75 



selected M. discors (Linn.) as the type of Miisciclus Roding-, this name replaces the commonly 

 accepted Modiolaria. 



A good description of the genus was published by Jukes-Browne, but from the exami- 

 nation of the available material at my disposai I am unable to agrée that it is possible to 

 distir]guish any subgeneric divisions based on the présence or absence of radial sculpture on 

 certain areas of the valves. 



1. MiLsctihcs cuneahis (Gould). (Plate II, figs. 34, 35). 



i86[. Modiolaria cuneata Gould, Proc. Boston Soc. Nat, Hist., VIII, p. 38. 



1862. Modiolaria aineata Gould, Otia Conch., p. 176. 



1885. Modiolaria cuneala Smith, "Challenger" Lamellibranchia, p. 278, pi. XVI, fig. 7. 



1891. Modiolaria inarinorata Smith, (ex parte), Proc. Zool. Soc. London, p. 393. 



1904. Modiolaria aineata Pritchard & Gatliff, Proc. Roy. Soc. Victoria, XVII, p. 254. 



1906. Modiolaria cuneata Hedley, Proc. Linn. Soc. N. S. Wales, XXXI, p. 464. 



1909. Modiolaria cuneata Lynge, D, Kgl. Dansk. Vidensk. Selsk. Skr. Nat. -Math., (7) V, p. 139. 



1910. Modiolaria cuneata Hedley, Austral. Ass. Adv. Sci., XII, p. 346. 



191 1. Modiolaria marmorata Pelseneer, (n e c Forbes), "Siboga" Lamellibranches (Anat.), p. 20, 



pi. V, figs. 6, 7, 9. 

 191 5. Modiolaria cuneata Bartsch, Bull. U. S. Nat. Mus., XCI, p. 189, pi. LU, figs. 5, 6. 



The spécimens, which I refer to this species, agrée in ail détails with the description and 

 figures of the Cotypes of Gould's M. cuneatus published by Bartsch. The "Siboga" shells are 

 only about half the size of the spécimens figured by Bartsch. 



Distribution ; — From the published records of the species M. ctmeatus appears to hâve 

 a wide distribution in the Indo-Pacific Area. 



The "Siboga" collection contains spécimens from Sailus Ketjil, Paternoster Islands (St. 37), 

 St. 164 (i°42'.5 S., i30°47'.5E., depth 32 mètres) and Anchorage off Pulu Jedan, east coast 

 of A. ru Islands (St. 273). 



2. Muscuhùs viiranda (Smith). 



1884. Modiolaria niiranda Smith, E. A., Rep. Voy. "Alert", p. 108, pi. VII, fig. N. 



1906. Modiolaria niiranda Hedley, Proc. Linn. Soc. N. S. Wales, XXXI, p. 464. 



1909. Modiolaria niiranda Lynge, D. Kgl. Dansk. Vidensk. Selsk. Skr. Nat. -Math., (7) V, p. 140. 



191 o. Modiolaria niiranda Hedley, Austral. Ass. Adv. Sci., XII, p. 346. 



19 17. Modiolaria niiranda Odhner, Kungl. Sv. Akad. Handl., LU, n° 16, 20. 



M. niiranda, as Smith pointed out, resembles M. varicosus in the outline of the shell, 

 but is distinguished by the greater coarseness and subgranular character of the anteriôr and 

 posterior ribs produced by the concentric ribs crossing over the radial ones. 



Distribution : — M. miranda was discovered in the Dundas Strait, and has since been 

 recorded by Hedley and Odhner from Australia, and by Lynge from the Gulf of Siam. 



In the "Siboga" collection the species is represented by a single adult shell from Sailus 

 Ketjil, Paternoster Islands (St. 37) and three young valves from St. 164 (i°42^5 S., i30°47''.5 E.). 



3. Mttsculus impactits (Hermann). (Plate II, figs. 36, 37). 



1780. Born, Test. Mus. Caes. Vindobon., p. 121, text-fig. d. 



1782. Mytilus inipactus Hermann, Naturforscher, XVII, pi. III, figs. 5 — 8. 

 1784. Mytilus cor Martyn, Uni versai. Conch., II, pi. LXXVII. 



