COXCIIOLOOT. 141 



singular apponda^oR. In otliers apfaiii all processes will disappear, all branchial 

 arniiijrenuiits vauisli, and we shall meet with forms almost as simple in their 

 Btructuro as the Nemertoid types amonp; anneli<ls. In their embryonic state these 

 lovely fragile mollusks arc supplied with little clear spiral shells, and swim like 

 ]'t(!ropoda fre(dy thri)Uf;h the water ; being furnished at this epoch of their lives 

 with two liead-rtns ami a large frontal veil. As they grow, however, the shell fulls 

 off, and the veil becomes modilied, but is nsually persistent in the adults." Adams 

 (Gen. Moll. vol. ii. p. 47). The Nudihranclis of Burnui are as yet wholly nnknown. 



In the Proceedings of the Zoological Society of London, however, for 1877 

 (p. 196), some 460 species of Authobranchiate mollusks are enumerated and described 

 by M. Phincas S. Abraham, of which uinety-tive are recorded from the Red 8ea 

 or tiic coasts of India, and many of which undoubtedly range to Burma. Of the 

 whole of these 460 species, only a single species, Boridopnif! limhafa, Cuv., is reported 

 as inhabiting both the Mediterranean and Red Sea, and Dork verrucosa, Cuv., the 

 Mediterranean Sea and Mauritius. 



Sub- class PROSOBRANCUIA TA . 



Gills plumose or pectinate, placed in a cavity above the neck or under the mantle 

 on the left side. Heart behind the gills. Sexes distinct. The adult and larva lioth 

 provided with shells, the latter also furnished with deciduous ciliated fins springiug 

 from the sides of the head. 



Ordrr rECTIXIBllANCHIATA. 

 Gills cond)-like on the left side of the mantle over the back of the neck. 



Sub-order PROBOSCIBIFERA. 



The prcdaceous gasteropods are armed with a retractile proboscis, by means of 

 which they firmly hold and perforate the shells of bivalves in order to feed on the 

 animal within. Their instinct would, however, seem occasionally to be at fault, as 

 spines of a sea-urchin have been found so di'illed, apparently by mistake on the part 

 of some hungry gasteropod. 



MnEEX, LinnmiH. 



Family Muricidse. 

 MUEICIN.1:. 



In this genus a ' varix,' or tliickening of the lip, is secreted at each thu'd of the 

 periphery of a whorl annually. 



,, ADUNCO-sPiNosus, Bcck. Andamaus. 



,, NiGRisprsosns, Reeve. Andamans. 



* ,, UXDATUS, Pfr. 



* ,, coxTEACTus, Rccve. 



* ,, Martiniakus, Pfr. 



* ,, rixNAins, Swain. 



* ,, TEKXispiRA, Lam. 



Sub-genus Chicokkus. 



* ,, CAPUorrrus, Lam. 

 *" ,, ADUSTUs, Lam. 



* ,, wicROPUi-LLUs, Reeve. 



Sub-genus OcrNEisRA. 



,, liREVicuLus, Sow. Andamans. 



M. tetragonus, Reeve (non Brod.). 



,, GiDBA, Pease. Andamans. Ceylon. 



