6 
ON A NEW SPECIES OF ENTEROPNEUSTA, 
appearance as if they were pressed out of position and overhang- 
the sides of the body more than the others, giving the rows 
a slightly irregular appearance. I have also met with two 
specimens in which as a further result of displacement two 
rows of alternating sacs were formed on each side in the middle 
part of the hepatic region. Both these specimens had lost 
the whole of the body anterior to the liver sacs, and a new 
proboscis was in course of formation at the anterior end of the 
hepatic region. In a third specimen the sacs were normal in 
arrangement up to the larger sacs, but the succeeding sacs 
presented a very irregular appearance, forming two lateral masses, 
composed of irregularly arranged sacs, on either side of the dorsal 
median line, and not showing the alternation of the sacs seen in 
the other two specimens. It might be that this irregularity is 
the result of regeneration of the posterior part of the body. 
(3) Tail Region: varies greatly in length in different 
individuals, but is usually about three times as long as the hepatic 
region. Its outline varies according as it is empty or full of 
sand; in the former case it is flattened, and in the latter more or 
less tubular. 
The median dorsal line in preserved specimens is occupied by a 
dark ridge extending to the posterior end of the body, and 
marking the position of the dorsal nerve stem; on the ventral side 
the ventral nerve stem occupies the bottom of a shallow longitu- 
dinal groove. The tail region in this species is especially 
characterised by the presence of two dorsally situated longitudinal 
epidermal stripes (fig. 2) running parallel with the dorsal nerve 
stem and at a short distance from it. Appearing in the hepatic 
region just external to the posterior small liver sacs they extend 
over about the anterior two-thirds of the tail region, and are 
situated immediately above the ciliated grooves of the intestine. 
The epidermal stripes can be distinctly seen not only in preserved 
specimens but also in the living animal. Indeed, I observed and 
floured them in the latter before I knew of the existence of the 
two ciliated grooves in the intestine. The two epidermal stripes 
appear as two longitudinal interruptions of the island-like groups 
