DESCRIPTIONS OF NEW ISOPOD CRUSTACEANS OF THE. 

 FAMILY SPH^EROMID^. 



By Harriet tiicHARDSON, 



Collaborator, Division of Marine Invertebrates. 



In order to give fuller diagnoses of some genera recent!}^ established 

 in my monograph on the Isopods of North America and to illustrate 

 some of the parts which were taken as a basis of generic distinctions 

 I have prepared the following- paper, in which I also offer descriptions 

 of a few new species and one new genus. Five of the species are 

 from South America, two are from Japan, one comes from Cape 

 Town, Africa, and the localit}' of another is unknown. All, with 

 the exception of Isodadus magellanensiH^ are in the collection of the 

 United States National Museum. 



Genus TECTICEPS Richardson. 



Body oval and somewhat flattened. Head sulxjuadrangular, broader 

 anteriorly than posteriorly with the anterior and lateral margins pro- 

 duced, concealing the antenna?. 



The antenuc^. which are entirely hidden, extend backward and lie 

 under the epimeral plates at the sides of the thorax. The first and 

 second pairs of legs in the male are subchelate; the first pair termi- 

 nate in a large hand and finger, bearing a small hook; the second pair 

 terminate in a more irregularly shaped hand. All the other legs are 

 simple in structure. In the female onl}^ the first pair of legs are 

 subchelate. 



The terminal segment of the abdomen is triangular and entire, and 

 is pointed at the extremity. The uropoda are double- branched and 

 lateral, and resemble closely those of the genus Sphxroma. Both 

 branches are well developed and similar in shape. 



This genus differs from the genus Ancinus of Milne Edwards — 



1. In having uropoda with two branches instead of one. 



2. In having the abdomen entire and not truncate at the tip. 



3. In the prominent projection of the anterior and lateral margins 

 of the head. 



4. In the concealment of the antennae, which are very conspicuous 

 in Ancinus. 



The type species of the genus is Tecticeps alasceitsis Richardson. 



Proceedings U. S. National Museum, Vol. XXXI— No. 1479. 

 Proc. N. M. vol. xxxi— 06 1 1 



