74 



PROCEEDINGS OF THE NATIONAL MUSEUM. 



VOL. XXXV. M 



The differences between Rhacura and Iolella are greater than those 

 between Iolanthe and Acanthaspidia and seem to warrant keeping 

 them apart. 



Type of the genus. — Rhacura pulchra, new species. 



RHACURA PULCHRA, new species. 



Body oblong-ovate, about twice as long as 

 wide. Dorsal surface covered with granulations. 



Head much wider than long, wi-th the front 

 produced in the middle in an obtuse triangular 

 process, which does not extend as far as the 

 antero-lateral processes; the lateral margins 

 are drawn out on either side in two acute tri- 

 angular processes, both directed anteriorly ; the 

 posterior one is slightly narrower than the an- 

 terior process. The eyes are minute and are 

 ^ situated closer to the posterior margin than to 

 the anterior margin. The first pair of antenna? 

 have the first article of the peduncle largest; 

 the second and third are subequal and are a 

 little shorter than the first; the flagellum is 

 composed of eighteen articles. The second pair 

 of antenna? are broken at the fourth article of 

 the peduncle in the only specimen; the third 

 article is furnished with an antennal scale. The maxillipeds have the 

 first three articles of the palp expanded and dilated. 



The first segment of the thorax has the lateral 

 margins drawn out on either side in one triangu- 

 lar expansion, acute at the extremity and di- 

 rectly anteriorly; the second and third segments 

 have the lateral margins drawn out on either 

 side in two triangular expensions, about equal in 

 width, one anterior and the other posterior; the 

 fourth segment has one triangular expansion to 

 the lateral margin on either side; the fifth and 

 sixth segments have the lateral margins drawn 

 out on either side in two triangular expansions 

 of about equal size ; the seventh and last segment 

 of the thorax has the lateral margins drawn out 

 in three triangular processes on either side, all 

 of equal size. 



The abdomen has the lateral margins drawn 

 out on either side in four triangular expansions, the last expansion 

 corresponding to the post-lateral expansion in the species of the genus 



Fig. 2. — Rhacura pul 

 chra. 



Rhacura pul- 

 Maxilliped. 



