No. 1633. 



SOME NEW ATLANTIC ISOPODA— RICHARDSON. 



75 



lolella; between the post-lateral expansions is a small rounded lobe. 

 The uropoda are lost in the only specimen. 



The first pair of legs are prehensile, the other six ambulatory in 

 character and furnished with bi-unguiculate dactyli. The margins 

 of the entire body are armed with minute acute spinules. 



The only specimen, a female, was found at Station 2572, steamer 

 Albatross, southeast of Georges Bank, at a depth of 1,769 fathoms. 



The type is in the U. S. National Museum, Cat. No. 38964. 



Genus HAPLONISCUS, new. 



Head without rostrum. First pair of antennas with the peduncle 

 composed of only two articles ; flagellum composed of several articles ; 

 second antennas with the peduncle com- 

 posed of six articles, the third article fur- 

 nished with an antennal scale. Eyes ab- 

 sent. 



Terminal segment of body with posterior 

 median lobe, on either side of which is a 

 small triangular process; uropoda small, 

 consisting of a single article. 



The legs are all ambulatory, similar, 

 with dactylus uni-unguiculate. They are 

 alike in both sexes. 



This genus differs from Nannoniscus 

 Sars, its closest ally, in lacking the large 

 median lobe of the head, in not having an 

 olfactory papilla to the first antenna, in 

 the differently shaped abdomen, and in 

 having the uropoda composed of a single 

 article and not double-branched as in that 

 genus. 



The type of the genus is Nannoniscus fig. 4.— haploniscus ex- 

 bicuspis Sars. a In 1899, Sars admitted CISDS - 

 that this species was not congeneric with the type species of the genus 

 Nannoniscus, but allowed it to remain there. 



The following species also belongs to this genus and is very similar 

 to Sars's species. 



HAPLONISCUS EXCISUS, new species. 



Body oblong-ovate, a little less than twice as long as wide. Color 

 in alcohol whitish. Surface smooth. 



a Norwegian North- Atlantic Expedition, XIV, Zoology, Crustacea, I, 1885, pp. 

 122-123. 



