CRUSTACEA FROM EAST COAST OF SCOTLAND 



03 



Thysanoessa borealis (G. O. Sars). 



1882. Thysanoessa borealis, " Oversigt over Norges 

 Crustaceer," Bd. I. pp. 52, 53. 



This Schizopod has been obtained in various parts of 

 the Firth of Forth, but never in quantity — one, or at most 

 only a few specimens being taken at a time. Thysanoessa 

 has the first pair of legs long, but not so long or so slender as 

 those of Nematocelis, which it somewhat resembles. It is 

 further distinguished from Nematocelishy the penultimate joint 

 of the first pair of legs being provided throughout its length 

 with stout ciliated setae, the last joint — which is very small 

 — being also furnished with a number of hairs. On the other 

 hand, the first pair of legs in Xanatocelis have both the pen- 

 ultimate and antipenultimate joints (which are long and 

 slender) naked, but there is a bunch of spiniform setae at the 

 apex of the legs. The first legs are very easily broken, so 

 that in handling specimens, or in collecting them, great care 

 is required to keep the legs intact. We are indebted to the 

 Rev. A. M. Norman for the name of the Thysanoessa here 

 recorded. 



Among a few specimens of Forth Schizopoda forwarded 

 to Dr. Xorman for identification, and which included the 

 Thysanoessa referred to above, he observed what he considers 

 to be a specimen of Nematocelis mcgalops (G. O. Sars) ; but the 

 specimen he examined, and one or two others that seem to 

 belong to the same species, having lost their first legs, and 

 thus wanting the character which chiefly distinguishes them, 

 it is perhaps better for the present to leave the claim of 

 Nematocelis mcgalops for a place in the Forth fauna in abey- 

 ance till more satisfactory specimens turn up. Dr. Xorman 

 informs us that Xanatocelis mcgalops was sent to him from 

 Banff by Thomas Edward twenty or thirty years ago ; from 

 Aberdeen by Mr. Sim in 1X72 ; and that it has quite 

 recently been obtained at Redcar. 



The eyes of 'Thysanoessa and Nematocelis have a marked 

 constriction near the middle, which divides the eye into what 

 appears to be a lower and upper eye, and thus imparts to 

 them a peculiar and rather striking appearance, and which 



