252 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 foUicles 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 "0063 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-defiued. 



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. Megnin 

 (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 difterent 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 Hymenolepls 

 on account of the shape of the segments, the character of the neck, and the limited 

 number of the testes. 



Order TETRAPHYLLIDEA, Carus. 

 Family Phyllobothriid^, Braun. 



PhyUohothrium, sp. (PI. II. figs. 3 and 4.) 



From the areolar tissue under the blubber of Weddelfs Seal there wei'e found on 

 two occasions examples of a bladder-worm whose features, especially those of the scolex. 

 are characteristic of the genus PhyUohothrium. 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. long 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 



(ROY. SOC. EDIN. TRANS., VOL. XLVIII., 450.) 



