82 CHARLES CHILTON 
gins. On the whole I look upon this form as a modified descendant of O. 
chiliensis. No altitude is given for the locality at which it was taken, but 
Portezuelo is a mountain pass about 590 metres high and I presume that the 
animal is a true terrestrial one found at about this elevation above the sea. 
The point of interest is that in the Juan Fernandez Isiands we apparently have 
the shore species Ovchestia chiliensts extending on to the land and reaching 
considerable altitudes, and in one case acquiring characters which make its 
general appearance similar to that of purely terrestrial species of Yalorchesta, 
while in other examples no modification appears to have taken place. Presum- 
ably the form I have described as a new variety has adopted a terrestrial mode 
of life for some considerable time, though not long enough to have caused any 
modification in the pleopoda, while the others that show no modification are 
to be looked upon as forms that have more recently taken to life on land. 
The figures accompanying this paper have been prepared by Miss E. M. 
Herriott, M. A., Assistant at the Canterbury College Biological Laboratory to 
whom my thanks are due. 
The following is a list of the species with their distribution: — 
1. Orchestia chiliensis Milne-Edwards. 
Chile, South America; New Zealand. 
2. Aora typica Kroyer. 
Widely distributed in all seas. 
Amphithoe femorata (Kroyer). 
South Pacific and South Atlantic. 
iS) 
4. Jassa falcata (Mont.). 
Widely distributed in all seas. 
5. Caprella cornuta Dana. 
Rio Janeiro, Brazil. 
Orchestia chiliensis Milne-Edwards. 
Orchestia chiliensis Milne-Edwards, 1840, vel, 3, p. 18.1 
Orchestia chiliensis ‘Thomson, 1899, p. 199. 
Orchestia chiltensts Stebbing, 1906, p. 537. 
Orchestia serrulata Dana, 1853—55, p. 870, pl. 57, figs. 7 a—1(¢), m—o (). 
Orchestza selkirki Stebbing, 1888, p. 603, pls. 1, 2; 1906 p. 538. 
Localities. 
Masatierra, »under stones throughout the island,» S. P. E. No. 2509. 
About 20 males, averaging 15 mm. in length, though one with the second gnatho- 
pod subchelate as in the male is only 8 mm. long; 12 females (or immature 
males) averaging 10 mm. long. One male has abnormal second antennae. 
1 The references are made by the year of publication to the list on p. 92. 
