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 sHghtly 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 lust 

 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 in 

 the result of regeneration of the posterior part of the l^ody. 



(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 tulailar. 



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 

 fif^ured 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 



