FISHERY BULLETIN; VOL. 77. NO. 4 



ing crest; rib of dorsolateral lobule terminating 

 proximally in flattened subrectangular process. 

 Ventrolateral lobule with distolateral portion 

 broadly rounded, its rather flexible marginal 

 part narrow and turned inwardly; ventral costa 

 curving abruptly dorsomesially and ending in 

 relatively broad process (with interior surface 

 excavate) reaching approximately to level of cin- 

 cinnuli; costa bearing ventral (inner) row of setae 

 along attached margin. 



Appendix masculina (Figure 32C,D) consider- 

 ably broader tham long (width 1.7 to almost twice 

 length), subelliptical, convex mesially, flat later- 

 ally, and bearing mesial patch of setae. 



Petasmal endopods becoming joined in male 12 

 mm cl. Armature of sternites XIII and XIV in very 

 small juvenile male (discussed on p. 723) illus- 

 trated in Figure 33. 



Thelycum (Figure 34) with anterior border of 

 plate of stemite XIV slightly to strongly inclined 

 posterolaterally, broadly arched on each side of 

 posteromedian projection of sternite XIII; plate of 

 stemite XIV with anterolateral extremities pro- 

 duced laterally into lobules of variable lengths, 

 and lateral portions setose and raised (ventrally), 

 slanting dorsomesially toward corresponding, 

 narrow, submedian depression; median ridge usu- 

 ally ovoid or tear-shaped, sometimes subtriangu- 



FIGURE 34.— Penaeopsis serrata, 9 29.5 mm cl, Dry Tortugas 

 Islands, Florida. Thelycum, ventral view. Scale = 1 mm. 



Figure 33.— Penaeopsis serrata, 3 10 mm cl, NE of Puerto Rico. 

 Somites XII-XTV, ventral view. Scale = 1 mm. 



lar, greatly raised except for short, low, anterior 

 part abutting projection of sternite XIII, and 

 naked posteriorly; posterior thoracic ridge also 

 lacking setae. Median plate of stemite XIII broad, 

 subsemicircular, cordiform or roughly pentag- 

 onal, with transverse depression across its entire 

 width, bearing or lacking minute anteromedian 

 spine, and covered with densely set setae an- 

 teriorly; posteromedian projection strongly de- 

 veloped, broad, with posterior margin slightly 

 emarginate to deeply bifid and studded with 

 numerous posteriorly pointed setae. Sternite XII 

 bearing posteromedian subconical tooth, its apex 

 pointed ventrally or anteroventrally; oblique pair 

 of ridges extending posterolaterally from base of 

 tooth. 



Seminal receptacles (Figure 35A, B) consisting 

 of paired bilobed membranous sacs, derived from 

 invaginations of sternite XIV. Submedian sac 

 large, extending posteriorly to rather near caudal 

 margin of sternite XIV, other smaller one extend- 

 ing laterally; both diverging from broad an- 



754 



