182 Dr. H. A. Nicholson and Mr. R. Etlieridge, Jun., on 



the entire mass is stratified, each stratum being from 2 to '6 

 millim. in thickness. The diameter of the corallites is 

 about one third of a millimetre. In the outer part of the 

 corallum, when complete maturity has been attained, the 

 corallites, still remaining cylindrical, become annulated with 

 numerous well-marked and close-set rings of the regular 

 Stenoporoid type. 



We were at first disposed to think that Stenopora informis 

 might be the outer portion of a massive Stenopora^ of which 

 S. crinita^ Lonsd., constituted the central or axial portion. 

 We have, however, abandoned this idea upon the ground 

 that the tubes in the deepest parts of the type-specimen are 

 always cylindrical, and are not in complete contact, whereas in 

 S. criuita they are basaltiform and in contact throughout. 

 Moreover the corallites in H. informis have a diameter of only 

 about one third millim., but reach half a millim. or rather more 

 in diameter in S. crinita. 



Locality. Lonsdale gives " Spring Hill, Tasmania," as the 

 locality from which the type-specimen was obtained. [Coll. 

 Brit. Mus.) 



Stenopora crinita^ Lonsdale. (Fl. IV. figs. 1-5.) 



Stenopora crinita, Lonsdale, in Strzelecki's Phys. Descript. New South 

 Wales, p. 265, pi. viii. figs. 5, 5 a (1845). 



Spec, char. Corallum massive or sublobate, of long coral- 

 lites which radiate outwards gently towards the surface. In 

 the axial region of the corallum the corallites are basaltiform 

 and in close contact throughout ; but they become trans- 

 versely wrinkled with narrow periodic annulations as they 

 approach the final period of growth. The corallites are 

 polygonal or subpolygonal, with comparatively thin walls, 

 their average diameter being about half a millimetre, Acan- 

 thopores are developed at all the angles of junction of the 

 corallites, and occasionally in other parts of the walls of the 

 corallites. The walls of the corallites are periodically thick- 

 ened by narrow ring-like annulations, which are found in all 

 regions of the corallum, but are most abundant in the outer 

 or peripheral zone. These annulations are comparatively 

 wide apart, and are separated by long unthickened internodes, 

 giving to longitudinal sections of the wall a characteristic 

 moniliform aspect (woodcut, fig. 2). Tabulge are very 

 sparsely developed in the axial region of the corallum, but 

 are comparatively numerous in the peripheral region, and 

 correspond in general with the thickened segments of the 

 corallites. So far as determined, the tabula? are complete and 

 imperforate. Surface not observed. 



