ANIMALS. 117 
of Leptena, which may be regarded as only differing from the marginal expansions of 
Camarophoria in their direction, being turned upwards, considering the perforate 
valve to be the inferior one. Perhaps, as is the case with the geniculated portions 
of Zeptena, the marginal expansions constitute one of the generic characters of 
Camarophoria: this is a pomt to which I may be allowed to draw the attention of 
those who have an opportunity of fully studying the characters of the Carboniferous 
Hypothyride. 
The histology of Camarophoria agrees with that of /Hypothyris. The valves 
consist of closely-packed, capillary fibres, which pass through them at a very slight 
angle, following, at the same time, a radiate arrangement as they succeed each 
other from the umbones to the margins. The punctures are extremely minute, 
and appear to intersect the fibrous tissue nearly at a right angle to the surface of the 
valves. 
Camarophoria, in the apophysis of its large valve, undoubtedly possesses a striking 
resemblance to Pentamerus; and as it appears to have succeeded the latter genus 7x 
time, 1 am disposed to regard both as being proximately related to each other. All 
that prevents my arriving at a positive conclusion on this point, is the dissimilarity 
existing between the apophysary system of their small valve; which, in Pentamerus 
consists of the two socket plates largely developed, and passing to a considerable distance 
into the cavity of the shell; whereas in Camarophoria it appears to consist of the medio- 
longitudinal plate equally as much developed, and expanded bilaterally at its free or 
upper margin. Perhaps a knowledge of the internal structure of some of the Penta- 
meri described and figured by M. J. Barrande, in his paper ‘ Ueber die Brachiopoden 
des silurischen Schichten von Bohmen,’ 1847, may destroy the dissimilarity just noticed 
by displaying the two plates of Pentamerus becoming gradually modified into the 
spatula-shaped process of Camarophoria.' 
Although related to Pentamerus, Camarophoria is also closely allied to Hypothyris,— 
especially in form ; the only difference is in their internal structures,— Hypothyris having 
the dental plates completely separated and diyaricating, as in Orthis, which is well 
displayed in several casts before me of /Hypothyris pleurodon, and some other species. 
The same amount of dissimilitude prevails between the apophysary system belonging 
to the small valve of both genera: in Hypothyris it simply consists of the homologues 
of the crura of the loop starting from within the socket plates, which are rarely 
developed to any extent, offering in this respect a striking contrast with the large size 
of the corresponding structures of Pentamerus. 
Concluding from what is at present known, Camurophoria does not appear to have 
been numerous in species, nor to have had much chronological range. About half a 
1 Some of the so-called Spirifers figured by Kutorga in plate vy of his paper entitled ‘Beitrag zur 
Paleeontologie Russlands,’ may throw some light on the affinity existing between Camarophoria and Pen- 
tamerus. 
