OaxHocEUA. MOLLUSC A. CEPHALOPODA. 235 



22. L. perlucida. — Shell with six equidistant, longitudinal 

 ribs. 



Ver. per. Mont. Test. Brit. 525, t. xiv. f. 3.— At Seasalter, Mr Boys. 

 Length about I'gth of an inch ; smooth ; rounded retrally with a small 

 knob ; aperture very small. 



** With decussating strice. 



23. L. squamosa. — Striae undulated, giving the shell an im- 

 bricated appearance. 



Verm, squam. Mont. Test. Brit. 526, t. xiv. f. 4 At Seasalter, Mr 



Boys. 



Shell minute, subglobose, the aperture a little produced. 

 *** Surface smooth. 



24. L. glohosa. — Nearly ovate, the mouth not produced. 

 Serp. Lag. la?vis globosa. Walk. Test. Min. t. 1. f. 8. — Sandwich, rare. 



Shell white, transparent ; the aperture round. 



25. L. Iccvis. — Ovate, with a produced cylindrical neck. 



Serp. I jag. loevis ovalis. Walk. Test. t. 1. f. 9 — At Sandwich, rare. 



Bluish-white, transparent ; it differs from the last in its more oblong shape 

 and produced mouth. 



26. L. marginata. — Compressed, marginated. 



Serp. Lag. marginata, Walk. Test. Min. t. 1. f. 7 — Verm. marg. Mont. 

 Test. Brit. 524 — On the English coasts, rare. 

 Shell nearly ovate ; the mouth but little produced. In a single speci- 

 men, which I found in sand, from Zetland, and which, by accident, was 

 broken on the stage of the microscope, appearances of internal plates, the 

 partitions of chambers, were indistinctly observed. 



27. L. urna. Globular, with a produced knob retraUy. 



Verm, umae, Mont. Test. Brit. 525, t. xiv. f. 1 — In sand from Shepey 

 Island. 

 Length about a line ; slopes suddenly into a short conic neck. 

 The place of this genus is far from being satisfactorily determined, and the 

 minuteness of the species composing it present great obstacles to an accurate 

 examination. 



Gen. IX. ORTHOCERA.— SheU (naked ?) nearly straight, 



the chambers separated by transverse perforated septa. 



a. Recent species. 



* With longitudinal ribs. 



28. O.jugosa. — Subcyhndrical, slightly curved, with nume- 

 rous longitudinal ribs. 



Nautilus jug. Mont. Test. Brit. 198, t. xiv. f. 4 — On the Kentish coast, 

 Mr Boys. 



Length about |th of an inch ; tapering little, chambers globose, nine in 



/ 



