ISOPODS OF NORTH AMERICA. 



377 



Fig. 409.— a, Head ok Synidotka uitteri 

 b, Head of Synmdotea consolidata. 



SYNIDOTEA RITTERI Richardson. 



Sijnidntea ritteri Richardson, Harriman Alaska Exp. Crust., X, 1904, pp. 219- 

 220; Proc. U. S. Nat. Mus., XXVII, 1904, pp. 063-6(55. 



Locality. — Lands End, San Francisco, California. 

 Body ovato in outline. Color 3'ellow, with markings of black; 

 terminal seg'nient almost entirel 3^ black. 



Mead with prominent rounded antero-lateral angulations, at }>ase of 

 whicli, and just above the eyes, is a conspicuous horn-like projection, 

 hook-shaped, directed upward and 

 forward, one on either side of the 

 head. In the median excavation of 

 the frontal margin on either side of 

 the median line is a prominent 

 tubercle. Between the eyes and in 

 line with them on the posterior por- 

 tion of the head are two low tubercles. The eyes are situated at the 

 extreme lateral margins on the posterior portion of the head, and are 

 somewhat elevated above the surface; they are black and conspicuous, 

 and c()m})osed of niany ocelli. The tirst pair of antenna? consist of 

 four joints, the last joint clavate and fringed with hairs. The second 

 pair of antenna? have a live-jointed peduncle 

 and a llagellum composed of eight joints; the 

 third joint of the peduncle has a prominent 

 tubercle. 



The first four segments of the thorax are 

 longer than the last three. The lateral parts of 

 all the segments are widely expanded, w ith mar- 

 gins well rounded. The lateral parts are not 

 separated from the dorsal portion of the seg- 

 ments, but are lirmly anch3dosed. 



The abdomen consists of one segment, with 

 suture marks, one on either side, indicative of 

 another partly coalesced segment; it tapers 

 gradually to a broadly rounded extremity, which 

 is slightly excavate in the median line. 



The seven pairs of legs are but sparingly fui'- 

 nished with hairs. The upper iialf of the 

 opercular valve is black, the lower half yellow\ 

 There are three longitudinal lines of low swellings on the body, one 

 median, the other two placed one on either side of the m(Hiian line. 



Only one specimen was taken at Lands End, California, by Doctor 

 Ritter and part3^ 

 This species is closely allied to Synidotea consolidata (Stimpson)," 



Fig. 410.— Synidotea kit 

 TERI. X 10. 



«Proc. Cal. Aoad. Sci., I, 1856, p. 97; Bost. Jour. Nat. Hist, VI, 1857, \,. 503. 



