22 



ARKIV^ FÖR ZOOLOGI. BAND Ii. NIO 13. 



in those Euryleptidoe which lack marginal tentacles or in the 

 Prosthiostomidce. The marginal eyes may then correspond to 

 the tentacular eyes of the former family. 



It is noteworthy that all the eyes, both the cerebral and 

 the marginal ones, are situated very close to the basement 

 membrane, the muscular layers being very thin. 



There is a ventral, transverse, sensorial furrow situated 

 closer to the brain than I have seen in any other polyclad. 

 This furrow is also deeper than that of other polyelads. A 

 special accumulation of ganglion cells occurs at the inside 



Fig. 5. 



Amyella lineata n. g. n. sp. Sagittal section of the animal. The small 



circles behind the brain and the sexual apparatuses represent young ovaries. 



The same eniargement as in text fig. 2, Zeiss Obj. AXOc. 2. 



of the muscular wall for the innervation of this organ. The 

 paired nerves connecting this assemblage of nerve-cells with 

 the brain must be very short on account of the close posi- 

 tion of the furrow to the brain; they are also very thick. 



The mouth is to be found in the anterior part of the 

 second third of the body. It occurs in the middle of the 

 pharyngeal area, and as the pharyngeal chamber has a con- 

 siderable size it is thus removed far from the anterior end. 



The sexual pores are placed very close to one another 

 and about halfway between the mouth and the sucker. On 

 account of the large size of the male copulatory organ in 

 relation to the small size of the animal the sucker thus lies 

 below the back end of the male apparatus. 



