BY VC. N. BENSON, W. S. DUN, AND W. R. BROWNE. 355 



specimens. (The djawing is a composite of tb'- characters of both.) The ears 

 are scarcely developed, the straight hinge-line being- broadly rounded on the ex- 

 tremities. These sliells appear to be quite symmetrical about the middle line. 



(f). The form illustrated in Plate xxiii., tig. 6, is represented bj a single 

 specimen only. The shell is depressed and subquadrate, the lower margin being 

 almost semicircular. The shell is depressed, the beak scarcely rising above the 

 hinge line. The anterior ear is marked, but rather smaller than the posterior ear 

 which extends to a sharp terminal angle. The hinge line is straight and slightly 

 oblique to the middle line of the shell. The umbo is subeentral but slightly an- 

 terior. There are seven prominent, rather angular, concentric folds crossed by 

 radial striae. No sign of adductor scars is noticeable. The dimensions of this 

 shell are: Height, 10 mm.; length, 9 mm.; thickness, 2.5 mm. 



The specimens are numbered F^ 12457 in the collection of the Geological 

 Survey. 



Spathella sp. indet. (Plate sxiii., figs. 5, 7.) 



Spathelhi. Hall, Geol. New York, Pal. v. (i.), Lamellibranchiata, 1885, p. xxxiii.; 

 Wheelton Hind, Brit. Carb. Lamellibranchiata, ii., 1897, p. 153, t. 23. 



There are two specimens which we refer to this genus with some hesitation, 

 seeing that they are certainly specifically distinct from any forms of which we have 

 seen figures. The larger form is an internal cast. The shell is elongated, rounded 

 at the terminations, with a sub-anterior umbo, which is narrow and shghtly m- 

 curved. There are faint traces of concentric gi'owth lines and the anterior ad- 

 ductor scar is strongly marked, but the posterior is faint. The smaller form ia 

 almost exactly half the size of the larger, and differs in the marked character of 

 the concentric growth lines giving the shell a lamellar appearance. It is slightly 

 constricted along a band running obliquely from tlie umbo to the middle of the 

 lower margin. The dimensions of these two shells are as follow: — Length, (a), 

 32, (h) 15 mm.; height, (a) 16, (b) 7; thickness (only one valve), {a) 7, (6) 3. 



The two forms are found on Specimen No. F. 4650 in the collection of tlie 

 Geological Survey, and were obtained by Tullen from the hills, two miles west of 

 Mount Uriari. 



Panenka porteei, sp. nov. (Plate xxi., fig. 10.) 

 Panenka, Barrande, Systeme Sil. Boljeme, vi., 1881, p. 128. 



This interesting shell is represented by a specimen in the Australian Museum 

 here illustrated, and Specimens 1752-3-4-5 and -7 in the collection of the Geolo- 

 gical Sur\-ey, obtained by Mr. Donald Porter from Swain's Conditional Purchase, 

 8 miles south-east of Carroll, and also by No. 1756, from Goonoo Goonoo. 'The 

 form illustrated has a lengfh of 51 mm., and breadth of 57. The thickness of 

 the single (right) valve is 14 mm. It is folded into numerous simple or inter- 

 polated straight, obtusely-rounded, radiating ridges, spaced about ten to the cen- 

 timetre. There is no concentric ornamentation or imbrication, though there are 

 a few growth lines and concentric undulations jjlaced irregularly. The postenoi' 

 ear is strongly developed, flange-like, and striated. The umbo is acute, highly in- 

 curved and slightly carinate. The posterior adductor scars are high and faintly 

 marked . 



Our forms resemble most closely Panenka niultiradktta (Hall), a Devonian 

 form, but are more delicately ornamented than this American t>T3e. The umlx) is 

 also more acute and incurved. This form is named in lionour of Mr. Donald Por- 

 ter, the first to make extensive collections of Bnrindi fossils in this region. 



