562 
ME. IT. N. EIDLET ON THE 
The alimentary tract, the vascular system, the nephridia, all 
exhibit the characters peculiar to or present in Urochcetci. 
There is but a single pair of seminal reservoirs, which have a 
greater extent than in U. corethrura (F. Miiller # ) ; for in the 
present specimen that lying on the left side passes through eight 
somites, that of the right side passes through twelve somites, 
commencing in somite xir., where are situated also the ciliated 
rosettes. 
I was unable to trace the sperm-ducts ; I could find no ovary ; 
I did not look for testes, as this would have necessitated some 
damage to the worm, which I was anxious to injure as little as 
possible. 
There are three pairs of spermathecse ; each is a very elongate, 
thin-walled sac, enlarged distally, and lying respectively in somites 
vii. , viii., ix. The chief difference between the two species of 
JJrochceta that have received names lies in the different position 
of the spermathecse. In U. coretlirur.a they lie in somites 
viii. , ix., x. ; in Z7. dubia (Horst) they are fouad in somites 
vi., vii., viii. ; in Beddard’s specimen from Australia they 
have the same position as in the present specimen. 
Such is a brief sketch of the anatomy of the worm A, from 
Fernando Noronha; it is sufficient, however, to identify it as 
belonging to the genus TJrochaeta ; but as to the species— 
whether it belongs to any of those already described or 
requires a new name — I feel rather diffident of expressing an 
opinion. In most points it agrees closely with Z7. corethrura ; 
but in the position of the gizzard (in somite vi. instead of vii.), 
in the position of the spermathecse, and in the fact that the setse 
are not bifid, the two forms differ. On this last point I think no 
great stress can be laid, as Beddard recognizes no bifidity in 
his Australian specimen ; and I agree with him so far as the 
present specimen is concerned, which differs also from Horst’s 
species, U. dubia, in the position of the spermathecse ; in 
fact, with regard to these organs, the present and Beddard’s 
specimen are intermediate between Horst’s and Perrier’s 
species. But are we justified in establishing a new species on 
such slender grounds, and from an examination of a single speci- 
men ? I think not, and prefer to leave the specimen unnamed, 
and to regard it as belonging to Perrier’s species, of which it 
may be a variety ; for we are at present ignorant as to how far 
* See Perrier, Arch. d. Zool. exper. et g6n. iii. 1874. 
