318 MALACOZOA. CEPHALOPODA. FORAMlNlPEltA. 



they are granulated ; the end of the last cell very large, cordate, 

 embracing the preceding turn, and having a nearly flat cover, 

 with two medial ridges, and two lateral series of pores ; the 

 colour greyish- white. Diameter about the fiftieth of an inch. 

 Found by me on the 9th January, 1843, not uncommon, on 

 Terebella conchilega, gathered on the beach near Aberdeen. 



6. Polystomella depressula. Smooth Polystomella. 



Shell nautiliform, with the sides flattened, the margins 

 rounded, the cells of the last turn about ten, slightly 

 convex, and with the interstices smooth, the centres 

 transparent. Depressulus, small and flattened. 



Shell nearly of the form of Nautilus Pompilius, having the 

 last turn of about ten cells, which gradually enlarge ; the sides 

 little convex, nearly even, glossy, smooth, the dissepiments 

 being little sunk, and radiating from a central pellucid space, 

 which is somewhat depressed ; the end of the last turn lunate, 

 little convex ; the colour greyish-white. Diameter about the 

 fiftieth of an inch. 



Nautilus spiralis subumbilicatus geniculis depressis plurimis. 

 Walker, Test. Min. liar. 19. PI. 3. f. 68. Nautilus depressulus. 

 Mont. Test. Brit. 190; Supplt. 78. PI. 18. f. 9. Nautilus depres- 

 sulus. Flem. Brit. Anim. 228. 



GENUS 2. NUMMULINA. P. 24, 34. 



GENUS 3. DISCORBIS. P. 24, 34. 

 2. Discdrbis pulchellus. Delicate Discorbis. 



Shell orbicular, depressed, convex above, with a cen- 

 tral prominence rounded by a depression, rather convex, 

 smooth, and glossy beneath, the margin rather thin, but 

 rounded ; of two and a-half oblique lobate turns, the last 

 with about fifteen lobes, which are little convex, smooth, 

 and glossy. Pidchellus, small and beautiful. 



Shell orbicular, depressed, spiral, of numerous rather small, 

 somewhat oblique, regular cells, in three and a-half turns ; the 

 lower surface rather convex, even, glossy ; the margin thin, 

 but rounded, and very slightly lobate ; the upper surface con- 

 vex, but with a central depression, in the middle of which is 

 a roundish knob ; the turns distinctly visible on the lower disk, 

 although neither they nor the cells are separated by sulci ; on 

 the upper surface, which is occupied, excepting the central 



