ECPLECTA. 



73 



This shell is clistinguislied from E, la>/anU and E. acctlhs by 

 want of perforation and carination and by simpler scnlpture. It 

 is also smaller. 



[I have found in one of Dr. W. T. Bianfords field note-boolis 

 a very good figure and a long description of the animal of this 

 species, which I give verbatim as it is so good, descriptions of this 

 sort from life being really of more value than those of the shells. 



" N. mucosa, W. Blf. : Nilgiris. — No linguiform processes to the 

 mantle. Mantle rather large. Animal dull orange, mantle yellow. 

 Tentacles blackish, with a dark line from the base of each to the 

 mantle. The lobe over the nuicous pore very large. Back not 

 carinate. Foot broadly margined by a single line. Animal and 

 mantle coarsely granulate throughout and \\ ith irregular dots of a 

 darker colour on the spaces between the wrinkles and especially 

 on the edges of the foot. Animal very active." 



This description is sufficient to enable anyone to recognize the 

 species and preserve the animal for dissection. 



Blanl'ord placed it next to E. j'ldchella ; but as there is con- 

 siderable doubt whether it belongs to the genus Euplecta, 1 

 transfer it to the end among other doubtful species.] 



[Confining comparison to the formvda of the radula in the 

 genus Euplecta and the sinistral and dextral forms of Arioplianta. 

 marked differentiation is displayed in the far fe^^■er teeth in the 

 radula of the first, whereas in the last two divisions the numbei- 

 is much greater in the proportion of 28 : 45. In the sinistral and 

 dextral species remarkable similarity is found, showing a close 

 relationship with each other and a more distant one with Euplecta, 

 differences (specific) being confined in Arioplianta more to the 

 form of the teeth themselves. To elucidate this. I have taken the 

 number of the admedian teeth, including the one or two of 

 transition form, of all the species now examined in : 



I. The sinistral Ariophanta'. 

 II. The dextral 

 III. Euplecta. 



The mean of all these formulae is interesting, sho\^■iug how much 

 more numerous the teeth are — that is, how much broader is the 

 central band of teeth set on quadrangular plates — in Nos. I. & II. 

 than in No. III., thus : — 



