220 
PROCEEDINGS COTTESWOLD CLUB 
1920 
piece. Surface of pygidium ornamented with rather coarse 
tuberculation, the tubercles forming low, round, pointed cones of 
2 — 3 sizes irregularly distributed (except on the axial rings) 
but sub-equidistant, becoming smaller near the pygidial 
margin. 
Dimensions. 
Length 12.0 mm. 
Width 17.5 mm. 
Remarks. — The characters of this species of Lichas are 
unusual and peculiar, and at first sight it does not seem to fit 
into any of the groups into which the genus has been divided. 
The absence of any projecting pleural points on the margin 
is, however, the only feature of importance by which it differs 
from the section Corydocephalus as understood and defined 
by the author in 1902. 1 The presence of two complete pleurae 
on the lateral lobes, the absence of median furrows on the 
posterior part representing the third pair of pleurae, the presence 
of two distinct rings on the axis followed by several indistinct 
annulations, and the narrow post-axial ridge continued to the 
marginal furrow are essential characters of this section. We may 
remark, however, that the post-axial piece in this new species is 
more an uninterrupted continuation of the axis than is typical, 
and that the border is less clearly marked off, while the entire 
regular margin is most unusual. No head-shield has been 
discovered in the collections from May Hill which can be 
associated with this pygidium. Here it may be remarked 
that the difficulty of classifying the species of Lichas is largely 
the result of the disconnected occurrences of different parts 
of the body, so that some authors use the head-shields and 
others the pygidia in their systems of classification. 
Probably our new species belongs to the section Liparges 
Giirich 2 (? = Dicranogmus, Corda) , which has not been separated 
from Corydocephalus by the author, and of which L. gibbus, 
Ang. 3 is an example. 
1 Reed, Quart. Journ. Geol. Soc., vol. lviii. (1902), pp. 61, 70. 
2 Giirich, Neues Jahrb. Miner. Geol., Beil. Bd. xiv. (1901), p. 529. 
3 Angelin, Palarnt. Scand. (1854), p. 71, pi. xxxvii., fig. 1. 
