136 n. 0. PUNNETT. 



(5) In the Linei d^e great variations occur in the range and 

 topography of the excretory system, and also in the number 

 of ducts. Neither here nor in the Eupoliidae is to be found 

 that incipient metamerism of the ducts which Oudemans 

 claims to have shown. 



(6) The vascular system of the Lineidfs shows but little 

 variation in the different species, except in so far as in the 

 precerebral region there may be either a well-marked head 

 loop or else a vascular network — a fact already pointed out 

 by Burger. It is worthy of note that there appears to be 

 some correlation between the extent of the excretory system 

 and the point of exit of the dorsal vessel from the proboscis 

 sheath. The vessel in all the species here described (except 

 in one case where the preservation was not sufficiently good 

 to determine this point) leaves the sheath within a few micro- 

 millimetres of the hinder termination of the excretory system 

 wherever the ducts of the latter may be situated (cf. 

 figs. 35—42). 



(7) The frontal organ which characterises the Lineidte is 

 not always present. 



(8) The structure of the cerebral organ and of the cutis is 

 characteristic for the different species. 



Gatby Marine Labokatory, 



St. Andrews, N.B. ; 

 March, 1900. 



List of Papers refeered to. 



1. Burger, 0. — " Unteisuchungen i'lber die Aiiatoniie uml Histologic der 



Nemertinen nebst Beitragen zur Systcmatiiv," ' Zeit. wiss. Zool.,' 

 Bd. 1, 1890. 



2. Burger, O. — " Sudgeorgische und andere exotisclie Nemertinen," 



'Z. Jahr. Abth. Sjst.,' Bd. vii, 1893. 



3. Burger, 0. — 'Die Nemertinen des Golfes von Neapel,' Berlin, 1895. 



4. CoE, W. R. — "On the Anatomy of a Species of Nemertean," 'Trans. 



Connect. Ac.,' vol. ix, 1895. 



5. lIuBRECiiT, A. A. W.— " Report on the Nemertea," ' Rep. Challenger, 



Zool.,' vol. xix, 1887. 



