ON THE FOSSIL rilYLLOrODA OF Tlli; PAI-KOZOIC HOCKS. 



85 



387, 



A broadly obovato Bhiold, when complete and looked at with an- 

 terior margin placed upwards. 'Pho fossil is broadly cordate in its 

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

 IS trnncato behind, along the niiddle of the posUirior margin, with a lin«» 

 (einuons by uncciual pressure jirobably) ccpial in length to half the 

 width of the carapace. Tho iigured specimen has the dorsum bent in 

 along a median lino, but not sutured. According,' to the figure tho 

 length (complete) would be about 48 mm. ; width where broadest •!•!> mm. 

 Nuchal suture sloping at 40°. Five specimens, Upp(;r Devonian, Uicken, 

 near Herborn. Tho largest example (Mr. Clarke says) measures 45 mm. 

 from the apex of tho notch to the posterioi- margin, and S")!") mm. broad. 

 The fossils mostly measure about .'{.'{ mm. long, and about 4^) m.u. broad. 

 He regards Spntli. Koeneni as a link between Sinilln'ocurix and Canl'uicariti ; 

 but tho truncation of the posterior margin puts it with Canliucaris, and 

 its wide notch is strange to Sitnlliivcariti. 



CAniMOCARIS. 



"7'i ~j 

 fifa\ . 



Ca rtl ioca fin It or iiinu 



n/ii r I (t, y^ ill Ooniatitc beds 



I 'cncris [ 

 KocHi'iii J 



[ niincslu'im"! 



J Hiidcsliciiii ,. ,, . „ 



\ „■• 1 1 • , Upi)er Devonian. 



tUickeii J 



VII. Dii'i'KiioCARis, J. M. Clarke, 1883. 'Amer. Journ. Science,' scr. 3, 

 ♦ vol. XXV. f. 121. 



A variety of fo.ssil Phyllopodous shields, oval or ovate in general 

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

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

 angular, and analogous to that in Discinocaris, AptijcJiopsis, ^x. ; the other 

 varies from a mere split to a broad ojien A-shaped notch. Tho 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 Dlpterocaris pes-cervco, J. M. Clarke, op. cil. 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 tho shield. Lower Chemung sandstone ; Canadice, Ontario co., New 

 York State. 



2. Apti/chus vetvst US, d^ Archiac a.nd do Verncuil, 1812, ' Trana. Geol. 

 Soc* 3er. 2, vol. vi. p. 343, pi. 20, f. 0, from the Devonian rocks of the 

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

 narrow hinder split. 



3. JJiplfrocan's procne, J. M. Clarke op. cit.\). 122, figs. 2 & 3, has tho 

 two notches both wide and deep. It is ridgeliko iii its dorsal bend. 



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

 State. 



4. D. pcnncc-da'dali, J. VL. Clarke, op. cit. p. 123, f. 1, has tho notches 

 large and deep and unequal, leaving only a small isthmns near the 

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

 stone CO., Now York State. 



5. These characters — small isthmus, deep notch, and large laterals, are 

 present also in figuic 21, of Plato 14, in tho ' I'Vssils of Oirvan,' 1880, 

 and regarded as an nndetermincd PhjUopod at p. 212. The specimen 



