576 



TAKU KOMA I : 



Aside from what concerns its habitat, Coeloplana bocki may be 

 distinguished from the two Coeloplana species {C. willeyi and 6. 

 mitsiikurii) previously described by Abbott* from the same locality by 

 the body being on an average much smaller and by peculiarities in 

 colouration as well as in the structure of polar plates. In all other 

 respects, but notably in internal organization, the new species may be 

 said to agree completely with both the species just referred to. 



C. bocki commonly measures only about 1.5 cm. in diamètre in 

 the fully extended state, although in rare and exceptional cases the 

 body may reach about 3 cm. in diamètre. In both the species of 

 Abbott the diamètre measures generally 2 or 3 cm. and sometimes even 

 as much as 5 or 6 cm. in the fully distended state Similarly as in C. 

 willeyi the colouration of body varies within a wide range, but is 

 characterized by the presence, on the dorsal side, of markings which 

 are generally rather conspicuous. The markings consist of a number 

 of deeply coloured branching and anastomosing stripes which on the 

 whole run side by side in the tentacular direction and may be deep 

 vermilion, dark red, brick-red, pinkish, orange or even greyish in different 

 individuals. The stripes number a dozen or more in large specimens ; 

 in the smaller ones they may be discontinuous and irregularly streaky. 

 At all times they grow indistinct towards the margin of body. The 

 ground colour of body is usually similar to that of the stripes though 

 very much lighter in tone. Rarely it is of a colour which more or less 

 contrasts with that of the stripes ; as for instance, I have found some 

 cases of individuals, in which it was of an orange hue while the stripes 

 were vermilion. The stripe marking constitutes a feature peculiar to 

 the species ; it is found in neither of the previously known species, both 

 which are uniformly coloured, though C. willeyi may show small 

 whitish patches confined to base of " dorsal tentacles " and to the 

 margin of body. 



* Abbott, J. F. (1902). Preliminary notes on Coeloplana. Annot. Zool. Jap., Vol. IV, 

 p. 103. 



Same (1907). The morphology of Coeloplana. Zool. Jahrb. Anat, Bd. 24, p. 41. 



