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with the rows of marginal eyes along the anterior edge of the 
body. Such ocelli have been pointed out in Stylochus arenosus 
and cinereus (Jacubowa 1906), frontalis, nebulosus, and zebra 
(Verrill 1893), reticulatiis (Meixner 1907), vigilax (Laidlaw), orientalis 
and pusillus (Bock). They are only detached or else form the forward 
continuation of the cerebral eye-clusters (for instance, in reiiculatus 
Meixner), or else they are very numerous and scattered over the 
anterior end (in frontalis Verrill). Frontal eyes are, moreover, found 
in Meixneria (detached), Enterogonia and Cryptophallus (numerous), 
Parastylochus (abundant). Discostylochus, and in Limnostylochus. 
Frontal eyes are absent in some Siylochus-spQciQS, (djiboutiensis 
Meixner, salmoneus Meixner, neapolitanus (Chiaje), pilidium (Goette), 
plessisi Lang, hyalinus Bock, vesiculatus Jakubowa, and tauricus 
Jacubowa); nor are they found in the genera Idioplana, Idioplanoides, 
Ilyplana, and Leptostylochus. 
In the genus Neostylochus we meet more peculiar conditions in 
regard to the distribution of the eyes. In this* case it is no longer 
possible to separate cerebral, frontal, and marginal eyes from each 
other, for the entire anterior end is diffusely covered with numerous 
small ocelli. This is particularly true in N. pacificus Bock and a 
Neostylochus-speciQS that I collected in Misaki, Japan. Judging form 
the text-figure given by Yeri and Kaburaki (1920), the above 
condition does not seem to be so marked in N. fulvopunctatus. Here 
the areas on the outer side of the tentacles lack ocelli, while in the 
Neostylochus-speciQS mentioned earlier the whole anterior end, even 
far back of the tentacle region, is dotted with eyes of homogeneous 
size and, peculiarly enough, without denser clusterings above the 
brain. In this scattered mass of ocelli the two small tentacular 
eye-groups, consisting of a few, 5—8, large ocelli located doser to 
the surface underneath the slight tentacular protuberances, which are 
characterized by a glandless epithelium, are distinguishable. Rows 
of marginal eyes continue along the sides of the body. 
Discostylochus may be said to hold a middle position as to the 
distribution of the eyes, with Cryptophallus and Parastylochus on 
the one side, and Neostylochus on the other. The entire anterior 
end of Discostylochus has a large number of scattered ocelli and 
the cerebral eye-clusters arc hardly differentiated. The poorly 
developed tentacles show likewise a close similarity to the genera 
