470 Mr. L. A. Borradaile o;» the 



II. Third leprs not chelate. Third maxillipeds 

 4-6-joiuted. End-joint in second maxilli- 

 peds nearly always lies as a strip along end 

 of joint before it. First maxillipeds have a 

 lobe on the base of the exopodites. Pleura 

 of second abdominal segment overlap those 

 of first. Abdomen has generally a sharp 

 bend. Phyllobranchiate CA HIDES. 



Key to the Families of the Pengeides. 



I. Last two pairs of legs well developed. Gills 



many Penaeidae. 



II. Last one or two pairs of legs reduced or lost. 



Gills few (up to 8) or wanting Sergestidae. 



Ke7/ to the Suhfamilies of the Penseidfe. 



I. Carapace covers le^s. Exopodites well deve- 



loped. [Podobranchs on some legs.] Cerutaspimi;. 



II. Carapace of normal size. Exopodites re- 

 duced or lost. 



1. Well-developed podobranchs on some legs. 



[Exopodites on maxillipeds and sometimes 

 on some legs. Arthrobranchs in double 

 series. First anteQna3 without leaf-like 

 appendage on first joint.] Arhtceince. 



2. No podobranchs on legs (vestige on first legs 



of Haliporus). 



i. No exopodite behind first maxillipeds. 

 Arthrobranchs in single series. No 

 leaf -like appendage on first joint in first 

 antennae Sicyonince. 



ii. Exopodites on all maxillipeds and usually 

 some legs. Arthrobranchs in double 

 series. A leaf-like appendage on inner 

 side of first joint in first antennae .... Penceinci^. 



Key to the SuhfavnUes of the Serge-stidge. 



I. All the thoracic limbs biramous. Gills 



present and resemble phyllobranchiae Amphionincp. 



II. Last seven thoracic limbs uniramous. Gills, 



if present, are dendrobranchiae. 



1. Head not greatly elongated. Gills present. Serf/estin(V. 



2. Head greatly elongated. No gills Leuciferince. 



Key to the SuiMrfamilies of the Caridcs. 



I. Second maxillipeds normal. [Exopodites 

 on some or all legs. Mastigobranchs on 

 none. First two pairs stouter than the rest, 

 with normal chelae and undivided wrist- 

 ioints. Mandibles without or with distinct 

 but small molar process, with or without 

 palps.] Pasiph.'eoida. 



