190 LINEUS LACTEUS. 



move out of its shelter or unroll. It readily reproduces heads or other portions in fragments of its 

 body, so that the irritation and discomfort of a long journey in a jar is found occasionally to increase 

 rather than diminish the number of specimens. The skin is acid to litmus-paper. 



Z. sanguineus feeds on Harmothoe imbricata and other annelids in a decaying or at least 

 dead condition. 



The ova are developed in October. 



After some hesitation I have referred the Planaria sanguinea of Jens Rathke to this species. 

 The Planaria unicolor of Dr. Johnston may also be the same animal; indeed, so far as can be 

 made out, it does not approach any other form. His preparation of Borlasia purpurea in the 

 British Museum belongs to the same species. This author does not seem to have been aware 

 that several varieties of Lineus gesserensis have a reddish-brown colour, when he described this 

 hue as distinctive of the present species, yet he probably had the true Z. sanguineus before him. 

 M. van Beneden remarks that his Nemertes communis is distinguished from L. gesserensis by the 

 length of the body and the double row of eyes. The latter character occurs in both species ; 

 and while his form, probably, differs from Z. gesserensis, he does not satisfy us as to its separation 

 from Z. sanguineus. I have made Prof. Keferstein's Nemertes octoculata synonymous after some 

 doubt, since there is little in his description to distinguish it from a pale variety of Z. 



4. Lineus lactetjs, Montagu, MS. Plate V, fig. 3. 



Specific character. — Snout similar to the foregoing, but the mouth is placed much further 

 behind the ganglia. Body reddish anteriorly, pale posteriorly. 



Synonyms. 

 1808. Lineus lacteus, Montagu. MS., p. 275. 



1867. Borlasia lactea, Mcintosh. Quart. Jour. Micros. Sc. ; Trans., p. 39. 



„ „ „ Parfitt. Catal. Annel. Devon. (Ext. Trans. Devonsh. Assoc, for the Advancement 



of Sc, &c), p. 6. 



1868. „ „ Mcintosh. Ann. Nat. Hist., 4th ser., vol. ii, p. 293. 



1869. „ „ Ibid. Trans. Roy. Soc. Edinb., vol. xxv, pt. ii, p. 372 et seq. 



Habitat. — South coast of England, under stones between tide-marks. 



Body. — One to two feet in length, rather less than a line in breadth, flattened, almost 

 insensibly tapered from head to tail, and marked by pale transverse lines. In contraction it is 

 rounded, and very frequently the animal advances with its body thrown into various stiff wrinkles 

 and dilated portions. 



Colour. — Uniform dull whitish or cream-yellow, with the regions before and behind the 

 ganglia (three quarters of an inch or more) of a fine rose-pink, which gradually fades posteriorly. 

 The coloured region behind the ganglia corresponds to the long circulatory space in front of the 

 mouth. Snout and tail translucent. 



Head. — Elongated, very slightly broader than the succeeding portion of the body, and in 

 many positions narrower, tapered anteriorly, with the tip rather rounded, and furnished with three 

 papillae. It is distinguished posteriorly by a slight incurvation at the termination of the cephalic 



