1883.] 'lightning' AND 'porcupine' EXPtUlTlONS. 95 



CiRCULUs STRiATUS, PhiUppi. 



Valvata striata, Phil, En. Moll. Sic. i. (1830) p. 147, t. ix. 

 f. 3, a-c. 



Trochus duminyi, B. C. iii. p. 315 ; v. p. 203, pi. Ixii. f. 5. 



' Porcupine' Exp. 1869 : Donegal B. 



Distribution. Bundoran in Donegal Bay, Atlantic coasts of France 

 and Spain, Mediterranean, and Atlantic ; 20-50 fms. 



Fossil. Pliocene : Coralline Crag and Italy. 



Solarium philippii, Cantraine, and Delphinula duminyi, Requien. 



A. Margarita, Gray. 

 1. Trochus fulgidus*, Jeffreys. (Plate XX. fig. 1.) 

 Shell globoso-conical, rather thin, transparent, and of a bright 

 lustre : sculpture, only some very fine and scratch-like spiral striae 

 round the base : colour clear white : spire raised : whorls 4, convex, 

 somewhat flattened below the suture ; the last occupies four fifths 

 of the shell ; apex depressed, and regularly spiral : suture rather 

 deep : mouth circular, incurved above ; the peristome is not con- 

 tinuous or complete, but similar to that of other species in the 

 present genus ; umbilicus narrow and deep ; operculum filmy, multi- 

 spiral, with obscure lines to distinguish the whorls. L. 0"1, 

 B. 0-085. 



'Porcupine' Exp. 1870: Atl. St. 9. A single but living speci- 

 men. 



i^ 2. Trochus minutulus^ Jeffreys. (Plate XX. fig. 2.) 



Shell pyramidal, rather solid for its minute size, opaque, and 

 polished : sctdpture none : colour white, with a yellowish tinge : 

 spire raised : whorls 6, moderately convex but compressed, regularly 

 enlarging ; the last is slightly keeled on the periphery, and occupies 

 about two fifths of the shell ; apex blunt : suture distinct and rather 

 deep : mouth representing an arc of two thirds of a circle, incurved 

 just below the periphery, and somewhat expanded below : umbilicus 

 sunken, with a small and deep perforation in the middle. L. 0*0625, 

 B. 0-05. 



' Porcupine' Exp. 1880: Atl. St. 16, \7a. A few specimens. 

 Fossil. Pliocene : Messina {Seguenza, as Margarita minima, MS.)! 

 As this name, however, has not been published, nor (as I believe) 

 been known to any but Seguenza and myself, I venture to change it 

 for an equally classical name which has not the objection of being 

 comparative in point of size. Perhaps hereafter a still more minute 

 species may be discovered, and thus the name minima would become 

 inappropriate. 



K 3. Trochus laminarum', Jeffreys. (Plate XX. fig. 3.) 



Shell conical, rather thin, semitransparent, and lustreless: sculp- 

 ture, numerous thin and delicate, but jagged and irregular curved 

 laminae in the line of growth, whicli do not extend to the umbihcus ; 



' Glittering. ^ Very small. ' Corered with thiu plates. 



