428 



A. W. WATEES 01ST FOSSIL CHILOSTOMATOTJS 



1. Catenicella ceibeieoemis, Waters. 



Catenicella cribriformis, Waters, Poss. Chil. Bry. from S.W. Vic- 

 toria, p. 317, pi. xvi. fig. 39. 



Loc. Fossil : S.W. Victoria and Bird Eock. 



2. Catenicella alata, Thorns. Plate XII. figs. 15, 16. 

 Catenicella alata, W. Thomson, " On new Genera and Species of 



Polyzoa," Zool. Bot. Assoc. Dublin, 1859, p. 80, pi. vi. fig. 4. 



Catenicella alata, Waters, Poss. Chil. Bry. from S.W. Victoria, 

 p. 317, pi. xvi. figs. 47, 48, 49 ; Chil. Bry. from Mt. Gambier, 

 p. 260. 



Catenicella alata, MacGillivray, Nat. Hist. Vict, decade iii. p. 21, 

 pi. xxiv. fig. 7. 



As this seems in many respects to be a very typical Catenicella, 

 we may use it lor distinguishing the various parts of the Catenicella^. 

 I propose to call the bead containing only one zooecium a globulus ; 



Pig. 2. 



av- 



c- 



Diagram of globulus of Catenicella. a, distal tubular connexion ; b, supra- 

 avicularian compartment; c, infraavicularian compartment; d, pedal com- 

 partment; av, avicularian compartment; e, cribriform area; o, aperture: 

 /, zooecial sac. 



those with two zooecia I call a biglobulus. In a globulus there are 

 at the side three compartments, which in the living state are 

 covered with a membrane. The compartment above the avicularium 

 I call the supraavicularian compartment ; that below, the infra- 

 avicularian compartment ; and the lower one, the pedal compartment. 

 This pedal compartment I consider the equivalent of the vittse in 

 such species as C. elegans &c. In C. alata the supraavicularian 

 compartment is very variable, sometimes rising into a prominent 

 spinous process ; in others there is no spinous projection. The other 

 two compartments are not so variable, and are usually of moderate 

 size ; but until the amount of variation in recent species has been 

 carefully studied, it will be very difficult for palaeontologists to de- 

 termine the Catenicella. As the shape of fig. 15 varies so much 

 from fig. 16, I have had some hesitation in uniting it with C. alata ; 



