214 University of California Publications in Zoology [Vou 23 
Scyra acutifrons Dana 
Scyra acutifrons Dana, Amer. Jour. Sci. (2), 11, 269, 1861; Crust. U. S. 
Expl. Exped., 1, 95, 1852, pl. 2, fig. 2, 1855; Holmes, Occas. Papers 
Calif. Acad. Sci., 7, 41, 1900; Rathbun, H. A. E., 10, 175, 1904; Wey- 
mouth, Stanford Univ. Publ., Univ. Ser., no. 4, 33, pl. 6, fig. 17, 1910; 
Way, Puget Sd. Mar. Sta. Publ., 1, 371, fig. 27, 1917. — 
a b 
Fig. 134. Scyra-acutifrons, g; a, dorsal view, X 44; b, ventral view of an- 
terior portion, X 34% (after Dana). 
Characters.—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; cardiae region with a large tubercle; a smaller one on the 
intestinal region. Rostrum 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—F rom Kadiak, Alaska, to San Diego, California. Low tide to 
40 fathoms (Rathbun). 
Remarks.—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 ecara- 
pace; the horns of the rostrum become widened at the base; the chelipeds are 
