24 Gr- 0. Sars- 



firmly adheriDg to the surface as only to be removed with 

 great difficulty. On Pl. III, figs. 1 and 2, are represented 

 a female and a male specimen, in which this crust was less 

 thick, and therefore more easily removable, so as to show 

 the sculpture of the shell. 



The shell of the largest female specimen measured in 

 length 8.30 mm. by 4. so mm. in height; that of the male- 

 specimens was considerably larger, attaining a length of 

 10.40 mm. and a height of 5. so mm. Compared with the 

 previously described specimens, the shell exhibits, on the 

 whole, a more compact appearance, being less elongated in 

 proportion to its height, and also somewhat less compressed. 

 Moreover, the lines of growth are much more numerous,^ 

 amounting on each valve to from 20 to 24 in all, the outer 

 ones being, as a rule, very densely crowded together. In 

 some of the specimens (see fig. 1) a narrow, sharply defined 

 marginal area is found, indicating a renewed growing period. 

 This area is of lighter colour than the other part of the 

 shell, and very finely concentrically striated. In the structure 

 of the several appendages, I have not found any essential 

 difference from that in the previously examined specimens.. 

 Fig. 3 represents one of the antennulæ of a male specimen. 



Besides the above-mentioned specimens, which were all 

 taken in the very same place, at Green Point Common 

 near Capetown, I have received some few males and 

 females from another locality, having been collected by 

 Mr. J. L. Drege at Port Elizabeth. They are of quite 

 unusual size, and in all of them the marginal area is 

 exceedingly large and very sharply marked off from the 

 adjacent part, thereby giving the shell a rather peculiar 

 appearance. But in spite of this I am convinced that they 

 belong to the very same species, the large size of the 



