SIXTEN BOCK, TWO NEW COTYL. GEN. OF POLYCLADS. 



as a protection against the rays of the sun. 



when the cerebral eyes must be exposed to 



pigment which has to protect the 



brain must be removed to the 



immediate neigbourhood of the 



brain, constituting an extensive 



and thick cover for this delicate 



organ. Such an arrangement of 



the pigment has not hitherto been 



observed for the polyclads. 



The pigment granules are 

 completely of the same kind in 

 the epithelium and in the paren- 

 chyma. They are of varying size, 

 V2— 2 (J., and usually more or less 

 elongate oval. The smallest, how- 

 ever, are spherieal. In shape 

 the large pigment granulae diverge 

 from the granulae in the pigment 

 cups of the eyes, which are al- 

 wäys spherieal. It is noteworthy 

 that while the pigment granulae 

 of the body vary much in size 

 those of the eyes have the same 

 size. Both kinds of granulae agree 

 exactlv in colour. 



Intestine. 



The external mouth is cen- 

 trally placed in respect to the 

 pharynx (text fig. 2). The pha- 

 ryngeal sac is spacious, occupying 

 more than one fourth of the body- 

 length and is situated in the an- 

 terior half of the body. It con- 

 tains a much folded pharynx and 

 agrees with the pharynx-type 

 which Lang (1884) has named 

 >>krausenförmig». As the preser- 

 vation of the pharynx is not good. 



Accordingly 

 the light the 



