134 TRANSACTIONS OF THE [maR. 17, 
somewhat oblique form of valve which is so characteristic of 
Beyrichona, and if one glances over plate 23 of Barrande’s sup- 
plement it will be apparent how different is Aristozoe in its 
general aspect from these Lower Cambrian species. H. Wood- 
ward, T. R. Jones and O. Novak all have referred Aristozoe to 
the Phyllocarida; but Beyrichona is certainly an Ostracod and 
the two species from the Olenellus zone agree in size better with 
the Ostracoda than the Phyllocarida, 4. bisulcata of Barrande, 
which Mr. Walcott compares with A. rotundata, has protuber- 
ances where the latter species has a sulcus or hollow. 
BEYRICHONA PAPILIO Pl. vii., figs. 4 @ to e. 
Trans. Roy. Soc. Can., vol. iii., p. 65, pl. vi., figs. 20,20 a and 6. 
(Reverse the description as regards the anterior and posterior 
ends. ) 
This should have been reported from Assise 4, not Assise 2. 
BEYRICHONA TINEA PI. vii., figs. 6 @ to e. 
Trans. Roy. Soc. Can., vol. iii., p. 66, pl. vi., figs. 21, 21 4 
and b. 
(Reverse the description of the two ends as in B papilio.) 
This was found together with the preceding and should also 
be reported from Assise 4. : 
BEYRICHONA PLANATA n. sp. PI. vii., fig. 1. 
Obliquely semi-circular, somewhat longer than high, moder- 
ately convex, most so in the middle; from the raised centre of 
the valve an arched ridge curves forward to the ocular tubercle, 
near the hinge line; in the opposite direction a low inconspicuous 
ridge extends backward to the posterior upper corner of the valve; 
behind the ocular tubercle is a broad furrow or pit that extends 
backward half of the length of the cardinal line, becoming nar- 
rower in its posterior half; on the anterior side of the valve there 
is a flattened band that extends to the lower margin, where a 
narrow obscure furrow appears, and extends thence to the pos- 
terior corner of the valve. The anterior half of the valve is 
somewhat tumid, and the posterior is flattened out toward the 
posterior margin so that the two valves together form there a 
sharp knife-like edge. 
Sculpture. The surface is uneven, minutely punctate and 
shining, like B tinea, from which its differs in its greater pro- 
portionate length, greater size, shallower cardinal furrows, flat- 
ter posterior border, and the obscureness of the border fold. 
Size. Length 5 mm.; height 44 nm. 
