186 RECORDS OF THE AUSTRALIAN MITSBTJM. 



Log. and Horizon. — Farley, near West Maitland — Lower Marine 

 Series ; 1 Wollongong, lUawarra District — Upper Marine Series. 



Genus LiMOPTERA, J. Hall. 

 (SSth Ann. Report N.York State Mus. Nat. Hist., 1884, p. 406a.)* 



LiMOPTERA 1 PERMOCARBONIFERA, sp. nOV. 



(PL xxxii., figs. 1 - 2). 



Sp. Char. — Shell obliquely subrhomboidal, length and width 

 almost equal, but the latter somewhat the greater, produced 

 postero-ventrally; valves very unequal, the left convex, the right 

 more or less flattened, but the greatest convexity of the latter 

 immediately below the umbone; hinge line straight, probably as 

 wide as the shell ; ligamental area not well preserved, but appar- 

 ently wide and deep beneath the umbones, and narrow posteriorly; 

 anterior ends or auricles flattened in both valves, separated from 

 the bodies of the valves by sharp declivities, the anterior margins 

 below obliquely and sharply rounded ; posterior ends or wings 

 triangular, flattened, much larger in the left than the right valve, 

 distinctly demarcated from the bodies of the valves, margins 

 sharply emarginate, then swelling out to round the protuberant 

 postero ventral portions. Left umbo prominent, nearly central 

 in position, the umbonal region abrupt on the anterior, but 

 gently sloping on tlie posterior side to form a posterior slope ; 

 umbonal cavity of the right valve containing a number of nodes 

 (in the cast) indicating pits for muscular attachment ; adductor 

 impressions and pallial scars not distinctly marked ; sculpture 

 of the left valve consists of irregular concentric laminte and 

 faint oblique radii, extending from the umbonal centre well on to 

 the posterior end ; the surface of the right valve is transversely 

 wrinkled on the cast. 



Obs. — The specimen is somewhat mutilated, but it presents 

 most of the principal characters of the genus Limoptera, with the 

 exception of the cardinal folds and the oblique posterior tooth. 

 The former however may be hidden by the matrix infilling the 

 deep ligamental recess beneath the umbones. The precise generic 

 aflinity of this shell, I am not at present prepared to give, but it 

 accords better with Hall's definition of Liinoptera than with any 

 other similar genus. It is more produced posteriorly than any of 

 the shells figured by Hall under this name, and is also specifically 

 distinct from any other yet described from New South Wales. 

 The outward form only is that of some GlyptodesmfE, or Pteriviea 

 as restricted, or even more so perhaps Leiopteria or Leptodesma, 



* It is impossible to unravel the mystery surrounding the first annunci- 

 ation of many of the late Prof. James Hall's genera. This reference is 

 simply given as one to a description of the genus. 



