one side. The ocecia are more prominent superiorly, the peris- 

 tomial arch thicker and stronger, and the surface occasionally 

 traversed by distinct lines. Some ooecia are coloured a bluish 

 purple, with the margin and peristome a dead-Avhite. 



>S'. dcffdcda, McG. Robe. 



*S'. hyalina, Linn, sp., var. tuhercidata. Robe. 



S, Ridleyij McG. 



S. Smeatoni, n. sp. Figs. 3 and 3a. Zoarium bilaminate. 

 Zocecia in longitudinal lines, separated by furrows, at the bottom 

 of which is a narrow raised line, elongated, raised in the centre, 

 with numerous small perforations ; mouth arched above, lower lip 

 with a wide sinus and a minute denticle on each side. Opercu- 

 lum with a narrow membranous fringe. Ooecia large, granular, 

 traversed by depressed lines, orifice wide, the lower lip with a 

 broad shallow sinus. 



The zocecia at the edge of the zoarium are much elongated, 

 farther back becoming shorter. They are arranged more or less 

 in lines, separated by furrows. The surface is covered with small 

 perforations, frequently arranged in a line towards each margin 

 and one down the centre. They are raised in the middle, and 

 below the mouth there is usually a smooth nodule or umbo. The 

 sinus in the lower lip is wide, tolerably deep, with the angle 

 rounded. On the ooecia there is generally a short, depressed line 

 extending vertically upwards and bifurcating so as to divide the 

 surface into three elevated portions. On the older parts of the 

 zoarium the separating furrows are nearly obliterated. 



HiPPOTHOA, Lamx. 

 H. divaricata, Busk. 



Pete ALIA, JIcG. 

 P. undata, McG. 



PORELLA, Graif. 

 p. jmpiUife7rc, McG. 

 P. marsupiivin, McG. 



PoRiXA, D' Orb igny. 

 P. larvcdis, McG. Semaphore. 



MUCRONELLA, llhicks. 



M. vidtur, Hincks. 



21. tricuspis, Hincks. 



M. dicq^kana, McG. Brighton. 



M. excavata, McG. This species is identical with J/, jjrcestans, 

 described by Hincks from New Zealand. The specimen figured 

 in the Zoology of Victoria had no avicularia, which, in fact, are 

 frequently absent. 



