44G D. BRYCE ON MACROTRACHELOUS CALLIDIN^. 



upper surface of the rami, before and behind the ridges known as 

 " teeth," are present also between these. 



Whilst conducting his investigations Zelinka kept specimens of 

 this species, and of some other forms, alive in water, in shallow 

 glass vessels, well covered, and provided with algse, from the 

 beginning of February to the beginning of July, the vessels being 

 daily looked over, all eggs removed, and the number of specimens 

 ascertained, so that young individuals could not unnoticed remain 

 in the vessels. Thus he proved that the one generation of 

 Callidinfie lived for five months, at the end of which period the 

 observations were given over. Such a period of active life, un- 

 broken by any interval of inactivity enforced from lack of water, is, 

 as he remarks, '• a much longer span of life than has hitherto been 

 imagined to be possible for these animals." 



He was also able to satisfy himself that Plate's ^, ^ state- 

 ments as to the discharge of the vascular canals into the cloaca 

 itself in the cases of JRotifer vulgaris and Call, magna applied 

 also to Call, russeola. The two canals unite into a single duct, 

 which opens into the cloaca at the boundary between it and the 

 intestine. There is no separate contractile vesicle such as is found 

 in all other Rotifera, except the Bdelloida, and such as, until 

 these most recent observations, has been assumed to be possessed 

 also by them. The cloaca itself is distensible and contractile, and 

 fulfils the double function of contractile vesicle and cloaca. This 

 new view is strongly supported by Janson,^ who regards the 

 contractile cloaca of the Bdelloida as additional evidence that this 

 group is the primitive group of the Rotifera. 



Gallidina vorax, Janson.* 



Sp. Ch. — Body usually very reddish. Corona very ample 

 and flat. Rostral lamellae somewhat laterally projecting. Spurs ^ 

 width of segment (16-5), with very wide interstice and perforate; 

 four toes; four mucus glands. Rami (23-4-24), with formula |-. 

 Maximum length (440). 



A large form somewhat resembling Call, russeola in build, but 

 easily distinguished by the form of the corona, the tooth-formula, 

 the foot structure, and the very wide interstice between the spurs. 

 The body is described as consisting of 16 segments, of which 

 seven belong to the head and neck, six to the trunk, and three 

 (in all) to the foot. Thus the head and neck have one more 



