TA KU KOMA! : 



tentacular canal. Sections show that the knob consists of the terminal 

 bifurcated part of the tentacular canal and of a rudimentary tentacle 

 basis intercalated between the canalar branches. The tentacle appara- 

 tus is thus in a very reduced condition in the adult ; in younger stages, 

 however, it is more typically represented, as will be described further on. 



Colour. — Judging from the statements of previous authors, the 

 three species of Ocyropsis originally described by RANG, viz., O.fi/sca, 

 O. crystallina and 0. maculala, seem to have been distinguished 

 exclusively on the basis of colouration. According to my observation, 

 however, this seems to be a very variable character. Among more 

 than twenty fresh specimens taken from a great swarm which appeared 

 at Misaki on April i of this year, I have met with some representatives 

 of all the above three forms. All the individuals observed on that 

 day showed a suffusion of chestnut-brown colour on the entire inner 

 surface of lappets. This suffusion varied considerably in degree. In 

 many cases it was fairly deep, making the individuals referable to 

 " O. ///sea." In other cases the suffusion was so slight as to be barely 

 discernible, apparently representing the state of colouration ascribed to 

 " O. . cry •stalli '//(/." Finally, a few individuals bore two conspicuous 

 dark patches on the suffused ground, a condition which without ques- 

 tion identifies them with " O. maculata" The fact that all the three 

 states of colouration are represented in individuals of the same swarm, 

 makes it highly probable that we have here to do merely with 

 individual variations within a species. The above specimens were 15- 

 55 mm. in the height of body proper. In individuals smaller than 

 20 mm. in height, the gonads are not yet developed, but the winding 

 of lappet-canals and of the branches of pharyngeal canals have nearly 

 attained the condition seen in the adult. 



Of the three alcoholic adult specimens from Tateyama Bay, which 

 were examined, two showed clearly the chestnut-brown suffusion, one 

 with and the other without the patches, while the third showed neither 

 the suffusion nor the patches. 



