The variety is more peculiar to the north, although oc- 

 curring everywhere with the typical form. As an upper 

 tertiary fossil this variety has been noticed in Ireland 

 (Brown), Clyde beds (Crosskey), Fort William (Bed- 

 ford and J. G. J.), post-glacial deposits in Norway, 130 

 feet, and glacial shell-banks in Aremark, Norway, 

 280-460 feet (Sars), and Coralline Crag (S. Wood). 

 Its foreign range comprises Spitzbergen (Torell), Green- 

 land (Moller), Sea of Okhotsk and coast of Russian 

 Lapland (Middendorff), Iceland (Steenstrup), and Scan- 

 dinavia (Loven and others), 050 f., where the ty- 

 pical form also occurs : this last ranges from Heligo- 

 land (Philippi) to Corunna and Vigo (M f Andrew) , and 

 thence to the Gulf of Lyons (Martin) and the ^Egean in 

 20 f. (Forbes) . M f Andrew found a dwarf variety at 

 Teneriffe. The variety arctica (under the specific name 

 aculeus, given to it by Professor Stimpson) inhabits the 

 northern sea-board of the United States. 



This little creature is by no means shy or sluggish. 

 It probably feeds on decayed seaweeds. Females are 

 the better halves in point of size. Some specimens are 

 slender, some ventricose, some of thin texture and deli- 

 cately striated, others are distorted by being twisted on 

 one side in the most lackadaisical fashion. Those from 

 deep water are much smaller than littoral specimens. 



Synonyms : R. minutissima, Michaud, R. communis, 

 Forbes, R. gracilis, Macgillivray, R. decussata, Pyramis 

 candidus, and P. discors, Brown, and R. pedicularis, 

 Menke. The young is the Turbo semicostatus of Mon- 

 tagu and Odostomia Mariona of Macgillivray, and the 

 variety is the R. saxatilis of Moller. Philippi considered 

 a species which he described in the ' Zeitschrift fur Ma- 

 lakozoologie ' for 1849 as R. delicata (from the Red Sea) 

 to be a tropical variety of our R. striata. 



