212 



the inhospitable shores of the Polar seas. Attracted by the regu- 

 larity of their form and the beauty of their coloring, the ancients 

 distinguished them as a group from all other shells. Aristotle and 

 Pliny indicated several species, and compared them to a comb or 

 pecten from the similitude of their ornamental rib-formed radii. 

 Distinguished artists have judged them worthy of representation 

 on their canvas, and the voluptuous form of Venus is seen sup- 

 ported on the waves by the valve of a 2^ecten. A beautiful species 

 which inhabits a portion of the Pacific is deified by the natives of 

 some of the islands in that ocean. In Catholic countries they are 

 commonly called Saint James' shells, and the pilgrims who visited 

 the shrine of St. James of Compostella, in Spain, were careful to 

 attach one or more to their dress, collected on the neighboring 

 shore, where they abound. 



It is not a little surprising that although all the earlier writers 

 separated these shells from others as a natural group, yet our great 

 master Linn6 placed them in his genus Ostrea, notwithstanding the 

 striking difierence in the structure of their animals, already indi- 

 cated by Lister and others. Bruguiere corrected this error and 

 restored them to the just rank of a separate genus, now universally 

 acknowledged. The family of Pectinides to which it belongs is 

 composed of the genera Lima, Plagiostoma, Pedum, Pecten, Hiii- 

 vite, Plicatida, Spondylus and Podojjsis. The latter is so nearly 

 related to Spondylus, and Plagiostoma, so closely resembles Lima, 

 that it has been proposed to suppress them both, which would leave 

 but six genera. Sowerby insists that Ilinnite cannot be a separate 

 genus, but must be united to pecten. Of these the three first only 

 are symmetrical, and furnished with a byssus. The apices of Lima 

 are distant and the auricles are similar in both valves. The liga- 

 ment in Pedum is inserted in a canaliform fossct on the inner face 

 of the summits, prolonged into the interior. 



The ears of Pecten are equal in some species and unequal in 

 others, but generally on one of the valves one of the ears is deeply 

 emarginated beneath, to admit the passage of the byssus, by which 

 the animal attaches itself to foreign bodies, as represented by 

 Reaumer in Mem. Acad, lloyale des Sc, 1711, pi. 2, fig. 12. 

 Some species have a small divergent tooth on each side of the 

 cardinal fosset in one valve, and corresponding depressions in the 

 opposite valve. In many species are several very small tubercles 



