508 Stimpson on the Crustacea and Echinodermata 



most interesting additions to the fauna of Washington 

 Territory. 



Mus. Smithsonian. 



LIVONECA VULGAKIS. Stimpson. 



PL XXII. f. 9. 

 Livoneca vulgaris, Stimpson ; Proc. Bost. Soc. Nat. Hist. vi. 88. 



This is the common fish-louse of the San Francisco mar- 

 ket. It is variable in shape, often distorted, and frequently 

 abruptly widened at the fifth thoracic segment. Head 

 small, wider than long ; inner antennae somewhat shorter 

 and stouter than the outer or posterior ones. Epimeral 

 pieces narrow, separated from the tergal piece in the ante- 

 rior segments by a distinct suture, in the posterior segments 

 by a deep incision ; the point reaching the margin of the 

 tergum in the anterior four segments, and not extending 

 much beyond it in the posterior three. Posterior thoracic 

 segment deeply sinuated for the reception of the middle 

 portion of the anterior abdominal segments. Lamelliform 

 caudal segment always transverse in the adult. Color yel- 

 lowish gray ; posterior pair of false feet always black. 

 Length, 1.5 ; breadth, 0.9 inch. It resembles L. Desmarestii 

 in general appearance. 



Parasitic on fish of several kinds. Tomales Bay, (Sam- 

 uels ;) San Francisco Bay, (Stimpson;) Monterey, (Trow- 

 bridge.) 



Mus. Smithsonian ; Bost. Soc. 



JEGA MICROPHTHALMA. Dana. 

 iEga microphthalma, Dana; Proc. Acad. Nat. Sci. Pldlad. 1854. vii. 176. 



Hab. " California," (Le Conte ;) Monterey, (Taylor.) 

 Mus. Smithsonian. 



The body in this species is generally considerably broader 

 in the young than in the adult. Upper surface covered with 



