DESCRIPTION OF A NEW ISOPOD CRUSTACEAN BELONG- 

 ING TO THE GENUS LIVONECA FROM THE ATI^NTIC 

 COAST OF PANAMA. 



By Harriet Richardson, 



Collaborator, Division of Marine Invertebrates, United States National Museum. 



Two specimens, representing a new species of Livoneca, were col- 

 lected in January, 1911, by Dr. S. E. Meek, of the Field Museum of 

 Natural History, and Mr. S. F. Hildebrand, of the United States 

 Bureau of Fisheries, who were connected with an expedition sent out 

 under the auspices of the Smithsonian Institution for a biological 

 survey of the Panama Canal Zone. The description of the new 

 species is herein given. 



LIVONECA LONGISTYLIS, new species. 



Body ovate, a little more than twice as long as wide, 13 mm.: 

 6 mm. Color light brown, marked with numerous black dots and 

 arborescent markings. 



Head a httle wider than long, 2 mm.: 1| mm., subtriangular in 

 shape with the front widely rounded. Eyes large, black, ovate, 

 composite, situated in the post-lateral angles of the head and extend- 

 ing from the posterior margin to the middle of the head. The first 

 pair of antennae are composed of eight articles and extend the length 

 of the last two articles beyond the posterior margin of the head. The 

 second pair are composed of eight articles and are equal in length to 

 the first. 



The first, fifth, and sixth segments of the thorax are of equal length, 

 being about H mm. in length; the second, third, fourth, and seventh 

 "segments are subequal, being each about 1 mm. long. The epimera 

 do not quite reach the posterior margin except in the last segment. 

 The thorax becomes gradually wider from the first segment to the 

 fifth, and then becomes gradually narrower again. 



The first five segments of the abdomen are short and subequal, each 

 being almost one-half mm. in length, although the fii-st is a little 

 shorter and the fifth a little longer than the other three. The length of 

 all five segments is 2 ^ mm . The lateral parts of these segments are pro- 



Proceedings U.S. National Museum, Vol. 42— No. 1891. 



173 



