MARSHALL: ADDITIONS TO "BRITISH CONCHOLOGY. 223 



O. diaphana. — Thin, smooth, and glossy; shaped as Limtuza 

 glabra. 



O. obliqua.—Thm and spirally striated; shaped as Z. palustris. 



O. warreni. — Striated at base only; turreted whorls; shaped as 

 Z. stagnalis. 



O. minima Jeffr. — 5 to 90 f. in fine sand with an admixture of 

 mud. Port Erin and Puffin Island (L.M.B.C); Berehaven 5 f. 

 (R.I. A. cruise); Roundstone Bay (Dodd) ! Antrim (Chaster); Lis- 

 more, 6 f. (Knight)! N. and E. Sutherlandshire (Baillie)! St. Magnus 

 Bay, 60 — 80 f. (Jeffreys); St. Aubin's Bay, Jersey; Guernsey and 

 Sark, 15 — 20 f. ; Scilly, 40 f. ; Falmouth, 19 f. ; Mount's Bay; Caw- 

 sand Bay, Plymouth, 12 f. ; Oban, 25 f. ; the Minch off Loch 

 Boisdale, 20 f. ; Raised beach, Skye (T. Scott) ! Also from Sooloom 

 Bay, Tripoli, (H.M.S. Shearwater)! 



A scarce species, and very minute; but patient examination of fine 

 dredgings with a microscope will not go unrewarded. In Jeffreys' 

 description 1 he says the inner lip " is united with the outer so as to 

 form a continuous but indistinct peristome," while in his text on the 

 next page he says the contrary, so that on page 16, line 5, the word 

 " nor " should be replaced by the words " and being." The characters 

 of the peristome and umbilicus are uncertain, and appear to me mere 

 individual variations ; in both these respects it is similar to immature 

 Pherusa gulsona'., with which it has some affinity; but under a micro- 

 scope the flexuous longitudinal striae of O. minima will be found a 

 marked character. Its general appearance is not unlike a young O. 

 nitidissima, but it has a bulbous apex instead of a spiral one. This mite 

 of a shell occurs in the post-tertiary estuarine clay at Magheramorne, 

 on Larne Lough, where 60 specimens occurred in a quarter of a cubic 

 inch of fine siftings (Praeger) ! Dr. Jeffreys had previously identified 

 one example found by Mr. Stewart in the same deposit. Some of 

 Mr. Praeger's specimens are two or three times as large as the recent 

 form, and have six whorls. It would thus appear that our little 

 Odostomia has sadly degenerated. 



Jeffreys' figure is a good one, though badly executed, but his micro, 

 figure is not near it; nor is Sowerby's figure anything like. Good 

 figures will be found accompanying the original description by 

 Jeffreys 2 ; it will be noted that the front one shows no trace of an 

 umbilicus or chink, and it has a " complete continuity of the 

 outer lip." 



O. nivosa Mont. — In rock-pools at low water and dredged dead 

 at all depths. Killala Bay (Miss Warren)! Lismore, 6 f. (Knight)! 



1 Brit. Conch., vol. 4, p. 115. 



2 Ann, Mag. Nat. Hist. (3) vol. 1, p. 45, pi. 2, fig, 3, 185S 



