REPORT ON THE BRACHYURA. 
269 
In the specimens, referred somewhat doubtfully to this species, 1 the carapace and 
chelipedes are punctulatecl and the frontal and gastric regions marked with a median 
posteriorly bifurcating suture. In the larger (female) specimen there is no trace of the 
posterior (fourth) rudimentary tooth of the lateral margins, which is very faintly 
indicated on one side only in the smaller male. The female specimen has also a relatively 
somewhat broader carapace, with the sides anteriorly slightly arcuated, and the antero- 
lateral teeth less prominent, as in the species of Chasmagnathus, and may perhaps belong 
to a distinct species, on which account I think it useful to figure it. Its dimensions are 
as follows : — 
Adult 9 . Lines. Millims. 
Length of carapace, . . . . . . . 6 12 - 5 
Breadth of carapace, nearly . . . . . . 8 16 '5 
Helice crassci, Dana. 
Helice crassa, Dana, Proc. Acad. Nat. Sci. Philad., p. 252, 1851; U.S. Explor. Exped.. vol. xiii., 
Crust., p. 367, pi. xxiii. fig. 8, 1852. 
,, „ Kingsley, tom. cit., p. 220, 1880, et synonyma (1). 
Port Jackson, Sow and Pig’s Bank, 6 fathoms (a small male). 
d. 
Lines. Millims. 
Length of carapace, nearly .... 
4 8 
Breadth of carapace, ...... 
4|- 9 
The carapace in this specimen, which is not fully grown, 
depressed than is usual in the genus. 
is flatter, and the body more 
Sesarma, Say. 
Sesarmci, Say, Journ. Acad. Nat. Sci. Philad., vol. i. p. 76, 1817. 
„ Milne Edwards, Ann. d. Sci. Nat., ser. 3, Zool., vol. xx, p. 181, 1853. 
„ Kingsley, Proc. Acad. Nat. Sci. Philad., p. 213, 1880, et synonyma. 
Body thick. Carapace quadrate, and normally broader than long, with the sides 
straight, not arcuated, entire or dentated. Front rather broad, and abruptly deflexed, 
with the anterior margin straight or sinuated ; the epigastric lobes prominent, and defined 
externally by a suture (except in the forms separated by Milne Edwards as Holometopus) . 
Orbits large, with a hiatus below the exterior angle; the interior subocular lobe is 
moderately developed and does not exclude the antenna from the orbital cavity. 
Epistoma transverse and very short. Endostomian ridges usually distinctly developed. 
Post-abdomen (in the male) distinctly seven-jointed, and covering the whole width of the 
1 They agree closely with specimens from the Mauritius, whence were obtained the types in the British (Natural 
History) Museum. 
