49 



In the present state of knowledge the following table may 

 suffice to discriminate the genera of this family : — 



(Second pair of trunk-legs wanting. 

 I. Paracrangon, Dana, 1852. 

 . Second pair of trunk-legs present, 2. 



Second pair of trunk-legs simple. 2. Sabmea, Owen, 1 835. 

 Second pair of trunk-legs chelate, 3. 



Fourth and fifth pairs of trunk-legs, seventh joint laminar. 



3. Argis, Kroyer, 1843. 

 Fourth and fifth pairs of trunk-legs, seventh joint not 

 laminar, 4. 



( Second trunk-legs subequal in length to the rest, 5. 

 \ Second trunk-legs much shorter than the rest, 6. 



[ Body dorsally little or not at all sculptured. 

 \ 4. Crmigon^ Fabricius, 1798. 



^' \ Body dorsally strongly sculptured. 



\ 5. Scleroa-angon, Sars, 1882. 



, ( With only five pairs of branchiae. 6. Philochcras, n.n. 

 I With more than five pairs of branchiae, 7. 



Apices of branchiae turned backward. 



7. Pontophilus, Leach, 181 7, 

 Apices of branchiae turned forward. 



8. ^gcoii, Guerin-Meneville, 1835. 



Gen. : ^GEON, Guerin-Meneville. 



1816. Egeon, Risso, Hist. Nat. Crust, de Nice, p. 99. 



1825. Egeon (part), Desmarest, Consid. gen. Crust., p. 218. 



1826. Egeon, Risso, Hist. Nat. Europe merid., vol. 5, p. 64. 

 1835. ^^geoii, Guerin-Meneville, Exp. Sci. Moree. 



1837. Crangon (part), Milne-Edwards, Hist. Nat. Crust., 

 vol. 2, p. 340. 



1862. jEgeon, Kinahan, Proc. Roy. Irish Acad., vol. 8, 



part I, p. 9. 



1863. Crangon (part). Heller, Crust. Siidl. Europa, p. 224. 



1 88 1. Crangon {Cher a phi his), Miers, Ann. Nat. Hist., Ser. 5, 



vol. 8, p. 365. 

 1885. yEgeon, Carus, Prodr. Faunae Mediterraneae, vol. i, 



p. 483. 

 1888. Pontocans, Bate, Challenger Macrura, Reports, vol. 



24, p. 495- 

 1890. ^geon, Ortmann, Zool. Jahrb., vol. 5, part i, p. 530. 

 1893. Egeon, Stebbing, Hist. Crust., Intern. Sci. Ser., 



vol. 74, p. 226. 



