DUEING THE « CHALLENGES ' EXPEDITION. 



93 



the natatory branch (fig. 3) are as follows : * 1 1 i\'w ^ u ^ > the seta, attached 

 to the second, third, fourth, and fifth joints are extremely short, equal in length, and 

 are armed with short stout spines along their outer margins (figs. 3, 4) ; the seta? of 

 the last four joints are from three to four times as long as the preceding and are not 

 spinous ; secondary branch simple, curved, one-jointed. The mandibular foot is four- 

 jointed, and is in the male (fig. 7) devoid of any masticatory process, but bears 

 numerous simple set*; in the female the first joint bears a bifid process, and the 

 second has, in addition to several simple setae, a small bisetose finger-like process at its 

 distal end (fig. 8). The first maxilla (fig. 6) consists of one stout principal lobe with 

 four smaller lobes, all of which are setiferous, most of the stouter setae having one of 

 the margins strongly denticulated : the principal lobe is two-jointed, the last joint 

 small and giving attachment to about six apical setae, which are graduated in size from 

 the first to the last and bear strong marginal teeth. The vermiform limb has a single 

 claw-like process at its apex. Caudal lamina? (fig. 10) short; the first three marginal 

 appendages consisting of very short slender setae, the fourth an unguiform spine about 

 twice as long as the preceding setae and very much stouter ; then follows another small 

 seta, then a second stout unguis about twice as long as the first, and lastly a third 

 unguis which is more than twice as long as the second. Eyes small, deep red, the 

 lenses irregularly placed and of very unequal size; in the male subrenifonn (fig. 11), in 

 the female smaller and globose. 



My first description of this genus was deficient in any account of the soft parts of 

 the animal, but I have recently by careful maceration of some of the dried shells been 

 able to obtain preparations which show, though imperfectly, some of the more 

 important structures. These are certainly sufficiently characteristic, and even apart 

 from the shell would constitute a valid generic distinction. 



The specimens were obtained from various localities among the South Sea Islands. 



Genus Sarsiella, Norman. 

 Saesiella sculpta, G. S. Brady. (Plate XVII. figs. 12, 13.) 



1888. Sarsiella sculpta, G. S. Brady, " Ostracoda collected in the South Sea Islands/' Traus. Roy. 

 Soc. Edinb. vol. xxxv. p. 517, pi. i. figs. 17-20. 



The original description of this species was taken from the shell only, but I have 

 recently succeeded in finding remains of the soft parts in a specimen taken by the 

 ' Challenger,' and from it I have here figured the end of the vermiform foot and one 

 of the caudal laminae. These, it will be seen, exactly agree with Sarsiella. 



The 'Challenger' specimen was taken at a depth of 7 fathoms in Flinders 

 Passage. 



vol. xiv. — part in. No. 8. — April, 1897. o 



