2 NEMERTINES OF PLYMOUTH SOUND. 
Great Britain ; two are new to the coast of Britain, Carinella poly- 
morpha and Micrura awrantiaca, these not being recorded previously 
north of the island of Herm ; while Drepanophorus rubrostriatus, if, 
as I believe, identical with Amphiporus spectabilis, has not been met 
with north of Guernsey. 
Of the parasitic forms I have only obtained Malacobdella. Ihave, 
however, examined several specimens of Galathea strigosa for Dieck’s 
Cephalothria Galathee, which he describes as parasitic upon the eggs 
and on the gills of this crustacean, and which I believe no other writer 
has seen. With regard to this species, | may remark in passing that 
it has been erroneously referred to the genus Carinella by Joubin 
and J. V. Carus (8). With the same want of success I have 
examined large numbers of specimens of Phallusia mammillata and 
other Ascidians for Joubin’s Amphiporus vittatus and Tetrastemma 
Marionis, and an examination of female specimens in berry of Carcinus 
menas has not resulted in finding Nemertes carcinophila. 
In spite of the, in many cases, brilliant colours exhibited by 
Nemertines, and although many of them are conspicuously marked, 
I have been unable to find any very definite relation in this respect 
to the surroundings. This want of relation is especially marked among 
the Tetrastemmide, which exhibit a very large amount of colour 
variation, and yet varieties the most divergent in this respect live to- 
gether under apparently the same conditions. The genus T'etrastemma 
exhibits a very high degree of variation among its members, not only 
in colour, but also in marking and in general appearance unconnected 
with colour. These variations will be described in some detail below. 
I will only now remark that varieties have been obtained which in 
many respects connect such well-marked species as 7. candidum, T. 
vermiculatum, and T’. inelanocephalum. 
The observations of Keferstein, Claparéde, and others on the 
existence of otocysts among the Nemertea seem not to be in favour 
with most modern writers. Birger (6), however, in a paper published 
in November, 1891, stated that he had observed otocysts of oval 
form which were situated one on each half of the brain in some un- 
identified enoplous Nemertines, which he found living in sand with 
Lineus lacteus and Amphioxus. A week later du Plessis (11) 
published a paper on the subject, in which he described a pair of oto- 
cysts which he found in a thin orange-red eyeless Nemertine of 15 to 20 
mm. in length, obtained under stones between tide-marks at Nice. 
These otocysts resembled those described by Biirger, and differed im 
many points from those observed by Claparéde and Keferstein. On 
May 14th I found in sand on Drake’s Island between tide-marks a few 
specimens .of an armed Nemertine associated with Lineus lacteus. 
Each of these specimens exhibited a pair of otocysts of relatively large 
