98 PROCEEDINGS OF THE 



If further researches should prove it distinct it might be called 

 C. quadratus. 



Amongst recent Chitons, Chitonellus (Notoplax) speciosa, II. 

 Adams, from Tasmania, has a granular coronet like the present 

 form of plate, and that described as C. subquadratus, K. and Y. 



Locality and Horizon. — Law Quarry, near Dairy, as before. 



Collection. — J. Bennie. 



Cliitonellus (?) patelliformis, sp. nov. — (PI. II., figs. 8 and 9).* 



/Sp. Char. — Anterior (?) plate conical, patelliform, longer than 

 wide, narrowing towards the front. Posterior margin broadly 

 rounded, anterior rounded but contracted — from the apex forwards 

 the plate is obtusely carinated, and gradually descends to the 

 front margin. Apex blunt, scarcely recurved, situated at about the 

 posterior third of the plate, at which point the latter is also widest. 

 From the apex proceeds two grooves forwards to the antero-lateral 

 margins, dividing the plate into three areas, a central one forming 

 the obtuse median ridge, and two others, one on each side, and 

 comprising by far the largest part of the plate. From, and pos- 

 terior to the apex, radiate six, and sometimes seven strong ridges to 

 the posterior margin ; between these are other fine interpolated 

 and quite microscopic granular striae, which are repeated on the 

 flanks of the plate, and in very well preserved specimens are visible 

 on the obtuse central keel also. The inserted portion of the plate 

 is small, forming only a narrow rim, or belt, round the margin of 

 the plate, and more highly developed towards the anterior. The 

 interior surface is quite plain, except that the posterior margin is 

 convoluted by the coarse ribs and intermediate valleys. 



Obs. — This peculiar plate, undoubtedly, resembles Chitonellus 

 antiquus, Howse, sp.,t to which it is closely allied by its general 

 character and appearance. It may, however, be distinguished by 

 the presence of the double groove from the apex forwards, the 

 constant presence of the six or seven posterior radiating ridges, the 

 more ridge-like character of the median line anterior to the apex, 

 and the broken style of ornament. 



Again, it is clearly an ally of Chitonellus subantiquus, K. and Y.,| 



* It is possible that fig. 17 (PI. I.) represents the posterior plate of this species. 



t Quart. Jour. Geol. Soc, xv., p. 619, t. 16, figs. 15-23. 



t Geol. Mag., iv., p. 341, t. 16, f. 12, 13. 



