Beaumont — Fauna and Flora of Valencia Harbour, Ireland. 823 



The coloTU'ing is very variable ; the majority are yellow or 

 yellowish green : pale yellow due entirely to gut ; deep yellow 

 where yellow granules are present in the skin ; the various 

 shades of green may be produced by the blending of the yellow 

 gut and outer tissues with green ovaries, or green gut and 

 yellow ovaries. A few specimens of a peculiar brownish pink 

 were met with. 



The pigment patch on head is usually dark brown, often with 

 a purplish tinge ; in some cases it is bright chesnut. In shape 

 it is highly variable ; in the greater number it is crescentic, the 

 horns of the crescent just reaching and sometimes concealing 

 the anterior eyes, and the convex posterior margin extending 

 abou.t half way between the anterior and posterior pairs of 

 eyes. Specimens were also seen with the crescentic band 

 situated nearer the posterior eyes, and others with the horns of 

 the crescent directed backward. In a considerable number of 

 individuals the patch was oval or oblong, placed transversely 

 across the head, concealing the anterior eyes usually, but in 

 no case extending to the posterior eyes. Again a number of 

 specimens were observed in which the patch was interrupted 

 by an unpigmented space in the middle. These latter show 

 varying degrees of approach towards T. vermicidatum, and 

 amongst them are examples having the pigmentation of Biirger'a 

 T. falsuni^ (1895, pi. xxix., fig. 32), In many individuals 

 probably the majority, patches of scattered flakes of opaque 

 white stand out more or less conspicuously on the head, both in 

 front of and behind the pigment-band. In many cases a nar- 

 row streak of similar gland- cells runs back along the mid-dorsal 

 line to the posterior end of the body, where it usually spreads 

 out fan-wise. This white line may consist merely of a single 

 row of scattered dots ; it may be incomplete anteriorly or pos- 

 teriorly, and may be present in individuals which have no white 

 patches on the head. 



1 T.falsum is a very doubtful species based on a single specimen. Apart from 

 pigmentation it is distinguished b}' the possession of eight eyes, in other w'ords 

 each of the four typical Tetrastemma eyes is double : an unreliable character in a 

 single specimen, for it is by no means unusual to meet with specimens of Tetrastemma 

 in which one eye is broken up into two, or into several scattered dots, and I 

 have seen a specimen of the form under consideration in which the two posterior 

 eyes were double. 



