286 Cephalopoda in Tate and Blake’s ‘ Yorkshire Lias. 
labelled in Blake’s handwriting : ‘ A. ibex, M.L. R.H.B.’ [^Middle 
Lias ; Robin Hood’s Bay], that may be the fossil to which Blake refers 
(p. 297), as ' one being of the variety having rounded ridges on the 
front like P. ibex .’ Tlie specimen is 79-2 mm. in diameter and exhibits 
rounded ridges on the periphery. Since the specimen is marked in 
Blake’s handwritng : ‘ A. ibex,’ and that that species is mentioned 
only under Phyllocevas loscombi, this specimen would seem to be the 
fossil there alluded to. 
Stephanoceras mass-um G. Young and J. Bird sp. (p. 300). 
The Blake collection includes an ammonite [B.M. No. C. 17902], 
which is evidently the original of Blake’s PI. VIII., fig. 5, the figure 
being somewhat reduced, the original being 66-4 mm. in its greatest 
diameter,, and 30 mm. in greatest thickness. It is labelled in Blake’s 
handwriting : ‘ PI. D, fig. 5,’ but has no locality label. The locality 
and horizon must therefore be regarded as a little doubtful, the ‘ Geological 
position ’ of the species given by Blake being : ‘ Zone of A. communis 
and, perhaps, serpentinus, Whitby, Boulby, etc.’ Blake assigned 
several of Simpson’s species to Young and Bird’s crassus -, and the specimen 
under consideration he considered to be Simpson’s puteolus [Blake, p. 
300). 
Stephanoceras fonticulum Simpson sp. (p. 301). 
The original of PI. I.,* fig. 10 is in the Blake collection [B.M. No. 
C. 17904], and is well represented of the natural size in Blake’s figure. 
The specimen lacks the morphological right half of the last half whorl. 
When received it was labelled ‘ ioa,” but bears no label indicating its 
locality and horizon. There can, however, be no doubt as to its being 
the figured example. Since the only horizon and locality given by 
Blake for this species is ‘Probably zone of A. serpentinus, Whitby,’ 
these particulars must be held to apply to the figured example. 
Harpoceras algovianum Oppel sp. (p. 302). 
A specimen in the Blake collection [B.M. No. C. 17900] is obviously 
the original of Blake’s PI. VIII., fig. 1. Its label is both imperfect and 
obscure, but seems to be : ‘ PI. D, fig. 1 ... . anus.’ There can, however, 
be no doubt whatever as to the identity of this specimen with Blake's 
figure, which is reduced, the original being 83-6 mm. in its greatest 
diameter. The specimen bears no locality label and since for the ‘Geol- 
ogical position ’ of the species Blake records : ‘ Zone of A. margaritatus , 
Hawsker, Staithes, Marske Mill, Saltburn, Rockcliff (rare) ; ’ whilst the 
horizon of the fossil is the ‘ zone of A, margaritatus , ’ the exact locality 
is, therefore, a little uncertain, although the matrix suggests this zone 
at Hawsker. Blake writes : ‘ The specimen figured is not a typical 
example, but one which I refer to this species, although its ribs are 
stronger and the tubercles are more distinct ; but this is probably due 
to size.’ , 
Harpoceras subconcavum G. Young and J. Bird sp. (p. 304). 
Blake’s PI. VIII., figs. 8, 8b, undoubtedly represents of about the 
natural size a specimen in the Blake collection [B.M. No. C. 17984]. 
It is labelled in Blake’s handwriting : ‘Am. Eseri U.L. Whitby,’ but' 
this species f is not referred to by Blake. But the form of the anterior 
end, and the irregularity of the ornaments on the last portion of the 
outer whorl of the specimen are so clearly indicated in Blake’s figure 
that there can be no doubt as to the identity of the figured example. 
Blake gives the ‘Geological positiork’ of the species as ‘ Zone of A. 
communis, Peak, Boulby, etc.’ 
* Unless otherwise stated the figures are not reversed, 
f See Oppel, ‘ Die Juraformation, ’ p. 245. 
Naturalist 
