304 MRS. JANE LOXGSTAFF ON SOME NEW [Sept. I912 



the Gilbertson Collection in the British Museum (Natural History) 

 from Bolland, there is one which is very like his figure, not only 

 the structure, but the colour-markings also being almost identical. 

 With this I have compared the only specimen of the species under 

 discussion and find that it differs in having a greater spiral angle ; 

 in the whorls being wider, more flattened above, and sloping out 

 more obliquely; in the groove above the band being much deeper; 

 and in the colour-blotches also being somewhat broader and 

 irregular. The band of this Bolland example agrees with the 

 figure in having simple bordering threads ; these, however, are much 

 worn. Two smaller individuals on the same tablet, which are 

 conspecific, have the band filled in between the margins in such a 

 manner as to suggest the possibility that they were produced to 

 form a keel. If the discovery of better preserved specimens should 

 prove this to have been the ease, Pleurotomaria conica Phill. should 

 be referred to this subgenus instead of to Mourlonia De Kon. 



Dimensions. — The holotype, which is the only known specimen, 

 is in Dr. Trechmann's collection. It has but three whorls pre- 

 served, which measure 14 millimetres in length, while 19 mm. is 

 the greatest width. 



Locality and horizon. — Stanhope-in-Weardale, in the Great 

 Limestone. 



Family MurcMsoniidae Koken. 



Genus Pithodea De Koninck. 



Diagnosis. — Shell of large size, buccinoid, ventricose ; spire 

 relatively short. Whorls convex, increasing rapidly, having a flat 

 band formed by the gradual filling-up of a broad but shallow sinus 

 in the outer lip. Ornamentation consisting of numerous raised 

 spiral threads. Aperture large, oval. Columella simple, thin, and 

 straight towards the base. iS"o umbilicus. 



Genotype. — PWiodea amplissima De Kon. 



Dimensions. — The specimens vary in length from 14 or 15 

 centimetres down to about 6 ; in width from 10 down to 5-4 cm. 



Remarks and resemblances. — De Koninck places this genus 

 provisionally in the family Turbinidse, because of its very thin test, 

 which does not appear to have been nacreous. Fischer, however, 

 refers it to the Pleurotomariidce, from which the absence of a 

 nacreous layer Separates it. On this account, as well as from the 

 fact that it has a sinus in the outer lip represented by a band 

 on the whorls, I consider it better to place it in the Murchisoniidae. 

 It should stand ia proximity to Caliendrum Brown,^ which it 

 resembles in contour, in the form of the lines of growth, and in the 

 character of the band. It is distinguished from that genus by pos- 

 sessing numerous raised spiral threads, and possibly by the structure 

 of the columellar lip, which does not appear to have been reflected. 



' ' Illustrations of the Fossil Conchology of Great Britain & Ireland ' 1849, 

 p. 52 & pi. xxxii, fig. 20. 



