4tt'J a. j. j ukes-browne's supplementary
ward was right in considering this supposed new species as simply a monstrosity, although he was probably wrong in referring it to A. lautus. It appears to me to be a malformed individual of the species A. auritus, the dorsal tubercles of one side being atrophied and thus allowing those of the other side to take a more median posi- tion. In every other detail of form and ornamentation it agrees with A. auritus; and there are now in the Woodwardian Museum other partially atrophied forms which clearly show the way in which this particular specimen came to possess such deceptive characters.
The other individual which shared the tablet of A. acaniho- notus is a very different form, being large, strong, and inflated ; it is, in fact, a similarly distorted specimen of A. Studeri, Pict. & Camp. The collection also possesses some interesting deformities belonging apparently to A. vraconnensis or to other varieties of A. Studeri. It is clear, therefore, that A. acanthonotus must be struck out of future lists of Cambridge fossils.
I may also call attention to a similarly malformed species, A. Ramsay anus, figured in Sharpe's Chalk Mollusca, and described at page 51. One side of it bears a very great resemblance to that named A. Woodwardi by Mr. Seeley, torn. cit. p. 236, pi. xi. fig. 3.
SCAPHITES HuGABDIANTJS, D'Orb.
Scajjhites Hugardianus, D'Orb., Heb. &Mun.-Ch., he. cit. p. 117, pi. v. fig. 7.
Scajphites Meriani, Pict. &Camp., see Quart. Journ. Geol. Soc. xxxi. p. 287, pi. xiv. fig. 1-3.
I was glad to observe that MM. Hebert and Munier-Chalmas also regard these two forms as varieties of one species, distinguishing them at the same time from S. cequalis as I had done in my former note on the Cambridge Scaphites. I ought to have given the pre- ference to D'Orbigny's name.
Tuerilites Wiestii, Sharpe.
The casts which in 1874 (see Quart. Journ. Geol. Soc. xxxi. p. 289) I identified as belonging to this species, appear in reality to be some- what intermediate between T. Wiestii and T. costatus, or rather to hold such a relation to both forms as we might expect were it the common progenitor of both. It resembles T. Wiestii in most particulars, especially in the position and number of the tubercles ; these, how- ever, are developed from indistinct costae, which are continued under the base of the whorls ; and their impress is seen on broken casts. In the typical T. Wiestii the tubercles are not connected by such elevations or ribs.
Prom T. costatus it differs by its narrower whorls and their greater spiral angle, as well as in the position of the tubercles, though, as I have elsewhere remarked, the ribs and tubercles of T. costatus appear to be very variable in their position.
Although it is sufficiently distinguished from T. Bergeri by only
