14. A Small Collection of Aniphipoda from 

 Juan Fernandez. 



By 

 Dr. CHARLES CHILTON, 



Professor of Biology, Canterbury College, New Zealand. 

 With 4 textfigures. 



. The Amphipoda described in this paper were collected at the Juan Fer- 

 nandez Islands by Mr. K. Backstrom of the Swedish Pacific Expedition of 

 1916-17. For the opportunity of examining them I am indebted to the leader 

 of the expedition, Professor C. Skottsberg and to Professor T. Odhner of 

 Stockholm. The collection is a small one including only five species and a 

 new variety of one of the species, the others being already known. I give 

 below a list of the species v.'ith a note as to the distribution of each. 



The only point calling for special attention concerns the first species, 

 Orchestia chiliensis Milne-Edwards. This has long been known from Chile and 

 from New Zealand; in the latter country it is extremely common in most places 

 on the sea shore, and does not appear to extend far beyond high water mark, 

 although under favourable conditions it may be found at some little distance 

 from the beach. In Juan Fernandez it appears to be common also, one bottle 

 being labelled »under stones throughout the island», but here it appears to 

 extend also to considerable distances from the shore and to heights above the 

 sea up to 500 metres. The tube labelled »500 m. above sea level » contains 

 several specimens similar in size and structure to those collected on the sea 

 shore. Other specimens labelled »in a brook» are much smaller, but I think 

 are only to be looked upon as young forms of the same species and the same 

 is true of another tube labelled sunder stones,* the altitude of the last two 

 not being given. Another specimen of larger size, 13 mm. in length, labelled 

 »Portezuelo, under stones» shows certain differences, and I am describing it as 

 a new variety. Its antennae and peraeopoda are much longer and more slen- 

 der than in the typical form of 0. chiliensis, and the second gnathopod also 

 shows some differences in the shape of the palm. The pleopoda are, however, 

 well developed, showing no reduction in size such as is found in terrestrial 

 species of Parorchestia, and the telson has numerous spines on its lateral mar- 



6 — S0131. The Nat. Hist, of Juan Fernandez and Easier Isl. Vol. III. 



