662 



PROCEEDINGS OF THE NATIONAL MUSEUM. 



VOL. XXVII. 



Fig. 2.— Idotea gracilli.ma (Dana). 



are described as bein^ a little shorter than half the body, with a ten 

 to twelve jointed flagellum. 



No figure of the form has ever been given. 



A species of Idotea was sent to the U. S. National Museum b}- Dr. 

 Kitter. The specimens, which are eight in number, were collected b}^ 



him at Bolinas, California. The}^ are 

 more closely- allied to I. gmcilUma than 

 to any other known species of Idotea 

 from the Pacific coast of North America. 

 Until evidence can be given of their dis- 

 tinctness, 1 shall consider them identical 

 with /. graciUiina. 



Description. — Bod}^ slender, about 

 seven times longer than wide,** with the 

 sides nearly parallel. Surface entirely 

 smooth; color in alcohol uniformly pink- 

 i.sh. A note referring to the color of the 

 specimens in life states that they are 

 green, brown, and striped. 



Head quadrate, with rounded antero- 

 lateral margins, and a slight median ex- 

 cavation in the anterior margin. Eyes 

 situated at the extreme lateral edge and 

 about the middle of the head; they are small, but distinct. The first 

 pair of antennae are four-jointed and extend a little beyond the extrem- 

 ity of the second peduncular joint of the second pair of antenna*. The 

 second pair of antennte are equal to half the length of the body; the 

 last two joints of the peduncle 

 are subequal; in the smaller 

 specimens the flagellum is com- 

 posed of ten joints; in the larger 

 ones there are eighteen joints. 



The first thoracic segment is 

 short in the middle but is pro- 

 duced antero-laterally on either 

 side; it is not wider than the 

 head. The second, third, and 

 fourth segments are subequal in 

 length, and are longer than the 



first segment. The fifth, sixth, and seventh segments gradualh^ 

 decrease in length. The epimera of all the segments are extremely 

 narrow; those of the second and third segments extend but half the 

 length of the segment; those of the fourth and fifth segments extend 

 three-fourths the length of the segment; those of the last two segments 

 extend the entire length of the segment. 



Fig. 3. — Abdome.n' of Idotea GRAfii.i.iMA, .showing 



VARIATIONS. 



" The female is figured. The body is somewhat broader than in the male. 



