r,6 Mr. T. II. WitlieiR oh 



In 1913 the (TPolopfioal Department of the Britisli !Mnsenm 

 ac(itiirc(l from Mr. II. T. Mail in two cirripedcs (ui a piece 

 o£ clialk, which he liad collected in tlie Niobrara scries of 

 Kansas, and which are referable to Sframenturn haivorthi, 

 Loj^an, sp., a species nndoubtcdly congeneric with Loricula 

 pulc/tella, G. B. Sowerby. The specimens looked nnproniisinj; 

 enongh when received, bnt carefnl development soon showed 

 certain points of structnre which enable us to add materially 

 to our knowledge of this anomalous type. The same 

 structural features had shortly before been discovered in the 

 tvpe-spceimens of Luricnin daririni, and it is on the com- 

 bined material that the following study of the genus is 

 based. 



History. 



Of this genus as many as nine species and two varieties 

 have so far been described, and in most cases the species is 

 known by more than one specimen. 



The first-discovered species, Loricula jmlchcUa, G. B. 

 Sowerby (IS-iS), was founded on a single nearly complete 

 specimen from the Tnronian (Middle Chalk) of Cuxton, 

 Kent. It was obtained by the late ^Mr. N. T. Wctherell, 

 whose collection is no\v in the Geological Department of the 

 British Museum, and the specimen is registered 59,150. 

 Darwin (1851) gave a masterly description of this specimen 

 in his Monograph. 



A few years later the species L. macadami was established 

 by Wyville Thomson (1858) for a fine specimen from tlie 

 Chalk of Antrim, and some obscure fragments of others of 

 a group are said to be scattered through the matrix. This 

 specimen sui)plcmcnts in many ways that of L. jndchella, 

 and, although it added much to our knowledge of the struc- 

 ture of the shell, it has not been referred to by any later 

 author *. 



In 1878 W. Dames described a single specimen from the 

 Cenomanian (Lower Chalk) of Lebanon, Syria, under the 

 name L. syriaca., and the specimen was subsequently 

 figured by Prof. Zittel (1881.). 



K. A. von Zittel (1884), for a single specimen from the 

 Senonian (Upper Clialk) of Diilmen, Westphalia, founded 

 tlie species L. lavissima. A plaster-cast of this is in the 

 Geological Department of the British Museum, registered 

 59,713. 



* R. Tate quotes the species ninoii<r n list of fossils, Quart. Journ. 

 Gool. Soc. LoudoiJ, vol. xxi. ISCo, p. 30. 



