310 SlDiNEY F. HARMKR. 



method employed, this preparation beiug the only one which 

 I have made with Mayer's cochineal tincture. The species 

 seems, however, to have a special development of pigment, 

 as indicated by Maplestoue.^ The compensation-sac develops 

 as in Vittaticella, 



Catenicella lorica,- Busk. 



The remarkable fertile zocBcia which characterise the 

 g-enus Catenicella are well seen in this species to be 

 pi-ovided with a large compensation-sac, with strong parietal 

 muscles. The three fenestra of the ordinary zooecia appear 

 to perforate only a single thin calcareous layer, the inner 

 laj'er being completely absent. 



Catenicella wilsoni,^ MacGill. 



The great size of the fenestra of the infra-avicularian com- 

 partment makes it an easy matter to see the outline of the 

 large compensation-sac of this species, and the arrangement 

 of its muscles. 



(d) Mi crop or ell oid Genera. 



Under this heading I consider a few of the forms with a 

 "median pore/' though I am by no means certain that all 

 such forms are related to one another. 



Calwellia gracilis, Maplestone^ i^g^- 61, 02). 



The zooecia are in pairs, back to back, the plane uniting 

 the middle line of two zooecia being at right angles to the 



' ' Trans. Proc. Hoy. Soc. Vict.,' xviii, 1SS2, p. 49. 



' Busk (1852), p. 0. 



» MacGillivray, ' Piodr. Zool. Vic.,' Dec. ix, 18S4, p. 30. 



"* The form wliicli I describe in this paper was (ij^iired by Maplestone, willi- 

 out description, in a paper entitled " Observations on Living Polyzoa," in 

 'Trans. Proc. Roy. Soc. Vict.,' xviii, 1SS2, p. 48, fij,'. 9 [the plate has no 

 number]. It lias not the triauf^ular siiape mentioned by VVyville Tliomson 

 (1858) in his original account of C. bicornis. It is not the sjiecies described 

 by !N[acGillivray as C. gracilis in 'Trans. I'roc. Roy. Soc. Vic!.,' xxii, 

 p. 128 ; see also the same journal (N. S.), ii, p. lOG. 



