118 University of California Publications. [| ZooLoGy 
KEY TO THE GENERA OF THE GYMNOPLEA. 
(The genera marked with an asterisk have been found in the 
San Diego region.) 
1. Inner ramus of third and fourth feet 3-jointed, figs. 12a, 19b..... 2 
1. Inner ramus of third and fourth feet 2-jointed, fig. 44d.......... 19 
2 inner ramus; OL Lrstsroot),.o-jOLULOd ot meme hte een iee eee eee 3 
2.) Loner ramus ob first’ £006 -2-jOIntediaw. «yejac ners oe eae eee 32 
2. inner ramus of first footie -joimbed) fia lod: eee lel ee ee 38 
3. A black or brown knob on the first segment of the cephalothorax 
oO 
in the antero-lateral angle, on the right or left side; figs. 33a, 
ERLE eray dio niche a Sa ee yate Rea an ewe) er oe ee eA ts eee *Pleuromamma 
This! knob VAbSeMba ary. 5 ke cetietsesite eto eens ers erel o Siete cteke alertness t 
. First joint of inner ramus of second foot with proximally curved 
hooks ‘on thesinner margins fos SOD. oie eteres vesine «ieee *Metridia 
2 Dhis' joint, Jike the rest, bearing a bristles: o/s... -\-11- se © brea 5 
. Terminal joint of outer ramus of third and fourth feet with two 
spines or thorns on outer margin, and one terminal bristle; fig. ld 6 
. Terminal joint as above, but with three spines on outer border; 
HPS). LTO LOD 2 coker ec tave sin morte Mayen Acie eee re averted eee 6a 
6. Terminal bristle of outer ramus of third and fourth feet with 
nroad smooth borders ne: 1d oes cre aise ree eae eter *Calanus 
6a. Terminal bristle bearing teeth or spines on outer border; figs. 
Oe DIP oxare ot a aha. 4, Bele Sick letgphe tc 1a ale seuel ore, s Lae atel s eitirstia tee ancl seee fea eae f 
7. One bristle of left ramus of furca much longer and thicker than 
Ghee OLher <LOrcal (DRISleS) 1... 04> wsitorale + erctero cls ane ereryeloe eects 8 
feebuncals bristles: SymiMetrCala. ciccs sen 2 crete: wie eee Crete ste mele 9 
8. Mandibular blade with three or four teeth, the ventral one 
hooked and separated from the others by a wide space; fig. 
ERS siesta seotels age cert oe Rieck eve euebcuhe. Sahu SECA ete, Sehiace *Heterorhabdus 
8. Mandibular blade with at least 8 teeth..................... Disseta 
9! AmtervoraAncenn ge SymMMenLICAl . hs spe sis o/es mm lois,ciets’s = fester stetaaiets 10 
9.,Anterior antennae (as ymimenm cally i. chy- see cision wines an sae es 14 
LO! Rami of ftth feet 3-jommteds mips S263 seo e ss wisis ees eiclege coeteereis 11 
1O:) Rami of fitthy feet. a —jommbe Merwe ss ate eel vol ofc paras eo oot *Augaptilus? 
10. Outer ramus 3-jointed, inner ramus 2-jointed............ Isochaeta? 
10. Outer ramus 3-jointed, inner ramus 1l-jointed............... Isias? 
10. Outer ramus 3-jointed, inner ramus lacking............. *Phyllopus? 
10. Outer ramus 1-jointed, inner ramus rudimentary; fig. 42b *Arietellus? 
11. Middle joint of outer ramus of fifth foot with a thorn-like pro- 
cess which is fused with the joint; fig 32c.......... *Centropages? 
11. This joint with an awl-shaped or rudimentary bristle on the 
inner vhorder: figs sOU,eoRey ar ee cet peel scce ter acter thee leet tte 12 
12. Terminal joint of inner ramus of fifth foot with five bristles; 
ik) Sasol Morea Sho arcane xi Gee oc Soo ae 0 *Lucicutia? 
12. This joint, withvat, least) sixes bristles: orto ore artnet eterno eer 13 
13: Abdomen with 4 seomentsi 7. )icte <tc sete tee tar ener ete Haloptilus? 
13. Abdomen’ with! 3) SeSmMents tse cele elelsiaietetet tated a *Augaptilus? 
