MALACOZOA. GASTEROPODA. SCUTIBRANCHIATA. 331 



63 and 170 as Fusus Laskeyi. It varies considerably in the 

 form of the outer lip, which however is ahvays very convex, 

 and in the number of its spiral ribs, as well as their breadth. 

 In one specimen the large ribs are all duplicate, or broad, with 

 a groove along the middle. The shell seems remarkably liable 

 to fracture of the outer lip, as that part is perfect in only one 

 of my specimens, and in all shews previous injuries, hi one 

 very rudely repaired. It has been found on the West coast of 

 Scotland, at Rothesa}', and Oban, as well as in Shetland, and 

 at Dunbar, and appears to be not very luiconnnon on the 

 Aberdeenshire coast. 



Fusus umbilicatus. Brown, Smith, Worn. INIem. viii. 98. PI. 1. 

 f. 2. — Trichotropis acuminatus. JefFreys, Malac. and Conch. Mag. 

 N. ii. 36 j Ann. and Mag. Nat. Hist. viii. 166. 



ORDER IT.— GASTEROPODA SCUTIBRANCHIATA. P. 6. 



Family I. — Fissurellina. P. 64, 1/6. 



Genus 1. Emarginula. P. 65, 1/7. 



2. Emarginula ciirvirostris. Curved-tipped Slit-Limpet. 



Shell conical, oval, with the summit re volute and in- 

 clined to one side, a vertical slit extending from the 

 anterior margin half-way up. Named from its form. 

 Rostrum, a beak ; curvus, bent. 



Sbell conical, with the aperture ovato-elliptical ; a vertical 

 median slit extending externally from its anterior part to two- 

 thirds of its height, but internally only to about half its 

 height, and there bordered at its termination with a promi- 

 nent margin of considerable transverse extent, tlie anterior 

 median outline convex, the posterior concave ; the apex re- 

 curved so as to make a complete volution, at first inclined to 

 tiie left, then to the right ; the surface with twenty-four pro- 

 minent nodulose ribs, and concentric striic ; the margin ex- 

 ternally crenated by the ribs, not extending behind much 

 beyond tlie apex. Length a tenth of an inch, height a fourth 

 less. 



The above description from a single decayed specimen 

 found by me adhering to an Actirda at Aberdeen. It differs 

 from Emarginula Fissiu^a in having the apex contorted and 

 turned aside. It appears that in full-grown shells the ribs 



