ISOPODS 219 



IDOTEA STENOPS Benedict. 



Idotea stenops BENEDICT, Proc. Biol. Soc. Wash., XII, pp. 54, 55, 1898. 

 RICHARDSON, Proc. U. S. Nat. Mus., xxi, p. 846, 1899. 



Locality not given (Dr. Ritter and party). 



IDOTEA OCHOTENSIS Brandt. 



Idotea ochotensis BRANDT, Middendorff's Sibirische Reise, II, Pt. I, Crust., 

 p. 145, pi. VI, fig. 33, 1851. MIERS, Jour. Linn. Soc. London, XVI, 

 pp. 32-34, pi. i, figs. 8-10, 1883. RICHARDSON, Proc. U. S. Nat. Mus., 

 xxi, p. 846, 1899. 



Localities. Lands End and Fort Point, California (Dr. Ritter and 

 party). Humboldt Bay on Popof Island, Alaska (Harriman Alaska Ex- 

 pedition). 



SYNIDOTEA RITTERI sp. nov. 



Type from Lands End, San Francisco, Calif. 



Body ovate in outline. Color yellow, with markings of black ; terminal 

 segment almost entirely 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 portion 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 antennas 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 margins 

 well rounded. The 

 lateral parts are not 

 separated from the 

 dorsal portion of the 

 segments, but are 



FIG. 99. a. Head of Synidotea ritteri sp. nov. (X 14)- 

 firmly anchylOSCd. b. Head of Synidotea consolidate (Stimpson) (X *4>- 



The abdomen consists of one segment, with suture marks, one on 

 either side, indicative of another partly coalesced segment. The abdo- 



