ISOPODS OF NORTH AMERICA. 



357 



Fifi.;W4.— Idothea gkacili.ima. x 5. 



filiform, the tlioracic scj^iuents subquadratc, liead quadrate. He refers 

 to the linear post-abdoraen, which is truncated at the apex, three- 

 jointed, and marked on either side with a suture. The antennjv are 

 described as being- n little shorter than 

 half the body, with a ten- to twelve- 

 jointed flao-ellum. 



A species of Idotlwn was sent to the 

 U. S. National Museum by Doctor Hit- 

 ter. The specimens, which are eight in 

 number, were collected by him at Boli- 

 nas, California. They are more closely 

 allied to 7. gvaclUiina than to any other 

 known species of Idotliea from the Pacitic 

 coast of North America. Until evidence 

 can be g-iven of their distinctness, 1 shall 

 consider them identical with /. gracil- 

 linia (Dana). 



Bod}' slender, about seven times 

 longer than wide," with the sides nearly 

 parallel. Surface entirely smooth. 

 Color in alcohol uniformly pinkish. A 



note referring to the color of the sj)ecimens in life says that they are 

 green, brown, and striped. 



Head quadrate, with rounded antero-lateral margins, and a slight 

 median excavation 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 

 antenna? are four-jointed, and ex- 

 tend a little beyond the extremity 

 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 pedun- 

 cle are subequal; in the smaller 

 specimens the flagelliun 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 produced 

 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. Tlie fifth, sixth, and seventh segments 

 gradually decrease in length. The epimeni 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 



Fig. 385. — Idothea gracillima. Abdomk.n, show 

 ing vakiations in form. 



«The female is? figured. The bodv is somewhat broader than in the male. 



