404 A. JE. Verrill—3Iarine Ntinerteans of Neto England, etc. 



nuchal band. But it is much more probable that those spots repre- 

 sented either the cephalic ganglions, which usually show themselves 

 in that position in this group, or else clusters of small ocelli. 



In the latter case there may also have been small anterior ocelli 

 that were overlooked. Either supposition is consistent with its sup- 

 posed relation to the known species of Ariq^Jdporus with many of 

 which it agrees in form. 



Although I have spent })art of several summers dredging in the 

 region of Grand Menan, and have dredged even in the same locality 

 where this species was obtained, I have never met with a Nemer- 

 tean that could be referred to the same species with certainty, even 

 after making allowances for errors in the original drawing. The 

 nearest approach to it that I have seen, is a red variety of A. angii- 

 latus in which the angular pale spots on the sides of the head are 

 nearly obsolete, and the front ocelli inconspicuous. I have, there- 

 fore, reproduced the original description and figure. 



Tetrastemma Ehrenberg, 1831. 



Folia {parb) Quatr , Ann. des sci. nat., vol. vi, 1846. 



(Erstedia Quatr., op. cit, p. 22! ; Dies., Syst. Helm , vol. i, p. 2-J7 {aon lluhreclit). 



Tetrastemma Diesing, Syst. Helm., vol. i, p. 2.'JG, 1850; ytiuipsoii, Prodroiiius, in 



Acad. Nat. Sci. Philad , p. 163 [19], 1853. 

 Nemertes {pars) Dies., Syst. Helm., vol. i, p. 269, 1850. 



Body rather small, moderately elongated, often nearl}' terete. 

 Head in some species wider than neck, but in many species of the 

 same breadth. Transverse fossae usually two on each side of the 

 head, more or less oblique. Ocelli four, arranged in a quadrangle. 

 Proboscis Avith a central stylet and two lateral chambers, each 

 usually containing two to four stylets. 



A terrestrial species of Tetrastemma ( 7\ agricola) has been 

 described from the Bermudas by Moseley. Fresh water species of 

 the same, or a closely allied genus, are also known. 



Tetrastemma candidtim. (Fabr.) (Ersted. 



? Fasciula Candida 0. Fabr. in 0. F. Miiller, Yerm. terreyt. et fiuv. hist., I, ii, p. 71, 



1774. 

 ?Planana Candida 0. Fahr. in 0. F. Miiller, Zool. Dan. Prodr., p. 223, No. 2704, 



1776; 0. Fabricius, Fauna Groenlandica, p. 327, 1780. 

 Planaria quadriocutata (pars) Johnston, Zool. Jour., vol. iv, p. 56, 1829. 

 Nemertes quadriocidata Johnston, Mag. Zool. and Bot., vol. i, p. 535, pi. xvu, fig. 4, 



1837. 

 Tetrastemma varicolor (pars) (Ersted, Kroyer's Naturhist. Tidss., iv, p. 575, 1837; 



Diesing, Syst. Helm., vol. i, p. 257, 1850. 



