Vol. 58.] MR. F. R, C. REED ON THE GENUS LICHAS. 67 
Uralichas Ribeiror. As one result, the fourth lateral lobes (the so- 
called second or middle) are more or less poorly defined. 
(c) The axial furrows may become obsolete posteriorly, and the 
posterior portion of the glabella comprising the fourth or first 
maxillary segment becomes fused with the fixed cheeks. The early 
stages are represented by a weakening of the posterior part of the 
axial furrows (as, for example, in Lichas scutahis, Hemiarges wesen- 
bergensis, and Arges armatus) ; and the final stage by their complete 
disappearance behind the third lateral furrows (as, for example, in 
Acanthopyge Haueri, Dicranogmus simplex, Platylichas margaritifer, 
and Lichas anglicus). 
(d) The first lateral furrows may become connected with the 
occipital furrow by an additional furrow (as, for example, in Lichas 
conicotuberculatus, Platylichas margaritifer, and Lichas ambiguus). 
This modification foreshadows the second great stage in the deve- 
lopment of the glabella of the Lichadide, but seems not to be in 
the direct line of descent. In Dicranopeltis scabra the first lateral 
furrows are directly continued back to the occipital furrow. 
(e) A transverse furrow may be formed across the base of the 
median lobe, thus connecting the third lateral furrows (as, for 
example, in Lichas anglicus, Acanthopyge Haueri, Corydocephalus 
palmatus, and Dicranopeltis scabra). 
2. The Lobes.—With regard to the lobes, there are several 
modifications more or less dependent on those of the furrows just 
described. Thus :— bial 
(i) The bi-composite lateral lobes may become undefined anteriorly 
or posteriorly by modifications (a) or (b) of the furrows. 
(ii) The fourth lateral lobes may become undefined or weakly 
marked off in front by modification (6); or may become laterally 
confluent with the fixed cheeks by modification (c); or may become 
marked off from the middle portion of the glabella by modification 
(d); or may unite to form a continuous ring by modification (e) 
without (d). 
(ii) The anterior part of the median lobe may become swollen, 
as in Lichas celorrhin. 
The development of occipital lobes at this stage may, or may not, 
take place; and in otherwise closely allied species this difference 
may be noticeable. In Acanthopyge Haueri, Lichas anglicus, ete. 
they are absent; but in Dicranogmus simplew they are present. 
On the other hand, species which show considerable differences in 
respect to the glabellar furrows may agree in possessing them, as, 
for example, Platylichas margaritifer and Dicranogmus simplex. 
In most members, however, of this stage exhibiting the bi- 
composite lateral lobes of the glabella, occipital lobes are present, 
as, for instance, Metopias Hubneri, Corydocephalus palmatus, Dicra- 
nogmus simplex, Dicranopeltts scabra, Lichas laciniatus, and Ura- 
lichas Ribewror. In a few cases, as in Arctinurus Boltont, they are 
obsolescent. Theshape and relative size of these occipital lobes vary 
FZ 
