664 ARTHROPODA SUB-KINGDOM VII 
other respects approaches the Astacidae. Carapace solid and roughened, cervical suture 
deep ; sternum narrow ; legs monodactyle, the first pair being the largest, and in some 
cases sub-chelate. Pemphiz, v. Meyer (Fig. 1388), 
occurs in the Muschelkalk ; Lithogaster and 
Glyphaea, v. Meyer (Fig. 1389), range from the 
Trias to Cretaceous; Pseudoglyphaea, Oppel, is 
Jurassic ; and Meyeria, M‘Coy, Neocomian. 
(6) The Astacidae are distinguished by the 
possession of a narrow sternum; chelate 
appendages, of which the first pair is very 
strongly developed, and an antennal scale. Both 
salt- and fresh-water forms occur. Eryma, v. 
Meyer (Fig. 1390), Pseudastacus, Stenochirus, 
Etallonia, Oppel, are found in the Lithographic 
Slates. Isolated chelae of Magila (Fig. 1391) are 
abundant throughout the Jura. Hnoplocytia, 
M‘Coy ; Nymphaeops, Schliit.; Hoploparia, 
M‘Coy ; Oncoparia, Bosquet; and Palaeastacus, 
Bell, occur in the Upper Cretaceous of West- 
phalia, Bohemia, and England. Homarus, Milne- 
Edw.; Nephrops, Leach; and Astacus, Fabr., 
range from the Upper Cretaceous to Recent. 
(7) The Thalassinidae 
have: the abdomen much 
elongated, carapace with 
two longitudinal sutures, 
anterior feet the largest 
Fic. 1391. and chelate, and whole 

" ies Hep ae ‘ Magila suprajurensis, body except the chelae 
rym leptodactylina, Germ. sp. itho- Quenst. sp. Upper Jura; ; ind = 
graphic Slates; Solenhofen, Bavaria. 1/, Soflingen, Wiirtemberg. enclosed in a thin integu 
(after Oppel). Chela. ment. Numerous chelae 
referable to Callianassa, 
Leach (Figs. 1392, 1398), are found in the Cretaceous and Tertiary. Thalassina, Latr., 
is Tertiary and Recent. 
(8) The Galatheidae differ from the last family in having the broad abdomen 
slightly recurved below ; cephalothorax strongly calcified and with numerous transverse 

Fia. 1392. Fic. 1893. 
Callianassa Archiaci, M.-Edw. Turonian; Mont- Callianassa antiqua, Otto. Turonian; Turnau, 
dragon. Var. (after Milne-Edwards). Bohemia. Right chela. 
furrows ; posterior pair of feet very small and delicate. Fossils are extremely rare, 
and consist only of chelae of Galathea from the Upper Cretaceous of Faxoe, Equally 
rare are the chelae of Pagurus, belonging to the Paguridae or Hermit Crabs, described 
from the Eocene of Hungary. 

