192 Descriptions of New, 



Port Phillip Heads. 



In a paper in the Proceedings of the Zoological Society, 

 of June, 1881, Mr. Stuart O. Ridley describes this species, 

 from a specimen dredged during the voyage of the "Alert," 

 in the Strait of Magellan, as S. marsupium, M'G. Unfor- 

 tunately, when I drew up my original description of 

 Lepralia marsupium, the specimens I had were worn 

 and imperfect, so that the exact structure of the mouth 

 was not distinctly seen. Consequently the present and 

 the true species, of which I have since procured numerous 

 perfect specimens, have been confounded. In the present 

 paper I give a more correct figure and fuller description 

 of L. marsupium. 



In young specimens of S. Ridley i the mouth, with its- 

 semicircular upper margin and straight lower lip with 

 rounded sinus, is well seen, as well as the small elliptical 

 suboral avicularium, situated on the raised semilunar 

 portion of the cell. In older and more calcified cells this 

 raised portion frequently becomes so developed as to obscure 

 the view of the mouth and avicularium ; in these also there 

 is usually a series of deep grooves, converging from the 

 margin to the raised suboral portion. 



Schizoporella arachnoides, n. sp. Fig. 4. 



Polyzoary encrusting ; cells oval, distinct, convex, smooth ;. 

 mouth arched above, with a deep rounded notch in the 

 straight lower lip ; a series of (usually) seven stiff spines,, 

 several of which, especially the lower, are situated at a 

 distance from the mouth ; ovicell rounded, smooth, the 

 margin usually sculptured. 



Port Phillip Heads. 



This very beautiful species is at once distinguished by 

 the arrangement of the oral spines. These are usually seven 

 in number. The lowest on each side is situated below and 

 to one side of the angle of the mouth, and several others are 

 frequently situated at a little distance from the mouth 

 margin. The edge of the ovicell is usually sculptured, as 

 in Microporella Malusii; sometimes, however, it is smooth. 



Porella marsupiwm, M'G. Fig. 2. 



Cells elongated, distinct, arranged in linear series, surface 

 smooth, minutely punctured or areolated at the margin ; 



