IVli) 



PROCKEDINGS OF Till'; M ALACOr,0(iICAL SOCIK'l'Y*. 



DESCRIPTION OF A NEW SPECIES OF CRYPTOPLAX. 



By the llev. A. H. Cooke, M.A., F.Z.S. 



Bead 11th Aiyril, 1913. 



Ckyptoplax evanescens, n.sp. 



Animal narrowly cylindrical, much elongated, foot exceedingly 

 narrow; ior^y thick and leatliery, covered with short deciduous spines 

 or fine scales, spines yellow or reddish-yellow ; body colour variable, 

 grey, yellow, or reddish, and hlotched with red underneath the spines; 

 gill-rows rather large, but occupying only about one-fifth of the entire 

 length of the animal ; valves very small, in a fresli specimen the 



fourth, fifth, and sixth are scarcely visible ; as the animal contracts 

 iu spirit they become more noticeable ; the two front valves are the 

 largest, third valve considerably smaller (these three valves are close 

 together) ; fourth valve remote from the third, very small, hardly 

 visible, buried deeply in the muscular integument of the back; fifth 

 valve remote from the fourth, hardly visible ; sixth valve remote 

 from the fifth, just visible ; seventh valve remote from the sixth, 

 more conspicuous; posterior valve conspicuous, much neai'er to the 

 seventh than the seventh is to the sixth. 



The avticulamentum is relatively large in proportion to the tegnienlum, 



