1897.] 



NATURAL SCIENCES OF PHILADELPHIA. 



393 



smaller than those of bicuspida; a larger series might change this. 

 The largest male S. marmorata measures 18 mm. in length and 7 

 mm. in width. A male S. bicuspida of about equal size, measures 

 17 mm. in length and 8 in width. 



Synidotea consolidata (Stimpson). Fig. 3. 



Idotea consolidata Stimpson, Proc Cal. Acad. Sci , I, p. (89) 97, 1856, 

 also Boston Jour. Nat. Hist., VI, p. 503, 1857. 



Edotia bicuspida (nee Idotea bicuspida Owen) Miers, Jour. Linn. Soc. Lond., 

 XVI, p. 66, 1883 (pars). 



Two specimens of this species, labelled 

 'Pacific Grove, California,' were received 

 from Mr. J. O. Snyder. 



The front is emarginate, the median notch 

 is large. The deep excavation of the front 

 in S. bicuspida is in sharp contrast to the 

 nearly straight front of this species. Be- 

 hind the frontal notch is a pair of large, 

 blunt tubercles transversely placed. The 

 lateral margins of the thorax are subparallel 

 in the male and strongly arcuate in the fe- 

 male. The margins are incised in this spe- 

 cies ; in bicuspida they are full. There is a 

 line of low swellings on the median line and 

 another line of like swellings part way be- Fig 3. Synidotea con- 

 tween the median line and the margin. The solidata (Stimpson). xf.* 

 abdomen is much like that of bicuspida. 

 Synidotea laticauda, new species. Fig. 4. 



A single specimen of Synidotea 

 was taken by Mr. C. H. Townseud 

 in San Francisco Bay ; it is readily 

 distinguished from any species yet 

 described. 



The head is wider than long, the 

 anterior margin is nearly straight 

 and is slightly produced horizon- 

 tally ; its whole upper surface is 

 evenly swollen and has neither ele- 

 vations nor depressions of any kind ; 

 the cephalic lobe is little more than 

 indicated. The eyes are large, 

 round, lateral and but very slightly 

 projecting. The antenna? are equal 



Fig. 4. Synidotea laticauda 

 Benedict, x 2J 



* Incorrect. The antennae should be placed as in the others and show 

 seven or eight joints in the flagella. 



