136 40 



Septifer excisus, Wiegni. 



Tichoyonia excisa, Wiegmann, Archiv f. Naturgeschichte, III, 1837, p. 49. 



— — — Mahtini u. Chemnitz, Conchyl. Cabin., VIII Bd., 3 Abth., p. 24. 

 Septifer excisus, — Rkcluz, Revue et Magasin de Zoologie. 2 ser., I, 1849, p. 129. 

 Mytilus — — Reeve, Conchol. icon., X, Mijtilus, Sp. 13. 



Septifer — — Crosse et Fischeh, Journ. de Conchyl., vol. 40, 1892, p. 75. 



— fuscus, RÉCI.UZ, Revue (et Magasin) de Zoologie, 1848, p. 279. — 1849, p. 128. 



Koh Lom, W. of Koh Chang (2). 



West Coast of Cambodge in the Gulf of Siam (Pavie). 



Long. 21 — 26 mm. 



Distribution: — Mergui Isl., Karachi, Gulf of Aden, Red Sea (pleistocene), 

 Mauritius, Madagascar, Mozambique, Querimba Isis. — Funafuti (Ellice Isl.). 



Tichogonia (Septifer) siamensis, Clessin' from "Siam," and also Septifer Troscheli, 

 Dkr.,^' undoubtedly belong to the present species. Clessin^ knows Septifer excisiis, 

 Wiegm. only from Dunker's description, and has hardly any clear conception of 

 it; neither has he examined Reeve's figure, as he writes: "Reeve hat die Art nicht 

 abgebildet, trotzdem sich dieselbe in der Cuming'schen Sammlung befinden muss." 



Lithodomus gracilis, Phil. 



Modiolu {Lithophagiis) gracilis, Pmi.ii'ri, Zeitschr. f. Malakozool., 1847, IV, p. 117. 



— gracilis, Phimppi, Abbild, u. Beschreib, neuer od. wenig gek. Conchyl., 1851, III, p. ö (19), pl. II, 



flg. 1. 

 Lithodomus gracilis, Phii.ippi, Reeve, Conchol. icon., X, Lithodomus, Sp. 4. 



— _ _ p. Fischer, Catal. d. moll. de llndo-Chine, p. 213. 



Lithophaga — — Dunker in Martini u. Chemnitz, Conchyl, Cabin., 1882, VIII, 3 Abth., p. 12, 



pi. 4, figs. 7-8. 



North end of Koh Chang, 1 — 12 fathoms, old coral blocks (many specimens). 

 Koh Kahdat, 1 fathom, sand (9). 



Long. 11 — 72 mm. 



Distribution: — Malacca, Mergui Isis., Madras, Ceylon, Mahlos-Atoll (Maldive 

 Archipel.), Red Sea, Seychelles,* Amirautés, Tschago's Isis., Mauritius, Bourbon, 

 Querimba Isis., Zanzibar. — Poulo Condor, China (Shanghai), Sunda Isis. (Java, 

 Flores, and others), Amboina, Sorong, Torres Strait, north-west Australia, Tahiti. 



With regard to the three closely allied forms — L. teres, Phil., L. gracilis, Phil., 

 and L. niger, d'Orb. — I do not doubt, judging from the material at hand, that 

 L. teres, Phil., is identical with L. gracilis, Phil. E. v. Martens has already stated in 

 "Die Mollusken d. Maskarenen u. Seychellen," (p. 143) that L. teres, Phil., cannot be 

 separated as a species from L. (gracilis, Phil. (Chemnitz's figure'' of Mytilus litho- 



1 Martini u. Chemnitz, Conchyl. Cabinet, Vlll, 3 Aljth., pp. 19—20, pl. 15, figs. 8—9. 

 - W. Dunker, Neue Mytilaeeen, Zeitschr. f. Malakozool., X. 1853, p. 87. 

 ' loc. cit., pp. 24-25. 



* Ph. Dautzenrerii records it (Bull, de la Soc. Zool. de France, 1893) from here, and says: "Litho- 

 domus gracilis Philippi, indiqué par von Martens sous le nom de L. teres Philippi." 

 •■ Chemnitz, Conchyl. Cabinet, VIII, 1785, pl. 82, fig. 729. 



