gaping a little distally, the convex outer margins having each two cilia 

 near the centre, and a spinule not far from the apex, the distal margin of each half 

 oblique, carrying a feathered cilium, a short stout spine, and three sets. 



Length of a good-sized specimen one third of an inch. 



Localities. The specimen figured was taken at a low tide in February 1889, at 

 Cumbrae, in the Clyde, by Mr. David Robertson. Other specimens examined and 

 considered to belong to this species were obtained by M. E. Chevreux, of le Croisic, 

 Loire-Inferieure, off the French coast, and in Balta Sound, Shetland, by Canon Norman. 

 M. Chevreux in recording Urotlwe mariims from " les environs de Cherchell," says, " le 

 genre Urothoe n'etait pas represente jusqu'ici en Mediterranee," but this is overlooking 

 Urothoe pulchella (Costa). 



Ueothoe norvegica, Boeck. (Plate lY. B.) 



1860. Urothoe norvegica, Boeck, Forhandl. ved de Skand. Naturf. 8de Mode, p. 647. 



1870. ,, „ Boeck, Crust. Amph. bor. et arct. p. 58. 



1876. „ „ Boeck, Do Skand. og Arkt. Ampli. p. 226, pi. vi. fig. 9, pi. vii. fig. 4. 



1882. „ „ Sars, Oversigt af Norges Crustaceer, p. 22. 



1887. „ „ Chevreux, Crust. Amph. dragues par VHirondelle, Bull. Soc. Zool. de 

 France, extr. pp. 13, 15. 



1887. J, „ Chevreux, Crust. Amph. Bretagne, Bull. Soc. Zool. dt France, t. vii. 



extr. p. 10. 



1888. „ „ Robertson, Catal. Amph. and Isop. of Clyde, p. 29. 



Postero-lateral angles of the first three pleon-segments acute, those of the first two 

 only minutely produced. 



Upjier aiitenncB. The first joint of the peduncle stout, the third joint decidedly 

 shorter than the first or second ; the flagellum of five joints, together httle longer than 

 the first or second joint of the peduncle ; the secondary flagellum three-jointed, about 

 half the length of the principal. 



Lower antennm. Fourth joint of the peduncle longer and much stouter than the fifth, 

 carrying a single row of about sixteen unequal stout spines near the convex margin, and 

 a row of setse apparently unmixed with stout spines; the fifth joint cariying five stout 

 spines and some setse ; the flagellum consisting of eighteen naked joints, the structure 

 being indicative of a male not fully adult. 



