68 



B. (//.) siibramosus is dlstinguished from other closely allied species, such as B. (//.) stria- 

 tuhis (Hanley) and B. {H.) subsidcatiis by its very much coarser sculpture; this consists of rather 

 distantly placed, thick and somewhat wavy radial ribs. 



Distribution : — B . {H.) suèramosus bas so far been recorded from Celebes, the Philip- 

 pines, New Caledonia and the Gulf of Siam. 



In the "Siboga" collection it is represented by two young shells collected at Bima 

 Anchorage, Sumbawa (St. 47). 



3. Brachidontes {Septifer) excistts (Wiegmann). 



1837. Tichogonia excisa Wiegmann, Archiv Naturges., I, p. 49. 



1848. Septifer fuscus Récluz, Rev. Zool., p. 279. 



1849. Septifer fiiscus and 5. excisiis, Récluz, Rev. Mag. Zool., I, p. 128. 

 1853. Septifer Troscheli Dunker, Zeitschr. Malakozool., X, p. 87. 



1855. Tichogonia excisa Berge, Conchylienbuch, p. 83. 



1857. Mytihis excisus Reeve, Conch., Icon., X, Mytiliis, pi. IV, fig. 13. 



1857. Septifer excisus Adams, H. & A., Gen. Rec. Moll., II, p. 523. 



1860. Mytilus excisus Reeve, Elem. Conch., II, p. 71. 



1865. Septifer excisus Fraser, Proc. Zool. Soc. London, p. 196. 



1869. Septifer fuscus Frauenfeld, Abhandl. Zool. -Bot. Ges. Wien, XIX, p. 885. 



1879. Septifer excisus von Martens, Monatsb. K. Akad. Wiss. Berlin, p. 741. 



1880. Septifer excisus von Martens, Môbius Beitràg. Meeresf. Mauritius, Seychell., p. 318. 



1886. Tichogonia [Septifer) siamensis and T. [S.) excisa Clessin in Martini & Chemn. Conch. 



Cab. (N. F.), VIII (3), MytUidae, p. 19, pi. XV, figs. 8, 9, p. 24. 



1887. Mytilus [Septifer) excisus von Martens, Journ. Linn. Soc. London (Zool.), XXI, p. 205. 



1890. Tichogonia excisa and T. fusca Paetel, Cat. Conch. Samm., III, p. 202. 



1891. Septifer excisus Smith, Proc. Zool. Soc. London, p. 430. 



1892. Septifer excisus Crosse & Fischer, Journ. Conchyliol., XL, p. 75. 

 1899. Septifer excisus Hedley, Mem. Austral. Mus., II, p. 492. 



1902. Septifer excisus Shopland, Proc. Malacol. Soc. London, V, p. 178. 



1906. Septifer excisus Melvill & Standen, Proc. Zool. Soc. London, p. 799. 



1909. Septifer excisus Lynge, D. Kgl. Dansk. Vidensk. Selsk. Skr. Nat.-Math., (7) V, p. 136. 



191 1. Septifer excisus Pelseneer, "Siboga" Lamellibranches (Anat.), p. 22, pi. VI, figs. 7 — 9. 



19 19. Septifer excisus Odhner, Ark. Zool., XII, N° 6, p. 25. 



1919. Septifer excisus Lamy, Bull. Mus. d'Hist. Nat. Paris, XXV, p. 45. 



1929. Septifer excisus Dautzenberg, Faun. Colon. Français., III, fasc. 4, p. 571. 



I agrée with Lynge that Septifer troscheli Dunker and Tichogonia [Septifer^ siamensis 

 Clessin are both synonyms oï B. [S.) excisus (Wiegmann). The species is very variable in outline, 

 form and colour, but the sculpture even in spécimens from such v^idely separated localities as 

 Japan on the one hand and Madagascar on the other, is quite similar. 



The shells of this species are much more inflated than those of the closely allied 

 B. [S.) bilocularis (Linn.). 



Distribution : — B. (5.) excistis is widely distributed in the Indo-Pacific area, and has 

 also been recorded from the Pleistocene beds of the Red Sea ^). 



In the "Siboga" collections the species is represented by two fresh shells from coral reefs 

 near the Anchorage off Labuan Pandan, Lombok (St. 34) and near the Anchorage off Beo, 



1) Newton, B. — Geolog. Mag., VII, p. 547 (1900). 



