1899.] A. Alcock — Carcinological Fauna of India, 131 



same plane with the antcnnules ; 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 cuillere, 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. 



The 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 pleurae 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. In the 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 Somolodromia, 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 eyea 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 Crustaces Nouveaux etc. pi. 39, fig. 2. Not the Homalodromia of 

 Miers, which ought to be placed with Pseudodromia. 



t E. L. Bouvier, Bull. Soc. Philom. Paris (8) VIII. 1895-96, p. 37, et seq. 



J. II. 17 



