= 
Estrerty.— Eucalanus. 
PLATE 5. 
All the figures on this plate were drawn from preparations stained in Mallory’s 
connective-tissue stain. Ithas been impossible to preserve satisfactorily in 
the monochromatic reproduction the desired values of the colored drawing. 
Fig. 44. Oblique sagittal section, seen from right side. Note the membrane 
Fig. 
Fig. 
Fig. 
Fig. 
Fia. 
Fig. 
Fig. 
45. 
46. 
47. 
48. 
49. 
50. 
51. 
about the optic nerve; it is continuous with the membrane about 
the brain (compare with Fig. 43). The eye rests upon the ventral 
body wall; the cells of the ventral ocellus are continuous with 
the hypodermis. The membranes which are believed to belong 
only to the lateral ocelli are shown at the anterior end of the 
dorsal portion of the eye. The nerves lie in the median plane 
in the pigment cell; some fibres may be seen passing through 
the basal plate of the median ocellus. Neurofibrillae are also 
shown. X 830. 
Anterior face of a cross section through the posterior border of the 
eye. Twenty-eight fibres of the optic nerve are shown, two of 
which run through the basal plate of the ventral ocellus. 
Similar to Figure 44. In addition, two fibres of the optic nerve are 
shown passing from the retinal cells into the central cell at the’ 
anterior end of the dorsal portion of the eye. X 830. 
Cross section of the optic nerve. Note the sheath, and a nucleus; 
also the hypodermal nuclei. X 830. 
Sagittal section seen from left side. Compare with Figures 44 and 
46, X 830. 
A cross-section, immediately anterior to that of Figure 45. Thir- 
teen optic fibres are cut in cross sections, and six leave the cells 
of the lateral and ventral ocelli. The neurofibrillae, especially in 
the lateral portions of the eye, may be seen to be directly continu- 
ous with the nerve fibre. The club-shaped distal enlargements 
of the neurofibrillae are in immediate relation to the interior 
bodies — this being shown best in the ventral ocellus. X 880. 
The next cross-section anterior to that of Figure 49. The structures 
in the two are practically the same. But note in Figure 50 the 
opening in the basal plate of the ventral eye through which a 
nerve fibre passes. It is shown cut lengthwise in figures 44 and 
48. X 830. 
Sagittal section of part of the brain and an organ of Claus. The 
membrane around the brain is shown, and the hypodermis be- 
neath it. A nerveleaves the organ. All the structures — interior 
bodies, nucleus, nerve — are similar to those in the median eye. 
xX 830. 
