450 DR JOHN RENNIE AND MR ALEXANDER REID ON 
As already stated, the “heads” are very irregular in form. In the neck region 
calcareous corpuscles are very numerous. 
The oldest proglottides are sexually immature. Only the testes are developed ; they 
lie in the middle layer, occupying the area between the excretory vessels. There are 
from 16 to 19 follicles in a cross-section through their region of greatest develop- 
ment. The follicles are oval in section and measure from ‘019 mm. to ‘038 mm. along 
their longer axis. . 
Calcareous corpuscles are extremely abundant, especially in the cortical area; they 
are oval or circular in form, and measure from ‘0068 mm. to ‘0095 mm. 
There is a pair of longitudinal excretory vessels on each side, placed dorsal and 
ventral, but quite near to each other; only the larger pair appears to be connected by 
transverse vessels. Both pairs have thick walls. 
The longitudinal nerve cords, which lie outside but near to the excretory canals, 
are very ill-defined. 
The question whether this type is normal is somewhat difficult to determine. 
The ill-defined nature of the scolex region is rather against such a view. MxrGNIN 
(quoted by Braun) considers that the pseudo-scolex condition is characteristic of the 
very old stages of worms, but in the present case the worms are immature. Again, 
this condition may be a case of retarded development. This is not altogether 
impossible, in view of the marked pathological condition set up in the intestine at 
the point of attachment, and the occurrence of the parasites in groups within a single 
cyst, both of which conditions are unusual in other cases of Cestode fixation. On the 
other hand, their occurrence in this way in several different specimens suggests that 
the features described are usual with this species. 
What positive structural data are available are not sufficient to permit of exact 
classification, but the type may provisionally be placed near the genus Hymenolepis 
on account of the shape of the segments, the character of the neck, and the limited 
number of the testes. 
Order TETRAPHYLLIDEA, Carus. 
Family PHYLLoBOTHRIIDa, Braun. 
Phyllobothrium, sp. (PI. Il. figs. 3 and 4.) 
From the areolar tissue under the blubber of Weddell’s Seal there were found on 
two occasions examples of a bladder-worm whose features, especially those of the scolex, 
are characteristic of the genus Phyllobothrium. One of the specimens is incomplete. 
The complete specimen consists of a scolex having four much-plaited or folded 
bothria. Accessory suckers are absent. Behind the scolex is a neck piece slightly 
flattened, 17 mm. Jong and about 2 mm. broad. Behind the neck is a long oval 
bladder, creased or wrinkled upon the surface, thick-walled and hollow, with terminal pore 
