226 POPULAR BHITISH CONCHOLOGY. 



A group now moves slowly on_, of thirty-seven small spe- 

 cies, of surpassing beauty, composing the genus 



EoLis. — In this genus the head is nearly as distinct as in 

 the land-slug; it has four tentacles, with eyes placed be- 

 tween the hinder pair near the base ; the gills, which are 

 simple papillse in form, are arranged in rows, or bunches, 

 along the sides, and by their exquisite tints and symmetrical 

 arrangement, impart great and varied elegance to the body. 

 Among the most splendid may be reckoned E. tricolor, 

 whose papillae are white, tipped with bright orange, then 

 with a soft pencilling of purple, passing into brown ; the 

 E. picta, richly marbled with brown ; the E. Northumbrica, 

 with the papillse placed in erect bunches of four on each 

 side, pencilled in the centre of each with brilliant dark green ; 

 E. cingulata and E. olivacea, with ringed papillge ; E. nana, 

 E. pellucida, and E. fufihranchialis, in which they are cen- 

 tred with deep red, as in E. Landshirgii, in which their 

 edges partake of the purple colour of the whole body. Per- 

 haps the greatest beauty of all is the E. coronata, in which 

 the papillse are tipped with white, centred with red, and 

 touched with bright blue, are numerous and gracefully 

 formed, and placed in oblique fasciculi along the tapering 

 body. The most curious of the species is E. desjoecta, in 



