\ CERITHIUM. 167 
The Comma-Group. 
This name is applicable to a group of shells which are rare in the Inferior 
Oolite of this country, but not so unfrequent in the Bajocian of Normandy. There 
can be very little doubt that they are included by Deslongchamps (op. cit., pl. xi, 
figs. 64—65) as forming part of his var. a, “ Melania scalariformis, Deshayes.” 
The other part of var. a, viz. fig. 63, is the basis of Cerithiwm subscalariforme, 
D’Orb. As this name, then, has been used for quite a different species of Cerithiwm, 
we must fall back upon Miinster’s name. The forms described below as distinct 
species are probably little more than varieties; but as, owing to their rarity in 
England, the missing links are not forthcoming, I propose to describe some two or 
three different forms for which more or less appropriate foreign names may be 
found. 
93. Ceritatum comma, Miinst., 1844. Plate X, fig. 2. 
1842. Menanta scanartrormts, Desi. (pars). Deslongchamps, Mém. Soe. Linn. 
Norm., vol. vii, pl. xi, fig. 64. 
1844. Crrrruium comma, Wiinst. Goldfuss, Petr., t. 173, fig. 14. 
1850. Synonym Ceriruium opis, D’Orb. Prod., vol. i, p. 271. 
Bibliography, Sc.—The following is the original description by Goldfuss: 
“Turrited, with twelve to fourteen whorls, quadrangular, subquadrate, beset in the 
upper part with numerous wrinkles. These wrinkles form at the suture elongated 
knots, and run off into feeble, somewhat crooked ribs, which split up, and terminate 
at the lower margin in a row of very fine knots. At one place are observed obscure 
traces of faint spiral lines.” The length of this specimen was about 20 mm. 
Description of an English specimen: Length 30 mm., width 9°5 mm. Spiral 
angle about 20°. Shell sharply turrited. Spiral angle regular, whorls numerous, 
about sixteen, flat or slightly concave, rather narrow, and increasing by steps. The 
spiral striz are very fine and numerous; longitudinals bold and prominent on the 
posterior half of each whorl, having a spinous projection upon the upper border. 
About half way across the whorls the longitudinals become attenuated, usually 
bifurcating and curving from right to left, so as to give the appearance of a 
comma. 
The body-whorl is less than one-third the total length of the shell; the 
