A Description of three Acoela from the Gulf of Naples. 
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white area (pi. 10, fig. 8) extends back for nearly one-fourth of the body 
length. The brown pigment begins abmptly, forms a transverse band 
reaching beyond the middle of the body, and gradually fades off into 
white again. The dorsal surface is distinctly mottled in appearance 
(pi. 10, fig. 8), but the ventral surface is light with the exception of 
two large brown patches on each side of a median white area (pi. 10, 
fig. 9). The margin is flecked with a more or less symmetrical row of 
brown spots. The brown color is due to the presence of granules imme- 
diately under the epithelium while the white areas are caused by the 
accumulation of the concrement which is so common in the Acoela. 
b) Anatomy. 
The body is covered everywhere with a thick coat of fine ciha which 
are uniform in length and distribution. There is no smooth ventral disc 
such as that of Haplodiscus (1895). The cilia also line the orifices of 
the body. Small mucus glands open at intervals along the surface (figs. 9 
and 12). The muscular system consists of a thick layer of circular and 
longitudinal fibres under the epithelium. Strong dorso-ventral Strands 
traverse the parenchyma. 
The frontal gland fills the anterior end of the body (pi. 10, fig. 10). 
This organ in ÄmpMscolops resembles the type found in Proporus veno- 
sus. The various lobes of the gland unite at the anterior end and open 
on the surface where they form a distinct frontal organ. There are many 
glandulär cells surrounding the reproductive organs. A collection of 
these accessory glands are shown in fig. 12 where they enclose the f emale 
genital opening, and in fig. 9, in the bursa seminalis. 
Between the muscle Strands the bulk of the body of Amphiscolops 
fuligineus is filled with vacuolated cells with large open spaces between 
them (figs. 9 and 12). The cells toward the outer wall are more closely 
packed together. Their nuclei stain deeply and are conspicuous in 
sections. i 
The nervous system resembles that of Amphiscolops cinereus, and 
therefore a description of its structure is omitted. The large spherical 
statocyst (fig. 11) lies near the anterior end of the body, and at the same 
level are situated the prominent red eyes. The eyes are not mere ag- 
gregates of pigment as in Otocelis rubropunctata, instead they possess a 
distinct lens such as occurs in Proporus venosus. 
The reproductive organs of Amphiscolops fuligineus resemble those 
of Amphiscolops cinereus so closely that one description might easily apply 
to both species. The penis is situated at the extreme posterior end of 
