276 Zoological Society. 



mode of gi'owth already described, two new frustules being gra- 

 dually formed within tlie old one ; but it differs from Isthmia in 

 having all its angles equal, and from both in having a four-sided 

 and not a compressed figm-e. 



1 . A. antediluviana, Eh. Frustules nearly square, lateral surfaces with 



the cells arranged in a radiate form. Pritch. Infus. p. 442. 



Parasitic on the smaller marine alga?. Ilfracombe, Devonshire ; 

 and by the Mumbles Light-house near Swansea. 



It is of a dirty-brown colom* when recent and becomes paler 

 in drying. 



Filaments elongated, frequently containing thirty frustules in 

 a chain ; frustules minute, nearly equal in length and breadth ; 

 each lateral portion has four slightly produced angles and no in- 

 termediate projections, and its cells are rather large and some- 

 what radiate. 



On a lateral view the figure is quadrangular with concave sides, 

 and at each angle there is either a round opening, or a large and 

 more strongly marked cell which presents the appearance of one. 



The central portion is fom--sided, and its reticulations, which 

 are smaller, are frequently arranged in lines. 



Mrs. Griffiths aptly compares the figures of the separated frus- 

 tules to bales of cloth made up watli bands for exportation. 



Plate VIII. fig. 5. a, Amphitetras antediluviana ; b, frustules deprived 

 of their colouring matter ; c, lateral view. 



[To be continued.] 



PROCEEDINGS OF LEARNED SOCIETIES. 



ZOOLOGICAL SOCIETY. 



Nov. 22, 1842.— Wm. Yarrell, Esq., Vice-President, in the Chair. 



The following descriptions of new species of Nerites, collected by 

 Mr. Cuming in the Philippine Islands, by M. C. A. Recluz, were read. 



Observation. — By length is meant the distance from the summit 

 of the spire to the external base of the columella ; by breadth, the 

 diameter formed by the extremities of a line which should pass from 

 the anterior to the jjosterior side ; and by convexity or thickness, the 

 distance comprised between the most convex parts of the columella 

 and of the last whorl. 



Second Section of the Genus. — Shells smooth, or striated length- 

 wise ; outer lip without teeth and without furrows internally ; colu- 

 mella not notched at the summit ; columellar lip sharp, or crenulated 

 at the margin. Neritina, Lamarck. 



* Orbiculatse sen subhemisphaericae. 

 1. Nerita labiosa (Sowerby). N. testa orbiculari, postice angus- 

 tatd, fornicatd, crassd, maxima, striatd,fusco-viridescente, nigra 

 ct rufo obsolete variegatd ; anfractibus duobus ad suturam com- 



