MOLLUSCA. 1 



247. Pecten passerinus. 



P. asper. Sow. Jun. Thes. Conch, p. 50. 



Inhab. New Guinea. In seven fathoms, on a muddy floor. 

 A fossil of the Paris basin and of the green sand in England claims priority 

 in Mr. Sowerby's name. 



248. Pecten rubidus, (Plate XVII, fig. 5.) Testa subtrigono-orbiculari, insequaliter duplo- 

 convexa, insequiauriculata. subtenui; valva sinistra convexa., costis parvis numerosissitnis, serratis, in 

 fasciculos duarum triumve alternate aggregatis, rufis, interstitiis pallescentibus; valva. dextra sub- 

 convexa, albida, costis majusculis, aggregatis; auriculis sulcatis, postica parva., obliqua; intus 

 alba. 



Inhab. Alashka, North-west America. At a depth of thirty-three fathoms. 



This species has both close geographic and structural relations with P. ice- 

 landicus. Four specimens were obtained at the same depth, and they agree in 

 the different state of convexity of the valves, their tumidness, the somewhat 

 elegant and methodical clustering of the small ribs, and the very small and 

 oblique posterior auricle. The colour, though at first apparently of an uniform 

 rose, is deeper on the ribs than in the interspaces, with concentric bands of the 

 same. None of the specimens approach in size P. icelandicus. 



249. Pecten digitatus, (Plate XVII, fig. 2.) Testa subtrigona, planiuscula, solida, sequi- 

 auriculata, pallida, sanguineo transversim nubeculata. ; valvis consimilibus, costis novem rotundatis 

 sulcatis ; auriculis sulcatis ; umbonibus subplanulatis, Isevigatis ; marginibus minute denticulatis ; 

 intus alba. 



Inhab. Bay of Guayaquil. In twenty-three fathoms, mud. 



250. Pecten fasciculatus, (Plate XVII, fig. 4.) Testa late subtrigona, planiuscula, tenui, 

 inasquiauriculata, rufo-violascente albo maculata, ; valvis consimilibus, costis parvis numerosis, 

 eleganter serratis, in fascibus quinque plerumque aggregatis, alteris interstitiis suppletis ; auriculis 

 inaequalibus, rectis, argute serratis, dentatis; intus violascente. 



Inhab. West coast of Veragua. In seventeen fathoms, among sandy mud. 



A beautiful and delicate shell, traversed by numerous small finely serrated 

 ribs, a large portion of which are gathered into five bundles, the others being less 

 aggregated and occupying the interspaces. The auricles differ in size, and are 

 strongly grooved, with intervening sharp ridges. Within, the valves are coarsely 

 ribbed, and of a rich peach colour. 



251. Pecten coruscans, (Plate XVII, fig. 3.) Testa suborbiculari, planiuscula, tenui, ins |ui- 

 auriculata, pallide violascente, prope umbones strigis parvis lacteis obliquis induta; valvis convexius- 

 culis, consimilibus, dextra pallidiore, costis quatuordecem serratis, argute sulcatis, interstitiis sulcatis ; 

 auriculis inaequalibus, serrato-sulcatis, postica minima, obliqua; intus pallescente. 



Inhab. Port Anna Maria, Nukuhiva, Marquesas Islands. In seven fathoms, 

 on a sandy floor. 



