148 Eev. T. Hincks's Contributions towards 



Buborblcular, the covering wholly membranous, occupying 

 about three fourths of the front of the cell ; margin much raised 

 round the sides and upper portion of the cell, tliin, smooth, 

 two spines on each side of the orifice^ the foremost pair very 

 tall and stout ; zooecium prolonged slightly below the area, 

 and on this portion is situated an avicularium borne on the 

 summit of a stout and rather tall peduncle, from the lower 

 part of which two spines often project, mandible acute, di- 

 rected downwards ; sometimes replaced by a linguiform 

 avicularium, slightly pedunculate, placed transversely. Zo- 

 arium of a reddish-brown colour. 



Log. Australia, on stone [Miss Gatty). 



The prolongation of the cell below the area is often small 

 and inconspicuous ; but its position is indicated by the 

 stalked avicularium which is always placed upon it. The 

 peduncle of this appendage, which is of remarkable length, 

 seems to consist of two parts — a short tubular base, which 

 frequently bears two spinous processes, and is permanently 

 attached to the cell, and a much longer cylindrical stem, on 

 which the avicularium is supported ; the latter is easily 

 detached, and seems to be jointed in some way or other to the 

 fixed basal portion. The structure is interesting, as showing 

 a modification in the direction of the higher articulate forms. 



Memhranipora hicolor^ n. sp. 

 (PL IX. fig. 1.) 



Zomcia oblong, narrow, alternate, very regularly disposed 

 in lines, the whole front filled in by a membranous wall, at 

 the very top of which is the opercular valve ; margin thin 

 and smooth ; the zooecia in each line separated by elongate 

 spaces, usually rather less than the cell in length, which are 

 covered in by a wliite calcareous roofing, terminating at one 

 extremity in an arch, with a somewhat thickened rim, which 

 incloses the orifice of the cell below, and at the other more or 

 less hollowed out, the depression extending to the base of the 

 cell above. No spines or avicularia. 



Loc. West Australia, spreading over weed [Miss Jelly). 



The elongate calcareous boxes interposed between the cells 

 in this species might naturally be taken for ooecia ; but they 

 are closed in at the end by a calcareous wall, in which there 

 seems to be no opening beyond some minute perforations. 

 They have probably, therefore, some other significance ; but 

 what it may be I am unable at present to determine. The 

 zooecia are really of a slender, elongate-oval shape, though 

 they sometimes appear quadrangular. The membranous 

 front wall extends to the top of the hollow or depression in 



