84 SUPPLEMENT TO THE CRAG MOLLUSCA. 
The little recent shell from the British seas, Zrochus pusilla, is given by Dr. P. 
Carpenter as a synonym to Margarita Vahlii; the young state of WM. trochoidea from the 
Crag could scarcely be separated from it. 
MareGarira arGEentata ? Gould. Supplement, Tab. V, fig. 12. 
MARGARITA ARGENTATA, Gould. Invertebrata Mass., p. 256, fig. 174. 
Locality. Chillesford bed, Aldeby. 
In a packet of shells found at Aldeby, and obligingly sent to me by Messrs. Crowfoot 
and Dowson, was the small and not quite perfect specimen figured as above. It is a 
young individual, and very distinctly striated all over, and I have (but with doubt) 
referred it to Marg. argentata, Gould. It has a small apex, differing in that respect from 
M. trochoidea of * Crag Moll.’ 
Length, 0:1. 
Mr. Jeffreys has, in vol. v, ‘ Brit. Conch., p. 202, given argentata as a synonym of 
Margarita glauca, Moller, ‘Ind. Moll. Groenl.,’ p. 8. The specimen now figured is more 
coasely striated than the representation of Zrochus glaucus in ‘ Brit. Conch.,’ vol. v, Pl. 
CI, fig. 6. Gould speaks of his shell as “composed of four convex whorls, the last of 
which is slightly angular.” His figure does not show this angularity, but it is perceptible 
in the Crag shell. 
ADEORBIS PuLCHRALIS, S. Wood. Crag Moll., vol. i, p: 139, Tab. XV, fig. 4. 
In the ‘Quart. Journ. Geol. Soc.,’ vol. xxvii, p- 495, it is said by Mr. Jeffreys, 
“ Adeorbis pulchralis. Swedish expedition, 320—600 fathoms. Margarita trochoidea, 
S. Wood, is the same species.” On a re-examination of my specimens I still believe they 
are distinct. 
ApgorBis striatus, Pfi/. Crag Moll., vol.i, p. 137, Tab. XV, fig. 7 (as Adeorbis 
striatus, 8. Wood.) 
Locality. As in Crag Moll. only. 
Tn ‘ Brit. Conch.,’ vol. in, p. 315, Adeorbis striatus, A. supranitidus, and A. tricari- 
natus are considered as varieties of a British shell called there Zrochus Duminyi, Requien. 
A specimen from the Oligocene of Cassel sent me by Dr. von Koenen, with the name 
carinatus attached, approaches as near, or even nearer, to the three Crag species as 
(judging from Mr, Jeffreys’ figure and description) does the recent Duminyc. While 
