538 PROCEEDINGS: BOSTON SOCIETY NATURAL HISTORY. 
body the brown color of the dorsal surface does not reach the lateral 
margins of the body, leaving the tip of snout and lateral borders of 
head and anterior portion of esophageal region of the same whitish 
color as that on ventral surface. 
Other specimens are orange anteriorly and yellowish in intestinal 
region, with dark reddish brown or dark gray intestinal canal (pi. 23, 
fig. 2). Still others are rosy flesh color with a tinge of gray dorsally 
and colorless, or whitish, ventrally (pi. 23, fig. 1). Other individuals 
exhibit various shades of ochre and gray from the deeper tints to 
very pale gray, while the very small worms are usually nearly white, 
or grayish white, or almost colorless. 
The brain is rosy or orange and often rather conspicuous; the 
eggs are yellowish, and the masses of spermatozoa whitish, affecting 
the color of the body in sexually mature individuals. The proboscis 
is very pale, or colorless, with a whitish or yellowish tinge. 
Most of the larger, more deeply colored individuals had their 
bodies filled with large embryos in the month of July. Solid masses 
of secretion scattered in the integument commonly give the appear¬ 
ance of very fine whitish dots covering the body. 
Ocelli .— The two ocelli of the anterior pair are nearer together 
and of larger size than those of the posterior pair, and of more regu¬ 
lar outline. The two of each side are commonly nearer together 
than those of either the anterior or the posterior pairs. In section 
the ocelli are found to be situated rather deep in the tissues of the 
head (fig. A, p. 540). Each ocellus is provided with a large pigment 
cup, sometimes nearly 0.1 mm. in diameter, which faces the lateral 
aspect of the head. From this cup a conspicuous nerve leads to the 
dorsal brain lobe. 
General Anatomical Peculiarities. 
Proboscis .— The rhynchocoel extends nearly, although not quite, 
to the posterior end of the body. Proboscis of large size, when 
partially extruded commonly equal in diameter to the body itself ; 
attached to tissues of head in anterior portion of brain region. 
Esophagus opens into rhynchodaeum directly in front of brain. 
The number of proboscidial nerves is somewhat variable, the 
majority of individuals having 13 ; a smaller number have 15, while 
one specimen examined had 14. Another, which must be consid- 
