MALACOZOA. GASTEROPODA. TECTIBKANCMIATA. 187 



1. Bulla a punctata. Punctulate Bullcea. 



Shell broadly ovato-elliptical, very thin, transparent, glossy, 

 with numerous longitudinal striae, and transverse raised lines, 

 leaving regular series of squarish depressions between them, or 

 presenting longitudinal lines of alternate prominences and de- 

 pressions ; the apex truncate, but with the first turn very 

 slightly projecting; the aperture wide, obovate, but very nar- 

 row at the right side ; the columellar margin exposed and a 

 little thickened, the outer edge thin, at the right end forming 

 a rounded lobe ; the colour hyaline-white. Length about a 

 twelfth, breadth nearly a third less than the length. 



Intermediate in form between Bullaea aperta and Bullaea 

 Catena, but differing from the latter in having the striae not 

 catenulate, but punctate. 



A specimen found by me among shell sand on the beach near 

 Aberdeen, 3d May, 1842; another in August. 



Bulla punctata. Adams, Linn. Trans, vi. PI. 1. f. 6, 7, 8. — Bul- 

 laea punctata. Turk Mag. Nat. Hist. vii. 353. 



2. Bullaa Catena. Oval Chain-streaked Bullcea. 



Shell oval, very thin, transparent, glossy, brittle, pure white ; 

 subtruncate at the right extremity, rounded at the other ; the 

 aperture extending its whole length, very wide, narrowed in 

 its upper fourth ; the outer lip very thin, crenulate, the colu- 

 mella exposed ; the apex depressed, scarcely umbilicate, with 

 two turns, the suture deep ; the surface with numerous regular 

 distinct divergent longitudinal elevated striae, which present 

 the appearance of two undulated lines intersecting each other, 

 or of a chain. Length three-twelfths of an inch, breadth two- 

 twelfths. 



Exactly similar in its markings to Bullaea catenulifera, but 

 more oval, and differing in the umbilicus. 



Not uncommon at Aberdeen, adhering to Actiniae and Asci- 

 diae, and often on the beach. First observed by me in January, 

 1842; about the same time by Mr. Davidson. 



Bulla Catena. Mont. Test. Brit. 215. PI. 7. f. 7.— Bulla Catena. 

 Flem. Brit. Anim. 294. 



3. Bullcea catenulifera. Ohlong Chain-streaked Bullcea. 



Shell oblongo-cylindrical, very thin, transparent, brittle, 

 pure white ; truncate at the right extremity, wider and rounded 

 at the other ; the aperture extending its whole length, narrow 

 for a fourth only, then dilated into an oblongo-truncato form, 



