171 



1891. Pythina Deshayesiana Smith, Ann. Mag. Nat. Hist., (6) VIII, p. 228. 



1905. Pythina Deshayesiana Hidalgo, Cat. Filip., p. 359. 



191 1. Pythina Deshayesiana Pelseneer, "Siboga" Lamellibranches (Anat.), p. 43, pi. XVI, fig. 9. 



The spécimens from the "Siboga" collection, vvhich I assign to this species, agrée in ail 

 respects with the shells of the species in the British Muséum (Nat. Hist.), London, 1 figure one 

 of the shells. 



Distribution : — P . deshayesiana has so far been recorded from the Philippine waters only. 



The "Siboga" shells of the species were dredged in Taruna Bay, Great Sangir Island (St. i 27). 



Family Montacutidae. 

 Genus Montacuta Turton. 



1822. Moniacuta Turton, Conch. Insularum Brittan., p. 58. 



1857. Montacnta Adams, H. & A., Gen. Rec. Moll., III, p. 1169. 



1886. Montacnta Fischer, P., Man. Conchyliol., p. 1027. 



1900. Montacnta Dali, Trans. Wagner Free Inst. Sci. Philadelphia, III, p. 1169. 



I differ from Dall in considering My sella Angas ^) [^ Rochefortia Velain) ^) as a subgenus 

 of Montacuta ; the form of the shell and the hinge fully confirm this view. The génotype of 

 Montacuta Turton is Montacitta substriata (Montagu). 



In référence to Mysella and Rochefortia, Dall considered Velain's genus Rochefortia 

 as earlier, but as Iredale ^) has shown Rochefortia can only be accepted as valid from 1878, 

 and Mysella Angas 1877, will, therefore, hâve priority over it. The type oi Mysella is Mysella 

 anomala Angas. 



I. Montacuta smithi sp. nov. (Plate V, figs. 26, 27). 



I dedicate this species to the memory of the late Mr. Edgar Smith of the British Muséum 

 (Nat. Hist.), London, to whom we owe the major part of our knowledge of this interesting 

 faniily of Bivalves. 



Species of moderate size ; shell elongate, subequilateral, cylindrical, rounded at both ends, 

 slightly deeper in front than behind, tumid, fairly thick-shelled ; longer anterior dorsal margin 

 horizontal, slightly excurved, posterior much shorter, also horizontal and slightly arched ; ventral 

 margin almost straight, ascending more abruptly posteriorly ; umbones hardly prominent, slightly 

 raised above hinge-line, acute, situated somewhat behind middle ; hinge-plate slightly thickened ; 

 sculpture consisting of minute concentric striae and few lines of growth. Shell of a dull white 

 colour 5 nacre glossy white. 



Measurements of Holotype : — Length 6.9 mm., height 4.5 mm., diameter 3 mm. 



Habitat : — The unique Holotype was collected at the i\nchoragè off Lilintah, south 

 coast of Misol (St. 176). 



i) Angas, A. — Proc. Zool. Soc. London, p. 176 (1877). 



2) Velain, C. — Archiv. Zool. Expev. Gen., VI, p. 132 (1878). 



3) Iredale, t. — Proc. Linn. Soc. N.B. Wales, LXIX, p. 207 (1924). 



