157 
and pusillus Bock. Limnostylochus amarus Kaburaki also belongs 
to this category. The marginal eyes have a still smaller extent in 
the case of Stylochus djiboutiensis Meixner, salmoneus Meixner, 
reticulatus Meixner, neapolitanus Chiaje, zanzibaricus Laidlaw, and 
pilidium Goette; in these cases they reach the level of the tentacles. 
Meixneria furva Bock and Idioplana australiensis Woodworth have 
marginal eyes only in the first quarter and Leptostylochus in the 
anterior half of the body. In Neostylochus fulvopunctatus Yeri & 
Kaburaki they occur within a short distance back of the tentacular 
region, while N. pacificus Bock has numerous eyes at least still at 
the level of the genital pores. 
Tentacular eye-groups occur in all the genera that I 
referred to the family Stylochidae in 1913. Regarding the remarkable 
and aberrant genus Bergendalia, see below. The genus Stylochus 
has large, partly retractile tentacles. The eyes are clustered at 
their base and may also occur in the interior of the tentacles. 
Moreover, definite tentacles are found in Idioplana (with ocelli on 
the anterior side of the tentacles), in Idioplanoides (in /. atlanticum 
Bock, with eyes both at the base and within the tentacles) and in 
Kaburakia. Meixneria, Cryptophallus, and Parastylochus have small 
tentacular protuberances with eyes situated underneath (Bock 1913). 
The same holds true for Discostylochus, Enterogonia, Leptostylochus, 
and Ilyplana. In Neostylochus, both in the case of N. pacificus Bock 
and N. fulvopunctatus Yeri & Kaburaki, I have pointed out small 
tentacular protuberances (Bock 1923, pp. 342 & 346) with under- 
lying tentacular ocelli which are located more superficially; i e. 
doser to the dorsal epidermis. In Limnostylochus, Stummer-Traunfels 
has observed in the case of borneensis and Kaburaki in annandalei 
and amarus tentacular eye-groups. But at the same time Kaburaki 
States directly that tentacles are totally absent. Nor does Stummer- 
number of eyes increases with age. As mentioned above, Meixner (1907, 
p. 115) has emphasized this Verrills’s communication when taking his 
stand against the arrangement of the eyes as a character to be used for a 
subdivision of the genus Stylochus. There is no question about the faet 
that Verrrill too much overlooked the systematic value of such a charac- 
teristic as marginal eyes. Consequently he was so completely misled that 
he has ranked this typical Stylochus-spQcles in the genus Planocera. He 
actually defmed (1893, p. 474) nebalosus „as a Planocera with marginal eyes“. 
