MALACOZOA. GASTEROPODA. CYCLOBRANCHIATA. 179 



the apex to the margin twenty-four prominent convex ribs, 

 alternating with smaller, and decussated by numerous irregu- 

 lar concentric rugae ; the margin crenulate ; the colour yel- 

 lowish-white, the interior white. Length of the aperture three- 

 twelfths, breadth two-twelfths, height two-twelfths. 



This species resembles Emarginula Fissura in form and 

 markings, but differs in the curvature of the apex, and es- 

 pecially in having the fissure at the top. It is nearly allied 

 to Emarginula Fissurella, from which it differs in having the 

 externaropening of the canal, not wide and of a rhomboidal 

 form, but a narrow chink. One malacologist has named it 

 after Noah, another after Dr. Fleming. I am unable to de- 

 termine the priority, and therefore take the living godfather. 



The above description from a dead shell, brought up from 

 deep water off Aberdeen, and found by Miss Isabella Mac- 

 gillivray, on the 30th of September, 1842. 



Sypho striata. Brown, IHustr. 36. f. 14, 15, 16. Cemoria 

 Flemingii, Leach. Fissurella Noachina, Sowerby. 



ORDER V. GASTEROPODA CYCLOBRANCHIATA. 



Respiratory organ a continuous fringed lamina placed 

 in the groove which separates the mantle from the foot. 



They are all marine, adhere to rocks, stones, shells, or 

 plants, feed on vegetable substances, and are covered 

 with a wide-mouthed more or less conical shell. 



FAMILY I. PATELLINA. 



Animal with the body broad, convex or conical, covered 

 by a conical expanded shell, to which the mantle adheres, 

 until toward the margin, beneath which, in the groove 

 between the mantle and the foot, the branchiae are dis- 

 posed in the form of a thickened border ; the head with 

 two conical tentacula ; the eyes situated near their base 

 internally ; orifice of the anus and generative organs over 

 the head toward the right side ; foot very broad, firm, 

 marginate. 



Shell of the form of a short cone, with the apex nearer 

 the anterior end. 



All the species marine. 



