CAPRELLIDAE OF WESTERN NORTH ATLANTIC 7 



6.(2) Pereopods 3 and 4 1-scgmented 7 



Pereopods 3 and 4 2- or 6-segmented S 



7.(6) Pereonites 6 and 7 fused Metaprotella hummclincki (p. 78) 



Pereonites 6 and 7 not fused Fallotritella biscaynansis (p. 58) 



8.(6) Pereopods 3 and 4 2-segmented 9 



Pereopods 3 and 4 6-segmented 15 



9.(8) Pereopod 5 2- or 3-segmeuted 10 



Pereopod 5 6-segraented 11 



10.(9) Abdominal appendage of male short, equal in length to penes. 



Mayerella limlcola (p. 73) 

 Abdominal appendage of male much longer than penes, recurved at tip. 



Mayerella rcdunca (p. 75) 

 11.(9) Pereopod 5 inserted near midlength of pereonite 5. 



Luconacia incerta (p. 68) 



Pereopod 5 mserted in posterior part of pereonite 5 12 



12.(11) Mandibular palp reduced; when 3-segmented, terminal article minute . 13 

 Mandibular palp not reduced, 3-segmented, terminal article not minute. 



14 

 13.(12) Mandibular palp represented by single seta; males with large triangular 

 projection on anteroventral margin of pereonite 2, basis of gnathopod 

 2 with proximal knob on posterior margin. 



Paracaprella pusilla (p. 82) 

 Mandibular palp represented by knob with seta or with several reduced 

 articles; males with small projection on anterolateral margin of pereonite 

 2, basis of gnathopod 2 without proximal knob. 



Paracaprella tenuis (p. 86) 



14.(12) Cephalon with dorsal spine Deutella californica (p. 54) 



Cephalon without dorsal spine Deutella mayeri (p. 54) 



15.(8) Abdomen of male with 2 pairs of appendages, females with 1 pair. 



Hemiproto wigleyi (p. 65) 



Abdomen of male with 3 pairs of appendages, females with 2 pairs , . 16 



16.(15) Carpus of gnathopod 2 longer than merus . . Phtisica antillensis (p. 89) 



Carpus of gnathopod 2 shorter than merus . . . Phtisica marina (p. 91) 



17.(1) Pereopods 3 and 4 1-segmented Hemiaegina minuta (p. 61) 



Pereopods 3 and 4 absent 18 



18.(17) Pereopods 5-7 without grasping spines 19 



Pereopods 5-7 with grasping spines 21 



19.(18) Cephalon with anteriorly directed triangular projection. 



Caprella peuantis variant (p. 35) 



Cephalon without anteriorly directed projection 20 



20.(19) Abdomen of male with hooked papillae at tip of appendage, female with 



small palplike appendage Caprella danilevskii (p. 22) 



Abdomen of male without hooked papillae on appendage, female without 



palplike appendage Caprella unica (p. 49) 



21.(18) Cephalon with large anteriorly directed dorsal spine or projection . . 22 



Cephalon witliout dorsal spine or with nonanteriorly directed spine . . 24 



22.(21) Cephalon with sharp anterodorsally directed spine, males with up to 9 



fused articles in flagellum of antenna 1 . . . Caprella scaura (p. 40) 



Cephalon with anteriorly directed triangular projection, males with less 



than 4 fused articles in flagellum of antenna 23 



23.(22) Palm of propodus of pereopods 5-7 convex . . Caprella andreae (p. 19) 

 Palm of propodus of pereopods 5-7 concave . Caprella penantis (p. 33) 



