I. DESCRIPTION OF A NEW SPECIES OF 



ISOPODA OF THE GENUS SYNI- 



DOTEA, HARGER, FROM THE 



GULF OF MANNAR. 



By Walter E. Collixge, D.Sc, F.L.S., etc., Research Fellow 

 of the University of St. Andrews. 



(Plate I). 



Dr. Annandale has kindly submitted to me for examination 

 and report, a small collection of Isopoda belonging to the family 

 Idoteidae, from the Indian Museum collection. 



As yet very little is known of the members of this family 

 from the Indian Ocean, and although the different genera and 

 species find their greatest development in the colder seas, there is 

 every reason to suppose that there are many genera and species 

 awaiting discovery in the Indian Ocean. 



The present collection contains a single new species referable 

 to the genus vSyn/^o/^a, Harger, from coral reefs at Kilakarai, Gulf 

 of Mannar. 



The genus Synidotea was constituted by Harger ^ in 1878 for 

 a group of Isopoda characterized by the following features: — a 

 multiarticulate flagellum of the antennae, a 3-jointed palp on 

 the maxillipedes, the absence of coxal plates on the dorsal side of 

 the mesosomatic segments, a single metasomatic segment, and 

 uropoda with an endopodite only. 



Miers^ regarded the genus, as known to him, as synonymous 

 with Edotia, Guerin-Men., but although these two genera, at first 

 sight, appear very similar, they are quite distinct from one another. 



In all there are some sixteen or seventeen species belonging 

 to this genus, but the detailed structure of very few of them has 

 been described and figured. Miss Richardson^ has given figures 

 of the maxillipedes of some species, but unfortunately these are 

 incorrect in many cases. 



The species here described is the first, I believe, that has been 

 collected in Indian waters, the remaining species being distributed 

 as follows : — 



1. S. hirtipes (Milne Edw.). Cape of Good Hope, South Africa. 



2. S hirtipes var. laevi dor salts {Miers). Jatiyama Bay, Japan. 



- Amef. Journ. Set., (Ser. 3), vol. XV, p. 374 (.1878). 

 * Journ. Linn. Soc. Land., vol. X\ I, p. 65 (1881). 

 •^ Btill. U.S. Nat. Mns., no. 54, pp. 376-393 (1905)- 



