Zoology] NATURAL HISTORY OF VICTORIA. \Polyzoa. 



Plates 96-7. 

 RETEPORA MONILIFERA (P. McGil.). 



[Genus RETEPORA (Impekato). (Sub-kingd. Mollusca. Class Polyzoa. Order Infun- 

 dibulata. Sub-order Cbeilostomata. Earn. Escharidae.) 



Gen. Char, — Polyzoaiy stony, reticulated. Cells opening on one surface only, immersed, 

 indistinct posteriorly. Posterior surfaces vibicate.] 



Description. — Polyzoary foliaceous, variously convoluted; fenestra oval, 

 narrower than the interspaces ; cells separated by narrow, raised lines, convex, 

 smooth or granular ; primary orifice arched above, straight below, or hollowed, or 

 with a minute sinus; secondary orifice with a sinus in the lower lip, permanently 

 open, or becoming closed, at one side of which is generally a small oval avicularium ; 

 operculum arched above, straight below; usually an elliptical avicularium on the 

 front of the cell, and others of various forms on different parts of the polyzoary; 

 ovicells prominent, rounded, or pyriform, with a beaded or granular band above the 

 orifice from which extends upwards a similar vertical band ; dorsal surface vibicate, 

 granular. 



References. — MacGillivra}', Tr. Roy. Soc. Vict. 1859 and 1883; Hincks, Ann. 

 and Mag. Nat. Hist., May 1878. 



This abundant species presents several forms so marked that it 

 may be doubtful whether they ought not to be considered as species. 

 In all, however, the mouth has essentially the same structure, a 

 fissure in the lower lip of the peristome with a small avicularium 

 at one angle of the opening. This fissure is sometimes closed by 

 the complete or partial coalescence of the opposite sides leaving 

 only a loop-shaped mark, or the lower end remaining perforated 

 by a round foramen. The angle supporting the oral avicularium 

 is frequently much produced forwards. The other avicularia are 

 extremely various. There is generally an elliptical one on the 

 front of the cell, and forms with semilunar mandibles are common. 

 On the inner edge of many of the fenestrae one or more are found 

 with long narrow mandibles closing in a rostrum which has a sharp 

 tooth on each side towards the point. These open horizontally 

 inwards. In all, the ovicell is prominent and marked by a beaded 

 line immediately above the orifice from the middle of which a 

 branch extends vertically upwards. In sinuata the upper part of 

 the vertical line frequently projects considerably forwards, in 



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