120 Mr. C. Spence Bate on Crustacea. 



four lateral dorsal spines, and tipped with a few spines and 

 hairs. 



We have taken several specimens of Nika ; and from their 

 general resemblance to N. Gouchii^ while possessing the chan- 

 nelled telson of N. eduUs^ so particularly pointed out by Bell 

 as specifically distinctive, I am much inclined to believe that 

 there is but a single British species yet known, and that 

 N. Couchii is but a variety of N. eduUsj Risso. An examina- 

 tion of its parts in detail has shown us that the mandibula 

 (PL XI. fig. 3) are formed on a plan that nearer associates 

 the genus with Grangon than with AlpkeuSj in the family 

 of which (Alpheidse), the latter being the type, Nika is placed 

 by Milne-Edwards and Bell, while Dana, more correctly we 

 think, has placed it in a subfamily of the Crangonidse, the 

 Lysmatinae. 



Two or three specimens of Athanas nitescens have been 

 taken off Polperro. 



Hippolyte Barleeij which was described by me from a Shet- 

 land specimen several years ago, must, I think, be expunged 

 from the list of species, since, as pointed out by the Rev. A. M. 

 Norman some time since, it is only an accidental variety of 

 H. Cranchil, Observations of the Stomapoda on the south- 

 western coast have been limited to a few of the commoner 

 species : whether this arises from the species not being abun- 

 dant on our southern shores as compared with those on the 

 northern, or from accidental causes attributable to collecting 

 arrangements, is yet to be determined. 



Amongst the smaller Crustacea, there is little to which I 

 should wish to draw special attention, except the recent dis- 

 covery of what may prove to be an undescribed Anthuraj and 

 some observations on the structure of Tanais, 



In 1861 Van Beneden asserted that the proper place of the 

 genus Tanais was near to that of the family of the Diastylidse, 

 because the cephalon was developed upon the type of the cara- 

 pace of the Decapoda. In 1864 this opinion was followed by 

 Dr, Fritz Muller, who stated that though he had been unable 

 to identify branchial appendages, yet he felt assured that it 

 possessed rudimentary organs, because he had observed a cur- 

 rent of water playing from beneath the carapace. Recently, 

 having obtained some living specimens, I have been able to 

 support Dr. Fritz Miiller's conclusion relative to the current of 

 water ; for, by the assistance of transmitted light, I have been 

 able, through the walls of the carapace, to see the branchial 

 appendage waving to and fro ; since which I have dissected 

 out the organ, a drawing of which accompanies this memoir. 

 (PI. XI. fig. 5.) 



