148 PROCEEDINGS OF THE MALACOLOGICAL SOCIETY. 



confess, however, it approaclies nearer to M. pura than any other of 

 the known Australian species. 



32. Mactra pdsilla, A. Adams. B.M. 



Mactra pusilla, A. Adams, Proc. Zool. Soc, 1855, p. 226 ; Smith, 



Challetuier Lamellibranchiata, p. 60, pi. v, figs. 8-8c. 

 nou Trigonella pusilla, Angas, Proc. Zool. Soc, 1867, p. 916 = 

 M. jacksonensis, Smith. 

 Hah. — Moreton Bay (Adams), Port Jackson (Smith), Brisbane 

 Water, New South Wales (J. McGillivray in Brit. Mus.), Queensland 

 (Hedley). 



33. Mactea qukenslanuica, n.sp. B.M. 



Testa trigono-ovata, inaequilateralis, mediocriter convexa, dilute 

 griseo-purpurea, apicem versus piirpurascens, pallide zonata, postice 

 anguste hians ; valvae teiiues, lineis incremeuti tenuiter striatae, 

 supra umboues fortius striatse ; margo dorsi utrinque declivis, 

 anterior leviter iucurvatus, posterior leviter vel vix convexus, 

 veutralis valde arcuatus ; latus anticura rotuiulatum, posticum magis 

 acuminatum ; umbones paulo ante medium siti, fera contigui ; lunula 



depressa, cordiformis, linea impressa circumdata ; area dorsalis 

 postica excavata, lanceolata, carina tenui marginata ; pagina interna 

 purpurascens, ad marginem ventralem flavescens, radiatim tenuissime 

 striata ; cicatrices subaequales, antica piriformis, postica ovalis ; sinus 

 pallii brevis, rotundatus ; dens cardinalis valvse sinistrse A-formis, 

 lamina tenui pone instructus ; dentes laterales tenues, breves, prope 

 cardinales. Long. 35, alt. 29, diam. 17 mm. 



^flJ.— Sandgate, near Brisbane, Queensland. 



A thin shell of a purplish colour within, excepting the ventral edge, 

 which is yellowish. Externally it is greyish-purfilish, but marked 

 with lighter zones, but towards the umbones it is more distinctly 

 purplish. Besides the fine keel marking off the dorsal escutcheon, 

 there is a second faint angle at the posterior end of the valves 

 radiating from the umbones to the hinder extremity. 



The line circumscribing the lunule is not incised, but merely 

 faintly impressed, and the marginal ligament, as usual, is distinct 



