NEWTON: MALAY TRTASSTC PELECYPODA. 133 



Dimensions. — Height (taken from anterior expansion to ventral end) 

 , 38, length (hinge direction) 32 mm. 



5. Actinodesma Bellahyi, n.sp. PI. XII, Fig. 2. 



This species is represented by a single internal cast of a right 



i valve, showing faint traces of the scar of the adductor muscle on the 



■ posterior side. Unfortunately the convex surface has been removed, 



" so that little more than a marginal outline of the shell is preserved. 



i It exhibits, however, the elongate, pointed, aliform extensions 



1 characteristic of Actinodesma, with indications of a median umbo. 



The hinge -line is straight, and shows certain irregularities which 



probably represent the position of the ligamental fossettes, whilst the 



body of the shell is oblong, slightly oblique, and highest on the byssal 



or anterior side. The genus founded by Sandberger (Verstein. 



Eheinischen Schicht. Nassau, 1850-1856, pp. 282 & 283, pi. xxix, 



fig. 17 ; type —A. malleiforme, Sandberger) is closely related to 



Pterinea, and correctly regarded by some authors as including 



Glyptodesma and Ectenodesma of Hall ; it is typical of the Devonian 



period, and has apparently not previously been recorded from any 



higher horizon. 



The specimen is named after its discoverer, Mr. H. F. Bellamy. 

 Dimensions. — Height 33, length of hinge 41 mm. 



6. Pletjrophortjs elongattjs ?, Moore. PI. XII, Fig. 8. 



Pleurophorus elongatus, Moore : Quart. Joum. Geol. Soc, vol. xvii 

 (1861), p. 503 ; op. cit., vol. xviii (1862), pi. xv, 

 figs. 14, 15. 



Two well-developed casts of left valves occurring together appear to 

 belong either to this species, or to be closely related thereto. They 

 exhibit a strong ridge crossing the valve from the umbo to the 

 ventral end, having above a depressed dorso-posterior angulated area. 

 Anteriorly there is evidence of a well-developed adductor scar, with 

 traces of an unbroken pallial line leading from it, slightly above and 

 parallel to the ventral margin. 



Dimensions. — Height 15, length 40 mm. 

 ' Distribution. — This species has been described by Moore from Beer- 

 Crowcombe, near Ilminster, where it occurs in Rhsetic deposits. 



7. Mttiltjs, allied to M. minttttts, Goldfuss. PL XII, Fig. 17. 



An internal cast of a right valve which, on account of the probable 

 terminal umbo, may be regarded as a Mytilus. It represents 

 a depressed form with an oblique angulated hinge area bearing 

 indications of a ligamental groove ; the opposite or anterior margin 

 is vertical, steep, and slightly excavated beneath the umbo. The 

 form is probably closely related to Mytilus minutus, Goldfuss (Petref. 

 Germanise, vol. ii, 1837, p. 173, pi. exxx, fig. 6), from the Trias 

 (Rha?tic) of Germany and other localities, 



Dimensions. — Height 26, length 13 mm. 



