168 FR. Cowper Reed—Fauna of the Bokkeveld: Beds. 
Ph. callitris is said by Schwarz (2, p. 394) to agree in many particulars 
with Ph. ocellus. Ph. Gydowit is similar in many respects, and 
Ph. Ceres is undoubtedly allied. In all these species there is a marked 
tendency for the second pair of glabellar lateral furrows to be reduced 
and not to enter the axial furrows, resulting in a more or less complete 
fusion of the first and second lateral lobes of the glabella. The same 
feature is met with in Acaste (= Phacopidella), which is a Silurian 
group, comprising Ph. Downingie. 
The genal angles are not produced into long spines, but where the 
head-shield is sufficiently known they seemed to have been angular 
(Ph. impressus), rounded (Ph. ocellus), or furnished with small laterally 
directed spines (Ph. callitris). Herein they differ markedly from 
typical Crypheus, and seem to furnish an additional point of 
resemblance to <Acaste. If a distinctive name for this group is 
required, the name MMetacrypheus is suggested. 
The remaining Phacopide from the Bokkeveld Beds seem to fall 
into another group which in many respects resembles that containing 
Dalmanites anchiops, Green, and was mistakenly referred by Hall 
and Clarke to McCoy’s subgenus Chasmops, which has completely 
different characters (4, p. 10). The definition of the subgenus 
according to Hall & Clarke (6, p. xxxiii) was apparently drawn up 
from the type of D. anchiops of the Oriskany Sandstone and Upper 
Helderberg, and runs as follows: ‘‘Genal angles usually produced 
into spines. Frontal lobe of the glabella large, transverse, and not 
intersected by the facial sutures. Lateral lobes unequal, the first and 
second pairs being coalesced and the third pair nearly obsolete. 
Pygidium large, sometimes with a terminal spine.”? DD. anchiops, 
Green (6, p. 59, pl. ix, figs. 1-6, 10, 12, 13; pl. x, figs. 1-14), has 
genal angles produced into stout long spines; there is a nuchal spine 
on the occipital ring ; the first and second lateral lobes of the glabella 
have coalesced owing to the reduction of the second lateral furrows ; 
the eyes are large and lunate and appressed to the first and second 
coalesced lobes; the pygidium has an axis with 9-14 rings and lateral 
lobes with 8—9 ribs, and it is produced into a more or less upturned 
tapering mucronate termination. In the South African Ph. cristagall, 
Ph. arbuteus, and Ph. acacia we see several of these features. The 
first has precisely the same type of pygidium, but it has only seven 
lateral ribs, and these are tuberculated, and the axis, which consists 
of etght rings, carries a single row of median spines like the thorax. 
The head-shicld is unknown. In Ph. arbuteus there is a slight 
reduction of the second lateral furrows, the neck-segment bears a strong 
median spine, and the pygidium has the typical mucronate shape, but 
only bears 8 rings on the axis and 5 ribs on the lateral lobes. The 
axis of the thorax bears a median spine on each segment, but they 
seem to be absent from the pygidium. In Ph. acacia the neck-segment 
bears a strong median spine, the genal angles are furnished with short 
spines; the third glabellar lateral furrows (as in Ph. arbuteus) are 
specially deep, the axis of the thoracic segments bears median spines 
as in the other two species. Ph. pupillus, only known by an 
incomplete head, has cranidial characters of precisely the same type. 
With regard to Ph. africanus, which has been suggested to belong 
