Cephalopoda in Tate and Blake's ‘ Yorkshire Lias.' 281 
it is not common, but grows to a diameter of 8 to 10 inches/ Its Geological 
position is stated to be ‘ In the limestone of the series to which it gives 
its name, Redcar/ 
Arietites bisulcatus Brugui&re sp. (p. 283). 
Respecting this species Blake writes : ‘ I keep this name for those 
forms that present a square front, almost transverse, with straight ribs 
tuberculated outside,’ and for the Geological position gives : ‘ Zone of 
A . Bucklandi, Redcar, Robin Hood’s Bay.’ The Blake collection contains 
an example [B.M. C. 19649], 22 mm. in diameter, labelled in his hand- 
writing : ‘ Buckl. Redcar, Ammonites bisulcatus,’ the word ‘Buckl. ’ 
evidently meaning ‘ Zone of A . Bucklandi .’ 
Arietites multicostatus J. de C. Sowerby sp. (p. 284). 
Respecting this species Blake writes : ‘ I have only seen two specimens 
in the Leckenby Collection and an imperfect one from Redcar, that I 
refer to this species ;’ and for the ‘ Geological position ’ he gives : ‘ Zone 
of A. Bucklandi, Redcar, and in boulders,’ but there is now no specimen 
in the Blake collection that appears to be referable to this species. 
Arietites obesulus spec. nov. (p. 284, PL- VI., fig. 2). 
Blake writes : ‘ This species is founded on specimens in the Leckenby 
Collection labelled A. nodulosus (Young and Bird), but as Young and 
Bird’s species of that name is a young form of A. margaritatus, and the 
name has been used for another form from Cheltenham, a new name is 
required. It is quoted in our Part I. as A. nodulosus.’ He gives its 
‘ Geological position ’ as : ‘ Probably zone of A. Bucklandi, Robin 
Hood’s Bay.’ The Blake collection does not contain any example that 
appears to be referable to this species. 
Arietites brooki J. Sowerby sp. (p. 284). 
Without any other remarks Blake simply writes : ‘ Geological posi- 
tion. — Zone of A. Bucklandi, Redcar, Robin Hood’s Bay (Simpson).’ 
In the Blake collection there is no specimen which has been marked as be- 
longing to this species. 
Arietites conybeari J. Sowerby sp. (p. 284, PI. VI., fig. 1). 
The figured specimen has not been recognised in the Blake collection, 
but the collection includes an ammonite [B.M. C. 19650], 118 mm. in 
diameter, labelled in Blake’s handwriting : ‘ Bucklandi. Redcar, 
Ammonites conybeari.’ 
Arietites spiratissimus Quenstedt sp. (p. 285). 
There is no example so labelled in the Blake collection. 
Arietites tar deer escens Hauer sp. (p. 285). 
A specimen in the Blake collection [B.M. No. C. 17879] is labelled in 
Blake’s handwriting : ‘ PI. A., fig. 5,’ and probably formed the basis 
■of Blake’s figure, but the latter has been restored and reduced, the greatest 
diameter of the original being 76’ 5 mm. It had no locality label, but 
Blake remarks about the species (p. 285) : ‘ It is very characteristic of 
the lowest beds of the Middle Lias, just at the base of the village of 
Robin Hood’s Bay, for which reason it is figured.’ Since the only 
horizon and locality for this species given by Blake is : ‘ Sub -zone of 
A. armatus, Robin Hood’s Bay,’ this may with safety be regarded as the 
horizon and locality of the fossil. Although figs. 5 and 5B. are connected 
by a dotted line, the two figures are not necessarily drawn from the 
same example, as evidenced also by other figures, e.g., PI. VI., figs. 
2A, 2B ( Aegoceras sagittarium), the original of fig. 2 being merely a 
1922 Aug.-Sept. 
