GASTEROPODA. | LOWER PAL-EOZOIC MOLLUSCA. 30! 
Position and Locality — Abundant in the irregularly calcareous schists of Knockdollian Quarry, three miles 
from Ballintrae, and at Aldens, on the Stinchar, Ayrshire. 
Explanation of Figures.—P1. 1. L. fig. 18, natural size, of rather small specimen, shewing the top and 
form of section of the whorls and umbilicus ; fig. 14, small perfect specimen, viewed from below. 
Genus. ECCYLIOMPHALUS (Port.) 
? =Serpularia Romer 1843 + Phanerotinus Sow. 
Gen. Char.—Shell discoid, of few rapidly tapering, widely disconnected whorls, the upper surface usually 
flattened, in one plane, or slightly elevated ; under surface rounded (no chambers). 
Mr Morris, in the notes to his “ Catalogue,” stated this genus to be identical with Cyrtolites of Conrad, 
and he has been accordingly followed by succeeding writers ; but as Mr Hall (Pal. New York, p. 308) informs 
us that the Cyrtolites ornatus was the type of Mr Conrad’s genus, it follows that as that is a symmetrical shell, 
allied to, if not identical with, Bellerophon, Eccyliomphalus of Portlock is perfectly distinct; and I have great 
pleasure in restoring it to its place in the system. 
EccyLiomMpHALus Scoticus (M‘Coy). Pl. 1. L. fig. 15. 
Sp. Ch.—Discoid, flat, of one and a half gradually enlarging, widely separated, spiral whorls; back obtusely 
subearinate, rounded, lower side rounded, upper side with a flat space, bounded on each side by one obscure keel, 
the outer one most distinct ; surface crossed by rather distant sharp lines of growth, each pair with four or five 
much finer intermediate strize. Diameter one inch five lines, proportional diameter of last whorl #4, height %. 
This species is more regularly involute than the #. Bucklandi (Portk.), and has the principal keel on 
the upper side nearer to the back. There are three or four of the larger strive in the space of one line about 
the middle of the under side of last whorl. 
Position and Locality—Not uncommon in the schistose chazy limestone of Knockdollian Quarry, three 
miles from Ballintrae ; also in the calcareous schists of Mulock Quarry, Dalquorhan, near Girvan, Ayrshire. 
Explanation of Figures.—P\. 1. L. fig. 15, natural size, under surface from the limestone of Knockdollian 
Quarry ; fig. 15a, another specimen, upper surface; fig. 15 5, section of whorl. 
17th Family. NATICID. 
Shell globose, body-whorl very large ; spire usually very small, of few convex turns ; aperture large, ovate, 
indented by the preceding whorl; outer lip thin, widely rounded in front, closed by an ear-shaped subspiral 
operculum ; umbilicus usually large, and more or less closed by a thick callous pad: (animal large, foot very 
large, oblong; mantle very large, usually reflected on the shell behind, head with two depressed tentacles). 
Genera :—1, Natica; 2, Narica; 3, Naticella; 4 Naticopsis; 5, Sigaretus. 
Genus. NATICOPSIS (Coy). 
Gen. Char.—Shell strong, globose, elliptical; spire very small, of few convex whorls; surface smooth, or 
only marked by lines of growth, strongest at the sutures ; aperture large, broad-ovate, modified by the preceding 
whorl, broadly rounded in front; columella thickened, callous, flattened (as in Purpura) in the anterior half, 
entirely concealing a minute umbilicus only visible in the casts. 
This genus includes most of the Paleozoic so-called species of Ampullaria, Natica, and Nerita. The 
former genus is terrestrial and pulmoniferous, and is therefore excluded from comparison with a marine genus, 
which however agrees with it in general form, with the exception of the /lattened, callous, columella; this 
latter character also separates it from Natica, reminding us of Purpura, from which it is completely dis- 
tinguished by the want of the anterior respiratory notch; from Nerita it is distinguished by the want of the 
teeth on the columella. 
