Koh Chuen, 30 fathoms (38). 
1) Long. 172 mm., alt. 112 mm. 2) Long. 183 mm., alt. 112 mm. 
Distribution: — Gulf of Suez, Red Sta. — Amboina, Australia. 
Pinna Strangei, Hanl., is undoubtedly only a form of the present species with- 
out scales upon the ribs. L.Morter! records Pinna Chemnitzi, Hanl., from “the 
islands in the Gulf of Siam;” can this be due to erroneous determination? The 
Danish Expedition, at any rate, did not bring home any specimen of this species. 
Ciessin, in his Monograph of the genus Pinna, in “Martini and Cuemnirz, Con- 
chylien Cabinet,” figures and describes quite another species under the name of 
P. Strangei, Hanl. PAGENSTECHER® records P. hystrix-forms from the Red Sea, and 
also forms haying ribs without scales (from the same locality), which he names 
P. atropurpurea, Sow. 
Pinna attenuata, Reeve. 
Pinna allenuala, Reeve, Conchol. icon., XI, Pinna, 1858, Sp. 46. 
— _ MENKE, Martini u. CHEMNITZ, Conchyl. Cabin., VII, 1 Abth., p.59, pl. 27, fig. 1. 
—  Stulchburii, REEve, Conchol. icon., XI, Pinna, 1859, Sp. 64. 
Marrini u. CHEMNITZ, Conchyl. Cabin., VII, 1 Abth., p. 74, pl. 30, fig. 2. 
Off Tung Kaben, 6 fathoms, mud mixed with sand (1). 
Long. 173 mm., alt. 51 mm. 
Distribution: — Madras, Gulf of Manaar, Gulf of Suez, Red Sea. — Moluccas, 
Moreton Bay (Australia). 
The specimen from the Gulf of Siam bears a few scales on some of the raised, 
longitudinal ribs; this is also found often to be the case in specimens from the 
Red Sea.* I have given P. Stutchburyi, Reeve, as a synonym, as I cannot see any 
difference, worthy of mention, between these two forms.! 
Pinna mutica, Reeve. 
Pinna mulica, REEVE, Conchol. icon., XI, Pinna, 1858, Sp. 33. 
= — _— Marvrint u. Coemnirz, Conchyl. Cabin., VIII, 1 Abth., p. 68, pl. 26, fig. 2 
Koh Chuen, 30 fathoms (1). Koh Kram, 30 fathoms (1 young specimen). 
Long. 38—147 mm., alt. 13—63 mm. 
Distribution: — Philippines. 
Pinna madida, Reeve, P. euglypta, Hanl., and P. vespertina, Reeve, show great 
resemblance to the present species, and will perhaps. prove to be synonyms of P. 
mutica, Reeve. 
Pinna serra, Reeve. 
Pinna serra, REEVE, Conchol. icon.. XI, 1858, Pinna, Sp. 43. 
= = = CvEssin in MarTIN1 u. CHEMNITZ, Conchyl. Cabin., VIII, 1 Abth., 1891, p. 60, pl. 28, fig. 2. 
1 Journal de Conchyliologie, vol. 37, 1889, p. 161. 
* Ueber die von Kossmann am Rothen Meere gesamm. Mollusken. Lpzg. 1877, p. 30. 
‘’ For details concerning this and the variation, etc. of P. Stutchburyi comp. PAGENSTECHER, 
Ueber die von Kossmann am Rothen Meere gesamm. Mollusken. Leipz. 1877, pp. 30—31. 
* Professor Ep. y. MARTENS says in a letter to me, that these two forms: “sind einander sehr 
ahnlich und gehoren vielleicht beide zu Einer Art.” 
