60 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL, 23 



1791, p. 3319). He also described Pecten dispar (p. 173), which is 

 identical with the west African species. 

 9. Sowerby (1842, p. 56, pi. 19, figs. 211-212; pi. 20, fig. 243) 

 realized the errors of Chemnitz, Gmelin and Lamarck. He referred 

 a shell from Gambia (west Africa) to Pecten Pscudamusium Klein, 

 thus first validating that name, and cited Klein's description and 

 figure. As synonyms he listed "P. cxoticus, Chem. ... P. dispar? 

 Lam. . . . Ostrea hybrida, Gmel. . . ." and said, "This is the true 

 P. Pseudamusiu/n of Klein, the P. Pseudamusimn of Chemnitz 

 being only a variety of his P. Danicus." 



10. Sowerby (1842, p. 57, pi. 20, figs. 231-232) described and figured 

 Pecten orbicularis ("British Museum Co. of Africa."), actually a 

 juvenile specimen of the same west African shell. 



11. Herrmannsen (1847, p. 340) listed Pseudamussium as a genus, first 

 changing Klein's spelling. He did not validate it, however, for he 

 gave no diagnosis or indication and did not designate a type species. 



12. Reeve (1852, sp. 13, pi. 3, fig. 13) synonymized under Pecten 

 Danicus Chemnitz, "Pecten pscudamusium, Chemnitz (not of 

 Klein)," and Ostrea septemradiata Gmelin (1791, p. 3327 == 

 septcmradiatus Miiller, 1776). Under "Pecten pscudamusium 

 Klein" (sp. 56, pi. 16, fig. 56), Reeve synonymized both Pecten 

 exoticus Chemnitz and Ostrea hybrida Gmelin, indicating his 

 realization that Chemnitz' Pseud-amusium had been erroneously 

 described and figured, and Gmelin's Ostrea hybrida was identical 

 with Klein's species. 



13. Morch (1853, p. 59) proposed Pseudamussium as a genus and 

 listed Pecten glaber Linne (1758, p. 698; glabra) and P. septcm- 

 radiatus as species, but did not designate a type. He incorrectly 

 synonymized P. exoticus Chemnitz under the totally unrelated 

 glaber and "P. pseudamussium Ch." under septcmradiatus, accept- 

 ing Chemnitz' error in regard to the latter. [Morch's work was 

 merely a sales catalogue itemizing the contents of the Yoldi collec- 

 tion for prospective buyers, and therefore was not generally avail- 

 able. According to the definition of publication, as clarified by the 

 International Commission on Zoological Nomenclature at its 1948 

 Paris meeting, the names in this catalogue are invalid.] 



14. Dunker (1853, p. 44, tab. 9, fig. 31) described and figured a very 

 small shell, naming it Pecten Loveni. The locality given was 

 "Guineam inferiorem" (Lower Guinea, at that time the name for 

 the coastal area of west Africa extending from the present Camer- 



