3i6 



The types in the British Muséum are without any locality, but R. [R.) viacrochisma has 

 been recorded from the Philippines. 



The "Siboga" spécimens were collected at the Anchorage off Sawan, Siau Island (St. 125), 

 Anchorage off Pasir, Pandjang, west coast off Binongka (St. 220), Nalahia Bay, Nusa Laut Island 

 (St. 234) and Anchorage east of Dangar Besar, Saleh Bay (St.- 313). 



2. Rocellaria [Spengleria) mytiloides (Lamarck). 



171 1. Rostrum Anatis terthim Rumph, Amboin. Rarit., p. 10, pi. XLV, fig. P. 



18 18. Gastrochaena mytiloides Lamarck, Anim. sans Vertèb., V, p. 447. 



1835. Gastrochaena mytiloides Deshayes in Lamarck, Anim. sans Vertèb., VI, p. 49. 



1842. Gastrochaena Mytiloides Hanley, Rec. Biv. Shells, p. 10, pi. IX, fig. 37. 



1856. Rocellaria mytiloides Adams, H. & A., Gen. Rec. Moll., II, p. 336. 



1860. Gastrochaena mytiloides Reeve, Rlem. Conch., II, p. 175. 



1862. Rocellaria [Spengleria) mytiloides Tryon, Proc. Acad. Nat. Sci. Philadelphia, p. 484. 



1862. Gastrochaena mytiloides Chenu, Man. ConchylioL, II, p. 16, fig. 72. 



1863. Gastrochaena Retzii Deshayes, Cat. Moll. Réunion, p. 7, pi. XXVIII, figs. i — 3. 

 1878. Gastrochaena Retzii Sowerby in Reeve, Conch. Icon., XX, Gastrochaena, pi. II, fig. 6. 

 1880. Gastrochaena [Spengleria) mytiloides and G. [S.) Retzii von Martens, Mobius Beitràge 



Meeresf. Mauritius, Seychell., p. 332. 



1886. Gastrochaena Retzii Cooke, Ann. Mag. Nat. Hist., (5) XVIII, p. 109. 



1887. Gastrochaena Retzii and G. mytiloides Sowerby, Thés. Conch., V, p. 130, pi. CCCCLXX, 



fig. 10, p. 131, pi. CCCCLXX, fig. 8. 

 1890. Gastrochaena mytiloides and G. Retzii Paetel, Cat. Conch. Samm., III, p. 8. 

 1894. Gastrochaena mytiloides and G. Retzii Clessin in Martini-Chemn., Conch. -Cab. (N.F), XI 



(4), Gastrochaenidae, p. 6, pi. III, figs. i, 2. p. 7, pi. III, figs. 15, 16. 

 1906. Gastrochaena mytiloides Melvill & Standen, Proc. Zool. Soc. London, p. 844. 



1922. Gastrochaena mytiloides Lamy, Bull. Mus. d'Hist. Nat. Paris, XXVIII, p. 310. 



1923. Gastrochaena mytiloides Lamy, Bull. Mus. d'Hist. Nat. Paris, XXIX, p. 395. 

 1925. Gastrochaena mytiloides Lamy, Journ. ConchylioL, LXVIII, p. 312. 



1928. Gastrochaena mytiloides Faustino, Summary Philippine Mar. Freshw. Moll., p. 116. 



1929. Gastrochaena [Spengleria) mytiloides Dautzenberg, Faune Colon. Français., III, p. 619. 



The largest shell of R. (S.) mytiloides in the "Siboga" collection is 30 mm. long and 

 14 mm. deep. The oblique furrow dividing the anterior from the posterior part of the shell is 

 well developed, and the form and sculpture correspond exactly with that of a shell of this species 

 in the British Muséum collection. 



Distribution : — R. (5.) mytiloides has been recorded from Mauritius, Jibouti, Madagascar 

 and the Philippines. 



In the "Siboga" collection the species is represented from the Bay of Nangamessi, Sumba 

 (St. 53), Anchorage off Beo, Karakelang Islands (St. 131) and Anchorage north of Salomakiëe 

 (Damar) Island (St. 144). 



Family Pholadidae. 

 Genus Xylophaga Turton. 



1822. 'Xylophaga Turton, Conch. Insularum Brittan., p. 253. 

 1856. Xylophaga Adams, H. & A., Gen. Rec. Moll., II, p. 326. 

 1887. Xylophaga Fischer, P., Man. ConchylioL, p. 11 35. 



