II. Rostrnm seiTated on its dorsal edge only : — 



1. A pleiirobranch on somite XIII but not on somite XIV : — 



i. Exopodites on all, or all but the last pair of the 



thoracic legs ... 

 ii. No exopodites on any of the thoracic legs 



2. No pleurobranchine on somites XIII and XIV : all the thora- 



cic legs with exopodites : — 



i. Epipodites absent from at least the last three pairs of 



thoracic legs 

 ii. Epipodites absent only from the last two pairs of 

 thoracic legs : — 



a. Last two pairs of thoracic legs of normal 

 fonn : — 



a. Antennular flageUa short 

 j3. Antennular flagella much longer 

 than the carapace 

 h. Last two pairs of thoracic legs flagelliform 



Peneus, Fabr. {sensu restricto). 



Metapenbits. 

 Parapeneus. 



Parapeneopsis. 



Teachypeneus. 



Attpopeneus. 

 Xiphopeneus. 



Sidney I, Smith, Proc. U. S. Nat. Mns. VIII. 1885, p. 170. 

 Type: P.caramote, Risso. 



Rostrum toothed both dorsally and ventrallj. Antero -inferior angles of 

 carapace not spiniform. Post-antennular sulcus of carapace defined by a dorsal 

 as well as by a ventral ridge. 



Antennular flagella short or of moderate length. Endopodite of maxillnles 

 (1st maxilte) elongate and distinctly three- jointed. Exopodites present on all, 

 or all but the last pair of the thoracic legs. 



Epipodites present on all but the last two thoracic appendages: pleur'o- 

 branchias present on the six posterior thoracic somites. 



Andricum symmetrical, simple, pod-shaped : it consists of two lobes finely 

 interlocking all along their anterior border and capable of loose apposition in 

 more or less of their posterior border, the opposed faces being concave. 



The dactylus of the 8rd maxillipeds often shows modifications of a second- 

 ary sexual nature in the adult male. 



The branchial formula is as follows : — 



Total 



6ep. + 1 



12 



= 6ep.-l-l9 



