136 40) 
Septifer excisus, Wiegm. 
Tichogonia excisa, WinGMANN, Archiv f. Naturgeschichte, Ill, 1837, p. 49. 
= — -- Martini u. CHEMNITZ, Conchyl. Cabin., VUI Bd., 3 Abth., p. 24. 
Septifer excisus, — Réciuz, Revue et Magasin de Zoologie. 2 sér., J, 1849, p. 129. 
Mytilus = — — REEVE, Conchol. icon., X, Mytilus, Sp. 13. 
Seplifer  — — Crosse et Frscuer, Journ. de Conchyl., vol. 40, 1892, p. 75. 
fuscus, Réciuz, 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 Isls. — Funafuti (Ellice Isl.). 
Tichogonia (Septifer) siamensis, Clessin' from “Siam,” and also Septifer Troscheli, 
Dkr.,? undoubtedly belong to the present species. CLEssin* knows Septifer excisus, 
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. 
Modiola (Lithophagus) gracilis, Pxitiert, Zeitschr. f. Malakozool., 1847, IV, p. 117. 
— gracilis, Puitipp1, Abbild. u. Beschreib. neuer od. wenig gek. Conchyl., 1851, III, p. 5 (19), pl. I, 
fig. 1. ; F 
Lithodomus gracilis, Puitipr1, Rerve, Conchol. icon., X, Lithodomus, Sp. 4. 
— — — P. Fiscuer, Catal. d. moll. de l’Indo-Chine, p. 213. 
Lithophaga — — Dunker in Marini u. CHEMNITZ, Conchyl. Cabin., 1882, VII, 3 Abth., p. 12, 
pl. 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 Isls., Madras, Ceylon, Mahlos-Atoll (Maldive 
Archipel.), Red Sea, Seychelles, Amirantes, Tschago’s Isls., Mauritius, Bourbon, 
Querimba Isls., Zanzibar. — Poulo Condor, China (Shanghai), Sunda Isls. (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. MaArTEns 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. (Cuemnrrz’s figure’ of Mytilus litho- 
1 Martini u. Cuemnirz, Conchyl. Cabinet, VIII, 3 Abth., pp. 19—20, pl. 15, figs. 8—9. 
2 W. Dunker, Neue Mytilaceen, Zeitschr. f. Malakozool., X. 1853, p. 87. 
3 loc. cit., pp. 24—25. 
4 Py. DaurzENBERG 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.” 
® Cuemnirz, Conchyl. Cabinet, VIII, 1785, pl. 82, fig. 729. 
