NEW TYPE OF APERTURE IN CONULARIA. 247 



Note on a NEW TYPE op APERTURE in CONULARIA. 



By Ohas. F. Laseron. 



With Plate XI. 



[Read before the Royal Society of N. S. Wales, October 4, 1911.] 



So little is known of the structure and systematic position 

 of the genus Conularia that any information concerning it 

 should be of some scientific value. In spite of the great 

 abundance of specimens found in some geological horizons, 

 examples showing the complete aperture are so rare that 

 in only two or three species is the aperture known. As 

 the specimen forming the subject of these notes has the 

 aperture exceptionally well preserved, it is, therefore, 

 worthy of notice. 1 



Conularia c{. laevigata, Morris. 

 (Strzleckis, Phys. Desc. N.S.W., p. 290, pi. 18, f. 9, 1845.) 



The specimen consists of a portion of the test about three 

 inches in length. The section is slightly rhomboidal at 

 the aperture, but this is evidently due to compression for 

 at the lower end it is practically square. All four sides 

 are equal, tapering from '75 to '5 of an inch in width at 

 the extremity. Thus the apical angle is very low, not 

 more than 7°. The sides are slightly convex, and are 

 separated by four deep longitudinal furrows. These furrows 

 are divided medially by ridges, upon which the continu- 

 ations of the transverse ridges alternately terminate. The 

 ridges are thin, angular and numerous, 32 being counted 

 within the space of one inch. They slope from the lateral 

 furrows upwards towards the aperture, and are intersected 

 in the centre of each face by a fine longitudinal mesial 

 ridge, upon which they alternate. 



1 The specimen was exhibited at a meeting of the Linnean Society of 

 N.S.W., see Vol. xxxiv, p. 590, 1909. 



