Two additional South- African Phyllopoda. \ 3 



a gentle curve, with the greatest curvature somewhat behind 

 the middle, whence it ascends obliquely towards the narrowly 

 rounded posterior extremity. The anterior extremity is very 

 short, and is bluntly rounded at the tip. 



Seen from above (fig. 2), the shell appears very much 

 compressed, and in this respect it much more resembles the 

 shell of a Limnadia than that of an Estheria, which is rather 

 tumid. When the valves are shut, the greatest width of 

 the shell scarcly exceeds X U of the length, and occurs far 

 in front of the middle. 



The valves are very thin and pellucid, and each exhibit 

 about 14 rather faint lines of growth, placed at regular 

 distances from each other, except the outermost ones, which 

 are more densely crowded together. The surface of the 

 shell between the lines appears at first sight to be perfectly 

 smooth; but when oblique light is applied, a very delicate 

 reticulation is found to exist (see PI. 3, figs. 1, 3). The 

 free edges of the valves are finely setiferous throughout 

 their whole length (see PI. 3, figs. 1, 4). The shell-gland 

 is very distinctly seen, when the animal has been removed 

 from the shell (see PI. 3, fig. 1), and exhibits a similar 

 structure to that in Limnadia, one of its ducts partly 

 encircling the insertion of the great adductor muscle of 

 the shell. 



The enclosed animal, owing to the pellucidity of the 

 valves, admits of being rather distinctly traced through the 

 shell, and the two sexes are thereby readily distinguished 

 without dissection, the sexual characters being very apparent. 

 In order to examine the animal closer, it is, however, neces- 

 sary to extract it from the shell, an operation which may 

 be effected rather easily, without any severe injury to 

 either the shell or the animal. 



