THE SPIDER CRABS OF AMERICA 



71 



KET TO THE SPECIE9 OF THE GENUS OREGONIA 



A*. Rostral norns long, parallel, contiguous. Supraorbital arch prominently 

 angled at posterior end. Body, including rostrum, subtriangular. 



gracilis, p. 71. 



A*. Rostral horns short, divergent. Supraorbital arch not prominent nor angled 

 posteriorly. Body suboblong bif urea, p. 79. 



OREGONIA GRACILIS Dana 



DECORATOR CRAB 

 Plates 24 and 25 



Oregonia gracilis Dana, Amer. Journ. Sci., ser. 2, vol. 11, 1851, p. 270 (type- 

 locality, Puget Sound; cotype, Cat. No. 1232, M. C. Z.); U. S. Expl. 

 Exped., vol. 13, Crust., part 1, 1852, p. 106; atlas, 1855, pi. 3, fig. 2a-c.— 

 Rathbun, Proc. U. S. Nat. Mus., vol. 17, 1894, p. 59; Harriman Alaska 

 Exped., vol. 10, 1904, p. 171.— Doflein, S.B., K. Abh. Bayer. Akad. 

 Wiss., math.-phys. Ivlasse, vol. 29, 1899, p. 183. — Holmes, Occas. Papers 

 California Acad. Sci., vol. 7, 1900, p. 19.— Way, Puget Sd. Mar. Sta. Publ., 

 vol. 1, 1917, p. 369, text-fig. 20.— Schmitt, Univ. California Publ. Zool., 

 vol. 23, 1921, p. 198, text-fig. 122. 

 Oregonia hirta Dana, Amer. Journ. Sci., ser. 2, vol. 11, 1851, p. 270 (type- 

 locality, Puget Sound; type not extant); U. S. Expl. Exped., vol. 13, 

 Crust., pt. 1, 1852, p. 107, pi. 3, fig. 3a-b. 

 Oregonia longimana Spence Bate, Proc. Zool. Soc. London, 1864, p. 663 

 (type-locality, Esquimalt Harbor, B. C; type in Brit. Mus.); Lord's 

 Naturalist in Brit. Columbia, vol. 2, 1866, p. 267, plate facing p. 262, fig. 5. 

 Diagnosis. — Rostral horns 

 long, parallel, contiguous. 

 Supraorbital arch prominently 

 angled at posterior end. Body, 

 including rostrum, subtrian- 

 gular. 



Description.- — Surface cov- 

 ered with setae and bunches 

 of longer hairs. Carapace un- 

 evenly tuberculate; cardiac 

 region somewhat depressed; 

 hepatic region with a tuber- 

 culate prominence below the 

 FIG. 19.— Oregonia graci- margin, Postorbital spine re- 

 us^ (17065), M..XILUPED, niotc f rom the ejc, loug, kuceo- 



late, directed abliquelv for- 

 ward, and projecting laterally beyond the eye. Supraorbital 

 border posteriorly dilated and terminating in a dentiform 

 projection. Rostral horns contiguous, sometimes distally diver- 

 gent, slightly arched, curving downward at the extremity, of variable 

 length, often more than half the postfrontal portion of the carapace. 

 Antennae long, often exceeding the rostrum. 



Fig. 20.— O REG o n I a 



GRACILIS, MALE 

 (14705), ABDOMEN, X 

 2.76 



