SUPER-ORDER I PHY LLOPODA 641 
striae. The latter character serves to distinguish this genus from Posidonomya 
(p. 371). The beaks are not sharply defined, and the primitive portions sometimes 
bear a strong ocular or muscular node. 
This genus has numerous fossil representatives, being first met with in the Devon- 
ian, and occurring 
mostly in brackish 
and shore deposits. 
It abounds in the 
productive Coal 
Measures, in the 
Permian, Trias (Let- 
tenkohlenmergel), 
and Wealden, and 

Fic. 13884. 
has been found in A, Leaia Leidyi, Jones. Coal Measures ; Potts- Fic. 1335, 
the Pleistocene ville, Pennsylvania. B, L. Baentschiana, Geinitz. Schizodiseus capsa, Clarke. 
Clavs of C 1 Coal Measures; Neunkirchen, near Saarbriicken Hamilton ; Centerfield, New 
Sas US ogy (after Goldenberg). York. 2/3. 
Leata, Jones 
(Fig. 1334). Carapace marked by one or two diagonal ridges which run from the 
anterior end of the dorsal margin toward the lower margin. Carboniferous ; Europe 
and North America. 
Estheriella, Weiss. Carapace as in Estheria, but with radial riblets crossing the 
concentric striae. Permian; Russia. Buntersandstein ; Saxony. 
Schizodiscus, Clarke (Fig. 1335). Carapace peltate, with a straight hinge which is 
in the major axis of the shield. Each valve nearly a semicircle ; 
surface marked with concentric ridges. Middle Devonian ; 
New York. 
Family 2. Apodidae. Burmeister. 

Eyes sessile and head with a large shield-like carapace 
extending over the thoracic segments; antennulae large and 
triflagellate; antennae greatly reduced except im the larva. 
{\ Thorax with thirty to forty pairs of foliaceous feet ; segmented 
meen aoee: abdomen without appendages save a pair of caudal filaments. 
Protocaris Marshi, Wal- Protocaris, Walcott (Fig. 1336). The oldest representative 
Scion Te Georgia, of the Apus-type, and exhibits a remarkable similarity to Apus 
in its univalve carapace, multi-segmented abdomen, and single 
pair of caudal spines. Lower Cambrian ; Vermont. 
Apus, Schaft. (Lepidurus, Leach). Characters of the family. Trias to Recent. 
Family 3. Branchiopodidae. Baird. 
Head distinct, eyes stalked ; carapace wanting. Thorax with eleven to nineteen pairs 
of foliaceous feet ; abdomen terminating in two caudal processes. 
Branchipodites, Woodward. Similar to the recent Branchipus. Oligocene of Bem- 
bridge, Isle of Wight. (B. vectensis, Woodw.) 
Anomalocaris, Whiteaves. This name has been applied to bodies from the 
Cambrian of British Columbia which resemble the segmented abdomen of a Branchio- 
pod, each segment bearing a pair of lamellate appendages. Although the objects 
abound where found, nothing is known of the carapace, nor is there any evidence of 
the surface markings which characterise most Crustacean shields. Its affinities are 
doubtful. 
VOL. I ae 
