126 



MOLLUSCA. 



Montagu, in describing that species, says, " the edge crenated." 



(Page 131.) 



With respect to Crassina multicoslata being "strangely 

 confounded" with C. elliptica by several authors, 1 have not 

 observed these. The former shell was first figured, described, 

 and named by me in the VIII. vol. of the Wernerian Memoirs. 

 It is a Fossil species belonging to the Newer Pliocene Depo- 

 sits, and has never been found recent to my knowledge. The 

 Professor is decidedly in error in referring my C. convexiscula 

 to this species. 



Genus Polystomella. — (Page 1.) 



4. Polystomella Gulielminje. 

 Polystomella Gulielmince, Macgillivray, Moll., p. 315. 

 Shell orbicular, discoidal, equally convex on both sides, and 



compressed, slanting to a thin subcarinated ambit or back; ex- 

 ternal volution consisting of about fifteen radiating chambers, 

 elevated, narrow, and convex, with transversely sulcated concave 

 interstices ; centres elevated, and the aperture semilunar, con- 

 vex, thickened at the margin, and moderately raised, with its 

 sides embracing the next convolution. Diameter about the 

 sixteenth of an inch. 



Found by Professor Macgillivray, on the beach near Aber- 

 deen, adhering to Terebella and Pectenarice. 



5. Polystomella crenulata. 

 Polystomella crenulata, Macgillivray, Moll., p. 316. 



Shell nearly round, discoidal, considerably compressed, with 

 somewhat convex sides; ambit rounded; external volution pro- 

 vided with about twenty inflated, curved, transversely crenated 

 chambers; partitions concave and crenated; aperture semilunar, 

 narrow, convex ; colour bluish-grey. Diameter about the fif- 

 teenth of an inch. 



Differs from P. crispa, in being much less, and in having the 

 entire surface and grooves crenated, and with a convex margin. 



Found by Professor Macgillivray, in shell sand from Cruden 

 Bay, and on the beach at Aberdeen, adhering to Terebella 

 conchilega. 



6. Polystomella Nautilina. 

 Polystomella Nautilina, Macgillivray, Moll., p. 317. 



Shell nautiliform, with uinbilicatcd, somewhat convex sides ; 

 ambit rounded ; external volution with from ten to twelve 

 small slightly inflated, narrow, smooth, glossy chambers, which 

 increase gradually, and then rapidly towards the last cell, which 

 is large, and granulated towards the umbilicus ; partitions de- 

 pressed, curved, and slightly striated ; flat, with two medial 

 ridges, provided with two series of pores, and a nearly flat 

 cover; aperture cordiform, and embracing the next convolution; 

 colour greyish-white. Diameter about the fiftieth of an inch. 



Found by Professor Macgillivray, adhering to Terebella conchi- 

 lega, on the beach near Aberdeen, where it is not uncommon. 



Genus Lagena. — (Page 3.) 



7. Lagena globosa, pi. LVI, f. 37. 



Lagena globosa, First Ed., pi. 1, f. 37 ; Fleming, Edin. Ency., 

 VII, p. 08, pi. 204, f. 10 ; Vermiculum globosum, Montagu, p. 

 523. 



Shell somewhat flask-shaped, white, smooth, transparent; 

 aperture small, and nearly orbicular ; base rounded. 



Found at Sandwich ; rare. 



8. Lagena reticulata. 



Lagenula reticulata, Macgillivray, Moll. Ab., p. 38. 



Shell somewhat ovatcly globose, considerably compressed, 

 white, smooth, glossy, and pellucid, with many internal, irregu- 

 lar, opaque, white, reticulated, quadrate spaces; internal cavity 

 simple, with parietal cells; aperture terminal, oval, and ample. 

 Length about the thirty-sixth part of an inch ; breadth con- 

 siderably less. 



Found by Professor Macgillivray, among shells and corallines, 

 from the Bay of Aberdeen. 



Genus 6. — Trichotropis Broderip. 



Turbinated, carinated, umbilicated ; aperture large, and 

 entire ; columella obliquely truncated ; outer lip thin, sharp ; 

 covered with a horny epidermis, produced into long cilia? ; 

 operculum horny, and elastic. 



1. Trichotropis acuminata, pi. LVII, f. 15. 



Trichotropis acuminata, Jeffreys, MSS. ; Fusus umbilicatus, 

 Brown, Wernerian Mem., VIII, p. 50, pi. 1, f. 2. 



Shell with seven turreted, deeply defined volutions, tapering 

 abruptly to an acute apex, and obliquely flattened above ; body 

 provided with seven strong, transverse ribs, and the volutions of 

 the spire with three each ; ribs and interstices crossed by fine, 

 oblique, longitudinal stria?, which are hardly visible without the 

 aid of a lens; aperture semi-ovate; pillar lip broadly reflected 

 on the columella, behind which is an elongated umbilicus, ex- 

 tending nearly to the base of the shell ; outer lip thin, and cre- 

 nulated on the exterior margin by the ribs. Length upwards 

 of half an inch ; diameter of body nearly three-eighths. 



Dredged from deep water in Rothesay Bay, by James Smith, 

 Esq., of Jordan Hill ; and has since been found at Oban, 

 Argyleshire, by J. Gwyer Jeffreys, Esq., of Swansea, Wales. 



Genus Buccinum — (Page 4.) 



10. Buccinum carinatum, pi. LVII, f. 18. 



Buccinum carinatum, Turton, Conch. Diet., p. 13, pi. 26, 

 f. 94. 



Shell oblong-oval, turreted; body large, inflated; spire small, 

 consisting of five or six flat-sided, abruptly decreasing volutions, 

 obliquely flattened above, which, as well as the body, are fur- 

 nished with a carinated ridge on their superior margin ; sutural 

 line of the spire very fine ; whole surface of a pale chestnut- 

 colour, covered by remote, transverse, parallel, nearly equidistant 

 stria?, upwards of a quarter of an inch apart from each other, 

 crossed by indistinct, irregular, longitudinal wrinkles ; aperture 

 subovate, dilated, and terminating below in a short canal; outer 

 lip somewhat thickened at the edge; inner lip smooth, white, 

 and broadly reflected on the columella, with two slight longitu- 

 dinal folds on the external side. Length four inches and a 

 quarter ; breadth two inches and a half. 



Discovered on the strand at Portmarnock, Ireland, by M. J. 

 O'Kelly, Esq., and is the specimen from which our drawing was 

 made. Dr. Turton says another was dredged at Bray, and has 

 also been found at Bulloch, Ireland, by the late Mr. Tardy. It 

 has since been met with at Exmouth. 



This may only be a litsus of Buccinum undatum. 



