ttALACOZOA. GASTEROPODA. PECTINIBRANCHIATA. 157 



the peristome slightly thickened, not reflexed on the pillar, 

 but ending in a very slight plait behind the umbilicus, which 

 is very small; the colour hyaline-white. Length half a twelfth 

 of an 'inch, breadth half the length. 



The peculiar markings of this species render it one of the 

 most easily recognized of the genus. The tooth is so little ap- 

 parent that, were not the peristome incomplete for a short 

 space, it might be referred to the genus Rissoa, to which it 

 forms the transition. I have named it after one of my daugh- 

 ters, Marion, who has greatly aided me in collecting the Mol- 

 lusca of the district, and evinced the greatest pleasure in find- 

 ing anything that could be useful to me. 



Found by me, in August, 1 842, in shell sand, between the 

 mouths of the Dee and the Don. 



D. Odostomia Annce. Anne's Odostomia. 



Shell oblongo-turrite, of five, rather thick, opaque, glossy 

 turns, destitute of markings, and separated by a not deeply- 

 impressed line ; the last turn convex and proportionally large, 

 the rest flattened ; the mouth ovate, nearly a third of the whole 

 length, with the peristome thin, its columellar portion rather 

 inflexed, and terminating in a small plait on the columella, 

 opposite the slight umbilicus ; the colour pure white. Length 

 half a twelfth of an inch, breadth a third of the length. 



Found, in August, 1842, by me and my daughter Anne, 

 after whom I have named it, her conchilegal propensity hav- 

 ing often been indulged in my behalf. 



This species is easily distinguished from all the rest by its 

 peculiar form. 



10. Odostomia ollonga. Oblong Odostomia. 



Shell oblong, subcylindrical, very slowly tapering, and end- 

 ing in an obtuse point ; of five flattened turns, of which the 

 upper three are smooth, the rest transversely marked with 

 numerous fine ribs ; the suture deeply-impressed ; the aperture 

 a fourth of the whole length, ovate, with the peristome ending 

 about the middle of the inner side in a prominent plait running 

 into the interior. Length scarcely half a twelfth, breadth a 

 third of the length. 



Very similar in form and markings to Rissoa truncata; but 

 not a third of the size, and having the essential character of 

 an Odostomia. 



sent 



Found by me among shell sand from the Bay of Cruden, 

 it by Mr. Alexander Murray, in November, 1842. 



