MARSHALL : ADDITIONS TO " BRITISH CONCHOLOGY." 295 



Then, the O. jeffreysi of Bucq. D. & D. (cited and approved 

 as a species by Jeffreys, 1 with a suggestion that the name must 

 be changed owing to its being preoccupied) is this same var. 

 intermixta; but var. fiexicosta Jeffr. is much more distinct, and 

 very different from that and every other form in its peculiar shape, 

 being a small, oval, pupseform shell, though having the typical 

 sculpture of O. interstincta — the latter character, in my opinion, 

 making it no more, and no less, a species than the others. The 

 difference in its outlines is certainly great, but not more so than in 

 some of the other varieties. I consider it the deep-water form of 

 this polymorphous species, as it has hitherto only been dredged in 

 deep water. It previously had the MS. names of O. flexuosa Jeffr. 

 and O. interrupt a Mtros., but Jeffreys subsequently adopted the 

 former name for another "Porcupine" Odostomia, while the latter 

 name must give place to that of fiexicosta. This form has not been 

 figured, but it has much resemblance to O. obdes Watson, from N.E. 

 Australia, and has some affinity with O. procuerta Mtros. 



O. spiralis Mont. — A common and well-known species, a 

 peculiar variety of which has the longitudinal sculpture obsolete on 

 the last whorl, and rarely on the penultimate as well, in all cases the 

 result of a fresh start in growth after a breakage or rest. A dwarf 

 variety from several districts has a rounder base and more convex 

 whorls. The finest come from the northern coasts of Scotland, and 

 are a line-and-a-half in length. 



Var. coarctata Marsh. (/. Conch, vol. 6, p. 347, 1891). — This 

 resembles some of the cylindrical forms of O. interstincta. It is found 

 very sparingly with the type, but is most prevalent at the mouth of 

 the Clyde, and off the Mull of Cantire, in 60 f. All the specimens 

 belong to this variety. 



Monst. — Whorls telescoped. This is found occasionally with the 

 type, but more frequently in Torbay, whence I have nearly a score 

 specimens. 



O. eximia Jeffr. — The Minch off Loch Boisdale, 72f. ; Linga 

 Sound, E. Shetland, 3of. Also 60 miles off the Scillies, 3oo-6oof. 

 (Porcupine) ! 



This species is minute and rare, and the tooth is of the slightest 

 description. Norwegian and Icelandic specimens are much larger 

 and more conical than British. The figures in "British Mollusca" 

 and Sowerby's "Index" are excellent; but Jeffreys' should be more 

 conical, the whorls more tumid, and the dimensions one-half; the 

 sculpture it is impossible to define. 



1 Moll. "Lightning" and Parcupine, Proc. Zool. Sec, 1884, pp. 353-4. 



