209 

 Synopsis of the family-groups of Paguridea. 



1. Carapace usually elongate and subcylindrical : abdomen usually soft, 

 it may be coiled or bent, but is never tightly tucked up against the 

 thoracic sternum which is narrow or linear : the caudal swimmerets 

 are always represented : the 4th pair of thoracic legs are very short Pagurodea. 

 II. Carapace crabshaped : abdomen broadly triangular and tightly flexed 

 against the broad thoracic sternum : caudal swimmerets absent : the 

 4th pair of thoracic legs are as long as any of those in front of them Lithodea. 



PAGURODEA, Henderson. 



Henderson, Challenger Anomura, p. 48 (et synon.). 



Carapace almost always elongate and subcylindrical, much less well calcined 

 behind the cervical groove than in front of it. Thoracic sternum narrow or 

 linear. 



Abdomen elongate ; usually soft, asymmetrical, and either coded to fit the 

 spire of the dead mollusk-shell that the animal usually inhabits, or bent ; only 

 occasionally well-calcified symmetrical and straight. Caudal swimmerets present, 

 narrow and falcate usually. 



The first 3 pairs of thoracic legs are well developed, the 1st pair being 

 massive and chelate and the 2nd and 3rd pairs being long stout and monodactyl- 

 ous ; but the 4th and 5th pairs— one or both of which may be chelate or sub- 

 chelate — are exceedingly short. 



Paired appendages may be present on the 1st and 2nd abdominal somites of 

 the male and on the 1st somite of the female, but on the 3rd-5th somites of the 

 male and the 2nd-5th of the female the appendages are usually developed on 

 one side only. 



Key to the Families of Pagurodea of the Indian Benthos and Oligobenthos. 



I. Abdomen perfectly straight and symmetrical, with all the terga well- 

 developed, well calcified, and in close contact one with another, and 

 with paired appendages on every somite from the 1st to the 6th ... Pylochelidj;. 

 II. Abdomen usually coiled and soft, with the terga ill-developed : in the 

 middle somites (3rd-5th), at least, the appendages are developed on 

 one side only ... ... ... ... ... Paguridj;. 



Family Pylochelidw, Ortmann. 



Pylochelidse, Ortmann in Bronn's Thier Reich, Malacostraca, p. 1144. 



Body as straight and as bilateraUy symmetrical as in any macrurous crus- 

 tacean. The abdomen, which is extended straight behind the cephalothorax as 



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