Notarchus and Hexabranchus. 3 



ohial cavity, the genital furrow begins. It runs from here, for- 

 ming an outwardly somewhat arched line, to its aperture close 

 behind the right anterior tentacle. — The foot is large and broad. 

 Its length is 102 millims, its greatest breadth, which is 38 millims, 

 is situated somewhat behind the central part of the foot. In 

 front the foot is enlarged. On the anterior part of the enlarge- 

 ment there is a narrow, groove-like, transverse plicature. Both 

 borders of this plicature are supplied with numerous indentations, 

 which are quite perceivable to the naked eye. The indentations 

 of the posterior plicature are deeper and larger. The foot ends 

 backwards in a short and broad point. The edge of the whole 

 foot is supplied with numerous, perceivable, rugose indentations. 

 The underside of the whole foot has the same appearance. 

 It is supplied with numerous circular pits and furrows and a 

 great number of irregular spots. — The hind part of the body is 

 not distinctly discernible from the central part. It is triangular 

 with a short, broad point. Its surface is covered with small, 

 soft, thready processes. These are situated very closely to each 

 other on the borders and at the point, but are situated more 

 remotely from each other on the rest of that part. A few of 

 the processes near to the border are flattened and provided with 

 thread-like appendages. On the middle line of the body not 

 far from the back of the central part, there is a process, larger 

 than those mentioned before 1 . It is leaf-like, level and pro- 

 vided with numerous, thread-like appendages. A similar process, 

 somewhat smaller, is to be found on the right side, a little in 

 front of the back point of the body. On the middle, close to 

 the end, there is another process which is a little longer and 

 narrower 2 . 



According to what I have been told, the colour of the 

 living animal was a blackish brown on the hind part, on the 

 lower part of the sides and on the underside of the head. The 

 remaining part of the body was greyish. Besides there are large, 

 circular, greyish speckles here and there on the dark brown parts 

 of the body. The whole upper side of the body is provided 



1 Owing to a mistake, this process has, on the plate, been placed a little 

 in front of the limit between the central and the hind part. 



- Unfortunately this is not to be seen very clearly on the drawing. 



