A Synopsis of the Recent British Ostracoda. 115 



tirely destitute of the filamentous brushes which give swimming' 

 power to many of the members of the preceding family ; but 

 the upper antennee (b) are beset with strong marginal spines or 

 seta3 ; and the lower (c) are provided with a single long tubular 

 flagellum, which communicates with a poison-gland (v), situated 

 in the anterior portion of the body of the animal. There is only 

 one pair of jaws (g), similar to the first pair of the Cypridse. Three 

 pairs of feet (r, s, t), all of which protrude from the shell, are 

 very similar in form, though increasing in length from the 

 first to the last, and are adapted for walking. The post- 

 abdomen is composed of two very small and inconspicuous 

 lobes (m). The ovaries are not produced between the two 

 valves. The male copulative organs are exceedingly large, 

 and of complex structure, and. are not provided with a 

 u mucous gland." The shell is mostly more or less quad- 

 rangular in outline, but sometimes ovate or subtriangular ; 

 very variable both in structure and in external ornamentation. 



Ctpeidinid^. — The antennae are here exceedingly large 

 and muscular, the upper pair (Fig. 10, b) often bearing very 

 long and slender terminal setae, as well as a densely-tufted 

 auditory seta. The lower (c) is especially powerful, composed 

 of an excessively large and muscular basal joint, to which is 

 attached a nine-jointed branch, bearing numerous plumose 

 setae, which constitute it a powerful swimming apparatus. The 

 mandible proper is rudimentary, but its palp (/) is developed 

 into a large prehensile limb. Three pairs of maxillae, of very 

 variable structure {g, h, i). One pair of feet, of very peculiar 

 structure (h), forming a long, flexuous, annulated, vermiform 

 process, bearing several toothed spines at its extremity and 

 evidently homologous with the second pair of feet of the 

 Cypridae. The post-abdomen is composed of two large closely - 

 appressed plates (m), which are powerfully clawed along the 

 posterior margin. Byes two (a), pedunculated. Shell subovate 

 or sub spherical, having a distinct beak, with a large under- 

 lying notch in front, through which the antennae are protruded 

 whilst swimming. 



Some of the members of this family have very slight 

 swimming power, and live chiefly amongst mud ; others are 

 very agile swimmers, and are often taken in the towing-net — 

 more especially at night — near the surface of the sea. They 

 seem, indeed, to contribute very materially to the production 

 of the wonderful phosphorescence of the tropical seas. 



Conchoeciam;. — Closely allied to the preceding family. 

 The upper antennae are, however, in the female, very small; 

 the lower antennae almost exactly as in Cypridina. Mandibles 

 distinct, narrow, and toothed ; palp large and pediform, termi- 

 nating in long claws. Two pairs of jaws. Two pairs of feet, 



