44 G. O. Sars. 



elongated form of the shell, and in the infero-posteal corners 

 being simple, not excised. 



Description of the female. 



The length of fully adult, ovigerous specimens does not 

 exceed 0,86 mm., and this form is accordingly of rather 

 small size. 



The form of the shell, when seen laterally (fig. 7), is 

 oblong oval, with the greatest breadth about in the middle, 

 and the posterior extremity narrowly truncated. The dorsal 

 margin is quite evenly arcuate, and forms with the posterior 

 one a distinct, though somewhat obtuse angle. 



The inferior edges of the valves are somewhat flexuous, 

 being rather convex in front, but posteriorly assuming a 

 straighter course. They are defined from the posterior 

 edges by a distinctly projecting corner, which sometimes 

 terminates in a sharp point. No notch, however, like that 

 generally occurring in A. excisa, is ever found above this 

 corner. 



The head, as in most other species of the genus, is 

 rather procumbent, terminating in a long, acuminate, some- 

 what posteriorly-curving rostrum. 



The surface of the shell is very conspicuously sculp- 

 tured, exhibiting in its posterior part a rather regular reti- 

 culation, the meshes being disposed in oblique rows, whereas 

 anteriorly, each valve exhibits a number of sharply-marked, 

 curved, transverse striæ. The inferior edges of the valves 

 are densely fringed with delicate bristles. 



The eye occupies its normal place, and is of mode- 

 rate size. 



The ocellus occurs much nearer to the eye than to the 

 tip of the rostrum, and is of very inferior size. 



