CARBONIFEROUS FOSSILS OF IRELAND. 21 



This beautiful species has the exact form of the N. cariniferus. Sow., or with the back slightly more flat- 

 tened, but differs from it in the row of close, blunt, compressed tubercles, which ornaments the edge of the 

 umbilicus on each side. Diameter two inches six lines ; length of mouth ten lines ; width of mouth two inches. 



The specimen figured was kindly lent by Dr. Haines, of Cork. 



Nautilus (Temnocheilus) costalis. Phil. sp. 



Nautilus costalis. Phil. Geol. York. 



Sp. Ch. — Spheroidal, depressed; umbilicus small, deep; whorls crossed by sharp, direct, transverse ridges, 

 and fine strias ; a few deep, direct constrictions on the cast. 



This species is at once distinguished by the curious transverse plaiting of the whorls ; these plaits are 

 few and obtuse near the umbilicus, but become thinner, sharper, and more numerous as they pass over the 

 broad, rounded back, between these are finer strige ; the sides are gently convex, the back rounded, and the 

 mouth lunate by the deep insertion of the preceding whorl. Diameter three and a half inches. The N. funa- 

 tus has thicker and fewer transverse ridges. 



Nautilus (Temnocheilus) ceenatus. M'Coy. (PI. II. fig. 9). 



Sp. Ch. — Discoid ; inner whorls exposed by a large umbilicus ; two strongly toothed, or serrated, keels, 

 within the umbilicus, and one obtuse keel outside it ; sinus in the lip shallow. 



I have only seen a fragment of the last chamber of this shell, but its characters are so strongly marked that 

 I have no hesitation in proposing it as a distinct species ; the two notched or crenated ridges within the innbi- 

 licus give a very striking appearance to the shell ; the back is flattened, with an obscure keel on each side ; the 

 mouth is hexagonal, and very much depressed, being three times as wide as long. I am not aware how many 

 whorls there were, but suppose they were fewer than in the N. biaiujluatus; neither do I know the diameter of 

 the shell when perfect, but suppose it to be about the size of the N, cariniferus; the fragment figured measures 

 one and a half inches across the back. 



Nautilus (Temnocheilus) fuecatus. M'Coy. (PL IV. fig. 13). 



Sp. Ch. — Discoid, compressed ; sides gently curved ; back rather narrow, rounded ; umbilicus small, 

 slightly exposing the whorls ; surface marked with large, strong, rounded ribs, each of wliich, a short distance 

 from the umbilicus, regularly branches into two of equal thickness, which, making a rather acute, forward bend, 

 in passing over the back, unite again on the opposite side, before reaching the umbilicus ; Intervening spaces 

 wider than the ribs, concave, smootli. 



This species can only be confounded with the N.fimatus, compared with which the following differences 

 are observable : in specimens of the same size, the ridges are nearly three times more numerous, in a given space, 

 in the N. funatus, than in the present species. In the former, all the ridges are simple, equal, and proceed di- 

 rectly across the shell ; while in the latter each rib branches boldly and regularly into two strong ridges, before 

 passing over the back; the umbilicus, also, is smaller in the N.furcatus than in the J^. funatus, and exposes 

 less of the whorls. The specimens are generally elliptical. Diameter two inches seven lines ; diameter of 

 last whorl thirteen lines ; thickness eleven lines. The specimen figured was obligingly contributed by Dr. 

 Haines of Cork. 



Nautilus (Temnocheilus) globatus. Sow. sp. 



Nautilus globatus. Sok: Min. Con. 

 Sp. Ch. — Subglobose, discoid; back very broad, slightly flattened; a deep sinus in the edge of the outer 

 lip ; umbilicus moderate, deep, with an angular edge ; whorls increasing very rapidly ; the last whorl slightly 

 produced, flattened below. 



F 



