A. E. Verrill — Marine Planar Ian s of Wew England. 469 



frontal nerves, antei'iorly, but often appear irregularly scattered, 

 occur farther from the margin than the main rows. 



Mouth subraedian, or at about the anterior third. Pharynx, wlien 

 everted, short and broad, with numerous short, flattened lobules. The 

 I'etraeted pharynx has about six or seven pairs of principal lateral 

 lobes and some smaller ones anteriorly and posteriorly. The six or 

 seven pairs of lateral branches of the stomach, and also the anterior 

 and posterior ones, have many dendritic branches at first, but distally 

 anastomose freely making an intricate network. 



The copulatory organs lie in an elongated whitish spot, close to 

 the posterior end. The most anterior part of this spot contains an 

 elongated, swollen, median seminal vesicle, which tapers backAvard, 

 and has two lateral lobes, continuous with the vasa deferentia ; back 

 of this the small, opaque white, elliptical or barrel-shaped male organ 

 is more or less distinctly visible ; the penis is short, straight, tapered, 

 and appears to end at a small distinct external pore. The vas 

 deferens extends forward, on each side, to the middle of, or some- 

 times nearly to the anterior end of the stomach, in the form of a 

 much convoluted opaque white organ, often distinctly visible from 

 beneath, through the integument, even with the naked eye. 



Just back of the penis, and more indistinct, there is a smaller, 

 swollen, short, pear-shaped female copulatory organ (vagina or copu- 

 latory pouch) which has thick, rather opaque, glandular walls ; it is 

 surrounded by, and connected with a larger translucent organ or 

 cavity, and opens externally by the small genital pore at its pos- 

 terior apex. The glandular part of the vagina, in most preserved 

 examples, appears to be short, ovate or pear-shaped when seen from 

 the ventral side, but its front end bends upward and then backward 

 on itself, the dorsal bend being of nearly the same shape and size as 

 the ventral part, is mostly concealed by it ; the apex of the dorsal 

 fold, in the largest examples, again bends forward, so that the entire 

 organ in profile, is somewhat S-shaped, but this is not the case in some 

 of the smaller specimens. From the external female orifice a narrow 

 but very definite duct runs forward, in the median line beyond the 

 penis and seminal vesicle to the gastric region, where it expands 

 into an elongated flask-shaped vesicle, which lies below the stomach.* 

 This appears to be a seminal receptacle or spermatheca. 



* An organ precisely like this is figured by Quatrefages (op. cit., pi. vi, fig. 2l\ as 

 present in his Stylochus maculatus (Helerostylochus maculatus V.), as described in 

 note on page 466. By him it was considered a copulatory sac or seminal receptacle, 

 and he called its duct the vagina. Others have doubted whether it forms part of the 



