INTERNAL ANATOMY. 325 
small spines is also borne on a slightly raised and thickened disc, but they are 
so inconspicuous that they are not represented in Plate 10, fig. 1. 
Liver and intestine — The posterior visceral mass, made up of the remain- 
ing portions of the alimentary tract and the ovotestis, occupies nearly the whole 
of the body-cavity behind the head. Its ventral surface is convex, rounded 
behind and in front, the black liver contrasting strongly with the light yellow 
intestine and the reproductive gland. The dorsal surface is deeply faceted 
with irregular depressions, caused by the pressure of the overlying organs, 
notably those of the reproductive system. 
At the posterior end of the third stomach, a series of low ridges in its inner 
layers converge toward the opening of the intestine. This portion of the diges- 
tive tract is imbedded in the liver, occupying a deep groove in its surface. The 
intestine passes into the right side of the liver, curving downward to its ven- 
tral surface, across which it passes to the left anterior margin, thence up to the 
dorsal surface, across which it passes obliquely backward, thence downward 
again in a loop upon the posterior surface between the liver and the ovotestis, 
returning after describing this curve to the right ventral side, whence it passes 
upward and backward to the anal opening at the base of the siphon. It thus 
forms in general a wide loop from below upon the left and dorsal surfaces, a 
disposition corresponding closely to that found in Tethys. The totallength 
of the intestine is circa 300 mm., and its average diameter 7.0 mm. 
At the posterior end of the third stomach, below and to the left of the 
pylorus, a spacious biliary cavity opens into it by a large channel. Into this 
cavity in turn open numerous bile-ducts, which ramify out into the poorly 
defined lobes of the liver. From the left of the biliary chamber the strongly 
curved hepatic caecum extends, approximately 25.0 mm. in length. Owing 
to the softened condition of the inner walls of this region the longitudinal folds 
dividing the lumen of the caecum and their relations to the biliary chamber 
and the intestine could not be made out clearly, but they appeared to be sub- 
stantially the same as in Tethys (MacFarland, 1909, p. 44). 
The whole alimentary canal, with the exception of the oesophagus, was 
quite uniformly distended with coarse detritus of an algal nature, mixed with 
considerable sand. In the intestine the latter was especially abundant, the 
organ being crowded full with it. 
REPRODUCTIVE System.— The reproductive system of Dolabella is com- 
posed of the following parts, which will be described in the order given. 
1. Ovotestis. 
