302 PLIOCENE MOLLUSCA. 



appear on the Avhorls immediately above it, with finer ones in the spiral interspaces, 

 squarely cancellated by strong longitudinal costae, which are continuous, generally 

 obliquely, across the shelf ; suture deej) ; mouth wide, oval, angulated by the keel, 

 ending in a very short and open canal which turns to the left ; outer lip thin, 

 rounded, expanded. 



Dimensions. — L. 5 mm. B. 3 mm. 



Distribution. — Recent : Norwegian coast, Christiania Fiord to Finmark, Lofoten 

 Islands. Atlantic coasts of France, Mediterranean (Kobelt). Eastern coasts of 

 North America. 



Fossil : Isle of Man, Kirkmichael. 



Pleistocene : Christiania region. Area-clay, Isocardia- and Tapes-banks. 



Bemarls. — Considerable difference of opinion exists as to the correct nomen- 

 clature of the northern shell described by Malm as Tro'plion (now Tarnnis) MorcJii, 

 some authorities identifying it with the Sicilian species Pleurotoma cirratmn of 

 Brugnone.^ Assuming that Brugnone's figure correctly represents the latter, I am 

 inclined to agree with Jeffreys, Prof. (x. 0. Sars and Mr. Friele, that the two are 

 distinct. The fossil here described under the present name was found by the 

 Rev. S. N. Harrison at Kirkmichael on the west coast of the Isle of Man. 



It must be admitted that the figures given by the authorities here quoted do 

 not always agree with one another, or with the Manxland specimen, either in form 

 or sculpture. Malm's shell having a single prominent spiral ridge, as has that of 

 Prof. Br0gger, while the one represented by Prof. Gr. 0. Sars, subsequently repro- 

 duced by Tryon, Locard and Kobelt, shows two, as does Mr. Harrison's shell ; on 

 the other hand, the spire of the Manxland fossil is very short, approaching in this 

 respect Sturany's T. aJexandrina" (copied by Kobelt in 1905^) and Prof. Br0gger's 

 T. cirrata with its single ridge. In most of the illustrations referred to, the 

 longitudinal costae are shown to be deflected obliquely as they cross the ridge, in 

 zigzag fashion, while in the Manx fossil they are nearly straight. 



I am inclined, however, on the whole, to regard such differences as varietal, 

 grouping all the forms now in question except those of Brugnone and Sturany as 

 varieties of one variable species. 



Seguenza reported Pleurotoma Morclii from the Sicilian Pleistocene of Monte 

 Pellegrino and Ficarazzi, and from the Upper Pliocene of Altavilla and Caltabiano ; 

 Avhether he was referring to Brugnone's P. cirratum, which he describes as 

 " rarissimo fossile de Ficarazzi," or to Malm's shell, I am unable to say. 



The generic term Taranis was proposed by Jeffreys in 1870; taking T. Murclii 

 as the type, he distinguishes it as being without an operculum, having a very short 

 canal and peculiar sculpture. 



» Mem. Pleur. foss. Palermo, p. 17, fig. 9, 1862. 



2 Moll. Pola, p. 11, pi. i, figs. 8, 9, 1896. 



3 Op. cit., p. 325, pi. xciii, fig. 5, 1905. 



