47 
The tahiihe of the Australian species appear to me to he undoiiljteclly 
complete, and their concavity is downwards. I have never seen an instance 
of a perforated tabula in the proper sense of the word, and I believed that 
the supposed incomplete tahuloe seen liy Prof. Nicholson and the Writer in 
S. australis^ are capable of explanation, by regarding the secondary infilling 
of the tubes in this and other species as of post-mortem origin, or, at any 
rate, accumulated under exceptional circumstances. Under the speciiic 
description of S. iasmaniensis it will be explained that the final closure of 
the mouths of the corallites cannot he explained in the sense of perforated 
tahulre. The misconception which may arise in connection with the closure 
of tubes by the zooids at the final period of growth is well exj)lained by a 
study of the tube infillings of Stenopora crinita (PI. Ill, Pig. G ; PI. VI, 
Pig. 3) . Many of the tubes would, on a superficial examination, he pronounced 
as so closed, hut the structure here exhibited arises from a regular concentric 
deposit of mammillated or concentrically-laminated carbonate of lime, with 
the edges of the layers cut across. A longitudinal view of the deposit in the 
corallites of the same species further explains its phenomenon (PI. VII, Pig. I.) 
In the article last referred to we pointed out how these supposed 
perforated tabulae differed from the undoubted structures of this nature in 
Stenopora Hoiosei, Nidi., in which tlie tabulae are very numerous, bearing 
central apertures quite apparent in long sections. It is probably for a 
similar coral that Mr. John Young^ has proposed the generic name of 
Tahullpora, but, excepting the structure of its tabulae, it agrees in every 
way with that of Stenopora. "We have already explained'^ that “if no 
other species of Stenopora possessed perforated tabulae there would be 
ground for accepting Tahullpora as a suli-genus of Stenopora, or, perhaps, 
as a distinct genus.” The view here adopted of the tube infillings of 
iS. australis, and the final closure of the mouth in S. tasnianlensls, will 
remove the doulits hitherto existing as to the validity of Tahullpora, 
which must be restored to its place as a distinct and separate genus. 
The nearest allies of the genus Stenopora are Gelnltzella, and the 
above-mentioned Tahullpora. The distinction between the first and the last 
of these genera has just been indicated. That between Gelnltzella and 
Stenopora appears to me to rest on a very slender basis, and to require further 
' Ann. Mag. Nat. Hist., 1886, XVII, p. 176. 
- Ann. Mag. Nat. Hist., 1883, XII, p. 154. 
^ Ann. Mag. Nat. Hist., 1886, XVII, p. 177. 
llct 50—91 H 
