Amplexus. MOLLUSCA. CEPHALOPODA. 
251 
10. B. spinulosa “ Depressed, undulations regular, every other one arm- 
ed with two sharp spines; ;opening elliptical; curvature very gradual;” struc- 
ture obscure Sower. Min. Conch, t. ccxvi. f. 1 — Green Sand, Blackdown. 
11. B. spiniger. — “ Depressed; undulations many, slender; two rows of 
sharp tubercles upon each side, those nearest the front largest ; curvature 
gradual.” — Sower. Mini Conch, t. ccxvi. f. 2. 
12. B. tuberculata “Depressed; undulations unequal, every third one 
largest, with two tubercles on each side, the lateral ones obscure ; curvature 
gradual.” — Sower. Min. Conch, t. ccxvi. f. 4, 5. — .Chalk Marl, Folkstone. 
13. B. turgida “ Depressed ; front irregularly swelled ; undulations re- 
gular, disappearing over the back ; two rows of obscure tubercles near the 
front ; curvature rather sudden.”— iS'owcr. Min. Conch, t. ccxvi. f. 6. — Chalk 
Marl, Folkstone. 
14. B. nodosa.—’-‘- Nearly round, undulations regular; two rows of obtuse 
tubercles upon the front, each tubercle placed upon two undulations ; aper- 
ture obovate.”— Min. Conch, t. ccxvi. f. 3 — Chalk Marl, Folkstone. 
15. B. 'j^licatilis — “ Slightly depressed, with numerous annular ridges; two 
rows of large, equal, flat tubercles upon each side ; curvature gradual. — Soio- 
er. Min. Conch, t. ccxxxiv. f. 1. — Chalk Marl, Warminster. 
Gen. amplexus. — N early cylindrical, divided into cham- 
bers by numerous transverse septa, which embrace each 
other with their reflexed margins. 
1. A. coralloides. — Tube irregular^ bent, longitudinally striated ; margins 
of the septa deeply reflected, and regularly plaited. The septa seem to have 
no perforations. — Sower. Min. Conch, t. Ixxii. — Transition Limestone, Cork. 
[The following extinct species in the genera Nautilus, Nummulita, and 
Orthocera, are here added, having been omitted at their proper places at 
pp. 229, 233, and 238.] 
1. Nautilus Subglobose, umbilicated, finely striated ; umbilicus 
small; sides of the aperture expanded — Sower. Min. Conch, t. cccclviii. f. 1. 
— Chalk Marl, Hamsey. 
2. N. biangulatus.—.Tiisc.o\A, subglobose, witifa large umbilicus, and a keel 
upon each side ; front rounded. — Smaer. Min. Conch, t. cccclviii. f. 2. — In 
Mountain Limestone, Bristol. 
3. N. glohatus. — Subglobose, smooth, umbilicated ; whorls few, inner ones 
concealed, rather flattened on the front, rapidly increasing ; umbilicus deep, 
with an angular margin ; aperture very wide, arched, with a deep sinus in 
the front — Sower. Min. Conch, t. cecclxxxi. — Probably my N. Wrightii is 
identical with this species.— From Cork. 
4. N. multicarinatus. — Discoid, subglobose ; inner whorls half exposed in a 
large deep umbilicus ; edge of the umbilicus angular ; front compressed with 
several carinse on each side the middle.— iShtcer. Min. Conch, t. cccclxxxii 
f. 1, 2. — Transition Limestone, Cork. 
5. N. earinatus, — “ piscoid, subglobose ; inner whorls half exposed, in a 
large umbilicus ; a keel in the middle of each side, and two ridges between 
it and the flattened front.”— t. cccclxxxii. f. 3.— Identical Avith N. ex- 
cavatus already described. 
