286 Records of the Indian Museum. [Vol,. XXIV, 



C 439/1. Port Blair, Andamans. S. Kemp, Feb., Two. 



I9I5- 

 C 440/1. Andamans. A. R. S. Anderson. Two. 



141 7. Upolu, Samoa. Purchased-. One. 



All the specimens from the Andamans were found in Mele- 

 agrina and it is from this genus of molluscs that the species has 

 generally been recorded. Borradaile notes, however, that it some- 

 times occurs in Tridacna. There is no note of the mollusc in 

 which the Samoan specimen was found. The species is probably 

 one of wide distribution in the Indo-Pacific region. 



Genus Typton Costa. 

 1917. Typton, Borradaile, Trans. Linn. Soc. (2) Zool. XVII, p. 394. 



Borradaile gives a full list of references to this genus and to 

 the two species which belong to it. Typton is readily distin- 

 guished from all other Pontoniinae except Paratypton by the rudi- 

 mentary character of the antennal scale. 



In T. spongicola, which is found in sponges in the Mediterra- 

 nean and western parts of the English Channel, the rostrum is 

 spine-like and toothless and there is a pair of very long supra- 

 orbital spines. In T. bouvieri, which is known only from Djibouti 

 in the Red Sea, the rostrum is short, with 2 or 3 teeth on its 

 upper edge, and there are no supra-orbital spines. , In both species 

 the dactylus of the three posterior legs is biunguiculate, but with- 

 out a basal process. 



Genus Paratypton Balss. 



1914. Paratypton, Balss, Zool. Ans. XI. IV, p. 83. 



1915. Paratypton, Balss, Denk. math.-naturw. Kl. K. Akad. Wien 



XCI, p. 27. 



This genus agrees with Typton and differs from all other 

 Pontoniinae in the rudimentary condition of the antennal scale. 

 It differs from Typton in a number of characters, of which the 

 most important are (i) the complete absence of the rostrum, (ii) 

 the absence of exopods from the second and third maxillipeds and 

 (iii) the simple dactylus of the last three peraeopods. The distal 

 endite of the maxilla is well developed in Typton, but quite rudi- 

 mentary in Paratypton. 



The only known species of the genus, P. siebenrocki Balss, 

 is recorded from the Red Sea, the south coast of Arabia and 

 Samoa. It appears probable from its structure that it is para- 

 sitic or symbiotic in its habits, but of this nothing is known. 



