204 PROCEEDINGS OF THE MALACOLOGICAL SOCIETY. 



One of three specimens in the British Museum no doubt represents 

 the type of attetmata, Reeve ; no locality is marked, the shells are 

 Cuming's. The form is closely allied to canaliculata (= lima), but is 

 larger, broader, somewhat less solid, sculpture more conspicuously 

 laminated, spiral ridges more numerous and smaller, shell without 

 the deep 'channel' below the suture, which gives the name to 

 canaliculata. No type of analoga, Forbes, seems to be preserved. 



The type of septentrionalis, Reeve, is similarly represented in the 

 Britisli Museum by one of several specimens; the shell is massive, 

 ■without flounces, and there is a variety with one broad white band 

 on tlie body-whorl. 



Vanatta (118) has pointed out — and he is undoubtedly right — that 

 P. saxicola of Valenciennes (Voy. Venus, Atlas, pi. viii, figs. 4, Aa) is 

 a form oi freycinetii, Desh. In the case of the Venus Mollusca, there 

 is no description to accompany the pictures in the Atlas. JEmarginata, 

 Desh., therefore becomes the type of the species, and the form 

 hitherto represented by the name saxicola, Val., will become fuscata, 

 Forbes. The type of fuscata is the larger of two specimens in the 

 British Museum, collected by Captain Kellett and Lieutenant Wood, 

 E..N., and erroneously said to come from the Sandwich Islands. The 

 spire is elevated, and the spiral ridges well marked. The form 

 ostrina has a low spire, with whorls almost or altogether destitute of 

 spiral ridges. 



Deshayes must have named his emarginata from a malformed 

 specimen with a marked indentation in the outer lip, hence his name. 

 He lays stress on this ' echancrure ', which "corresponds to the 

 second row of tubercles on the last whorl, and is comparable to the 

 impression wliich the finger-nail might have left on the edge, had it 

 been softened". His locality is "New Zealand", but there can be 

 little doubt that his shell is the form which has been commonly 

 recognized as emarginata. 



As regards distribution, the lima group is found, in the far north, 

 in Plover Bay, North-East Siberia, and Norton Sound, North-West 

 Alaska (Dall 20, as canaliculata), in the Pribiloff and Commander 

 Islands, Behring's Sea (Dall 23), and southward to Monterey 

 (Berry 11). 



The plicata group extends from Sitcha and Kandjak Islands, 

 Konyagen (Middendorff, as Murex lactuca) and Alaska (Coll. A. H. C), 

 through all British Columbia (Taylor 115), to the neighbourhood of 

 San Francisco, but apparently not so far south as Monterey (Berry 11). 

 I have a specimen from Hidaka, Yesso (Hirase). 



The emarginata group extends from Ounalaska (Cooper 18, as 

 saxicola) to Margarita Bay, Lower California (Pease in Carpenter 14, 

 p. 152), in the form ostrina. 



LIST OF AUTHORS QUOTED. 



1. Adams, A. "On some species of Proboscidiferous Gasteropoda which 



inhabit the Seas of Japan": Ann. Mag. Nat. Hist., ser. IV, v, 418- 

 30, 1870. 



2. Adanson, M. Histoire Naturelle du Sinigal : Coquillages ; Paris, 1757. 



