202 Transactions of the Royal Canadian Institute 



a similar coloured broken latero-dorsal line. This forks from the other 

 line at the base of the oral tentacle and runs backwards and downwards 

 below the other base of the rhinophore to the first group of cerata. It 

 passes as a short line about 2-4 mm. long from the end of the first to the 

 beginning of the second group of cerata and again from the last cerata 

 for about 5 mm. to join the mid-dorsal line at the beginning of the tip of 

 the foot. The colour of these lines is generally of an iridescent opaque 

 white but they may appear bluish or greenish. The reason for this is 

 apparent when they are examined under a binocular microscope when 

 it is seen that the colour is due to an enormous number of minute dead 

 white spots with which are mixed a lesser number of spots of intense 

 blue and orange. This causes the iridescence and the variation in the 

 number of the coloured spots alters the general colour of the line. 



In the somewhat diamond shaped space between the branches of the 

 dorsal line is an area of deep orange colour which may be continued a 

 short distajUce in front of the rhinophores. I have not encountered a 

 similar area slightly further back as figured by Cockerell and Eliot (4) 

 although in some species there has been an indication of a broadening 

 or even splitting of the mid-dorsal line. 



Below the base of the rhinophore and below the broken lateral line 

 on each side is a small oval area of bright orange. In the area in front 

 of the rhinophores between the branch of the dorsal line and the com- 

 mencement of the broken line are a tiumber of blue spots always suffi- 

 cient to give a distinct blue tinge but sometimes a deep blue area. 



These markings have been dealt with in some detail because they 

 entirely disappear a few hours after preservation and have not been 

 satisfactorily described by Cooper, Bergh, or Cockerell and Eliot. The 

 last two having dealt with only preserved material do not mention either 

 the lateral line or the orange and blue lateral marks, indeed, the former 

 of them does not mention even the mid-dorsal line. In all living speci- 

 mens I have seen, 60-70 from different localities, they have been present 

 and it is to their presence that the animal owes much of its beauty. 



The cerata are of a pale translucent yellowish grey in the middle of 

 which the liver diverticula form a core which varies in colour from a 

 reddish to a very dark chocolate colour. A thin finely granular white 

 opaque line passes up the outside border of the cerata and forms a cap 

 at the top save that the extreme tip is left without pigment and so appears 

 as if it were perforated. Cockerell and Eliot state that the cerata have 

 "bluish tips" but I think this is a slip for they do not figure it in their 

 drawing and it has not been noticed by any other wTiter. A blue tip is 

 characteristic of Janolus coeruhopictns. Many of the larger cerata in 

 the mid-body region have scattered minute spots of pale blue, pale green, 



