110 Descriptions of JS r evj, 



which slopes backwards, and is wide above and contracted 

 below. The lower lip is straight, and has usually a minute 

 rounded sinus, and is destitute of oral avicularium. The 

 slightly thickened sides of the mouth unite at an acute 

 angle with the elevated margins of the cells. The operculum 

 is also of a very characteristic shape, in correspondence with 

 the form of the mouth. Besides the avicularia on the front 

 of the cells and those on the back of the polyzoary, there are 

 frequently one or more with long pointed mandible opening 

 horizontally inwards on the edge of the fenestras. There 

 is also occasionally an avicularium with a semicircular 

 mandible above a fenestra in front. 



R. carinata, n. sp. 



Polyzoary expanded. Fenestras elongated, narrower than 

 the interspaces. Cells ovate, broad, separated by narrow 

 raised margins. Mouth (primary) with the lower lip entire, 

 or (secondary) with a deep sinus at one side and a large 

 avicularium towards the base of the prominent peristome ; 

 operculum rounded above, hollowed below, broader than 

 high. On the inner margin of the fenestras, slightly in front, 

 several avicularia with long pointed mandibles directed 

 vertically from before backwards. Ovicell sub-immersed, 

 pyriform, with a vertical sharp ridge slightly bulbous at its 

 upper- extremity. Dorsal surface granular, traversed by 

 slightly raised vibices, and with a few rounded avicularia 

 about the edges of the fenestras. 



Port Phillip Heads. 



The only specimen I have seen is quite perfect, and forms 

 a waved, somewhat fan-shaped expansion seven-eighths of an 

 inch wide by about three- fourths deep. It is of a beautiful 

 orange colour. The cells are mostly broad, prominent, tuber- 

 cular, and glistening. The mouth is broad, arched above, 

 and in the youngest seems to be entire and straight below 

 or slightly convex. The peristome is rapidly developed on the 

 lower lip, projecting as a plate with a deep notch at the 

 angle of the mouth on one side, and receding gradually from 

 this to nearly the level of the opposite angle, but without 

 any notch at that side ; the margin is frequently finely 

 serrated. There is a considerable, prominent avicularium 

 below the lower lip, with the broad mandible directed 

 upwards and usually inclined to the angle formed by the 



