10 
ON A NEW SPECIES OF ENTEROPNEUSTA, 
The splanchnic epithelium continues on the surface of the 
ventral septum which, as Spengel has shown, represents a median 
fold of the ventral proboscis wall, and is connected at intervals 
with the limiting membrane of the epidermis. The two ventral 
proboscis pockets separated from each other by the ventral septum 
are usually filled by a loose connective tissue; however, in some 
cases, a distinct space bounded by this tissue may appear (fig. 12, 
vp.) Behind the posterior free edge of the septum the ventral 
pockets unite to form the ventral unpaired portion of the proboscis 
coelom. 
Exceptionally two folds may arise from the limiting membrane 
of the epidermis to form the proboscis septum; the two folds 
enclosing a median pocket between them unite with each other 
along the mid-ventral line of the proboscis gut. Further pos- 
teriorly the point of union of the two folds gradually passes 
ventrally until the median pocket is obliterated, and the septum 
assumes the normal condition. On the dorsal side the two 
proboscis pockets separated by the heart bladder are in different 
individuals of this species very varied in their relations. The 
proboscis pore may be single or double, and occupy a median 
position or it may be single and situated on the right side of the 
median line. 
(a) In the majority of individuals the proboscis pore occupies a 
median position (fig. 12, p.) and it may then be formed in three 
ways — K l) The two dorsal proboscis pockets may unite with each 
other behind the heart bladder to form a single median proboscis 
canal which opens by the median proboscis pore; (2) the left 
pocket alone may form a proboscis canal, the right ending blindly; 
(3) the right pocket may form the canal, the left ending blindly. 
(b) There may be two proboscis pores, the two dorsal pockets 
giving rise to two proboscis canals (fig. 10, pc.) which both open 
to the exterior (fig. 11, p.). 
(c) The proboscis pore may be single and open on the right 
side; in this case the left pocket ends blindly while the right 
continues posteriorly, taking an almost median position above the 
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