6 REV. T. E. R. STEBBING ON THE 



slip of the pen is called t\\e first, is in reality the fourth joint of the peduncle, and it is 

 surmounted by two, not three, rows of spines, although sometimes the spines of one 

 row by lying over in opposite directions give the appearance of a double row. The 

 flagellum consists of two joints, a long and a short one. The first pair of gnathopods 

 are said to be much smaller than the second; but, while this would be unusual in the 

 genus, there is a fairly certain proof that the gnathopods have been interchanged in 

 the description, since the larger gnathopods are figured as having on the distal margin 

 of the wrist the little row of spines which is distinctive of the first pair. It is true that 

 both in the Museum Catalogue and in the ' British Sessile-eyed Crustacea ' these 

 gnathopods are figured with the branchial vesicle attached, which of course cannot 

 belong to the first pair, and no doubt it was this apparent attachment of the breathing- 

 organ which led to the confusion. The segments carrying the two pairs of gnathopods 

 are in this genus so closely tied together, that the accident might easily arise of the 

 second gnathopod being detached, while leaving its branchial vesicle in apparent 

 connection with the first gnathopod. Of the crooked finger ascribed to the fifth 

 perseopods I can give no account, except that it appears to be abnormal or accidental. 

 The character most easy to seize for this species is to be found in the uropods, of which 

 the first pair have a short peduncle and short unequal rami, the inner ramus being the 

 shorter and much curved. In Spence Bate's figure the tips of these rami do not reach 

 to the end of the short peduncle of the second pair, but in their natural position they 

 reach much further than this, since the fourth pleon-segment much overlaps the fifth 

 at the sides. The telson is accurately defined as " subapically furnished with a short 

 spine and several fine hairs," but in no specimen that 1 have seen is it cleft quite to the 

 base as in the figure. The length of the animal is said in the Museum Catalogue to 

 be " -^ths of an inch ;" but in the ' British Sessile-eyed Crustacea ' we read " length 

 ^-Q-ths of an inch," without any explanation of the change. In the latter work a line 

 presumably indicating the natural size measures -^ of an inch, and there can in fact 

 be no doubt that ^| is a misprint. Nevertheless Urothoe marinus is a much larger 

 and more robust species than Urothoe elegans. 



Urothoe norvegica, Boeck, 1860, from Norway, was the species next established. 

 Figures and detailed description of it did not appear till 1876, and even with these the 

 species is still left in some obscurity. It may be presumed from the small size of the 

 lower antennae that the specimen examined was a female'; for, though Boeck states 

 that the flagellum has four joints, an inspection of the figure makes it tolerably certain 

 that there were actually no more than the usual two. Of the third pleon-segment 

 Boeck makes two statements — one, that the postero-lateral angle is produced upwards, 

 the other, that it is acute. His figure does not correspond with either particular. Of 

 the third perseopods he remarks that the first joint is not much dilated. Specimens 

 obtained by Canon Norman from " Sleat Sound, 1866," and " Shetland, 1867," agree with 

 ' For a different opinion, see Chevreux on this species, 1887. 



