FISHERY BULLETIN: VOL. 83, NO. 1 



somedian carina delimited ventrally by depres- 

 sion lying just dorsal to well-defined cicatrix. 



Telson with pair of small but well-developed 

 fixed spines. Rami of uropod subequal in length 

 and falling slightly short of or overreaching apex 

 of telson by no more than 0.10 its own length. 



Petasma (Fig. 33A , B ) with short distal plate of 

 dorsomedian lobule bearing distolaterally small, 

 scalelike process bent inwardly (posteroven- 

 trally). Projection of distolateral lobule acicular, 

 extremely long, about 0.75 as long as body of 

 lobule, with heavily sclerotized triangular plate 

 proximodorsally and flexible flagellum arising 

 from ventrolateral surface; flagellum long, reach- 

 ing between 0.60 and 0.75 length of projection 

 from level of apex of triangular plate. Projection of 

 ventrolateral lobule also long, about half length of 

 acicular projection, bladelike and flexible, except 

 for sclerotized tip curving proximally. 



Petasmal endopods coupled in males with 

 carapace length as little as 5.5 mm, about 22 

 mm tl, but sometimes unjoined in individuals 

 with carapace length as much as 11 mm, about 39 

 mm tl. 



Appendix masculina as illustrated in Figure 

 33C. 



Thelycum (Fig. 34) with plate of sternite XIV 

 raised in paired, well-marked, elongate bulges 

 sloping toward deep, narrow, median depression. 

 Median plate of sternite XIII lanceolate, tapering 

 gradually into slender spine reaching as far as 

 proximal 0.20 of basis of extended second 

 pereopods; posterior component with relatively 

 shallow posteromedian emargination (occasion- 

 ally replaced by longitudinal incision) often form- 

 ing small notch anteriorly, and flanked by short, 

 rounded, posterolateral processes marked basally 

 by deep transverse suture. Sternite XI armed 

 posteriorly with pair of broad based, acute spines. 

 Posterior thoracic ridge with anteromedian mar- 

 gin sharp and raised (ventrally), its lateral mar- 

 gins usually well marked, occasionally flush with 

 plate of sternite XIV. 



The smallest impregnated female encountered 

 has a carapace length of 8.5 mm, about 33 mm tl. 



Color. — Available information based on speci- 

 mens that had been recently caught in the Gulf of 

 California is limited to a purplish brown spot, 

 with a yellow center not sharply defined, postero- 

 ventral to the hepatic spine; sometimes the entire 

 spot is purplish brown (Anonymous 1980). Lock- 



FlGURE 33. — Sicyonia penicillata, 6 21.5 mm cl, west of Punta T^sca, Isla Santa Margarita, Baja California Sur, Mexico. 

 A, Petasma, dorsal view; B, ventral view of same; C, right appendix masculina, dorsolateral view. Scale = 1 mm. 



40 



