229 



margin and on either side of this a robust, conical, obliquely ascending spine. 

 The sternal area is i)rovided with a small fenestrse, and each of the lateral sur- 

 faces of the gonozoa^cium with a pear-shaped oval, most probably pedal, lateral 

 chamber. The frontal surface of the covering kenozowcium has 4 — 10 larger or 

 smaller fenestrse of very variable form. When occurring in small numbers several 

 of these fenestras are very large and show by their lobate form, that they have 

 arisen by coalescence of several smaller ones. We may distinguish between an 

 outer, arch-shaped group and a group on the distal side of the ajjerture. All 

 four lateral chambers are developed, and the scapular one ai)j)ears as a small 

 avicularium, while the two su])ra-scapular chand)ers have coalesced into one, 

 which lakes up the entire breadth of the kenozott'cium (lig. 7 a), and which has 

 on either side a vertical, pointed, calcified outer wall. This chamiier has besides 

 a group of rosette-plates in the roof of each avicularium, a greal many scattered 

 plates in the median part, which is separated by a low ridge from the frontal 

 as well as from the dorsal surface of the kenozonecivim. On the outer and the 

 basal side of the avicularium there is a small, oval, infra-scapular chandjer and 

 separated from it a large, trapeziform pedal chamber. 



Form of colony. Apart from the fact that rows of 1 — 5 single zooecia, (which 

 may arise from both a mother- and a daughter-zocecium), may appear as ter- 

 minal branches, the allernalion of uni- and bi-zocecial internodes is otherwise 

 regular, and two bizooecial internodes nowhere succeed each other. 



Of this species I have been able to examine some fragments from Port Wes- 

 tern, Victoria (Miss Jellj). 



Scuticella margaritacea Busk. 

 Catenicella margaritacea Busk, Voyage of Rattlesnake, I, pag. 356, Catalogue of 

 Marine Polyzoa, Cheiloslomata, pag. 9, PI. VI, tigs. 1, 2, 3. 

 (PI. XX, fig. 3 a, 1^1. XI, figs. 5a-5 c). 

 The zooecia rhombic-oval \Vith an aperture, the pi-oximal, more or less con- 

 cave margin of which is provided centrally with a small, well defined, sometimes 

 however quite rudimentary sinus, the entrance of which is bounded by two ex- 

 tremely short spines directed somewhat distally and pointed at the end. These 

 spines are sometimes widely separated, and the sinus then reaches its maximum 

 (colonies from the Bass' Strait), sometimes almost concurrent at the ends and 

 the sinus is then rudimentary or reduced to a pore (Port Phillip Heads). The 

 operculum, which does not entirely till the aperture, has a proximal, concave 

 margin, and the sternal area is provided with five fenestra; disposed in an arch 

 or angularly. The cryptocyst lamina is of a broad, rounded triangular form, and 



