F. R. Cowper Reed—Fauna of the Bokkeveld Beds. 169 
to Acaste (= Phacopidella, Reed), the head has exactly the same 
general characters as the foregoing species, i.e., a strong nuchal spine, 
a very deep third glabellar furrow, a median spine (probably, according 
to Lake) on each thoracic axial ring, and a pygidial axis produced 
beyond the margin bearing 9 rings, with 5 ribs on each lateral lobe. 
Schwarz (2, pp. 398-399) has indeed hinted that it may belong to the 
eristagalli group, and Salter believed that the genal angles were 
spined, thus increasing the resemblance. There does not therefore 
appear to be sufficient grounds for separating it from this group, and 
I would refer this whole set of species to a special subgroup of 
D. anchiops characterised (1) by fewer (typically 8) segments in the 
pygidium, only 5 pairs of ribs being present as a rule on the lateral 
lobes; (2) by the presence of median spines on the axis of thorax and 
pygidium ; (3) by small, instead of stout and long, genal spines (in 
D. anchiops, var. armatus, Hall (6, p. 62, pl. ix, figs. 7-9), the genal 
‘spines are inconspicuous or obsolete); (4) by less pronounced 
coalescence of first and second lateral lobes of glabella. (Nom. prop. 
Anchiopella.) Clarke (8, p. 83) considered the Maecurt species 
described by him as Dalmanites galea as a representative of the genus 
Acaste, Salter, on the strength of the coalescence of the first and 
second lateral lobes of the glabella, rounded genal angles, and general 
characters of the head-shield on which the species was founded. In 
discussing its resemblance (8, p. 57) to D. gonzaganus, Clarke, from 
the same horizon in Parana, he alludes to its resemblance to 
D. anchiops, var. sobrinus, Hall, of the Schoharie grit. 
The relations of several of the trilobites to South American forms 
have been pointed out by Lake and Schwarz, and in the light of 
recent knowledge the identical or allied species are as follows :— 
(B. = Bolivia; Br. = Brazil; A. = Argentina.) 
Phacops arbuteus ... abe Phacops cl. arbuteus. B. 
( Cr. giganteus, Ulr. B. 
Ph. (Crypheus) caffer Cr. paituna, Clarke. Br., B. 
\ Cr. convexus, Ulr. B. 
( Ph. (Acaste) devonicus, Ulr. B. 
Ph. africanus Dalmanites galea, Clarke. Br. 
| D. gonzaganus, Clarke. Br. 
Ph. Ceres ... oe iB Cr. giganteus, Ulr. B. 
j D. Clarkei, Ulr. B. 
"1 D. maecurua, Clarke. Br., B. 
Homalonotus Herscheli ... H. Derbyi, Clarke. Br. 
The relations of the two South African groups of Phacopide to the 
North American D. Boothi and D. anchiops have been above discussed. 
‘Clarke (8, pp. 80, 98) has remarked that the cephalon of D. galea 
and Ph. devonicus, Ulrich (9, p. 21, t. i, figs. 14a, 6, 15), have 
a Silurian type of Phacopid structure, and Lake also alludes to it, but 
except in the reduction of the second pair of glabellar furrows the 
resemblance is rather remote. 
The affinities of the species of Homalonotus from South Africa with 
those of South or North America are not very marked, and Lake 
‘compares some of them to European species of Coblenzian age. 
According to Schwarz, all the Bokkeveld Homalonot: have a strong 
family likeness, and they do not seem allied closely to any of the 
Dalmanites sp. 
