TROCHUS. 305 



Another Clyde fossil, the Margarita olivacea of Brown, 

 appears to be the M. glauca of Mdller^s Catalogue of 

 Greenland Mollusca. 



Margarita elegantissima of Bean, from the glacial de- 

 posit at Bridlington, also lives in the Arctic Ocean ; it 

 is the M. plicata of Sars, and M. po'laris of Danielssen. 



The M. aurea of Brown (described as '^ destitute of 

 an umbilicus ^^) has been identified by Forbes and 

 Hanley with Turbo sanguineus of Linne, a Mediterra- 

 nean shell. 



B. Low-spired and umbilicate. Gihbula, Leach. 



4. T. MAGUS ^, Linne. 



7. moQus, Linn. S. N. p. 1228; R & H. p. 522, pi. Ixv. f. 6, 7, and 

 (animal) pi. D D. f. 3. 



Body yellowish, mottled with purple and brown, or speckled 

 with reddish-brown and white, and closely covered with short 

 papillae : mantle sometimes forming an incomplete branchial 

 fold on the right side ; pallial lappets large and broad, some- 

 times orange bordered with yellow, left fringed, right plain : 

 Jiead broad, but not prominent, ornamented in front with a 

 veil or hood, the centre of which is brown and its ends 

 yellow ; this veil is divided into two lappets with white fringed 

 edges, which often hang over the head ; the extremity of the 

 snout is also fringed or setose: tentacles very long and slender, 

 more or less annulated with black : eyes very large, turquoise 

 or black in the centre, encircled with a bluish line ; stalks 

 short and somewhat angular : foot broad in front and bluntly 

 pointed behind : appendages 3 on each side, springing from 

 short sheaths, of a lighter colour than the tentacles, and with 

 a white tubercle at the base of each. 



Shell forming a depressed cone, somewhat scalariform, 

 solid, opaque, of a rough and rather dull aspect : sculpture, 

 numerous but irregular spiral ridges crossed obliquely by 

 minute and close-set striae, which are laminar or imbricated 



* From its supposed resemblance to the turban of a magician. 



