Trof. T. R. Jones — On some Palceozoic Phyllopoda. 353 



The tests referred to this genus are much like those of Biscinocaris, 

 but the posterior margin is irregular, not entire, in its outline, and 

 in some cases is indented, leading, as it were, to the posteriorly 

 notched forms of Dipterocaris. 



1. a Roemeri, H. W., 1882. Loc cit. PI. IX. Figs. 1—7. 

 Eather slipper-shaped, of various sizes. One of the small specimens 



preserves its triangular cephalic piece in place. This most interesting 

 circumstance takes Cardiocaris, and by presumption its allies, out 

 of the category of opercula, although Goniatites, which are thought 

 by some to have Aptijchi, abound in the same series of strata 

 (Devonian) at Biidesheim in the Eifel. 



2. G. hipnrtita, H. W, Op. cit. p. 388, Figs. 14 and 15. 



Near C. Boemeri in shape ; marked along the back by a kind of 

 linear fold or crumpling, owing to pressure on a somewhat convex 

 test, — a condition seen in other specimens. From Biidesheim, Eifel. 



3. G. Veneris, H. W., 1882. Op. cit. p. 387, PL IX. Figs. 8-12. 

 Shield broader and shorter than C. Boemeri, with broad cephalic 



notch. From the same Devonian beds at Biidesheim, Eifel. 



4. C. Koeneni (Spathiocaris Clarke), 1884. N. Jahrb. f. Min. etc. 

 1884, i. p. 182, pi. 4, fig. 1. 



A fine broad Disciiwcaris-like test, but truncate and somewhat 

 sinuous on the posterior margin. Its wide notch separates it from 

 Spathiocaris. It is from the Upper Devonian of Bicken, Nassau. 



VII. — Dipterocaris, J. M. Clarke, 1883. Amer. Journ. Sci. ser. 3, 

 vol. XXV. p. 121. 



The test or shield is here split on the posterior portion medially 

 for a greater or less distance, as well as in front, leaving only an 

 isthmus connecting the two lateral pieces. The front notch is broad ; 

 the hinder notch or cleft is usually longer than the other, and very 

 wide, but in some cases it is very narrow. The several species are : — 



1. D. pes-cervce, J. M. Clarke, loc. cit. figs. 4, 5. 



2. 7). vetusta (d'Arch. et de V.), already noted. Devonian, Eifel. 



3. D. procne, Clarke, loc. cit. figs. 2, 3. 



4. D. penncB-dcedali, Clarke, loc. cit. fig. 1. 



5. D. Etheridgei, nobis. Fossils of Girvan, etc., 1880, p. 212, 

 pi. 14, fig. 21. The last is from the Lower Silurian of Ayrshire, 

 Scotland ; and Mr. Clarke's specimens are from the Upper Devonian 

 of Western New- York State. 



It is difficult to determine whether the posterior cleft in the cara- 

 pace was filled with a wedge-shaped median piece, as the anterior 

 notch presumedly was. 



The shield of Fholadocaris with its posterior triangular facet seems 

 to present an analogous feature. 



VIII. — Pterocaris, Barrande, 1872. 



This somewhat obscure fossil is only a cast, but has certain 

 characters which connect it with Dipterocaris, namely, its front and 

 bind notches, the former of which retains the little triangular 

 cephalic piece in the unique specimen figured and described as 



DECADE III. VOL. I. — NO. VIII. 23 



