. A^D ON THE NORTH EAST- GOAST OF ENGLAND. ■ - 63 



In most respects like j/jT. r/r<?/z/"^r, but smaller and much 

 more slender in all its parts. 



Female. — ^The antennules (fig. 6) are extremely slender and 



very sparingly setiferous, nine-jointed, the relative lengths of 



the joints being as follows : — 



I- 2- 3- 4- 5- 6. 7. 8. 9. 

 9 9 lo 7 3 3 2 I- I 



The hand of the posterior footjaw (fig. 7) is very slender, its 

 width at base being equal to about one-third of the length, 

 whereas in ^. chelifer the. width is one-half of the length; the 

 terminal unguis is also longer and more slender than that of 

 H. chelifer. The first four pairs of feet of the two species are 

 alike, except that those of H. gracilis are more slender, and 

 have a much more delicate setose and spinous armature (fig. 

 8). The fifth pair has the terminal joint narrower and more 

 elongated (fig. 12). The ovisacs are remarkably small, con- 

 taining usually only three or four large eggs. 



Male. — The male is smaller and less robust than that of 

 H. chelifer, but is not otherwise distinguishable. The spinous 

 prolongation of the inner branch of the second foot (fig. 10) 

 is, however, longer than in H. chelifer. 



The only examples of this species which have come 

 under my notice are contained in a tow-net gathering 

 made in Roundstone Bay in 187 1 by myself and my late 

 friend Dr. David Robertson. These had been overlooked — 

 probably confused with H. chelifer — until a recent over- 

 haul of the collection brought them to light. They agree 

 completely with the description and single figure of H. 

 gracilis given by Dr. Claus, who, however, does not describe 

 the male; and so far as I am aware the species has not been 

 observed by any other author, unless doubtfully by Kritchagin 

 \loc. cit.) in the Black Sea. The figures given by that author 

 are, however, scarcely recognizable, and his memoir being 

 written in Russian, I am unable from the description to form 

 any opinion on the matter. 



