SUBCLASS IT 



EUCRUSTACEA— EUCARIDA 



■67 



cinus Leach, is stated to occur in the fresh -water Miocene deposits of Oeningen. 

 Archaeoplax Stimpson is found in the Miocene of Gay Head, Massachusetts. 



The Cyclometopoiis faniilies have niany representatives in the Tertiary and a few 

 in the Cretaceous. The earliest are of Ccnomanian age, inchiding Etyus Mantell and, 



Xanthopsiti kre.->'sniberg(msis v. Meyer. 



Fio. 1492. 

 Eoceiie ; Kressenberg, Bavaria. Male, 



?ntral aiul dorsal aspects, 1/2. 



doubtfully, the Recent Xantho Leach. Titanocarcinus and Palaeocarpüius Milne 

 Edwards, appear in the Upper Cretaceous. The Recent Panopeus Milne Edwards, is 

 Said to date back to the Cretaceous. In the Eocene are found Harpactocarcinus Milne 

 Edwards ; Lohocarcinus Reuss (Fig. 1491) ; Xanthopsis M'Coy (Figs. 1492, 1493) ; and 

 Neptocarcinus and Carcinocarcinus Lorenthey. The Recent genera Cancer Linn. ; 

 Ätergatis de Haan ; and Etisus Milne Edwards, are recorded from the Upper Eocene, 



Ficj. 1493. 



Xonthopsiiihruckraanniv. Meyer. Eocene; Sonthofen, 

 Bavaria. Ventral view of female, Vi- 



Fig. 1494. 



l'mmmoair cinus hericarti (Desni.). Middle Meeressanci 

 (Miocene) ; Le Giie-ä-Tresraes, France (after» A. Milne 

 Edwards). 



although the demonstration of their precise identity with Recent forms is not in all 

 cases satisfactory. 



The easily recognised Swimming-crabs of the family Portunidae are certainly 

 represented as early as the Eocene by such forius as Psammocarcinus Milne Edwards 

 (Fig. 1494); Portunites Bell ; and the B.ecent Neptunus de Haan. The River-crabs 

 {Potamonidae) are said to be represented in the fresh-water Miocene of Oeningen by 

 the Recent genus Potamon Savigny {Thelphusa Latreille). 



