I80PODS OF NORTH AMERICA. 



377 



FIG. 409. a, HEAD OF SYNIDOTEA RITTERI. 

 6, HEAD OF SYNIDOTEA CONSOLIDATA. 



SYNIDOTEA RITTERI Richardson. 



Synidotea ritteri RICHARDSON, Harriman Alaska Exp. Crust., X, 1904, pp. 219- 

 220; Proc. U. S. Nat. Mus., XXVII, 1904, pp. 063-665. 



Locality. Lands End, San Francisco, California. 

 Body ov 7 ate in outline* Color yellow, with markings of black; 

 terminal segment almost entirety black. 



Head with prominent rounded antero-lateral angulations, at base of 

 which, 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 composed of many ocelli. The first pair of antennae consist of 

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

 pair of antennae have a five-jointed peduncle 

 and a flagellum 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, with mar- 

 gins well rounded. The lateral parts are not 

 separated from the dorsal portion of the seg- 

 ments, but are firmly anchylosed. 



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 fur- 

 nished with hairs. The upper half 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 median line. 



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

 Ritter and party. 

 This species is closely allied to Synidotea consolidates (Stimpson), 



FIG. 410. SYNIDOTEA RIT- 

 TEKI. x 10. 



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



