SYNOPSIS OF GENERA. lxi 



abundant cephalopod and furnishes the only instance observed, alter the most 

 careful examination of the rocks, of any such association of these bodies, and 

 also the only example of the occurrence of a body resembling Dipterocaris in 

 these beds. If this association is not purely accidental, and if there actually 

 existed any organic connection between the Goniatite and the enclosed body, 

 the latter has certainly not been similar in function to the aptychi. 



While it is necessary to recognize the fact that of the bodies included under 

 the genera Spathiocaris, Cardiocaris, Discinocaris, Dipterocaris, Pterocaris and 

 Pholadocaris some are undoubtedly crustacean and others, with certainty, 

 cephalopodous, with our present knowledge it is impossible to draw the divid- 

 ing line between them. 



ORDER, DECAPOD A. 



Family, Carididje. 



Genus PAL.EOPAL M MON, Whitfield. 1880. 



Diagnosis. Cephalothorax not rostrate (?), keeled upon the dorsum and sides. 

 Antennules not observed. Antennaj with very strong basal joints, exceeding 

 in strength any of the thoracic appendages. Eye-peduncles probably short. 

 Thoracic ambulatory appendages slender, not forcipate. Abdomen composed of 

 six segments. Telson short, rapidly tapering and connected by a membranous 

 expansion with the lateral caudal spines. In the midst of this caudal expansion 

 lies a pair of thin lamellar spines articulated at their proximal extremities to 

 both telson and lateral spines. 



ORDER, PHYLLOPODA. 



Family, Limnadiad.e. 

 Genus ESTHERIA, Rvppell. 



(devonian species only.) 

 1846. PosidoTwmya, Eichwald. Geol. Russia. 

 1S49. Asmusia, Pacht. Devon. Kalk in Livlaml. 



