A Synopsis of the Recent British Ostracoda. 127 



usually very distinct. Sars considers it most likely that these 

 creatures derive their nutriment from the juices of the fuci, 

 etc., amongst which they are usually found, for though the 

 structure of the suctorial apparatus is very much akin to that 

 of the parasitic Entomostraca, none of the Ostracoda have ever 

 been found as parasites. It is, indeed, impossible to regard 

 the members of this genus as parasitic, but neither do I 

 think it likely that the poison gland and urticating setae, 

 which are with them very largely developed, can be meant to 

 assist the creatures to prey upon vegetable food. It seems 

 more likely that they serve an office similar to the urticating 

 filaments of the Actinias in paralyzing the more minute 

 animal organisms on which their owners probably subsist. 



The genus is an especially littoral one, almost all its 

 members being met with in tidal pools, though some of them 

 range also into and beyond the Laminarian zone. The shell 

 is usually very thin, pellucid, and variously marked with shades 

 of olive, deep purple, or black. 



Family — Cypridinid^:, Baird. 



Philomedes, Lilljeborg. — Upper antennas six-jointed, 

 scarcely attenuated at the apex, antepenultimate joint bearing 

 a stout seta, which is set with numerous long auditory cilia ; 

 last joint short, and bearing two setae, which are much longer 

 than the antenna itself. Secondary branch of lower antenna, 

 three-jointed, geniculated, last joint turned upwards. First 

 pair of jaws slender, palp bearing simply a small trisetose lobe ; 

 second pair having neither a mandibuliform appendage, nor 

 clawed spines. Animal swimming with long jerks. 



P. interpuncta (Baird) . — This is the most abundant of the 

 British Cypridinidae, being sometimes taken in considerable 

 numbers by the towing-net, and occasionally in tidal pools. 

 It ranges, in our islands, from Guernsey to Shetland. The 

 shell is thinner than in others of the family, and often finely 

 reticulated on the surface. Identical with P. longicomis, 

 Lilljeborg. 



Cylindroleberis, nov. gen. — Upper antennas of the male 

 (Fig. 11) bearing at the apex two excessively long, annulated 

 setae, four shorter setae and a short curved claw ; penultimate 

 joint bearing at its apex a stout, densely ciliated auditory seta ; 

 upper antenna of the female (Fig 12) terminated by a stout 

 curved claw, and six or seven subequal plumose setae, which do 

 not exceed in length that of the last four joints ; penultimate 

 joint bearing a stout seta or process, from the extremity of 

 which spring six similar setae. Second joint of the natatory 



