590 MK. UNSDALL EICHAEDSOX ON [Nov. I906, 



given to me by the late Prof. J. F. Blake, the fossils which Terquem 

 & Piette identified with Phillips's Dentcdium giganteum are de- 

 scribed as 'Dentcdium Terquemi, n. sp.' Tate thought therefore that 

 Terqnem & Piette's fossils were wrongly identified, and created 

 for their reception the specific name of D. Terquemi. 



As I have not seen the specimens, and sio.ce the authors say that 

 the ornamentation of the shells from the Plicatula-spinosa and 

 angidata-zcmes, is similar, of course I do not seek to argue that the 

 specimens from these horizons belong to distinct species ; but this 

 certainly seems probable, and it is also possible that while those 

 from the Plicahda-spinosa zone have been correctly identified with 

 Dentcdium giganteum, Phillips, those from the angidata-zone require 

 to be distinguished therefrom, and may bear Tate's suggested name 

 of D. Terquemi. This seems to be the most legitimate conclusion, 

 until more information is available. 



Dentalitjm teigozsale, Moore. (PI. XLY, figs. 4 a-c & 5 a-Q d.) 



T.d. 1867. Proc. Somerset Arch. & Nat. Hist. Soc. vol. xiii, p. 202. 

 T.f. Ibid. pi. v, fig. 22. 

 T.l. Carnerton [near Radstock, Somerset], 

 H. ^Middle Lias/ [Pliensbachian.] 

 t], \_armati/\ 

 Colin. Moore, Bath Museum. 



Syn. 1 ? 1858. Serpula triedra, Quenstedt, ' Der Jura ' pp. 200, 329 & pi. xxiv, fig. 55. 

 1875. Dentalium compressum, Tate, Quart. Journ. Geol. Soc. vol. xxxi, 



p. 504. 

 1904. Dentalium aff. limatulum, Richardson, ' Handbook to the Geology of 

 Cheltenham ' p. 219 & pi. xv, fig. 2. 

 Won ? 1850. Dentalium compressum, d'Orbigny, ' Prodrome de Paleont. : Liasien * 

 vol. i, no. 135, p. 233. 



Protolog {T.d.). — ' Shell triangular, thick, sheath-like, elongate, 

 smooth, slightly curved, sides flattened, or rather convex, covered 

 by numerous very fine annular oblique concentric strise, every 

 fourth or fifth of which is slightly raised and increased in thickness ; 

 section of the shell somewhat triangular, the base being thick, 

 broadest, and with a slight sinus, whilst the opposite or dorsal [_s>c] 

 margin is obtusely angular or carinated ; aperture elliptical.' 



Moore's description mentions, as being possessed by a certain 

 form, characters which really belong to two distinct species. The 

 sides ' are flattened, or rather convex,' he wrote, and ' the dorsal 

 [sic] 2 margin is obtusely angular or carinated.' If the sides are 

 flattened and the ventral margin carinated, then the form belongs to 

 the species D. subtrigoncde : if rather convex, with an obtuse ventral 

 margin, to the species D. trigoncde. 



Moore possessed three fragments of Dentcdium (?) trigoncde, which 

 he obtained from the Middle Lias of Carnerton. Prom these 

 syntypes he restored what he believed to be the shell of Dentcdium 

 (?) trigoncde, but he portrayed a specimen very much more erect than 

 the evidence at his disposal warranted. It is probable, however, 



1 See also Dentalium snhovatum, p. 587. 



2 Should be ' ventral.' The concave side of the shell is the dorsal. 



