306 SIDNEY F. HARMER. 



Vittaticella coruuta,^ Busk (fig. 56). 



Maplestone" has recently suggested the generic name 

 Vittaticella for the " vittate " species of Catenicella^ the 

 subdivision of which appears to me desirable. 

 - Fig. 56 shows that Vittaticella is provided with a well- 

 developed compensation-sac (c. s.). The younger zooecium 

 further illustrates the fact that the development of this 

 structure is typically Lepralioid. The sac is figured by 

 Jullieu (1888^ 3, pi, xi), in two species of Catenicella^ iu 

 both the young and the adult condition. A wide crescentic 

 opening into the sac is seen in the younger zooecium (hg. 56) 

 between the base-line of the operculum and the proximal 

 border of the orifice. Amongst the parietal muscles which 

 radiate from the wall of the sac can already be distinguished 

 a distal group {j). 'in.'), the future divaricator muscles. In the 

 next zooecium the compensation-sac is so large as to underlie 

 nearly the whole of the frontal surface. 



Each vitta [v.] is a tubular cavity, running longitudinally 

 along the edge of the zooscium, and bounded externally by a 

 delicate uncalcified membrane. The cavity communicates by 

 a single series of funnel-shaped tubes with the body-cavity.^ 

 In the young zooccia the whole of this arrangement is tilled 

 with a brilliantly staining cellular material ; but the structure 

 is identical in the older zooocia, in which remains of cells 

 may still be made out. 



1 refer to the morphology of the vittio below when dealing 

 with Catenicella hastata. Their function is_, perhaps, to 

 assist in the deposition of the calcareous wall. Tlie 

 zooecium in this species is strengthened by a great thicken- 

 ing of its edge, which is more pronounced iu the i-egiou 

 of the vitta than elsewhere. The vitta extends along the 

 whole length of the lateral thickening, and in the more 

 elongated zooccia it may have as many as ten pores. 



' Busk (fS52j, p. 11. 



= 'Proc. Koy. Soc. VicL.' (N. S.), xiii, I'JOl, p. 201. 



' Cf. Waters (1881), p. 318. 



