214 University of California Publications in Zoology [Vol. 23 



Scyra acutifrons Dana 



Scyra acutifrons Dana, Amer. Jour. Sci. (2), 11, 269, 1861; Crust. U. S. 

 Expl. Exped., 1, 95, 1852, pi. 2, fig. 2, 1855; Holmes, Oecas. Papers 

 Calif. Acad. Sei., 7, 41, 1900; Eathbun, H. A. E., 10, 175, 1904; Wey- 

 mouth, Stanford Univ. Publ., Univ. Ser., no. 4,' 33, pi. 6, fig. 17, 1910; 

 Way, Puget Sd. Mar. Sta. Publ., 1, 371, fig. 27, 1917. 



a , o 



Fig. 134. Scyra acutifrons, J 1 ; a, dorsal view, X %; o, ventral view of an- 

 terior portion, X 3% (after Dana). 



Cliaracters. — Carapace furnished with rounded tubercles; gastric region with 

 an acute tubercle near the center, behind which is a larger and more obtuse 

 tubercle; branchial regions bearing a large projecting tubercle, in front of which 

 is an elevated prominence, which may bear several small tubercles though often 

 it is quite smooth ; cardiac region with a large tubercle ; a smaller one on the 

 intestinal region. Bostrum short, horns ovate-lanceolate, about one-quarter the 

 length of the carapace. Chelipeds of male large, hand long, narrow, compressed, 

 palm below the wide carina often inflated ; fingers deflexed and in old males gaping 

 at base, in which case there is generally a large tooth near the base of the 

 movable finger. 



Dimensions. — Type, male: length of carapace 27.5 mm., width 18 mm. 



Color. — Dull, usually gray or tan with more or less red on chelipeds and walk- 

 ing legs; usually so encrusted with bryozoans that it is difficult to see the color. 

 Like other spider crabs, they are usually covered with a variety of decorative 

 materials. Sponges, hydroids, and bryozoans are used by them more than algae 

 (Way). 



Type Locality. — Oregon. 



Distribution. — From Kadiak, Alaska, to San Diego, California. Low tide to 

 40 fathoms (Eathbun). 



Bemarks. — The individuals of this species vary considerably with age. In 

 old males the tubercles on the carapace are rougher and more prominent, the 

 posterior tubercle on the branchial region projecting over the sides of the cara- 

 pace; the horns of the rostrum become widened at the base; the chelipeds are 



