Nigerian Eocene Mollusca. 31 



is furnished with a well-elevated plication, which forms the inner or left 

 boundary to the short posterior canal. In its possession of a smooth 

 protoconch, well excavated columella, regularly spiral and ridge-like sculpture 

 crossed by longitudinal striations, the long and nearly closed condition of the 

 anterior canal and other details suffice to illustrate its connection with the 

 European species. In many ways, also, the fossil approaches M^^,rex asper, 

 Solander from British Eocene deposits although that shell differs by having a 

 prominent postero -lateral and canaliculated spine situated at the posterior 

 angulation of the labrum. As acknowledged by M. Cossmann, both 

 M. tricarinatus and M. asper present close affinities with each other, although 

 he separates them, respectively, under Pteropurpura and Bayle's Alipurpura 

 (type = M. acanthoptems, Lamarck of Eastern seas : Bayle, in Fischer's 

 "Manuel Conchyliologie," 1884, p. 641), and refers to differences which 

 appear somewhat trivial for real purposes ^of distinction, and extremely difficult 

 to trace. The spire of the Nigerian shell is covered in places with a polyzoan 

 growth (Membranipora). 



DISTRIBUTION. Lutetian to Bartonian. Europe. 

 OCCURRENCE. Cutting No. i. 

 COLLECTOR. Mr. Kitson. 



Poirieria cf. oalcitrapa (Lamarck). 



PLATE 3, figs. 22, 23. 

 Murex calcitrapa. l 



Lamarck : Ann. Mus. Hist. Nat. Paris, 1803. Vol. 2, p. 223. 



Murex calcitrapoides. 



Lamarck : Hist. Nat. Anim. sans Vert., 1822. Vol. 7, p. 573. 



Murex calcitrapa. 



Deshayes : Desc. Coq. Foss. Paris, 1835. Vol. 2. pp. 588, 589, pi. 81, figs. 26, 27. 



Mtirex {Poirieria) calcitrapoides. 



Cossmann & Pissarro : Icon. Coq. Foss. Eocene Paris, 1911. PI. 36, figs. 169 (22). 



REMARKS. The collection contains rather more than 30 examples of a 

 small Muriciform shell exhibiting close relation with Lamarck's M. calcitrapa 



1 Lamarck founded the name of Murex calcitrapa, for a French Eocene shell in 1803, using the same 

 name afterwards for another Gastropod belonging to recent seas {Hist. Nat. Anim. sans Vert., 1822. Vol. 7, 

 p. 162). With the view probably of preventing the double employment of a specific designation, Lamarck 

 altered the fossil species to M. calcitrapoides, instead of substituting a name for the second M. calcitrapa. 

 This confusion of nomenclature has existed for a long period and even modern writers have adopted 

 M. calcitrapoides for the fossil instead of the original AT. calcitrapa, which has priority of several years, 

 notwithstanding the fact that the latter name had been accepted by Bronn in 1848 and by Orbigny in 1850, 

 for the fossil shell. 



