LITTORINA. 295 
four serrated spirals of nearly equal prominence; in some cases the fourth spiral 
has a slight salience, and where the suture gapes a fifth spiral without tuber- 
culations may be detected towards the bottom of the hollow. 
The body-whorl rather exceeds half the height of the shell; it is slightly 
angular, and not ventricose; ornaments as in the whorls of the spire; base full 
with about six finely cut spirals. Throughout the shell the interspiral striz are 
deep, and the serrations of the carinze almost tooth-like and somewhat bent up- 
wards; but there is considerable variety in the nature of the ornaments. 
Aperture ovate with a straight pillar lip, in the earlier stage slightly reflexed 
anteriorly. 
Relations and Distribution.—Our specimen is rather more conical than the 
one figured by Goldfuss, but there are others which correspond in almost every 
particular. In younger specimens which are free from matrix intermediate 
spirals of shght salience may be seen. 
This is a sort of average form, which may be said to inosculate with others in 
the Jurassic rocks. The abundant Littorina muricata of the Corallians might be 
regarded as a micromorph on a higher horizon. Some varieties of Amb. Millert 
are also near. On the other hand, the eucycloid varieties approach the ornata- 
group in many ways. 
Littorina prextor is rare. My own specimens are mostly from the Murchisonx- 
zone of Bradford Abbas. There is a specimen in the Woodwardian Museum 
stated to have come from Dundry. 
The handsome shell, Pl. XXIII, fig. 4, may possibly represent a modifica- 
tion of Litt. pretor on a higher horizon, viz. the concavus-zone. In most shells of 
this class the pillar-lip is straight with a considerable deposit of callus. This 
specimen is the only one I have seen of the kind. 
929. Lirrorina (Tectarius or Hehinella) porytimera, sp. nov. Plate XXIII, figs. 
12, 18. 
Cf. Turso Davrpsont, Laube. Gast. braun. Jur. Balin, p. 8, pl. ii, fig. 1, for this 
and the following species. 
Description : 
Length - ; ; ‘ . 15—20 mm. 
Length of body-whorl to total height . . 60: 100. 
Spiral angle : ; 2 4628. 
Shell thick, conical; spire pointed. Number of whorls about seven, the 
apical ones being convex and smooth, the remaining whorls nearly flat, and 
marked off by a channelled suture. The ornaments are peculiar ; they consist of 
