604 F. W. GAMBLE AND F. W. KEEBLE. 



the body appears of a dull grey colour, the red marking 

 being much less distinct. Along the mid-dorsal line from 

 the rostrum backwards, spots of brilliant yellow or greenish 

 yellow, previously invisible, are now distinct. On parts of 

 the tail lobes, eye-stalks, and limbs, which appeared trans- 

 parent by transmitted light, similar bright yellow spots are 

 now to be seen. 



We were able to follow the change in the coloration of 

 this variety for some little time. " Ked liners " appear in 

 great numbers in July among the finer sorts of red weeds 

 in Piel Harbour. Many of them measured only 4 mm. in 

 length, but as they increase in size the red pigment accumu- 

 lates along the ventral stripe and the cross-bars ; with this 

 accumulation these regions appear of a dark red or even 

 blackish colour. These " black liners " become fairly 

 common in September, much more so in December, when 

 some of them measured 15 mm. in length, and would now be 

 described as transparent, and boldly marked by black and 

 grey or dark purplish lines, the " hump " or point of flexure 

 of the tail being nearly free from pigments. Were these 

 forms to increase considerably in size they would present an 

 appearance identical with that of Hippolyte fascigera, 

 whose characteristic habitat is the zoophyte-clad stems of 

 Halidrys siliquosa, and whose independent specific rank 

 is no longer maintained by such authorities as Dr. A. M. 

 Norman and A. 0. Walker, Esq., F.L.S. 



The occurrence of '' green liners," a specimen of which is 

 shown in PI. 32, fig. 2, in which the red colour is more or less 

 replaced by green in the stripes and bars, is not infrequent. 

 But in this case the data for the probable progress of sea- 

 sonal colour-change are not forthcoming. More striking than 

 these " liners " is the black-barred colour form, fig. 3, 

 which lives amongst the dark alga Cladostephus spon- 

 giosus. The body is transparent and crossed by two bands 

 of dark brown, almost black tint, a broad band across the 

 carapace and a narrower one near the base of the tail ; not 

 infrequently a third band runs across the apices of the tail 



