XAUTILIDJE. 
173 
Solenocheilus crassiventer, de Koninck, sp. 
1878. Nautilus crassiventer, de Koninck, Fanne dii Calcaire Carboni- 
lere de la Belgique (Annales du Miis. Kov. d’Hist. Nat. de Bel- 
gique, tom. ii.), p. 94, pi. ix. ff. 2 a-c, 3 a-c, 4«, 4 6. 
/Sp. Char. Shell globose, of medium size, having three or four 
whorls, rapidly increasing, with a very small funnel-shaped um- 
bilicus : the body- chamber occupies half of the last whorl ; the 
aperture is somewhat wider than high, its sides spreading out to a 
breadth which is double that of the last septum ; the sutures of the 
septa are nearly straight ; the septa themselves are only slightly 
concave, their transverse section is subreniform, their distance from 
each other could not he ascertained in the Belgian type. The 
siphuncle is a little transversely elliptical, and is situated close to 
the external (ventral) border of the shell. The test has been seen 
in the Belgian example near the edge of the aperture ; it is very 
thin, and its surface quite smooth, showing no traces even of lines 
of growth. The aperture is strongly emarginate. 
Bemarl's. The specimen in the Collection (No. 2973) referred to 
the present species has the septa partly exposed in one or two 
places, and shows them to be half an inch apart where the trans- 
verse diameter of the whorl is about two inches. 
This species is closely allied to Solenocheilus dorsalis., Phill., but 
it is distinguished therefrom by its smaller umbilicus and its much 
more venbricose form. 
Horizon. Carboniferous Limestone. 
Locality. England? 
Eepresented in the Collection by a single examidc. 
Solenocheilus cyclostomus, Phillips, sp. 
1836. Nautilus cyclostomus, Phillips, Geol. of Yorkshire, pt. ii. p. 232, 
pi. xvii. f. 29, pi. xviii. f. 3, pi. xxii. f. 26. 
1844. Nautilus cyclostomus, de Koninck, Descrip, des Auim. Foss, du 
Terr. Carbonifere de la Belgique, p. 553, pi. xlv. f. 10, a, h, 
pi. xlix, ff. 2, a, b. 
1844. Nautilus cyclostomus, M^Coy, Synop. Carboniferous Foss. Ireland, 
p. 23. 
1845. Nautilus cyclostomus, de Verneuil, in Murchison, de Verneuil, 
and de Keyserling’s Paleont. de la Russie d’Europe, vol. ii. pt. iii, 
p. 365. 
1847. Nautilus cyclostomus, cTOrbigny, Paleont. Universelle, pi. xcix. 
ff. 6, 7. 
