SOME ARTIIROSTRACA FROM ST. KILDA 219 



SOME ARTHROSTRACA AND OTHER INVERTE- 

 BRATA FROM ST. KILDA. 



By C. GORDON HEWITT, M.Sc. 



THE following list of certain invertebrates collected during 

 a month's visit to St. Kilda, in July 1907, has been written 

 to assist in the completion of a fauna of that island. As 

 Mr. Waterston of Edinburgh has published one or two 

 short lists describing his collections of the previous year, 

 I shall only include in this short paper those species which 

 he has not already recorded, as repetition is both use- 

 less and confusing. A list of the Coleoptera, together with 

 those collected by Mr. Waterston, is to be published by 

 Professor Hudson Beare in a separate paper. The following 

 list contains the Isopods and Amphipods, together with 

 certain Lepidoptera and Hydroids : 



ARTHROSTRACA. 



AMPHIPODA. 



Gammarus tocusta, Fabr. This species is common on the shore, 

 beneath the rocks. 



G. pulex, Desm. This is common in both streams, and occurs in 

 several of the wells. 



ISOPODA (Marine). 



Eurydice pulchra, Leach. This was common, swimming about in 

 the pools beneath the rocks on the shore. 



Idotea baltica, Pallas. These occurred in the same situations, and 

 were rather small specimens. 



Jizra marina, Fabr. Under stones beneath the tide-marks. This 

 species has a wide distribution throughout the Atlantic coasts. 



Ligia oceanica, L. This species was interesting, as I found mature 

 specimens in the crevices of the rocks on the top of Ruadval, 

 almost 450 feet above sea-level. Its presence there, like that 

 of the littoral mollusc Littorina littorea, is explained by the 

 almost constant presence of spray from the Dun passage. 

 The largest specimens were below the normal size. I found 

 the young individuals on the stones between tide-marks. 



