Pacific Coast of North America. 171 



. Head not at all immersed. 



b. Body relaxed. Posterior angles of first segment of 

 body prominent or produced, very often acute ; 

 posterior angles of the following segments in- 

 creasing gradually in length, the first of these 

 very often scarcelv prominent, the posterior ones 

 very often produced, abruptly longer than the 

 first. Epimera of the first segments very often 

 involuted, and extending beyond the posterior 

 angle of the segment ; posterior ones produced, 

 acute. Sides of the first five segments of abdo- 

 men more or less profoundly incised 10. Neroeila, 



b' . Body compact. I'osterior angles of first segment 

 of body scarcely prominent, occasionally produced, 

 those of following five segments scarcely or not 

 at all prominent; those of seventh segment pro- 

 duced. Epimera of first segments very often 

 almost reaching, or not reaching by a short 

 distance, the posterior angle of the segment. 

 Sides of the first segments of the abdomen whole 

 or obscurely emarginated, of the posterior ones 

 craduallv more profoundly emarginated or in- 

 cised . . 11- Anilocra. 



8. Meinertia, Stebbing*. 



15. Meinertia (?aMC?ic^aMC?a (Milne-Edwards). 



Cxjmothoa Gaudichaudii, Milne-Edwards, Hist. Nat. Crust, iii. 1840, 



Cer'atoth'oa rapax, Heller, Reise Novara, Crust, xii. p. 146, fig. 17. 

 Ceratothoa Gaudichaudii, Schiodte & Meinert, Naturhistorisk Tids- 

 skrilt, xiii. 1881-83, pp. 335-340, pi. xiii. figs. 11-15. 



Hah. Mazatlan. 



9. LivONECA, Leach. 



Analytical Key to the Species o/Livoneca. 



a. Terminal segment obscurely carinated, 



and sides infolded. Caudal appen- [& Meinert. 

 dages destitute of accessory lamellae . . 16. L. californica, Schiodte 

 a'. Terminal segment not carinated, sides 

 not infolded. Caudal appendages fur- 

 nished with accessory lamellae. 

 b. Inner branch of uropoda a little longer 

 and wider than outer branch. I'er- 

 minal segment sublinguate. Abdo- 

 men deeply set in thorax 17. i. vulgaris, Stimpson. 



b'. Inner branch of uropoda a little 

 lono-er and much narrower than 

 outer branch. Terminal segment 



semicircular. Abdomen less deeply [& Meinert. 



inserted in thorax 18. X. panamensis, Schiodte 



• Hist, of Crust. 1893, p. 345. 



