R. ETHPJRIDGE, JTTN., ON LOWER-CARBONIFEROUS INVERXEBRATA . 17 



Genus Pandora, Bruguiere. 

 Pandora? typica, E. Eth., Jun. PI. II. figs. 22, 23 (and 21 ?). 



Leptodomus ? clavatus, R. Eth., Jun., Ann. & Mag. Wat. Hist. 1876, 

 xviii. p. 102, pi. 4. figs. 9, 10. 



Sp. char. Somewhat clavate, a little arcuated, very inequilateral, 

 gibbous in the umbonal region ; length much exceeding the height. 

 Anterior side short, convex, its margin rounded ; posterior side 

 much more compressed, transversely elongated, its margin sharply 

 truncated ; umbones prominent, quite anterior, but the beaks not 

 terminal. A blunt diagonal ridge traverses each valve from the 

 umbo to the posterior ventral angle ; posterior slope a little con- 

 cave. Dorsal margin long, slightly arcuated ; dorsal and ventral 

 posterior angles sharp and well defined. Ornamentation consisting 

 of concentric stria?, which are suddenly deflected on reaching the 

 diagonal ridge, and traverse the posterior slope parallel to the pos- 

 terior margin in a very regular manner. 



Obs. My former description of this species was drawn up from 

 crushed specimens ; but the acquisition of nearly perfect examples 

 enables me to give a more definite diagnosis. Eor individuals in the 

 crushed state the characters given in the ' Annals ' are quite appro- 

 priate ; for it is a fact worthy of note that, when crushed, all speci- 

 mens of this species which have come under my notice appear to be 

 compressed into a similar form and to a like degree the outline 

 becomes more clavate and arcuated, the posterior end recurved and 

 truncated obliquely, the posterior slope still more concave, and 

 divided down its centre by a groove from the beak backwards, and 

 the surface a good deal wrinkled. 



The reference to Pandora is made exclusively on the close external 

 resemblance this species bears to that genus. I have not seen any 

 of the internal characters ; neither can I say whether the shell was 

 inequivalve or not, as it should be if a true Pandora. P. ? typica 

 resembles in many respects Lutraria elongata, M'Coy *, and to some 

 extent Pandora clavata, M'Coy f , and will, perhaps, occupy an in- 

 termediate position between the two. I have assigned to the spe- 

 cies the name typica, from its great prevalency in certain beds of 

 shale in the Cement-stone group around Edinburgh. Mr. Henderson 

 notices its occurrence, under the name of Pandora sp., in his paper 

 on the Wardie Shales, previously referred to. 



Loc. and Horizon. In the bed of shale at Woodhall, as before ; 

 Drumsheugh, near Dean Bridge, in a similar bed ; in ditto behind 

 the western breakwater at Granton Harbour ; in ditto above the 

 sandstone at Craigleith Quarry. Cabinets of Messrs. Henderson and 

 Gall ; and collection Geol. Survey Scotland, collected by Mr. James 

 Bennie. 



I also give figures of two undetermined bivalves (figs. 24 & 25) in 

 the collection of Mr. Gall and Mr. Henderson, from Drumsheugh 

 and Water of Leith respectively. 



* Synopsis Carb. Foss. Ireland, 1844, p. 52, t. viii. fig. 3. 

 t Ibid. p. 51, t. xi. fig. 1. 



Q.J.G. S. No. 133. c 



