4 
was established in 1878 by Nicholson and R. Etheridge for the reception 
of Paldeopora favosa M’Coy (1850 and 1851) from the Craighead lime- 
stone, near Girvan, Scotland. There are several specimens of this species 
in the Sedgwick Museum including two syntypes, which were used as the 
basis for M'Coy’s somewhat idealized figures (1851). These are S.M. 
A5526a (for Plate Ic, figures 3, 3c, and ? 3d) and A5527 (for Plate Ic, 
figures 3a, 3b) (Plate I, figures 2, 4a, b; Plate II, figures 3a, b). Thin 
sections have been made of these and other specimens. In the first place 
a question relating to the original description must be considered. M’Coy 's 
figures, Plate Ic, figures 36, 3a, show what are called in the description of 
plates “ intervening polygonal tubuli ” in the wall between corallites. 
Nicholson and Etheridge (1878, 28), however, w’ere unable to see this 
structure in their material. Edwards and Haime (1851, 250), apparently 
on the s-trength of this described coenenchymal s-tructure, make Palaeopora 
favosa a synonym of Heliolites inter stincta. T]ie present writer has care- 
fully examined the original specimen of the figure in question and finds 
that a bryozoan has at some time encrusted part of it and a very thin 
film of this remains on one corner, so that the solid corallite wall appears 
to have the polygonal structure that really belongs to the overlying and 
nearly transparent bryozoan. 
Kiaer (1929, 62) has revised the family Lyaporidae. He finds there 
are two genera: Lyopora Nich. and Ether., and Reuschia Kiaer. The 
former he diagnoses (62, 63) as “Lyopora Nich. and Ether. The coralla 
are close or more spreading fasciculate, to massive, basaltiform. The 
corallites are most often thick-walled with strong relatively rare tabulae.” 
Kiaer recognizes two species, L. incerta (Billings) i=Colu7nnaria incerta 
Bill. 1859, and Fletcheria incerta (Bill.) Lambe 1899), and L. favosa. 
Kiaer describes L. favosa as very common in the Mjos limestone 
(upper part of the Middle Ordovician) of Norway. He first recorded it 
as Calapoecia sp, (1897, 40), but after comparing it with material from 
Girvan changed his opinion. In discussing Lindstrom’s suggestion that 
Lyopora might possibly be congeneric with Calapoecia, Kiaer says (60) 
“ The skeleton in this case must be so strongly thickened that the mural 
pores have entirely disappeared. Nevertheless, there is very little likeli- 
hood of such a relationship, as it has never been possible in Lyopora to 
prove the presence of coenenchymal structure between the corallites. 
Neither does the coral, wdth its massive tabulae, show the slightest resem- 
blance to known forms of Calapoecia ” (translated). The last two remarks 
are not true reasons for opposing the amalgamation of the genera, because 
coenenchymal structure is not a generic character in Calapoecia, and also 
the external form of Lyopora is in many cases very similar to that of certain 
Calapoecias, where the septa are obscured in preservation and differ only 
in the thickness of elements and remoteness of tabulae in the former genus 
(four in 5 mm.). 
Although thin sections of Lyopora favosa show very thick and solid 
walls, the reverse of the cribriform condition diagnostic of Calapoecia, this 
species cannot be dismissed so readily from consideration of the synonymy. 
All the material of L. favosa that the writer has examined is probably 
strongly recrystallized and it seems to him that the features considered 
