SYNOPSIS OF GENERA. 
lix 
Genus DIPTEROCARIS, Clarke. 1883. 
1883. Bi'pterrocaris, Clakke. Amer. Jour. Science. 
1883. Bipterocaris, Etheridge, Woodward and Jones. Kept. Committee Foss. Phyllop. 
1884. Bipterocaris, Jones and Woodward. Geol. Mag-azine. 
1884. Bipterocaris, Etheridge, Woodward and Jones. Second Kept. Committee Foss. Phyllop. 
1885. Bipteivcaris, Clarke. Dev. Faunas Ontario county. 
1885. Bipterocaris, Etheridge, Woodward and Jones. Third Rept. Committee Foss. Phyllop. 
1885. Bipterocaris, Zittel. Handb. d. Palieontologie. 
1886. Biptarocaris, Clarke. Geol. Succession in Ontario Co. 
Diagnosis. Carapace in one piece, ovate in general outline; normally with 
an elevated dorsum and sloping sides. Each extremity is strongly notched, 
dividing the carapace into two broad alee, connected by a narrow isthmus which 
shows no evidence of a dorsal suture or anchylosis. Surface ornamented by 
concentric elevated lines or wrinkles. 
The true organic character of the bodies included under the genera Spathio- 
caris and Dipterocaris and allied forms, from the Devonian horizons of Great 
Britain and Europe, has been a subject of some debate among recent writers. 
A diversity of opinion has arisen from the fact that while some of the species 
included under the closely related genera Peltocaris, Salter, Aptychopsis, Barrande, 
Discinocaris, Woodward, Aspidocaris, Reuss, Cardiocaris, Woodward, Ellipsocaris, 
Woodward, and Spathiocaris, Clarke, have afforded 
indisputable evidence of a free rostral plate cover¬ 
ing the anterior cleft, e. g., Peltocaris aptychoides, 
Salter; Aptychopsis prima, Barrande ; Cardiocaris 
Acemen, Woodward; Discinocaris Browniana,N[oodi- 
ward; since the original description of the species 
as Crustacea, others have been found in the body 
chamber of a single species of Goniatites {G. intumescens) {Cardiocaris lata. Wood¬ 
ward, Spathiocaris Kaneni, Clarke, both from the middle Devonian limestones 
at Bicken, Westphalia), From this fact, together with the similarity of these 
latter bodies in many respects to the aptychi of Mesozoic Cephalopoda, and 
their agreement in outline with the transverse section of the body chambers in 
which they have been found, there is no doubt that these two species at least 
have had some organic connection with the cephalopoda, serving a similar 
Discinocaris Browniana, Woodward. 
