106 PYRAMIDELLID.E. 



that of tlie latter species and of A. ascaris), thinner and 

 of a more delicate texture, and exquisitely polished, 

 having the whorls less convex, the outer lip more ex- 

 panded, and the pillar-lip nearly straight and spread out 

 at the base, and in the umbilicus being contracted. 



5. A. Gulso'n^"^, Clark. 



Chemnitzia Guhonce, Clark in Ann. & Mag. N. H. 3rd ser. vi. p. 459. 

 Odostomia Gulsoncs, F. & H. iv. (app.) p. 281, pi. cxxxii. f. 6. 



Body flake-white, with a faint tinge of yellow : mantle even 

 with the shell : neck very long, cylindrical (like that of Odo- 

 stomia spiralis), and finely wrinkled across ; the vertical fissure 

 of the mouth lies under the tentacular membrane : tentacles 

 thick, broad, short, not very membranous, rounded at the tips, 

 each of which has a minute flake-white lobe or inflation ; they 

 are united by an intermediate membrane : eyes black, not very 

 near together, immersed close to the base of the tentacles, on 

 minute white circles ; they do not in the least invade the area 

 of the neck, but rather infringe on the tentacles : foot exceed- 

 ingly short, narrow, deeply bifurcated in front, rounded be- 

 hind when at rest, and a little lengthened in action ; the front 

 edge (or mentum) is long, slender, grooved at the margin in 

 front and on each side, the upper and lower surfaces being 

 entire : opercidar lobe plain : liver light green : ovary very pale 

 red, and granular : branchial plume narrow and curved, con- 

 sisting of about 15-18 rather coarse, opaque, pale drab strands : 

 heart and auricle intense snow-white. (Clark.) 



Shell slender, rather cylindrical than conical, very thin, 

 transparent, and lustrous : sculpture, none : colour clear white : 

 spire gradually tapering to a blunt and nearly globular point, 

 which is decidedly introverted but not sinistral : whorls 6-7, 

 convex: suture deep, rather oblique: mouth roundish-oval, 

 having the outer base somewhat truncated and deeply sinuated 

 or almost notched : outer lip remarkably flexuous, prominent, 

 and expanding : inner (or pillar) lip short, nearly straight, and 

 slightly reflected near the base, not united with the outer lip ; 

 behind it is a slight depression and narrow chink, but no 

 umbilicus [: operculum "«an almost invisible film, pear-shaped 



* Named out of compliment to Mrs. Grulson, a lady at Exmouth, to 

 encourage her inclination for natural history. 



