231 



• 



The animal does not inhabit a shell, but is protected by the soft fleshy 

 coenosarc of a colony of Actiniarian polyps. This forms a sort of sheet or 

 blanket, one end of which is tucked round the telson of the crab and is firmly 

 held by the hook-like swimmerets of the 6th abdominal somite and by the folded- 

 in telson, while the corners of the other end are firmly grasped by the chela? of 

 the penultimate thoracic appendages in such a way that the sheet can be drawn 

 right over the back of the crab as far as the eyes. 



The colour of the crab is red : the coenosarc of the polyp-colony is bluish, 

 the polyps themselves are dark purple. 



A large male, lying in the natural position with the telson bent under, 

 measures, from the tip of the rostrum, 63 millim. ; and the chelipeds of the same 

 individual, measured along their convex curve, are 68 millim. in length. 



An egg-laden female measured in the same way, is 37 millim. long and has 

 chelipeds 35 millim. long. 



205 specimens, representing both sexes in all stages, were dredged by the 

 Investigator off Cape Comorin, in 102 fathoms. 



Regd. Nos. 3 -^i 7 (Types of the species): 31e9 - 3189 . 



LITHODEA, Henderson. 



Lithodea, Henderson, Challenger Anomura, p. 41 (et synon,). 

 Lithoiinis, Bouvier, Ann. Sci. Nat., Zool. (8) I. 1896, p. 1. 



Carapace uniformly well calcified, crab-shaped, having sharply defined 

 lateral borders, its regions well defined : a spiniform rostrum is present and 

 conceals the ophthalmic somite. Thoracic sternum broad. 



Abdomen broadly triangular, tightly flexed against the thoracic sternum, as 

 in crabs : it consists of 7 segments, of which the first 2 form, dorsally, a sin°-l e 

 undivided plate while the next three (3-5) consist of two lateral and a median 

 series of plates. Caudal swimmerets are never represented. 



The first 4 pairs of thoracic legs are well developed, the 4th pair being at 

 least as long as any of the others ; but the 5th pair are short slender and weak, 

 and are folded within the branchial chambers. The first pair are chelate. 



Abdominal appendages are present in the female only, as a rudimentary pair 

 on the 1st somite and as rudiments only on one side of the next four somites. 



A single family — Lithodidse. 



Key to the genera of Lithodidee of the Indian Oligobenthos. 



I. The median portion of the 3rd-5tk abdominal somites is covered with 



small calcareous platelets ... ... ... ... Lithodes. 



II. The median portion of the 3td-5tk abdominal somites consist of large 



calcareous plates ... ... ... ... .,. Pakalomis. 



