168 Canon A. M. Norman on a 
two more species to the genus—H., algiricus, from Algeria, 
and H. provincialis, from Golfe de Saint-Tropez. The species 
now to be described comes nearest to H. Orstedi. 
Heterotanais Gurneyi, sp. n. 
(Pl. V. figs. 1-7; Pl. VI. fig. 1.) 
Heterotanais sp. (?), Robert Gurney, “‘ The Fresh- and Brackish- Water 
Crustacea of East Norfolk,” Trans. Norfolk and Norwich Naturalists’ 
Soe. vol. vii. 1904, p. 650. 
Mr. Robert Gurney, in his excellent paper on the fauna of 
the Broads &c. of Norfolk, indicated as above a T'anaid which 
he had found in brackish water. He was subsequently so 
kind as to send me a male specimen and also drawings of the 
female, with a request that I would describe the species ; 
from that specimen and the drawings the following characters 
are given. 
The length of the female is equal to about five times that 
of the breadth, and the breadth is nearly equal throughout. 
The cephalosome is as long as the first three segments of the 
mesosome and half of the fourth ; the fourth and fifth seg- 
ments of the mesosome are the longest; and the metasome 
equals the two and a half preceding segments in length. ‘The 
antennules are three-jointed, the first exceeding in length the 
two distal joints combined. ‘The cheliped is almost exactly 
like that of ZZ. Orstedi, the thumb having three crenations 
and as many sete. ‘The second pair of legs have the 
characteristic formation usual in the genus. 
The male has the cephalosome produced and very com- 
pressed, narrowed greatly in front to the region of the eyes. 
The metasome is fully equal in length to half the mesosome. 
The antennules consist of five articulations, of which the 
terminal is the shortest, and the second nearly equals the 
combined lengths of the last three. The cheliped in general 
structure resembles that of /7. Orstedz, but as seen from the 
outside the carpus is not projected so far forwards, while the 
thumb-process 1s of entirely different form, (not narrowed at the 
base, and thence widening, but) narrow throughout its length 
and of subequal breadth, until near its termination it is bent 
forwards, and pointed at the extremity. ‘The uropods have 
the outer branch minute, two-joimted; the inner four-jointed, 
the two distal joints being subequal to the second in length. 
This species very nearly resembles H. Orstedi in most 
