or Little Known, Polyzoa. 109 



considerably greater size. The convolutions of the poly- 

 zoary form large calyculate or funnel-shaped cavities, and 

 are not closely plicated, as in the form monilifera. The 

 peristome is usually much elevated forwards, with a loop- 

 sharped mark or occasionally a fissure, on one angle of which 

 is a small avicularium. This avicularium is very frequently 

 absent. It is also sometimes very much elevated on a pro- 

 duction of the peristome. There is occasionally a thin spine 

 at each side of the mouth above, but I have never seen the 

 large jointed spines found in the other forms. 



Two varieties are distinguishable. In the one, lunata\ 

 the supra-fenestral avicularium has the mandible semilunar 

 or semicircular and very large, and the loop of the peristome 

 is usually imperforate. In the other, acutirostris, which 

 is also usually altogether stouter, the supra-fenestral avicu- 

 larium has an enormous pointed mandible, and the peri- 

 stome of the lower lip is usually perforated. Occasionally 

 both forms of large avicularia occur on the same specimen. 



R. formosa, n. sp. 



Polyzoary expanded, twisted and convoluted so as to 

 form large funnel-shaped compartments. Fenestras rounded 

 or oval, narrower than the interspaces. Cells elongated, 

 raised and expanded above, separated by distinct raised 

 lines, surface minutely granular. Mouth sloping backwards, 

 narrowed below, the thickened lateral margin uniting at 

 an acute angle with the raised cell-margin ; the lower lip 

 straight, with a minute notch. Usually an elliptical avicu- 

 larium directed vertically or obliquely on the front of the 

 cell towards the middle or to one side. Ovicell large, 

 prominent, a small beaded band on each side above the 

 aperture, meeting at an angle in the middle, and extending 

 vertically upwards to end in a slightly clavate extremity. 

 Posterior surface strongly vibicate, granular, and with 

 numerous elliptical or rounded avicularia close to the edges 

 of the fenestras. Operculum expanded upwards, slightly 

 contracted below, higher than broad. 



Port Phillip Heads, 10 to 18 fathoms. 



This beautiful species in the appearance and size of the 

 polyzoary resembles the munita form of R. monilifera. It 

 is, however, at once distinguished by the form of the mouth, 



