188 MALACOZOA. GASTEROPODA. TECTIBRANCHIATA. 



the outer lip very thin, the columella exposed and gently 

 waved ; the surface with regular distinct divergent longitudinal 

 striae, which are moniliformly marked, or present the appear- 

 ance of two undulated lines intersecting each other, and faint 

 lines of growth ; the colour white. Length two-eighths, breadth 

 one-eighth. 



The markings are exactly similar to those of Bullsea Catena, 

 to which however this species has no other direct resemblance. 



Common in deep water off Aberdeen, frequently brought up 

 by the lines adhering to Actiniae, Ascidise, Shells, and other 

 bodies ; generally dead, and opaque dull white, or tinged with 

 brown, but sometimes alive, in which state I have several times 

 found it. 



GENUS 2. BULLA. 



Body oval or oblong, somewhat convex, transversely 

 divided into two parts ; hind part of the mantle bent 

 upwards ; head scarcely distinct, without tentacula; 

 branchiae dorsal, placed under the hind part of the 

 mantle. 



Shell partially covered by the mantle, oval, or oblong, 

 convolute, with the aperture wide at one end, the outer 

 lip thin, the place of the spire occupied by a cavity. 



1. Bulla Crdnchii. Cranch's Bulla. 



Shell subelliptical, subtruncate at the right extremity, some- 

 what narrowed at the left ; the aperture extending its whole 

 length, narrow at the right end, widened at the other, the outer 

 lip extending a little beyond the spiral depression, which is 

 small and deep, with the margin rounded, the columella visible 

 for a third of its length, and there decurved ; the surface rather 

 glossy, but longitudinally divergingly striate, about ten of the 

 striae at the right end, and eighteen at the left larger, all punc- 

 tate, and crossed by fine faint lines of growth ; the colour 

 white, with a broad medial zone of a faint reddish tint. Length 

 five-twelfths of an inch, breadth three-and-a-half twelfths. 



The above description is from an individual found by Mr. 

 Alexander Davidson, in the Winter of 1841, adhering to a 

 fishing-line, at Footdee, Aberdeen. Another specimen, in my 

 possession, was found by Mr. James Smith. It is considered 

 by Dr. Fleming as identical with his Bulla Cranchii, and pre- 

 sents, on being compared with his specimen of that shell, no 

 other difference than that of size. It was recognized by him, 



