TAN AID ACE A 477 



Fam. 7. Pseudocumidae. Resembles Diastylidae and Lampropidae, 

 but the telson is very small and flap-shaped, and the inner rami of the 

 iiropods are unsegmented. Pseudocuma G.O.S., 1 sp. found in the Caspian 

 Sea ; Petalosarsia Stebbing ; and the 4 following hitherto only known from 

 the Caspian : Pterocuma G.O.S. ; Stenocuma G.O.S. ; Schizorhynchus 

 G.O.S. and Caspiocuma G.O.S. 



Fam. 8. Nannastaeidae ( = Cumellidae). Telson and pleopods absent; 

 thoracic appendages 4-7 with exopodites in the males. Nannastacus 

 Sp.B. with paired eyes ; Cumella G.O.S. with a median eye. 



Fam. 9. Campylaspidae. Carapace very large depressed in front, 

 vaulted behind; endopodite of 1st thoracic appendage (1st maxilliped) 

 rudimentary. Campylaspis G.O.S. 



Order 4. TAN AID ACE A (CHELIFERA).* 



Malacostraca with a cephalo-thorax formed by the fusion of the 

 two anterior thoracic segments with the head, and produced on each 

 side into a fold forming a respiratory chamber. The second 

 thoracic limbs end in large chelae, and the abdominal appendages 

 are lamellate and natatory. 



The small Crustacea belonging to this order, occupy an inter- 

 mediate position between the Cumacea on one hand and the 

 Amphipods and Isopods on the other. 



FIG. 294. Apseudes spinosus (from Claus, after G. 0. Sars). 



The body is elongated and nearly cylindrical. The second 

 thoracic segment which in most Amphipods and Isopods is the 

 first free one is here, as in the Laemodipoda, united with the 

 head to form a cephalothorax, the sides of which are produced 

 into two folds, enclosing a respiratory chamber. The eyes, when 

 present are raised on short stalks but are not mobile. The first 

 antennae are biramous in Apseudes, uniramous in Tanais and 



* Claus, Ueb. Apseudes latreillei und die Tanaiden. Claus' Arbeiten, 

 T. v and vii. Sars, Crustacea of Norway, Isopoda. 



