18 BRITISH STROMATOPOROIDS. 



In the year 1879 appeared several memoirs dealing with the Stromatoporo ids. 

 One of these was a memoir by Principal Dawson on " The Microscopic Structure 

 of the Stromatoporidoe " (' Quart. Journ. Geol. Soc.,' vol. xxxv, pp. 48 — 66), in 

 which he maintained his previously-expressed opinion as to the Rhizopodal affini- 

 ties of these organisms. He altogether rejects the asserted relationship between the 

 Stromatoporoids and the Hydractiniida, as supported by Carter and Steinmann. 

 Two new species are described under the names of Caunopora hudsonica and 

 Coenostroma galtense ; and the Stromatoporo, compacta of Billings is stated to be 

 apparently a true Coral. The author considers that the Stromatoporoids " have 

 apparently always been calcareous when recent." Lastly, the author has some 

 remarks upon some of the genera of the Stromatoporoids, in which he adopts 

 Coenostroma, Winch., in much the same sense as that of its original founder, but 

 includes under Caunopora, Phill., forms which have not usually been placed in 

 that problematical genus. 



In the same publication (' Quart. Journ. Geol. Soc.,' vol. xxxv, p. 67) Mr. 

 Champernowne has a " Note on some Devonian Stromatoporida? from Dartington, 

 near Totnes." This note deals chiefly with the mode of occurrence of 

 Stromatoporoids in the dolomitic limestone of Dartington ; but the author 

 makes the interesting observation that in certain specimens of Caunopora 

 he has seen the tubes not to be open, but to be lamelliferous, and to present 

 " some appearance of a columella." "With regard to the affinities of the Stromato- 

 poroids, the author concludes that " it is difficult to regard them as forming a 

 compact group of Galcispongia}" and adds — what later observations have fully 

 borne out — that they " clearly seem to embrace structures similar to that of the 

 Mill&poridoB." 



In the ' Annals and Magazine of Natural History' (ser. 5, vol. iv, p. 101, 

 1879) Mr. Carter published a paper on " The Mode of Growth of Stromatopora, 

 including the Commensalism of Caunopora." In this paper he maintains that 

 Stromatopora is essentially an encrusting organism, " not only entering into and 

 filling up the open interstices of other calcareous organisms during their growth, 

 but enveloping their detritus." This view is, however, based upon a study of 

 Stromatoporoids of particular species, or growing under particular conditions. 

 There is, of course, no doubt that Stromatoporoids very commonly do enclose and 

 envelop other organisms of all sorts in the course of their growth, and they also 

 occasionally form thin crusts parasitically attached to foreign bodies. A very large 

 number of the Stromatoporoids, however, have an epithecate base, with a single 

 narrow peduncle of attachment, and are no more given to surround other organ- 

 isms than are the species of Alveolites or Favosites, which occur in the same strata. 

 Mr. Carter also now expresses his conviction that the genus Caunopora, Phill., is 

 (as long previously maintained by Ferdinand Roemer) really founded upon speci- 



