APPENDIX A. (LONSDALE ON CORALS.) 
629 
How far a perfect examination of the numerous fossils which have been considered referable to Fenes- 
tella may suggest the necessity of forming subgenera, the describcr cannot offer an opinion, many of the 
published species not having been accompanied by detailed illustrations ; but he would suggest for the 
consideration of the palaeontologists, who may pursue the inquiry, the following generic characters for 
Fenestella : — 
A ramose, cellular, calcareous polypidom; cells variously distributed on one side of the branches, with or 
without dividing ridges: branches connected by transverse or oblirjue processes, cellular or not, forming gene- 
rally expansions or funnel-shaped bodies ; the latter with the cellular surface sometimes on the inner, some- 
times on the outer side ; cells cylindrical, obliquely arranged, overlying, mouths inclined outwards, more or less 
distant ; interior of mature specimens, a layer of vertical capillary tubuli ; reverse side of young specimens, 
the layer of tubuli if mature specimens, a crust perforated by minute pores ; in aged specimens both cellular 
and reverse surfaces greatly thickened, all external ribs or sculpturing obliterated, and oral apertures more 
or less contracted ; a row of foramina or chambers between the parallely disposed cells, or a small shallow 
cavity over the mouth in species with cells in quincunx. 
In the tabular list of Permian fossils given in page 255, eight species of Fenestella are included ; but 
only Fen. infundibuliformis and Fen. retiformis claim particular attention, Fen. antiqua and Fen.? dubia 
being included in the list on the authority of Schlotheim, and the other four species. Fen. anceps, Fen. 
flustracea, Fen. ramosa and Fen. virgulacea, not having been discovered in Russia. For an opportunity 
of examining a fine series of English and continental specimens, the author is indebted to Mr. King, 
Curator of the Museum of the Natural History Society of Northumberland and Durham ; and under- 
standing that that gentleman purposes to publish a monograph of British magnesian limestone fossils, he 
feels it is totally unnecessary for him to offer any remarks on the English species, further than his belief 
that they possess all the essential structures of Fenestella;. With respect to Fen. anceps, which exhibits 
a peculiar mode of growth, he conceives that, unless this character be accompanied by other more im- 
portant differences, it should not be regarded as the grounds for a generic separation. 
Fenestella infundibuliformis. 
Irregularly bifurcated; branches compressed, broad; rows of cells exceeding two, alternate ; capillary tubuli 
distinct ; no external layer exhibited on the reverse side. 
Gorgonia infundibuliformis, Goldfuss, Petrefacta, p. 98. pi. 3G. fig. 2a (Ural); De Blainville, Man. 
d’Actinol. p. 506. 
The principal fragment of the coral assigned to tills species scarcely exceeded three lines in height and 
width, but it agreed perfectly, so far as it could be compared, with the Ural fossil figured by Goldfuss. 
Under the same name that authority has also included the Escharites retiformis of Schlotheim from the 
Zechstein of Thuringia, and another polypidom from the older palaeozoic rocks of Wiipperfurt. Con- 
fining, however, the attention to the Permian or zechstein corals, a comparison of figure 2 a in plate 36 of 
the * Petrefacta,’ and the Russian specimen collected by Mr. Murchison with figures 2 5, 2 c, proved a 
perfect want of agreement in the form and arrangement of the branches as well as of the cellular open- 
ings, especially as the Russian specimen was evidently not aged. It was therefore considered right to 
adopt M. de Blainville’s limitation of the specific name infundibuliformis to the Russian fossil (loc. cit.) 
and to retain M. Schlotheim’s retiformis for Fenestella;, agreeing in character with the zechstein polypi- 
dom of Thuringia. The imperfect condition of the specimen did not permit any structural details to be 
ascertained, demanding special notice. 
Locality and Formation. — Ilchegulova, in the Government of Orenburg. Permian. 
4 M 
