368 PLEUROTOMID^. 



others) , Adriatic (Chieregliini and others) , and JEgean 

 (Forbes) . 



It frequently turns upon its back and floats. The 

 shell varies in size and in the length of the spire. Spe- 

 cimens from the Clyde district resemble those of the 

 Mediterranean in their deep but bright colour. 



Fleming described this species as Pleurotoma sinuosa, 

 supposing it to be the Murex sinuosus of Montagu ; it 

 is the P. zoncdis of Delle Chiaje_, P. inflata of Cristofori 

 and Jan_, P. concinna of Scacchi, Fusus Boot Mi of Brown, 

 and (according to Nardo) Murex caudicula of Chiere- 

 ghini. P. Levfroyi of Homes appears diflferent. 



4. D. linea'rts"^, Montagu. 



Murex linearis, Mont. Test. Br. (i.) p. 261, t, 9. f. 4. Mangelia linearis, 

 F. & H. iii. p. 470, pi. cxiv. f. 1-3, and (animal) pi. EE. f. 6. 



Body white, with occasionally a faint tinge of yellow or 

 lleshcolour, and sometimes minutely speclded with flake-white : 

 palllal tube varying in compactness and length, with a wide 

 opening : head very small, short, and flat : tentacles conico- 

 cylindrical, extensile, occasionally safFroncolour, with bulbous 

 tips : eyes rather prominent, about halfway up the tentacles, 

 on the usual stalks : foot expansile, sometimes narrow and 

 very long, more or less deeply cloven in front, with triangular 

 and recurved corners, tapering behind to a fine point. 



Shell very much smaller than D. Leufroyi, and of a 

 narrower shape, always solid, opaque, and not so glossy: 

 sculpture, strong, curved, and buttress-like longitudinal ribs, 

 which extend not only to the base but to the suture ; the 

 body- whorl and the next have each about a dozen, the next 

 about 10, and in the same proportion upwards ; these ribs are 

 traversed by thread-like spiral striae, of which about a dozen 

 are on the body- whorl, 5 or 6 on the next, 4 or 5 on the next, 

 and so on ; crests of the ribs muricated ; third whorl slightly 

 keeled in the middle, and top whorls reticulated, as in the last 

 species ; the entire surface is microscopically and closely reti- 

 culated, and the lines of growth are rather distinct : colour 



* Marked with lines. 



