444 Dr. H. Woodicard — On El/ipsocans Deicalquei. 



III. — Note oi^ Ellipsocaeis Dewalquei, a new Phyllopod Crusta- 

 cean Shield fkom the Upper Devonian of Belgium.^ 

 By Henry Woodward, LL.D., F.E.S., F.G.S., 

 of the British Museum (Natiu-al History) . 

 rpHE specimen which forms the subject of this note has been 

 _L kindly placed in my hands by Professor G. Dewalque for ex- 

 amination, and is of extreme interest and importance to me in 

 my researches upon the Fossil Crustacea. It is not, as was at first 

 supposed, the metastome of Eurypterus or of Pterijgotus ; on the 

 contrary, it represents an almost entire carapace of a new genus and 

 species of Phyllopod Crustacean allied to Peltocaris. 



The name Peltocaris was given by Mr. J. W. Salter, in 1863,^ to a 

 circular head-shield of a Phyllopod from the Llandeilo Flags, Dum- 

 friesshire, having a semicircular cervical suture (c, d, c) and a 

 straight dorsal suture (d, d) (Fig. 1). 



Fig. 1. 



Fig. 2. 



Fig. 3. 



Shield of Feltocaris. Discinocaris. 



In 1866,^ I described another form of head- 

 shield of a Phyllopod from the Lower Silurian 

 of Dumfriesshire, under the name of Discino- 

 caris (Fig. 2), having a rectangular cervical 

 suture (c, c, c) and no dorsal suture. 



In 1872,* I described a third form of Phyl- 

 lopod shield, from the Middle Silurian of 

 Plawick, under the name Aptychojms, in which 

 the cervical suture is rectangular (Fig. 3, c, d, c) 

 and a straight dorsal suture d, d, is also present. 



The specimen with which I have now been 

 favoured by Professor G. Dewalque offers a 

 fourth form to this interesting series of Phyl- 

 lopod shields from the Upper Devonian. It 

 presents us with an elliptical shield (Fig. 4), 

 in which the cervical suture (c, c, c) is semi- 

 circular, as in Peltocaris, but the dorsal suture 

 is absent, as in Piscinocaris. 



Apthycopsis. 

 Fig. 4. 



Ullipsocar 



1 Translated from the Annales de la Societe Geologique de Belgique, Aug. 1882, 

 T. viii. Memoires, 4, pp. 45-49. 



- Quart. Journ. Geol. Soc. vol. xix. p. 88, fig. 1, pi. xxi. fig. 10 (1863). 



^ Quart. Jom-n. Geol. Soc. vol. xxii. p. 504, pi. xxv. figs. 4-7. 



4 Geol. Mag. 1872, Yol. IX. p. 564, id. 1873, Brit. Assoc. Eep. 1872. 



