238 GNATHIIDEA • GNATHIIDAE 



Family Gnathiidae Harger, 1879 

 DIAGNOSIS As for the suborder Gnathiidea. 



Gnathia Leach, 1814 



DIAGNOSIS In addition to features mentioned in diagnosis of suborder: Eyes 

 present in most species. Pylopod with two small articles distal to broad oper- 

 cular article 2, terminal article minute. 



Key to species of Gnathia ( S only) 



1 . Anterior margin of cephalon with medial process or slightly convex . . 2 

 Anterior margin of cephalon concave or lacking medial process 9 



2. Anterior margin of cephalon broadly triangular, projecting, with small 



lateral teeth triospathiona 



Anterior margin of cephalon not triangular and projecting 3 



3. Cephalon and two free anterior pereonites dorsally granular 4 



Cephalon and two free anterior pereonites smooth 5 



4. Lobe of outer margin of mandible notched; pereonite 5 twice wider 



than middorsal length velosa 



Lobe of outer margin of mandible rounded; pereonite 5 1.5 times wider 

 than middorsal length 6 



5. Anterior margin of cephalon with distinct medial process virginalis 



Anterior margin of cephalon barely convex, lacking medial process 



rathi 



6. Inner proximal lobe of mandible distinct 7 



Inner proximal lobe of mandible indistinct samariensis 



7. Inner proximal lobe of mandible entire 8 



Inner proximal lobe of mandible with rounded toothlike marginal 



structures Johanna 



8. Pereonites 3-5 poorly defined puertoricensis 



Pereonites 3-5 clearly defined magdalenensis 



9. Anterior margin of cephalon concave, lacking projections gonzalezi 



Anterior margin of cephalon with four projections beethoveni 



