2 4 o DISCOVERY REPORTS 



with green. The underside is buff or yellowish. The head appears lighter than the body 

 but is, in fact, more distinctly green, and there shows faintly upon it a pale mid-dorsal 

 longitudinal streak. The posterior end of the body is yellowish. Under low magnifica- 

 tion black specks can be seen scattered thickly over the head and body. The eyes are 

 many and small. They occur in four sectors over the head, leaving three narrow paths 

 devoid of eyes diverging from one another from the tip of the snout (Plate XV, fig. 3). 

 As the eyes are embedded in the muscles of the head the number seen in life — about 

 twelve in the inner and eighteen in the outer group on each side — is not only variable 

 but is nothing like the total number, because the posterior groups only become visible 

 on clearing in anilin or clove oil. 



A specimen similar to this form, 50 mm. long and 1-2 mm. broad (breadth of head 

 0-75 mm.), was collected at the end of July. A transverse groove encircled the body a 

 short distance behind the head. The eyes were very indistinct. The ganglia showed 

 brown through the skin and the swollen body was tinged with orange. This specimen 

 was a ripe male. 



(2) Brown form. Three specimens from kelp roots from the outer rocks were similar 

 in size and shape to the green form but were of a light brown colour very distinctly 

 tinged with mauve. A slight speckling of reddish brown occurred, especially anteriorly. 

 The ganglia showed green through the skin. The eyes were irregular in size and arrange- 

 ment (Plate XV, fig. 12). 



(3) Colourless form. Twenty-four specimens were taken. The largest was 34 mm. 

 long and 0-5 mm. broad. They were almost transparent at the edges of the body and 

 white or very faint yellow when seen against a dark background. The eyes appeared to 

 be even more irregular than in the brown form. They were collected from inside and 

 outside the Bay (Plate XV, fig. 6). 



The fifth colour variant was similar to the colourless forms, but there was a pale 

 brown collar in the region of the ganglia. One specimen only was taken. 



Form and colour of preserved specimens. Shrinkage takes place but the body form is 

 retained. In about half the specimens the proboscis is partially protruded. Both the 

 coloured forms retain a hard bright blue-green colour on the back, and this colour 

 resists spirit for at least two years. The underside of preserved specimens is pale yellow, 

 and the colourless forms are white. No eyes can be seen. The proboscis pore is situated 

 just ventral to the tip of the head. Cephalic furrows can be seen curving round dorsally 

 as they pass back from the snout. 



On clearing in anilin oil three groups of eyespots can be seen on each side of the head. 

 Two of these groups are the ones already mentioned. The third group are dorso-lateral 

 on the body immediately behind the head. The eyes are small, variable sized and cup- 

 shaped. Those of the outer anterior group — about fifty — open forwards; those of the 

 inner anterior group — forty to forty-five — open rather backwards ; and the posterior set 

 — thirty or so — open mainly laterally (Fig. 13). In the uncoloured forms the eyespots 

 themselves are bright green. 



Internal structure. No frontal organs could be recognized in sections. The epithelium 



