156 DR. CHARLES CHILTON ON THE SUBTERRANEAN 
Basa of the last three pairs of pereiopoda broad, with the pos- 
terior margin expanded, convex, greatest breadth three-fourths 
of the length. 
Third uropoda reaching only slightly beyond the extremity of 
the preceding pair; the outer branch one-jointed, twice as long as 
the peduncle, inner branch rudimentary, minute. 
Telson reaching well beyond the end of the peduncle of the 
third uropod, hinder margin somewhat emarginate, lateral angles 
with 2 or 3 sete. 
Length about 4 mm. 
Habitat. Ringwood in Hampshire, and Marlborough in Wilt- 
shire. (In Europe recorded from Munich and Prague.) 
This species was first described by Spence Bate from a single 
specimen found at Ringwood. From the figures given by de 
Rougemont [17. pl. i. figs. 1 & 2, and pl. ii. fig. 1], it appears 
that he really had before him either the present species or 
a closely allied one of Crangonyx; but his account of it adds 
nothing of importance to what was already known, and his asser- 
tion that it was merely a young stage of Niphargus puteanus 
has been already criticised by Humbert and Wrzesniowski and 
shown to be erroneous. The species does not appear to have 
attracted further attention till 1896, when Vejdovsky published 
his important paper [21] and dealt exhaustively with its sense- 
organs and internal anatomy. In his revision of the Gammarida, 
Stebbing [31. p. 423] gave to the species described by Vejdovsky 
the new name Hucrangonyx Vejdovskyi, saying that it appeared 
to him to differ from Spence Bate’s species: the points of differ- 
ence to which he refers apparently being the possession of a small 
wmner branch to the terminal uropoda and of an emargination in 
the telson. I have received from Mr. Stebbing a small mounted 
specimen of Crangonyx subterraneus from Marlborough, and 
have been able to compare it with mounted specimens of Vej- 
dovsky’s species ; and after careful examination I have no doubt 
that both belong to the same species, and Professor Vejdovsky, 
who made a hasty comparison of the same specimens when I 
visited him in Prague in March last, was of the same opinion. 
In all points that can be observed the different specimens seem 
to be practically identical. The specimen from Marlborough is 
very small, and in its present mounted condition itis not possible 
to be quite certain whether it possesses a small inner branch to 
the terminal uropoda or not, though I think it has; but this 
