PHYSIOLOGY OF ASCIDIA ATRA LESUEUR 231 
rior, dorsal, and ventral. As a result, however, of the embryo- 
logic investigations of his time, Kupffer (’75) applied these desig- 
nations correctly. The nomenclature suggested by him has been 
accepted by all of the later workers (Herdman, ’82), and will be 
used in the description of the present species. 
Fig. 1 Medium sized specimen of Ascidia atra, life size, showing view of right 
side. 
The large opening of the animal is within the rim of the oral 
siphon, and the smaller one is within that of the atrial siphon. 
These two openings are at the anterior end, the oral being to- 
ward the ventral edge, and the atrial toward the dorsal edge. 
The place of attachment is at the end opposite the siphons, and 
constitutes the posterior part (fig. 1). Consequently, the side 
of the animal which shows many creases and irregularities in 
the test is the right side, and the smooth face forms the left 
side. 
