I05 



The single shell in the "Siboga" collection was picked up on the pearl banks near the 

 Anchorage off Pulu Jedan, east coast of Aru Islands (St. 273). 



3. Maliens daeinonicus Reeve. (Plate III, figs. 13 — 18). 



1858. Maliens daemoniciis Reeve, Conch. Icon., XI, Alalleiis, pi. II, fig. 6. 



1860. Maliens daeinonicus Reeve, Elem. Conch., II, p. 65. 



1884. Maliens daemonicns Grasset, Ind. Test. Viv., p. 304. 



1887. Maliens daemonicns von Martens, Journ. Linn. Soc. London (ZooL), XXI, p. 204. 



1890. Maliens daemonicns Clessin in Martini-Chemn. Conch. -Cab. (N. F.), VIII (i), Malleacea, 



p. II, pi. III, fig. 5. 

 1905. Maliens daemonicns Hidalgo, Cat. Filip., p. 368. 

 191 1. Maliens daemonicns Pelseneer, "Siboga" Lamellibranches (Anat.), pi. VII, figs. 9 — 11, 



pi. VIII, fig. I. 

 1929. Maliens daemonicns Faustino, Simimary Philippine Marine Freshw. Moll., p. 27. 



Malleus daevtonictt-s is a very interesting- species in that its shell appears to undergo a 

 great deal of change, in its outline, during growth. The youngest shell, which I hâve seen, is 

 about 10 mm. in length and is very thin, subquadrate in outline and without any trace of auricles 

 on either side of the hinge. Older shells appear to grow more obliquely, and are either tongue- 

 shaped or even subquadrate ; they often hâve an auricle anterior to the hinge-line. Older shells 

 also show the concentrically ridged laminae referred to by Reeve in his description of the species. 

 The largest spécimen of the species in the "Siboga" collection resembles full-grown shells of 

 M. régula (Forskâl) in shape, but is comparatively much broader and has the internai longi- 

 tudinal ridge in the calcareous posterior elongated part of the shell less v^ell developed. I figure 

 a séries of shells of différent âges of this species. 



Distribution : — This species has so far been recorded from the Philippines and Mergui 

 Archipelago. 



In the "Siboga" collection there are shells of ail âges from St. 25 (8°48'.9S., ii5°38^E. ; 

 118 mètres), Pulu Sanguisiapo, Tawi Tawi Islands, Sulu Archipelago (St. 93), Fau Anchorage 

 (St. 149), Saleyer Anchorage (St. 213), Banda Anchorage (St. 240) and Anchorage East of 

 Dangar Besar, Saleh Bay (St. 3 1 3). 



4. Malletts régula (Forskâl). 



1775. Ostrea regîda Forskâl, Descr. Anini., p. 124. 



1785. Ostrea Forskalii Chemnitz, Conch. -Cab., VIII, p. 15, pi. LXX, fig. 657. 



1788. Ostrea regnla Schroter, Conch. -Cab. Namen. Reg., p. jy. 



1790. Ostrea valsella Gmelin, Syst. Nat., (éd. XIII), p. 3333. 



1791. Bruguière, Encyclopéd. Méthod., pi. CLXXVII, fig. 15. 

 1798. Pinctada regzila Rôding, Mus. Boltenianum, p. 168. 



1802. Maliens vnlsella Bosc, Hist. Nat. Coq., II, p. 290. 



1817. Martean Savigny, Descr. Egypte, pi. XIII, figs. i : i — 3, 2: i — 3, 3: i — 3, 4. 



18 17. Himantopoda trnncata Schumacher, Essai Nouv. Conch., p. i 10. pi. II, figs. la, b. 



1817. Ostrea regida Dillwyn, Descr. Cat., I, p. 273. 



18 19. Malleus vulsellatus Lamarck, Anim. sans Vertèb., VI, p. 145. 



1823. Maliens vnlsellatits Blainville, Dict. Sci. Nat., XXIX, p. 258. 



1824. Malleus vulsellatus Blainville, Dict. Sci. Nat., XXXII, p, 314. 

 1824. Malleus vulsellatus Dubois, Epitome, p. iio. 



SniOGA-F.XPEDTTlF. LIIIC. I4 



