66 



Expédition at St. 260 (5° 36'. 5 S., i32°55'.2E.) and two adult shells at Anchorage East of 

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



Relationships: — G. dautzenbergi is superficially very like the young shells of G. maskatensis 

 (Melvill) ^), but is distinguished by the form of the shell, its much broader hinge-plate and a 

 quite différent type of sculpture. 



Family Mytilidae. 



Genus Brachidontes Swainson. 



1840. Brachidontes Swainson, Treat. Malacol., p. 384. 



1846. Brachyodontes Agassiz, Nomencl. Zool. Ind. Univ., p. 51. 



1886. Bracitydontes Fischer, P., Man. Conchyliol., p. 968. 



1889. Brachydontes Dali, Bull. U. S. Nat. Mus., N" 37, p. 38. 



1898. Brachydontes Dali, Trans. Wagner Free Inst. Sci. Philadelphia. III, p. 790. 



1905. Brachyodontes Jukes-Browne, Proc. Malacol. Soc. London, VI, p. 222. 



1925. Brachydontes Woodring, Miocène Mollusks from Bovvden, Jamaica, Pelecypods tic, p. 85. 



1930. Brachidontes Stewart, Spécial Publication Acad. Nat. Sci. Philadelphia, N" 3, p. 100. 



In accepting Brachidontes Swainson as a genus I hâve followed Jukes-Browne. A good 

 description of the genus and of the two subgenera Hormomya Morch -) and Septifer Récluz *) 

 is published in Jukes-Browne's paper cited above. The type of Brachidontes is B. siilcatus 

 (Lamarck), of Hormo?nya — B. (//.) exustzis (Linn.) and of Septifer — B. {S.) biloctdaris (Linn.). 



I. Brachidontes [Hormomya) variabilis (Krauss). 



18 17. Monte Savigny, Descr. Egypt., MolL, pi. XI, fig. 5. 



1827. Mytiliis exiistns Audouin (nec Linn., non Lamarck), Expl. pi. de Savigny, p. 205. 



1848. Mytiliis variabilis Krauss, Sùdafr. Moll., p. 25, pi. II, fig. 5. 



1857. Mytilus variabilis Adams, H. & A., Gen. Rec. Moll., II, p. 513. 



1865. Mytilus exustus Vaillant, Journ. Conchyliol., XIII, p. 114. 



1869. Mytilns variabilis Issel, Malacol. Mar. Rosso, p. 94. 



1870. Mytilns pharaonis Fischer, P., Journ. Conchyliol., XVIII, p. 169. 



1870. Mytilns [Anlacoinya] variabilis MacAndrevv, Ann. Mag. Nat. Hist. (4) VI, p. 448. 

 1877. Mytilns [Aidacomya) variabilis Pagenstecher, Zool. Ergebn. Reise Rothen Meer. Mollusk., 



p. 38. 

 1879. Mytilns variabilis von Martens, Monatsb. K. Akad. Wiss. Berlin, p. 741. 

 1879. Mytilus variabilis Smith, Phil. Trans. Roy. Soc. London, LI, p. 476. 



1886. Mytilns variabilis Cooke, Ann. Mag, Nat, Hist., (5) XVII, p. 137. 



1887. Mytilns senegalensis Clessin (ex parte), in Martini & Chemn. Conch.-Cab. (N. F.), VIII (3), 



Mytilidae, p. 38, pi. XI, figs. 3, 4. 



1890. Mytilus variabilis Paetel., Cat. Conch. Samm., III, p. 193. 



1892. Mytilns variabilis Sowerby, Marine Shells, S. Africa, p. 64. 



1893. Mytilns variabilis Dautzenberg, Bull. Soc. Zool. France, XVIII, p. 84. 



1901. Mytilns variabilis Sturany, Denkschr. Kais. Akad. Wiss. Wien (Math.-Nat.), LXIX, p. 288. 

 1904. Mytilus [Aulacomya) variabilis Smith, Journ. Malacol., XI, p. 25. 



1906. Mytilns variabilis Melvill & Standen, Proc. Zool. Soc. London, p. 799. 



1907. \ Mytilus senegalensis Lamy (non Lamarck), Bull. Mus. d'Hist. Nat. Paris, XIII, p. 152. 



1) I figure a shell of this species, from the Persian Gulf, for comparison (Plaie II, figs. 19, 20). 



2) Morch, O. A. L., — Cat. Yoldi, II, p. 53 (1853). 



3) Récluz, C. A., — Rev. Zool., pp. 225 — 227 (li 



