im perfectly -defined Species of Jurassic &c. Nautili. 399 



than high. Umbilicus closed, though open iu the cast. 

 Septa rather numerous, slightly curved upon the sides, a very 

 obscure sinus upon the periphery. Siphuncle situated below 

 the centre. Ornaments of the test consisting of numerous, 

 very coarse, prominent, obtuse ridges, separated by inter- 

 spaces of about half their own width. The ridges are each 

 about 3 lines wide upon the periphery, where they form a 

 narrow backwardly-directed sinus. 



Remarks. Pictet and Campiche, in the Pal. Suisse *, have 

 adopted the name Nautilus Necherianus for a form which is 

 evidently identical with Sowerby's N. radiafus, and the source 

 of error seems to have been in the locality of the type speci- 

 men of the last-named species, which is referred to by 

 Sowerby f in the following words : — " Lately found in the 

 neighbourhood of Maltor, probably in the lower part of the 

 Green Sand formation. I have received but one specimen, a 

 cast in Marly Limestone, mixed with grains of Silex and of 

 blackish Green-earth." Possibly the locality quoted by 

 Pictet and Campiche was taken from the supplementary index 

 to the ' Mineral Conchology ' by Mr. John Farey, who gives 

 " New-Malton, E.," as the locality of the type. 



We have been able to identify Sowerby's type in the 

 " Sowerby Collection," and the matrix agrees with that 

 described by Sowerby, showing that the specimen came from 

 the Lower Greensand. In its mode of preservation and 

 general appearance as to colour, texture, &c, it closely re- 

 sembles specimens from the Lower Greensand of Hythe. 

 Without doubt Sowerby's specimen was derived from the 

 Lower Greensand, but we have not been able to obtain any 

 clue as to the locality (Maltor), furnished by him in his 

 description, above quoted. 



There seems to be no ground whatever for Young and 

 Bird's statement on p. 271 of their work on the Yorkshire 

 Coast (2nd ed.), that " Sowerby's N. radiatus (tab. 256) 

 was found near Malton, most probably in the grey limestone 

 under the Oolite." Those authors were probably misled by 

 the locality given by Farey in the Supplementary Index 

 to vol. iv. of the ' Mineral Conchology.' 



Nautilus bifurcatus, Ooster J, somewhat resembles the 

 present species, but differs in its more compressed form, and 

 in the possession of fine and numerous longitudinal ridges. 



* S6r. ii. pt. i. 1859, p. 132, pi. xvi. 

 t Min. Conch, vol. iv. 1822, p. 78, pi. ccclvi. 



\ Cat. des Cephalopodes Fossiles des Alpes Suisses, pt. iii. 1858, p. 10, 

 tab. ix. fig. 6, tab. x. tigs. 1, 2. 



