22 SYNOPSIS OF THE CHARACTERS OF THE 



This species lias but few whorls, the inner ones being partly concealed by those which follow ; they in- 

 crease very rapidly in size, so that in old individuals the spii-e does not indent the mouth; the back is flattened, 

 and, in young individuals, the sides are also somewhat flattened ; when very young, there are some spiral 

 grooves on the back, and in that state has perhaps been described as a distinct species ; the mouth is very large 

 and semicircular, mth a deep sinus in the outer lip. Professor Phillips' shell seems distinct. 



Nautilus (Temnocheilus) multicaeinatus. Sow. sp. 



Nautilus multicarinatus. Sow. Min. Con. 



Sp. Ch. — Discoid; inner whorls half exposed in a deep, conical umbilicus ; back flattened, with three or 

 four keels on each side ; one keel within the edge of the umbilicus. 



This species much resembles the N. cariniferus in form, but it is distinguished by the number of keels 

 with which it is marked ; there are four on each side in young, well-marked individuals, but by age the keels 

 on the back become more or less eflaced ; the keel witliin the umbilicus is more constant than any of the others, 

 in fact, I do not remember an instance in wliich it was not present. Diameter four inches, thickness two 

 inches and a half 



Nautilus (Temnocheilus) pinguis. M'Coy. (PI. IV. fig. 12). 



S]j. Ch. — Discoid, smooth; umbilicus rather small, conical, half exposing the inner volutions ; whorls about 

 four, gradually increasing, ventricose, carinated on the sides ; keel vanishing towards the mouth ; back broad, 

 rounded ; umbilical slope convex ; mouth broad, oval, about one-third wider than long. 



This species most nearly resembles the Nautilus ( Temnocheilus) cariniferus but diflers in having its 

 volutions less broad and more ventricose, the umbilicus smaller, and its sides convex, and in the much greater 

 convexity of the back. The deep sinus in the outer lip, found in all the species of Temnocheilus, is visible 

 in the specimen figured. Diameter two inches one line ; length of mouth nine lines ; width of mouth one inch 

 two lines. 



The specimen figured is one of several rarities from the cabinet of Mr. Newenham of Cork. 



Nautilus (Temnocheilus) poecatus. M^Coy. (PI. III. fig. 6). 



Sp. Ch. — Discoid; back very broad, flattened, having a slight mesial sulcus, and marked by ten spiral 

 ridges, the two mesial ones being smallest ; umbihcus very large, with an angular edge ; one spiral keel similar 

 to the dorsal ones within the edge of the umbihcus; surface smooth. 



This species resembles the N. multicarinatus. Sow., but is distinguished by its smaller size, the greater num- 

 ber and equaUty of the spiral ridges, and the mesial hollow. 



Nautilus (Temnocheilus) sulcifeeus. Phil. sp. 



Nautilus sulciferus. Phil. Geol. York. 



Sp. Ch. — Globose; umbihcus large, with a jirominent angular margin; back convex, flattened and sulca- 

 ted in the middle. 



Only a very few imperfect specimens have occurred of tliis species. 



Nautilus (Temnocheilus) tubeeculatus. Sow. sp. 



Nautilus tuberculatus. Sow. Min. Con Nautilus tuberculatus. Phil. Geol. York. 



I have not seen in any of the Irish rocks, specimens which would exactly agree with the true N. Tuher- 

 culatus. Sow., which has the general form o£ the Nautilus (Temnocheilus) coronafus, M'Coy, but has the 

 -schorls thicker, the umbihcal slopes tumid, and the" tubercles of the edge of the umbihcus fewer, larger, 

 rounder, and more nodulous than in that species. 



