ON THE FOSSIL PHYLLOrODA OF THE TAL.EOZOIC ROCKS. 85 



A broadly obovate shield, when complete and looked at -with an- 

 terior margin placed upwards. The fossil is broadly cordate in its 

 present condition, having a wide and rather shallow cephalic notch. It 

 is truncate behind, along the middle of the posterior margin, with a line 

 (sinuons by unequal pressure probably) equal in length to half the 

 width of the carapace. The figured specimen has the dorsum bent in 

 along a median line, but not sutured. According to the figure the 

 length (complete) would be about 48 mm. ; width where broadest 49 mm. 

 Nuchal suture sloping at 40°. Five specimens, Upper Devonian, Bicken, 

 near Herborn. The largest example (Mr. Clai-ke says) measures 45 mm. 

 from the apex of the notch to the posterior margin, and 55 mm. broad. 

 The fossils mostly measure about 33 mm. long, and about 45 mm. broad. 

 He regards Spath. Koeneni as a link between Spathiocaris and Cardiocaris ; 

 but the truncation of the posterior margin puts it with Cardlocaris, and 

 its wide notch is strange to Spathiocaris. 



Cardiocaris. 



Cardiocaris Roemeri ~\ f Biideslieim"| 



,, tripartita \ ■ n . ... . , J Biidesheim , T ^ . _ 



r/ . > in Goniatite oecls •< r, .. ! , ■ >Lpper Devonian. 

 „ venerrs I Budesheim ( 1 1 



„ Koeneni J (^Bicken J 



VII. Dipterocaris, J. M. Clarke, 1883. 'Amer. Journ. Science,' ser. 3, 



vol. xxv. f. 121. 



A variety of fossil Phyllopodous shields, oval or orate in general 

 outline ; but this is interrupted by two notches of varying width and 

 depth, one in front and one behind. The anterior or nuchal notch is 

 angular, and analogous to that in Discinocaris, Aptychopsis, Sfc. ; the other 

 varies from a mere split to a broad open A-shaped notch. The shield 

 seems to consist of one piece, and was probably ridge-like to some extent, 

 but occasionally pressure has caused the median line to be specially 

 depressed, or otherwise affected, so as to look like the place of a suture. 

 The shields have concentric lines of growth for ornament. 



1. In Dipterocaris pes-cervce, J. M. Clarke, op. cit. p. 123, figs. 4, 5, 

 the front notch is open, with its outer width almost equal to one of its 

 sides. The hinder notch is very narrow, and reaches up half the length 

 of the shield. Lower Chemung sandstone ; Canadice, Ontario co., New 

 York State. 



2. Aptychus vetustus, dArchiac and de Yerneuil, 1842, ' Trana. Geol. 

 Soc' ser. 2, vol. vi. p. 343, pi. 26, f. 9, from the Devonian rocks of the 

 Eifel, is a Dipterocaris, with a very broad, angular frontal notch, and a 

 narrow hinder split. 



3. Dipterocaris procne, J. M. Clarke, op. cit. p. 122, figs. 2 & 3, has the 

 two notches both wide and deep. It is ridgelike in its dorsal bend. 



Middle Chemung (sandstone) ; Hoskinsville, Ontario co., New York 

 State. 



4. D. pen7i03-dcedali, J. M. Clarke, op. cit. p. 123, f. 1, has the notches 

 large and deep and nnequal, leaving only a small isthmus near the 

 centre to unite the lateral portions. Lower Chemung ; Dansville, Living- 

 stone co., New York State. 



5. These characters — small isthmus, deep notch, and large latei-als, are 

 present also in figure 21, of Plate 14, in the ' Fossils of Girvan,' 1880, 

 and regarded as an undetermined Phvllopod at p. 212. The specimen 



