PROSOBRANCHIATA. 195 



Var. filifer. Testa latiori ; marginibus posticis anfractuum concentrice lineatis ; 

 lineis irregidaribus, aliquando granulatis. 



Shell oblong, inversely conical, smooth, with an elevated, nearly conical spire, in 

 height a little exceeding a third part of the whole length of the shell, and terminating 

 in a small pointed pullus of three volutions. The whorls, 8 — 10 in number, exclusive 

 of the pullus, are narrow, angulated at the shoulders, the posterior margins slanting 

 backwards towards the preceding whorl, and concave ; the sutural edge finely plicated 

 by the strongly marked lines of growth. The early whorls present on the shoulders a 

 row of small rounded tubercles, which are continued, more or less, on the later whorls, 

 in different individuals. The aperture is straight and narrow; the outer lip thin, sharp- 

 edged, not much arched, and separated from the suture by a wide, shallow curvature. 



In the specimens from Bracklesham Bay, forming the variety filifer, the shells are 

 wider than in the type, the posterior margins of the whorls present concentric lines, 

 variable in number, and occasionally finely granulated where they are decussated by 

 the lines of growth, and a single row of very small, bead-like knobs runs round the 

 sutural edge, instead of the plication usually found there, in this respect somewhat 

 resembling C. concinntcs. The specimens from Bramshaw agree better with the French 

 shells than do those from Bracklesham Bay ; in the latter the shells generally are 

 somewhat wider, the tubercles on the angles of the whorls disappear more early, and 

 the shoulders are blunter than in the typical form. I regard these differences, however, 

 rather as merely local variations than as sufficient to justify the separation of the shells 

 from the present species, with which they agree in the elevated spire, the slanting 

 concave margin and crenulated edge of the whorls, and the size of the shell itself. 



With regard to the nomenclature of the French shell, much confusion has arisen, 

 the origin of which is explained by M. Deshayes in a note in the 2d edition of 

 Lamarck's ' Histoire Naturelle' (vol. xi, p. 155). From this it appears that the shell 

 described by Bruguiere as having been found at Courtagnon, and to which he gave the 

 name C. antediluvianus, was, in fact, a Sub-apennine shell, and that Lamarck, misled by 

 this, quoted C. antediluvianus as a Paris-basin species in his Memoire, published in the 

 'Annales du Musee.' In 1814, Brocchi, in his work, applied the name given by 

 Bruguiere to the Sub-apennine shells, to which it strictly and properly belongs ; but 

 Lamarck, in 1822, in the first edition of his 'Histoire Naturelle/ again recorded 

 Bruguiere's species as occurring in the environs of Paris. Subsequently, M. Deshayes, 

 in his ' Description des coquilles fossiles,' &c, pointed out the fact that Bruguiere's 

 description referred to an Italian species not found in the Paris basin ; but unfortu- 

 nately, in describing the French Eocene shells, he applied Bruguiere's name to them. 

 Bronn also, in the ' Letlmea Geognostica/ retained the name C. antediluvianus for the 

 Paris-basin species, erroneously associating it with C. concinnus (Sow.), a species per- 

 fectly distinct ; and he proposed the specific name C. Apenninicus for the Sub-apennine 

 shells. The same author subsequently, in his ' Index Palaeontologicus,' again united 



