Dr. W. Baii'd on new Entomostracous Crustacea. 3 



setse, and variously marked with dark-green streaks, and, when 

 examined by the lens, appears entirely covered with punctations. 

 The ventral margin is slightly concave or sinuated in the centre, 

 while the dorsal margin is nearly straight for half its length, 

 then slopes down at each extremity, the anterior of which is 

 rounded, and the posterior somewhat acuminate. The valves 

 of the carapace unite closely in the centre of the ventral margin, 

 but are slightly gaping at both extremities. Internally the 

 centre of the valve is of a dull colour, while the two extremities 

 are shining and smooth, and there is a slight duplicature of the 

 shell at the edge. The spot marked externally by the slight 

 protuberance near the' anterior margin is internally represented 

 by a depression. The lucid spots on the carapace are small and 

 indistinct. 



Length 3 lines; breadth 1^ line. 



Hab. Freshwater ponds, Cape Colony. 



This is about the largest species belonging to the family 

 Cyprididse that I have yet seen. A number of dead valves were 

 found in the mud, but only two or three living specimens made 

 their appearance. One, which must have been bred from a dried 

 ovum, made its appearance at the end of April. At first small, 

 it gradually grew to what I suppose, from the size of the dead 

 specimens in the mud, to be its full growth, about the middle 

 of May. It is the specimen figured. Its habits were rather 

 peculiar. It generally kept close to the bottom of the vessel in 

 which it was preserved, either walking upon the mud or, when 

 the weather was cold, digging under the surface or creeping 

 under the little lumps "of earth that remained unincorporated. 

 When it rose to the surface of the water, it was by walking up 

 along the side of the vessel, descending afterwards, as it were, 

 by its own gravitation. 



A few other species of Ostracodous Entomostraca from other 

 habitats have occurred to me, figures and descriptions of which 

 I here subjoin. 



1. Cypris unispinosa, Baird. Plate I. figs. 2, 2 a, b. 

 Carapace elongately oval, a little narrower anteriorly than 

 posteriorly. The carapace is moderately tumid, the most pro- 

 minent portion being near the anterior extremity. Ventral 

 margin nearly straight, slightly sinuated or concave ; the dorsal 

 margin is nearly straight for about half its length, then slopes 

 down to each extremity. Externally the carapace appears to be 

 smooth, until examined by a tolerably high power, when it is 

 seen to be minutely punctate, and it is marked by several dark- 

 green streaks and lines. The right valve is peculiarly marked 

 by being at its posterior extremity prolonged into a short sharp 



1* 



