80 ZOOLOGISCHE MEDEDEELTXGEN — DEEL IL 



XI. — TALORCHESTIA BRITO STEBBING AND ORCHES- 



TIA BOTTAE H. MILNE-ED WARDS, WITH A KEY TO THE 



DETERMINATION OF THE TALITRIDAE OBSERVED ON OUR 



COASTS. 



BY Dr. J. J. TESCH. - (with plate hi and 3 textfigures). 



1. Talorchestia brito Stebbing. 



In examining a lot of Orchestia gammarellus (Pallas) (= 0. littorea 

 (Montagu)) collected many years ago at Katwijk by Dr. J. A. Herklots, 

 late conservator of Invertebrates at the Leiden Museum, I came across 

 some fine specimens of Talorchestia brito Stebbing, which have evidently 

 been picked up together with the common Orchestiae. 



The sample was undated, but as Dr. Herklots died in 1872, the 

 specimens must have been caught on our sea-shore long before Stebbing 

 described his new species, in October 1891 (Ann. Mag. Nat. Hist., ser. 6 

 v. VIII p. 324 — 328, pi. XY), obtained plentifully in the summer of this 

 year „on YYoolacombe and Saunton Sands, in North Devon". Afterwards 

 Chevreux found it, likewise in abundance, on the shore of Yerdon (Gi- 

 ronde) in August 1893 (Rev. biol. d. Nord d. 1. France, t. VII, 1894—95, 

 p. 158), but no further record seems to have been given since that time. 



Though Stebbing characterized his species with his usual accuracy 

 and gave some figures of the gnathopods, the last joints of the pereiopods 

 and the telson, I have thought it not superfluous to give a full account 

 of the characters of my specimens, which were all males (12 in all). I 

 have not been able to recognize the females of this species, which in 

 my opinion are scarcely, if at all, to be distinguished from Talitrus saltator 

 (Montagu) (= T. locusta (Pallas)), as I shall explain further on. 



YVith regard to the distinctive characters of Talorchestia, it has 

 been rightly remarked by Stebbing, that this genus is composed of the 

 genera Orchestia and Talitrus, indeed in such a manner, that the males 

 of Talorchestia should be referred to Orchestia, while the females are 

 Talitri. 



From Orchestia gammarellus, with which my specimens of Talorchestia 

 brito were found to be associated, the latter could be easily separated by 

 their more compressed shape of the body, by thinner integuments, which 

 exhibit a milk-white colour in alcohol-preservation, whereas Orchestia 

 was lightly straw-coloured, by dark-brown eye-pigment (black in Orchestia) 



