148 
G. W. Lee — Trepostomata. 
enough for its time, and Stenopora found a general acceptance ; but owing to the non¬ 
recognition of the taxonomic value of internal characters, it was made to cover a 
heterogeneous assemblage of forms which happened to agree in their external features. 
Nicholson was the first to undertake a revision 1 of the genus based on modern 
methods of research, and the examination of topotypes led to a diagnosis in which stress 
is laid on the beaded appearance of the walls as seen in long sections. The tabulae are 
described as complete. In “ The G-enus Monticulipora ” and in his memoirs in 
collaboration with Mr. R. Etheridge, Jun., 2 complementary descriptions are given, the 
important point of which is that the tabulae are then regarded as perforate. The modern 
interpretation of the genus rests essentially on the labours of .these two authors, and is 
thus summarised by Ulrich :— 
“ Zoaria ramose, sub-lobate, massive, laminar or parasitic. Surface even or 
montiferous. Zooecia-walls periodically thickened in the mature region. Large 
acanthopores at many of the angles between the zooecia. Mesopores never very numerous, 
irregularly distributed. Diaphragms sometimes very scarce, but in most American 
species abundant in the peripheral region, and with a large central perforation. Sub- 
carboniferous to Coal Measures.” 3 
The above interpretation being now firmly rooted in modern literature, it is un¬ 
fortunate that it has to be modified owing to the fact that an important memoir of 
Mr. Etheridge, containing an unexpected emendation, somehow failed to be noticed in recent 
works, although it was published in 1891 4 . Mr. Etheridge, after a renewed examination of 
Australian topotypes is led to the conclusion that in the genus Stenopora the tabulae are 
really complete 5 , as stated by Nicholson in his first description. According to Mr. Etheridge, 
a peculiar accumulation of calcite, of post-mortem origin, produces a deceptive appearance, 
previously intepreted by Nicholson and himself as being that of perforated tabulae. Mr. 
Etheridge’s view is strengthened by the fact that the Indian Stenoporae described by Waagen 
and Wentzel 6 , which are closely allied to the Australian species, are delineated as having 
complete tabulae. Using Mr. Etheridge’s description as a basis, the emended diagnosis 
of the genus Stenopora is as follows :— 
Zoaria ramose, sub-lobate, massive, frondescent, laminar or parasitic. Surface even 
or with maculae and monticules. Zooecia-walls usually periodically thickened in the 
mature region, but sometimes of uniform thickness. Acanthopores present. Mesopores 
absent, but a cell smaller than the average is occasionally present at the junction- 
25, p. 168. 2 28, 29. 3 44, p. 277. 4 7. 5 Op. cit., p. 47. 6 49. 
