Cestode ec. from Spitsbergen. 425 
Tetrabothrius, lying dorsally to the ovary and with the 
horns of the crescent directed posteriorly. Its wall is 
composed of cells which stain very deeply with hematoxylin. 
It gradually expands in the older segments, but never 
entirely loses its original crescentic shape. 
Onchospheres have not been observed. It may be that 
the gravid segments are lost before the full development of 
the ova in the uterus has taken place. 
In view of the arrangement of the genital organs, it 
seems necessary to regard this form as very closely related 
to Tetrabothrius. In addition to the difference in the struc- 
ture of the scolex, the condition of the excretory system 
(absence of dorsal vessels and transverse ventral vessels) 
and the shape of the cirrus-sac (as distinct from the squat, 
spherical or triangular shape usual in Tetrabothrius) are 
possibly characters of generic importance. 
The family Tetrabothriide is at present usually restricted 
to the genus Tetrabothrius. (The form described by the 
writer (1914) under the name of Octopetalum probably does 
not belong to this family.) The presence of auricular 
appendages, therefore, has hitherto been regarded as a 
family character, and the inclusion of Anophryocephalus in 
the family necessitates alteration of the family diagnosis in 
this particular. The family diagnosis given by Liihe (1910) 
also includes the condition of the excretory canals usual 
in Tetrabothrius, but this is omitted by other authors 
(Fuhrmann (1908), Ransom (1909)). 
It is interesting to observe that some species attributed 
to Tetrabothrius are recorded in Cetacea, although the 
majority of the species are found in birds. In seals, up to 
the present, all the cestodes recorded appear to belong 
to the Pseudophyllidea (genera Diphyllobothrium, Pyramico- 
cephalus, Diployonoporus, &c.). 
NEMATODA. 
Fam. Ascaride. 
Contracecum osculatum (Rud., 1802). 
A small immature individual, probably belonging to this 
species, was taken from the stomach of the same seal. 
ACANTHOCEPHALA. 
Corynosoma strumosum (Rud., 1802). 
Several specimens were found attached to the wall of the 
large intestine of the seal already mentioned, 
Ann. & Mag. N. Hist. Ser. 9. Vol. ix. 28 
