Pinnixa sayana Stimpson 



Figure 195 



Pinnixa sal/ana Stimpson, 1860a, p. 236 ; Rathbun, 1918b, p. 

 15,6, text-fig. 98, pi. 34, figs. 2-4 (rev.). — Hay and Shore, 1918, 

 p. 446, pi. 36, fig. 3. 



Recognition characters. — Carapace smooth, pol- 

 ished, lightly pubescent on sides, depressed at 

 middle, a low, ill-defined, transverse ridge parallel 

 with and close to posterior margin extending 

 about one-third width of carapace. Anterolateral 

 slope with similar ridge, lateral two-thirds of 

 crest beaded. Front deeply grooved above. 



Chelipeds with hands stout, compressed, hardly 

 twice as long as broad; immovable finger very 

 short, with truncate basal tooth; dactyl strongly 

 curved. Walking legs long and slender, smooth; 

 first walking leg reaching to propodus of second ; 

 second and third leg same length ; fourth reaching 

 beyond middle of carpus of third ; merus of third 

 leg approximately 3.5 times as long as w T ide, lower 

 margin, and that of propodus, minutely denticu- 

 late; dactyls of first two legs slightly curved, of 

 third straight, posterior edge, of last dactyl 

 slightly convex. 



Measurements. — Carapace : male, length, 5 mm., 

 width, 10 mm.; female, length, 4 mm., width, 

 7 mm. 



Variations. — Females differ from males in that 

 the cardiac ridge is lower and less sharp, the fin- 

 gers do not gape, the immovable finger is longer 

 and less bent, and the dactyl on the chela is more 

 oblique. 



Color. — Almost white, but lightly stained with 

 brown. 



Figure 195. — Pinnixa sayana Stimpson. Male in dorsal 

 view, legs of left side uot shown, 1 mm. Indicated. 



Habitat. — The species has been found free in 

 the water, has been dug out of mud, and is said 

 to be found in the tubes of Arenicola cristata; 

 shore to 26 fathoms. 



Type locality. — Mouth of Beaufort Harbor, 

 N.C., 6 fathoms, sandy mud. 



Known range. — Vineyard Sound, Mass., to 

 Beaufort, N.C. ; Sarasota Bay, Fla., to Grand Isle, 

 La. 



Remarks. — Ovigerous females have been re- 

 ported in August from Narragansett Bay, R.I. 

 (Rathbun, 1918b), and are known in September 

 from Louisiana. The last zoeal stage of a Pinnixa, 

 commonly found off the New England coast and 

 described by Faxon (1879), was tentatively re- 

 ferred to this species by Smith (1880a). Both 

 Faxon and Smith found the first crab stage to fol- 

 low immediately the last zoeal stage. These stages 

 in development of P. sayana were summarized and 

 illustrated by Hyman (1924a). 



Pinnixa retinens Rathbun 



Figure 196 



Pinnixa retinens Rathbun, 1918b, p. 139. text-figs. 83-84, 

 pl. 41, figs. 1-2. 



Recognition characters. — Carapace nearly twice 

 as wide as long, almost flat, except sloping down- 

 ward toward margins; regions indicated. Lateral 

 margin marked by sharp, granulate ridge reach- 

 ing to subhepatic sulcus, no cardiac ridge; postef- 

 rior margin preceded by a subparallel groove. 

 Outer maxilliped with obliquely spatuliform 

 dactyl attached to middle of inner margin of 

 propodus. 



Chelipeds small, approximately as long as first 

 leg; hand with lower margin straight, suboblong, 

 marginate below; fingers slender, subequal, not 

 gaping; dactyl with tooth at proximal third of 

 gripping edge. First and second walking legs 

 similar; second a little longer, dactyls slightly 

 curved, long, pointed. Third walking leg stout, 

 exceeding second by length of dactyl and half of 

 propodus; lower edge of ischium, merus, and pro- 

 podus armed with stout spinules; posterodistal 

 end of ischium prolonged in a stout, curved spine 

 with point directed upward and backward; dactyl 

 more curved than in first and second legs, pointed. 

 Last leg extending to distal end of third merus; 

 dactyl stout, nearly straight, tip curved slightly 

 upward. 



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