1889.] ON SOME FRESHWATER OSTRACODA AND COPEPODA. 37 



shell appear rather convex, and the anterior extremity is much 

 narrower and nnne pointed than the posterior. The surface of 

 the shell is smooth, though everywhere finely dotted with small 

 dark spots of an irregular form, and is only sparingly beset 

 with hairs, more distinct at both extremities. 



The valves are in full-grown specimens remarkably unequal, 

 the right being by far the larger and to a considerable extent 

 overlapping the left at both extremities, especially at the an- 

 terior. Moreover, this valve exhibits a double lip, the inner 

 fitting to the edge of the left valve, when the shell is closed, 

 whereas the outer projects freely beyond it at a distance more 

 or less great. Both lips (see Fl. V, fig. 5) are highly chiti- 

 nised and without any distinct pellucid border, whereas they 

 exhibit numerous transverse grooves, generally dividing at the 

 edge into 2 or more branches, each of which gives origine to a 

 fine marginal hair. The distance between the two lips is espe- 

 cially in the anterior part very considerable, and the valve here 

 looks as if it were composed of two superposed valves. In 

 younger, not yet sexually mature, specimens, the inner lip is, 

 howerer, quite wanting and the valves nearly of equal size. The 

 inner duplicating of the valves are rather large, especially the 

 l ,: U't lying in front, which, as in Sh-iin^/pri*, forms a broad, se- 

 milunar, shelf-like plate, bounded interiorly by a strongly curved 



The colour of the shell in a living state of the animal is 

 light yellowish, more or less clouded with grass-green, especially 

 i» the dorsal and posterior part. From the centre of the shell 

 oil either side two diagonal lighter bands run to the posterior 

 extremity, the lower representing the place, where the coecal 

 appendages of the intestine lie imbedded between the lamellae 

 of the valves, the upper indicating the ovaries. 



The eye (see PI. V, fig. 5) is rather large and conspicuous 



The antennae (ibid.) also rather agree in shape with those 

 wgans in the latter form. The set* of the upper antennae are, 

 however, somewhat shorter, and those of the lower antenna are 



