6 
pocket and that this presents only shallow diverticula. 
The mouth is just in front of the last third of the body. 
The male and female apertures are very close to 
each other (text-fig. 6), and the distance to the mouth 
is a little less than that to the caudal end of the body. 
The organization of the genital apparatus, on which 
the raising of the species to generic rank is warran- 
ted, will be treated in a special chapter. At present 
it is only necessary to mention that the ductus vagi¬ 
nalis is of the same length as the vagina (text-fig. 6). 
Geratoplana colobocentroti var. hawaiiensis n. var. 
Locality: Hilo, Hawaii, underneath Colobocentrotus 
atratus (L.). 
Material; Four specimens collected by Dr. Th. 
Mortensen April 15, 1914. 
The specimens from Hawaii agree to a great 
extent with C. colobocentroti from Krakatau as to the 
general bodily structure; yet they differ in some 
respects (text-fig. 4). 
The alcoholic specimens do 
not show any sign of pattern or 
colour on the dorsal side (Platel, 
Fig. 2, 4 and 8). However, as 
only preserved material is at 
hånd, and no information as to 
the colour of the living animals is to be found, 
one should perhaps not attach too much import¬ 
ance to this dissimilarity to the Krakatau- 
specimens. The sections verify, nevertheless, 
the total absence of pigment in the muscular 
Wall of the body that gives colobocentroti 
its characteristic appearance. On the other 
hånd, sparse clusterings of pigment in the 
parenchyma are distinguishable in the sections, 
as in colobocentroti, but this pigmentation is on 
preserved animals invisible from the outside. 
The eye-clusters (text-fig. 5) show a greater 
Text-fig. 4. 
Geratoplana colobo¬ 
centroti var. haivaiiensis 
n. var. 
Text-fig. 3. 
Geratoplana 
colobocentroti. 
Outline draw- 
ing of pharynx 
and pharyn- 
geal pocket. 28 x. 
