51 147 
young, were dark-coloured, quite an individual character. In the new edition of 
“Martini & Cuemnirz, Conchyl. Cabinet,’ CLessin has worked out the genus Perna,! 
but nowhere does he mention Cuemnirz’s P. Spengleri. 
Perna isognomon, L. 
Ostrea isognomon, LINNE, Syst. Nat., ed. X, 1758, p. 699, No. 176. — ed. XII, p. 1149. Mus. Ludov. UIr., 
p- 533, No. 120. 
Melina Isogonum, — _ Rerzius, Nova Testaceor. Gen., 1788, p. 23. 
Ostrea isognomon, — GMELIN, Syst. Nat., ed. XIII, p. 8338, No. 125. 
Perna isognomum, — REEVE, Conchol. icon., XI, Perna, Sp. 24. 
—  isogonum, —  Cvessin in Martini u. CHEMNIrTz, Conchyl. Cabin., VIII, 1 Abth., pl. 8, fig. 1. 
East of Koh Chuen, 9—10 fathoms, shells (2). 
Distribution: — Singapore, Mergui Archip., Madras, Madagascar and Mozam- 
bique, Mauritius. — Poulo Condor, Philippines, Amboina, Moluccas, Sorong, New 
Guinea, Thursday Isl. 
Of the two specimens brought home from the above-mentioned locality the 
larger (long. 59mm., alt. 99mm.) should be referred to the variety femoralis, Lam.,’ 
and the smaller (long. 34 mm., alt. 73 mm.) to the variety curvala, Ch.° 
Perna rudis, Reeve. 
Perna rudis, REEVE, Conchol. icon., XI, Perna, Sp. 20. 
— — — Martini u. Curmnirz, Conchyl. Cabin., VIII, 1 Abth., p.31, pl. 9, fig. 6. 
North end of Koh Chang, 1 fathom, old coral blocks (1). Koh Kahdat, 1 
fathom, sand (38). 
Alt. 14—98 mm. 
Distribution:— JoussEAuME* records that one specimen of this species 
was taken at Obock (Gulf of Aden). Collected by VortrzKow at Zanzibar. 
The present species is closely allied to P. isognomon L. A. H. Cooke” thinks 
that P. rudis, Reeve, is synonymous with P. legumen, Gmel. (= linguaeformis, Reeve 
= laticostata, Reeve = caudata, Reeve). 
Perna Cumingi, Reeve. 
Perna Cumingti, Reeve, Conchol. icon., XI, Perna, Sp. 3. 
Cumingi, — MartTINI u. CHEMNITZ, Conchyl. Cabin., VIII, 1 Abth., p. 40, pl. 15, fig. 1. 
Melina cumingii, — Eve. Smiru, Zoolog. Collect. of H. M.S. “Alert,” p. 113. 
' The extremely unsatisfactory and unscientific way in which this has been done is much to be 
regretted. As an example of the superficiality which characterises the work may be mentioned that 
one of the best-known species, P. isognomon L., is called P. isogonum L. throughout the whole work. 
? Hist. nat. d. anim. s. vert., 2 éd., VII, p. 76, No. 5. 
* CHEMNITZ, Conchyl. Cabin., VII, 1784, p. 256, pl. 59, fig. 583. 
* Mém. de la Soc. zoolog. de France, I, 1888, p. 219. 
° Annals and Magaz. of Nat. Hist., 5 Ser., vol. 17, p. 138. 
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