4-24 CARRONIFI^ROUS LAMELLIBRANCHIATA. 



pressioii from the umbo downwards to the lower border, which is markedly 

 sinuous at this place. 



I have given my reasons for supposing that Fleming's Hiatella sulcata was 

 founded on specimens of both species (see above, p. 320), and need not repeat 

 them here. 



With regard to the pallial sinus, very few specimens indeed are in the proper 

 state of preservation to show the interior, but I think that three specimens in my 

 possession show indications of this character, PI. XLVIII, figs. 4, 8. 



Unfortunately a sinuated pallial line has been intensified in King's type 

 specimen by drawing it in with ink. The specimen is now preserved in the 

 museum at Newcastle-on-Tyne, and I have been unable to obtain permission to 

 borrow the shell for the purpose of figuring it. I have only been able to see the 

 muscle-scars in one example out of the many I have examined, from Redesdale, 

 where this species is one of the commonest fossils in the ironstone beds. 



Mr. Neilson has obtained a fine series of specimens (from the excavations in 

 Garngad Road, Glasgow) which have the outer portion of the valve preserved, and 

 show that it was covered with rows of fine tubercles, PI. XLVIII, fig. 7, agreeing 

 in this character with Edmondia sulcata. 



Complete examples of A. sulcata are rare, the extreme posterior end being often 

 wanting. There is, however, in m^^ opinion, good evidence that this shell gaped 

 slightly behind, but it was certainly close in front and below. 



The hinge has not been isolated, but I think it probable that hinge-teeth were 

 either absent or very small, because the valves are often found slightly slipped, the 

 left generally overlapping the right. 



Allorisma variabilis, M'Coi/, sp., 1851. Plate XLIV, fig. 2; Plate XLVIII, 



figs. 1, 2. 



Sanguinolites variabilis (pars), M'Coy, 1851. Ann. Mag. Nat. Hist., 2ijd ser., 



vol. vii, p. 174. 



— — — Morris, 1854. Cat. Brit. Foss., 2nd edit, 



p. 223. 



— — — ilf'Coi/, 1855. Brit. Pal. Foss., p. 508, pi. 3 F, 



figs. 6—8. 



— — — Young and Armstrong, 1^11. Trans. Geol. Soc. 



Glasg., vol. iii, Suppl., p. 54. 



— — Armstrong, Young, and Robertson, 1876. Cat. West. 



Scott. Foss., p. 55. 



— — Bigshg, 1877. Thesaurus Devouico-Carboniferus, 



p. 313. 



— — Etheridge, 1888. Brit. Foss., pt. 1, Palaeozoic, 



p. 290. 



