314 
THE VOYAGE OF H.M.S. CH ALLEN GEE. 
The largest male of the Challenger series, 
dimensions : — 
from Station 
138, presents 
the following 
Adult $ . 
Lines. 
Millims. 
Length of carapace, about . 
13 
28 ■ 
Breadth of carapace, about . 
11 
23-5 
Length of a chelipede, nearly 
34 
72 
Length of first ambulatory leg, 
15 J 
33 
The smallest specimen (male) from the same locality measures as follows 
Young £. 
Lines. 
Millims. 
Length of carapace, .... 
8 
17 
Breadth of carapace, nearly . 
. 
7 
14-5 
Length of a chelipede, 
31 
Length of first ambulatory leg, 
18 
The examination of the Challenger series compels me to unite, under the designation 
Myrafugax, several species which I have hitherto supposed to be distinct. In young 
specimens the carapace is more or less distinctly carinated in the median dorsal line, and 
the post-abdomen in the male is flat and smooth, without the subbasal prominences and 
the tubercle which sometimes exists on the penultimate segment in adult examples ; the 
margins of the carapace also are more distinctly granulated, and the chelipedes relatively 
shorter. In adult males the chelipedes are sometimes very considerably elongated (as in 
the figure of de Haan cited above) and — in specimens I have examined in the collection 
of the British (Natural History) Museum — the three posterior spines of the carapace 
strongly developed and acute ; perhaps these may be referable to a distinct variety 
or species ; the chelipedes, however, are usually more slender and more elongated in 
adult males than in adult females. 1 
1 I may note in regard to the synonymical citations, that the Cancer cupheeus of Linne was founded on a 
specimen wanting the chelipedes, and cannot therefore be identified with certainty with any species of this genus. 
Cancer punctatus, Herbst, resembles Myra fugax in the form of the body and limbs, but differs in coloration from any 
specimen I have examined. Hilgendorf, who refers (tom. cit.) to the type, adds no information regarding it. The form 
I have described, from Japanese types ( Proc . Zool. Soc. Lond., p. 42, 1879), as Myra dubia, is probably identical with 
Myra coalita, Hilgendorf, described in the preceding year ( Monatsber . d. h preuss. AJcad. d. Wiss. Berlin, p. 812, pi. i- 
figs. 6, 7, 1878), from Zanzibar, and maybe a variety of Myrafugax, although the types are distinguished from all 
specimens of that species I have seen by possessing a tubercle on the intestinal region in front of the median spine of 
the posterior margin. They are probably not fully grown. A similar tubercle was observed by Hilgendorf in 
specimens referred to Myra fugax. 
