754 



ARTHROPODA 



PHYLUM VII 



Suborder E. DISCINOCARINA Clarke. 



Sub-circular or oval shields with a triangulär rostrum filling an anterior notch. 

 Sarface ornamented loith raised concentric lines. Suhstance chitinous. 



Family 1. Discinocaridae Woodward. 



Test convex, sometimes mesially ridyed ; m a smgle piece. 



Discinocaris AVoodw. Shield sub-circular, rostral notch and rostrum angulai. 

 Abdominal segments and caudal spines have been referred to this 

 genus by Jones and Woodward. Silurian ; Great Britain, 

 Bohemia. 



Aspidocaris Reuss. Similar to Discinocaris, Raibl Bedt^ 

 (Upper Trias) ; Hallstadt. 



Dipterocaris Clarke (Fig. 1460). Shield with a deep posterior 

 notch, shorter than the anterior or rostral notch. Sides of shield 

 sloping. Silurian ; Scotland. Upper Devonian ; New York. 



Fig. 1460. 



Dipterocaris rctustm 

 d'Arch. and Vern. De- 

 vonian ; Bifel. Vi- 



Family 2. Peltocaridae Salter. 



Shields mesially sutured. 



Peltocaris Salter. Circular shields with a rounded rostral notch and plate. 

 Abdomen unknown. Ordovician ; Great Britain. 



Aptychopsis Barr. (Fig. 1461). Like Peltocaris, but with the 

 rostral notch angular. Silurian ; Bohemia and Great Britain. 



Pinnocaris Etheridge. Similar to Dipterocaris, but bivalved. 

 Ordovician ; Scotland. (P. lapworfhi Etheridge jun.) 



Addendum. 



Fi<i. 1461. 



Aptychopsis primus 

 Barr. Ordovician (D) ; 

 Branik, Bohemia. i/i 



A iiumber of generic names, such as Gardiocaris (Fig. 1462), 



Ellipsocaris, Pholadocaris Wood ward, and Spathiocaris Clarke, 



have been applied to Devonian fossils which closely resemble the 



Silurian Discinocaris, of whose Crustacean nature there seems to 



be no doubt. Some of these bodies, however (Gardiocaris), have 



been found in the living Chamber of Goniatites (G. intumescens), 



and have undoubtedly served as opercula or aptychi of these 



Cephalopods; of others the nature is not fully understood. 



Lisgocaris Clarke is not a Crustacean; Gryptocaris Barrande is 



Fio. 1462. probably the operculum of a Hyolithoid ; Myocaris Salter is 



(■urdioturis (Anapty- stated to be a Pelecypod ; Proricaris Baily was founded on 



tvvlv'^i'^y'^ni^n] P*^^« of Geratiocaris ; Grescentilla and Pterocaris Barrande are 



Bttdeslieini, Eitel. Vi- doubtfully Crustacean. 



Series II. EUMALAOOSTRAOA Grobben. 



Abdomen of six somites, all of which may hear appendages, and a telson which 

 never bears movable furcal rami Thoracic limbs rarely all similar, typically 

 pediform. ^ ^ jr j 



The remains of Crustacea presenting the primitive "caridoid facies," as 

 described above occur in the Carboniferous, and it may be that the Eumala- 

 costraca had their origin in that epocli. If certain Devonian fossils are 



