94 



1909. Pteria rnao'optera Melvill, Trans. Linn. Soc. London (Zool.), XIII, p. 124. 



1909. Pteria macroptera Lamy, Bull. Mus. d'Hist. Nat. Paris, XV, p. 468. 



1910. Pteria macroptera Hedley, Austr. Ass. Adv. Sci., XII, p. 344. 



191 1. Avicnla macroptera Pelseneer, "Siboga" Lamellibranches (Anat.), p. 24, pi. VIII, fig. 8. 

 1916. Pteria macroptera Hedley, Journ. Froc. Roy. Soc. W. Australia, I, p. 155. 



1929. Avicnla lotorium and A. macroptera Dautzenberg, Faune Colon. Français., III, Fasc. IV, 



pp. 562, 563. 



1930. Pteria macroptera Thiele, Faun. Sùdwest Austral., V, p. 590. 



It is unfortunate that the Lamarckian name of this well known species has to be replaced 

 to the earlier one of Rôding, but there can be no doubt that the Lamarckian name is synonymous 

 with the earHer one of Rôding. I hâve also no doubt that Lamarck's second species A. lotorium 

 is based on only shghtly différent shells of this wide-spread species. 



Distribution : — Pteria pengiiin has been recorded from Australia to Madagascar. 



The "Siboga" Expédition collected a number of shells of this species in the Bay of Badjo, 

 west coast of Flores (St. 50). 



6. Pteria triangularis sp. nov. (Plate III, figs. 1,2). 



The following is a description of this nevv species: — Shell small, fairly thick; alniost 



triangular, oblique, inequivalve ; surface of shell covered with low, concentric Unes of growth 



except on the smooth umbonal area ; moderately inflated, right valve slightly concave on the 



inner surface, left valve inflated, maximum inflation medial, rising from the umbonal and gradually 



narrowing down to posterior margin of shell; dorsal margin long, straight; umbo low, narrowly 



rising above dorsal margin; anterior auricle comparatively small, triangular, separated from the 



umbonal inflated area by a shallow diagonal groove; no posterior auricle; posterior margin 



almost straight; ventral margin slightly arched; cardinal area narrow, extending to about ^3 from 



posterior margin of shell. Colour of shell dusky brown ; younger shells more yellowish ; nacre 



steely blue. 



Measurements (in millimètres). 



Holotype Paratype 



Length 21.5 14.4 



Height 1 1.6 7.5 



Maximum diameter . . 4.8 3.2 



Habitat: — P- triangtilaris is represented by 2 complète shells collected at St. 166 



(2° 28'. 5 S., i3i°3'.3E., 118 mètres) and St. 310 (8° 30' S., 1 19° 7^.5 E., 73 mètres) respectively. 



Remarks : — The peculiar shape and texture of this species distinguish it from previously 



described species. 



7. Pteria tomlini sp. nov. (Plate III, figs. 3, 4). 



The following is a description of this new species : — Shell' small, thin ; trapézoïdal in 

 outline ; inequivalve ; almost smooth ; left valve greatly inflated along a diagonal area from the 

 umbo to the posterior ventral margin, greatest inflation at about one third of the height from 

 the anterior margin, descending gradually to the posterior but more abruptly to the anterior 

 margin ; right valve almost flat ; dorsal margin long, almost straight, umbo prominent, moderately 



