VESTI NAUTILUS PLNGl'IS. 89 



Kildare ; Cork (near the city, but exact locality unknown ; probably Blackrock) ; 

 Little Island, near Cork. 



Vestinautilus pingois, L. G. de KonincJc, sp. Plate XXV, figs. 3 a, h. 



1844. Nautilus pingdis, L. G. de Kotiinck. Dfscrip. Auini. Foss. Ttrr. Carb. 



Belgiqiie, p. 551, pi. xlviii, fig. 10 (jwt of M'Coy). 

 1878. — — L. G. Je Koninch. Fauiie Calc. Carb. Belgique (Ann. 



Mu8. Koy. d'Hist. jVat. Belgique, torn, ii), pt. 1, 

 p. 136, pi. xsx, figs. 6, 7. 

 1891. CffiLONAUTiLTJS PINGUI8, A. H. Foord. Cat. Foss. Ceph. British Museum, 



pt. 2, p. 117, fig. 18. 

 1893. VESTiNAriiLus PINGI'IB, A. Hyatt. Carbouiferous Cephulopods. Second 



paper. Geological Survey of Texas, Fourth 

 Annual Eeport, 1892, p. 420. 



Description. — Shell thick-discoid, composed of about three slightly embracing 

 volutions, the sides of which are exposed in a deep, funnel-shaped umbilicus, with 

 a central vacuity of moderate size. The whorls increase somewhat rapidly in 

 their dimensions, their section in the adult is trapezoidal and decagonal. The 

 periphery is very broad, and, compared with the height of the whorls, dorso- 

 ventrally, as 22 : 37 ; it is divided into three areas, the median one the broader, two 

 narrower areas on each side of it descending abruptly to the urabihcal margin ; 

 the median area may be slightly depressed in the centre. The lateral area is 

 represented only by a narrow zone, sloping inwards a little, bounded above by 

 the keel bordering the umbilicus, and below by the second keel within the latter. 

 The umbilical declivities are inflated considerably botli in the young and in the 

 adult shell. 



The body-chamber occupies about one half of the last whorl. 



The septa are moderately distant; thus, where the width of the peripheral 

 area is 40 mm. they are 10 mm. apart, where the width is 31 mm. they are 7 mm. 

 apart. Their course is tortuous; beginning at the suture-line of the penultimate 

 whorl, they are bent slightly backward, and again upon the latei'al zone ; then, in 

 crossing the periphery upon the area sloping upwards to the median zone, they 

 arch forwards, making a broad, backwardly directed sinus on the median zone 

 itself. 



The siphuncle is not seen in the Irish specimens tliat have come under my 

 notice, but de Koninck describes its position as being witliin the upper third of 

 the septa. 



The ornamentation is very conspicuous. It consists of prominent keels strong 

 enough to leave their impression distinctly upon the cast. The first whorl, fur 



14 



