F. R. Cowper Reed—Recent Work on Bokkeveld Fossils. 35 
contend owing to the fossils occurring only as casts or impressions, 
and frequently in an imperfect condition. In the first place it cannot 
be denied that all the species described from these beds are 
closely allied, and that many intermediate forms occur which might 
be referred to one or other of the species with equal justice. Only 
the most marked forms at the extremity of each series of variations are 
in reality capable of precise definition, and it is by them that the 
specific characters have been established. Therefore the reference of 
many of the transitional examples and debatable specimens depends 
largely on the personal equation. In my case it should be remembered 
that I had the advantage over Professor Schwarz of examining the 
type-specimens in London. Professor Schwarz would restrict the 
name Sp. Orbignyt, Morris & Sharpe, to those forms possessing a more 
semicircular shape and a less incuryed beak and more backward 
sloping hinge-area on the pedicle valve than Sp. antarcticus, Morris & 
Sharpe. To the transversely fusiform shells with nearly a vertical 
hinge-area and rather strongly incurved beak in the pedicle valve, 
which I included under the name Sp. Orbignyi, Professor Schwarz 
applies the name antarcticus, Morris & Sharpe. In spite of the 
differences pointed out, and in view of further specimens which 
I have seen, I am reluctant to adopt his view, for the characters on 
which he relies do not seem to be constant. 
My Sp. cf. pedroanus Professor Schwarz would include in his 
Sp. antarcticus (= Sp. Orbignyt, mihi), but with this view I cannot 
completely concur, for there appear to be special features in the 
number, character, and relative size of the ribs which I have 
previously mentioned (Ann. S. Afr. Mus., loc. cit., p. 183, pl. xxi, 
fig. 5). Professor Schwarz also misunderstands my description by 
thinking that I took Sp. pedroanus to have only 10-16 ribs in all, but 
the fact that I largely rely for the comparison on the number of the 
ribs (20-22) in the South African form should have been sufficient to 
indicate that I had clearly in my mind Hartt’s statement that there 
were 10-16 ribs on each side of the fold and sinus. I am, however, 
teady to admit that my Sp. cf. pedroanus may not be identical with 
the South American species bearing this name, and may be only an 
extreme variety of the Sp. antarcticus of Professor Schwarz. 
In the case of Sp. Ceres, mihi, Professor Schwarz believes that one 
of the specimens figured by me (pl. xxii, fig. 6) is an overgrown 
example of Sp. Orbignyt or Sp. antarcticus, though his very reasons 
for adopting this view considerably weaken his arguments in fayour 
of the separation of Sp. Orbignyi from Sp. antarcticus. Likewise his 
inclination to identify Sp. Ceres with Sp. Hawkinsi (for which 
I cannot see sufficient evidence): proves that he allows much latitude 
of variation in his specific interpretations. 
It is always a misfortune to have to multiply specific names, 
particularly in connection with poorly preserved fossils, and 
one would be glad to reduce the number of species of Spirifer 
recorded from the Bokkeveld Beds. But when local varieties 
or zonal mutations may be suspeeted it is wise not to neglect 
minor differences observable in specimens from other localities 
and rocks than the type; and particularly does this seem to be 
