1 cm. 



Figure 5. — Penaciis (L.) seti- 

 fcrus (L. ). Ceplialothorax, 9 

 41.5 mm. c.l., off Cocoa Beach, 

 Fla. 



length of petasma. Distoventral comer of lateral 

 lobe rounded and with nearly symmetrical S- 

 shaped ridge on free border; anterior half of ven- 

 tral border with two narrow ribs joined at both 

 ends. Emargination median to imier lappet shal- 

 low. Outer surface of lateral lobe with relatively 

 narrow band of spines, three to four, rarely five, 

 rows abreast distally and decreasing to one or two 

 proximally. Pair of crests flanking band of spines 

 distally, crest close to median lobe more prominent 

 and sharp than crest near free ventral margin; 

 latter crest plain, not bifurcated. Lateral lobe at 

 ahnost same level as median lobe, extended only 

 slightly anteriorly. 



APPENDIX MASCULINA (fig. 9 d, e) 



Subtriangular, its length almost twice width at 

 base, and armed with shoit spines along distal 

 portion of median margin and with long spines on 

 distal portion ; distal spines slightly less than half 

 length of appendix. Anterior surface subplane, 

 postei'ior surface strongly concave, concavity 

 bordered by strong arch-shaped ridge. 



SPERMATOPHORE 



Elongate, podlike, actually consisting of two 

 spennatophores ; in mature males each lying com- 

 pletely formed in paired terminal ampullae and 

 joined when discharged. Anterior end, when at- 

 tached to female, bearing pair of winglike lateral 

 processes, each armed ^vitll short triangular pro- 

 jection at posterior edge. Post^rodorsal portion ex- 

 tended into horizontal plate. 



THELYCUM (fifes. 10 and 11) 



Open type. Stemite XIV with two anterolateral, 

 prominent and sharp ridges; posterior portions 

 of ridges converging mesially but not meeting near 

 middle of sternite; occasional sharp, short rib 

 present between converging ridges. Posterior por- 

 tion of sternite XIV with pair of conspicuous, 

 closely set, anteriorly produced, fleshy, usually 

 light-colored lobes, separated in large individuals 

 by low median rib. Sternite XIII with strong 

 median plate extending posteriorly as fleshy, 

 emarginated, shelflike projection overhanging 

 sternite XIV; ridge on posterior margin of plate 

 moderately strong; on anterior portion of sternite 

 XIII, fleshy tonguelike lamella bordered by 

 minute setae fonning floor of cavity roofed by 

 strong transverse ridge on posterior margin of 



474 



U.S. FISH AND WILDLIFE SERVICE 



