Carcinological Fauna of India. 131 
same plane with the antennules ; the second joint has its antero-external 
angle produced to form a coarsish spine: the antennal flagella are 
longer than the carapace. 
The palate is particularly well demarcated from the epistome and 
is rather broader in front than behind: the ridges that define the ex- 
piratory canals are very distinct. The epistome is in the closest 
possible contact with the front, but without complete fusion. The 
external maxillipeds are distinctly operculiform, but owing to the 
moderate expansion of the merus and to the coarseness of the palp, they 
have a slight pediform cast: they close the buccal cavern, but not so 
tightly as in Dromia. 
The chelipeds are equal and are rather slender, though consider- 
ably stouter than the legs: the fingers are well calcified and are 
hollowed en cwillére, the tip of the dactylus shuts into a notch in the 
tip of the opposed finger. 
The legs are cylindrical: the first two pairs are very long, the last 
two are short, subdorsal in position, and cheliform rather than subcheli- 
form. 
‘he sternal grooves of the female end opposite the openings of the 
oviducts, without tubercles. 
The abdomen of both sexes consists of seven distinct segments. In 
both sexes the pleure of the 3rd—6th abdominal somites are remarkably 
free and independent (i.e. not in contact with those in front and behind) 
and the last abdominal tergum is nearly as long as the preceding five 
combined. Inthe male this last tergum is marked in a way that 
suggests its formation out of a segment fused with a pair of appen- 
dages. 
This crustacean, as I have previously remarked, so closely resembles the Homolo- 
dromia described and figured by Milne Edwards* and referred to by Bouvier,t} that 
at first sight it might be supposed to be the same form. 
In Homolodromia, however, it is distinctly stated that the antennules are not 
retractile, and that there are no special orbits. 
In Arachnodromia, on the other hand, there are orbits formed on exactly the 
same plan as, and hardly less perfect than, those of Dromia, and they afford 
complete protection to the retracted eyes and antennules, the antennulary flagella 
folding, as in Dromia, behind the eyes. 
* A. Milne Edwards, Bull. Mus. Comp. Zool. Vol. VIII. 1880, p. 32, and Recueil 
de figures de Crustacés Nouveaux etc. pl. 39, fig. 2. Not the Homalodromia of: 
Miers, which ought to be placed with Psewdodromia, 
t+ E. L, Bouvier, Bull. Soc. Philom. Paris (8) VIII. 1895-96, p. 37, et seq. 
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