144 48 



Pteria (Margaritifera) vulgaris, Schuin. var. occa, Reeve. 



Avicula occa, Rf.kvk, Concliol. icon., X, 18.')7, Avicula, Sp. 24. 



— {Meleugrina) occa, Reeve, Mahtini u. Chemnitz, Conchyl. Cabin., Vll Bd. ;i Abtii., p. 42, pi. 13, 



fig. 5. 



Koh Kram, 30 fathoms ('/a). 



Long. 28 mm., alt. 29 mm. 



Distribution: — Red Sea, Gulf of Aden (Joussiîaumi:). 



Professor Ed. v. Martens, to whom I sent the specimen for comparison, writes 

 to me as follows: "vermuthlich occa Reeve, wenn man annehmen kann, dass bei 

 der llirigen die Schuppen abgerieben seien." A.H.Cooke' and H. L. Jameson^ are 

 certainly right in considering A. occa, Reeve, a form of Marg. vulgaris, Schum. 

 (= A. fiicata, Gould).'' The present species has probably a far wider distribution 

 than that stated above, but to ascertain this, further investigations will be necessary. 

 A. GiAHD* has collected what he believes to be its synonyms, and according to 

 these its geographical distribution becomes considerably wider. 



Pteria (Margaritifera) nigra, Gould. 



Avicula nigra, Gould, Proc. of tlie Boston Soc. of Nat. Hist., vol. 3, 1850, p. 309. 



— — — Un. St. Expl. E.\ped. Moll., p. 438, pi. 40, fig. 4.'-.4. 



— tristis, Dunker, Martini u. Chemnitz, Conchyl. Cabin., VII, 3 Abtli., p. 44. pi. 14, fig. 3. 



East of Koh Chuen, 9 — 10 fathoms, shells. 



Long. 48 mm., alt. 38 mm. 



Distribution: — Singapore. 



A smaller specimen (long. 19 mm., alt. 16 mm.), which, with some doubt, I 

 refer to the present species, was taken at Koh Kahdat in one fathom, on a sandy 

 bottom. 



Pteria (Margaritifera) citrina, Dunk. 



Avicula (Meleagrina) citrina, Dunkek, Zeitschr. f. Malakozoologie, IX, 18r)2, p. 78. 



— — — — Martini u. Chemnitz, Conchyl., Cabin., VII I5d. 3 Abth., pp. 14 and 



71, pi. 3, fig. 4, and pi. 25, fig. 1. 

 Pteria {Margaritifera) — — Jameson, Proc. Zool. Soc. London, 1!)01, p. 383. 



Strand of Koh Kahdat ('/s). 

 Long. 24 mm., alt. 2.5 mm. 

 Distribution: — Dutch India (E. v. Martens in litt.). 



' Annals and Magaz. Nat. Hist., Ser. 5, vol. 17, pp. 136—37. 

 -' Proc. Zool. Soc. London, 1901, p. 384. 



' A. Pagenstecher describes various forms of P. occa, Reeve, from the Red Sea in "Ueber die v. 

 R. Kossmann am Rothen Meere gesaram. Mollusken," 1877, p. 35. 



^ Comptes rendus hebdomad, d. seances de la Soc. de Biologie, Paris, Tome 56, 1004, pp. 255 — 57. 



