Volva. MOLLUSCA. SOLENOSTOMATA. 331 



Length about fths of an inch ; breadth |ths ; of a pink colour with or 

 without (C. arctica) dark dorsal spots ; stria? distinct, bifurcated at the sides. 

 In the young state, the shell is smooth, except some appearances of striae on 

 the inner-lip, and the apex exhibits two or three whorls, — in which state it 

 is the C. bullata of Mont. Test. Brit, 202. t. vi. f. 1. The C. pediculus dif- 

 fers from the present species, with which it has been frequently confounded, 

 by the roughness of the stride, and the presence of a longitudinal dorsal 

 groove. 



EXTINCT SPECIES. 



1. C. oviformis. — Egg-shapped, tumid, smooth, slightly marginate ; aperture 

 widest at the lowest end, left side of the aperture obscurely toothed ; right 

 lip involute, tumid Sower. Min. Conch, t. iv. — London Clay. 



2. C coceinelloides.— Ovate "sphaeroidal, transversely striated ; striae nu- 

 merous, acute, not interrupted ; aperture slightly arched, not contracted in 

 the middle Sower. Min. Conch, t. ccclxxviii. f. 1. — Suffolk Cvag. 



3. C. retusa. — Obovate, sphaeroidal, transversely striated ; striae elevated, 

 uninterrupted, few, remote ; aperture a little curved at the narrowest end. 

 —Sower. Min. Conch, t. ccclxxviii. f. 2. 



4. C. avellana. — Obovate, sphaeroidal, transversely striated ; striae nume- 

 rous, remote, elevated, interrupted by a longitudinal sulcus ; aperture a little 

 curved at the narrowest end. — Sower. Min. Conch, t. ccclxxviii. f. 3. 



OVULAD.E. 



Gen. LXIV. VOLVA. — Canal at each extremity, produced ; 

 external lip simple. 



— 295. V. patula. — Oblong, white, spirally striated ; pillai 

 with a shallow furrow. 



Bulla patula, Penn. Brit. Zool. iv. 117- 1. 70. f. 85, A. Don. Brit. Shells, 

 t. cxliii. Mont. Test. Brit. 207 — North and South Britain, rare. 

 Length about an inch, breadth half an inch ; outer-lip regularly rounded ; 

 inner-lip protuberant in the middle, twisted and subreflected retrally ; back, 

 rounded. 



GEN. CALPURNA. — Canals abbreviated ; external lip 

 simple. 



1. L. Leathes'%. — Elliptical, elongated, rather ventricose in the middle ; 

 smooth ; a large plait on the pillar ; outer-lip smooth, very thick, and rather 

 flattened— Ovula Leath. Sower. Min. Conch, t. cccclxxviii.— .In the Crag at 

 Walton. 



