452 BTJLLID.E. 



4. P. quadra'ta*, Searles Wood. 



Bullaa quadrata, S. Wood in Ann. N. H. iii. p. 461, pi. vii. f. 1. P. 

 quadrata^ F. & H. iii. p. 541, pi. cxiv. e. f. 2, 3. 



Body whitish and semitranspareut : head rounded : tentacles 

 not separate : eyes wanting : foot oblong, symmetrical and 

 even with the head in front : gizzard minute ; plates elliptical. 



Shell squarish-oval, convex, contracted or compressed on 

 the upper part below the spire, and bluntly angulated in the 

 middle ; it is not very thin, is semitranspareut, and when 

 fresh of a glistening lustre : sculpture, numerous rows of fine 

 spiral striae, which are composed of minute oval dots and ap- 

 pear punctate ; these striae are irregularly disposed, being in 

 some parts more close together than in others, and they here 

 and there form intermediate and slight lines ; the upper part 

 of the body-whorl is thickened and rounded, and the middle 

 is furnished with a blunt and slight spiral rib, which is usually 

 visible also within the mouth ; the top of the outer lip is de- 

 licately scalloped : colour white, crystalline when extracted 

 from the animal : spire small, more or less sunken ; apex ob- 

 scure : ivhoids 2-3, rounded ; the inner ones are minute : 

 suture deep : mouth broadly oval, contracted above by the 

 periphery, and expanded below, with the base obliquely curved 

 and somewhat truncated : it occupies about two-thirds of the 

 underside of the shell : outer lip nearly straight in front and 

 forming an obtuse angle at the junction of that part with 

 the base ; the top is rather higher than the spire, and projects 

 outwards ; outer corner bluntly angular or rounded ; inner 

 corner receding and acute-angled, but not exhibiting any 

 further disjunction of the outer whorl from the next : inner lip 

 broad and thick. L. 0'25. B. 0*2. 



Habitat : Mud and sand, Dogger bank (Mennell and 

 J. G. J.); Whitburn (Abbes and Howse, fide Alder); 

 Arran Isles, co. Galway (Barlee); Moray Firth (Gor- 

 don) ; Aberdeenshire (Dawson) ; Orkneys, 12-40 f. 

 (Thomas, fide Forbes) ; Shetland, 3-76 f. (M f Andrew 

 and others) ; Coralline Crag, Sutton (Wood) ; post- 

 glacial beds in Norway, 60-100 feet (Sars) . Its exist- 



* Square. 



