I I IS COLLECTIONS FROM MELANESIA. 



This so-called species, also G. donacina, Lamarck, G. cvmingii, A. 

 Adams, C. castanea, Reeve, C. errones, Reeve, and C. decipiens, 

 Reeve, I believe to be mere variations of one and the same form, 

 namely ft hingicola, Lamarck. The composition of the hinge is the 

 same in all, and the peculiar colouring of the interior is similar (vide 

 Reeve, fig. 16, and Delessert, pi. iv. fig. 1 b). The variation in form 

 is partly due to age ; for instance, a young ft decipii ns has the form 

 of donacina, and it is only towards maturity that the posterior end 

 becomes markedly produced ; and the same observation applies to ft 

 errones. The amount of concentric ribbing is not constant ; but all 

 intermediate forms are met with, from ft castanea and G. donacina 

 (type), which have least, to G. pukhra, which has most, being cos- 

 tate throughout, except at the posterior extremity. The pallial line 

 in every specimen examined does not appear to be parallel with the 

 margin of the valve, but becomes gradually more remote anteriorly, 

 the space between it and the margin being radiately shallow ly 

 subsulcatc, seen better in some lights than others. The epidermis 

 scarcely varies at all : in some examples it appears to have lost the 

 dull bloom which covers others ; but this defect is the result of fric- 

 tion, for a dull specimen in perfect condition is easily rendered 

 glossy by merely being rubbed with a wet cloth, the bloom disap- 

 pearing as it does from fruit under similar circumstances. Judging 

 from the specimens in the British Museum with reliable localities 

 attached to them, it appears that the species ranges from Queensland 

 on the east side of Australia, along the north coast to Swan River on 

 the west. I find a specimen of the variety cumingii from Port 

 Curtis and another from Sandy Cape on the north-east coast ; var. 

 pulchra from Port Essington ; vars. decipiens and castanea from 

 Swan River. 



50. Modiola, sp. 

 Hah. PortMolle. 



A single distorted specimen only is before me, remarkably like 

 the European M. barbata. 



51. Modiola glaberrirna. 

 Dunker ; Reeve, Conch. Icon. fig. 48. 

 flab. Sydney (DunJcer) ; Port Jackson (Goppinger and Angus). 



52. Modiolaria niiranda. (Plate VII. fig. N.) 



Shell transversely elongate, highest at the middle, of pale greenish 

 tint, varied with a few indistincl light reddish irregular markings, 

 not glossy, rather strongly radiately ridged at both ends and very 

 finely on the central portion of the valves. Whole surface concen- 

 trically striated, producing a subgranose appearance upon the cos- 

 tulae ; the anterior are about ten in number, the posterior about 



