Dr. Dawso7i's ' Dawn of Life. ^ 367 



In one case Dr. Dawson has departed from his usual plan : 

 he has represented in figure 18 c?, page 67, a '' seiiDentine cast 

 of a chamber, decalcified, and showing casts of tubuli" — in 

 other words, having " a tubulated cell-wall preserved with 

 structure similar to that of Eozoon canadense^^ (p. 91). Now 

 with reference to this case we would simplj ask Dr. Dawson 

 why, while accepting its processes as " casts of tubuli," he 

 rejects the Isle-of-Skye " grain A x " of serpentine, which 

 " has its surface quite hispid with separated aciculi " *, and 

 pronounces the latter processes to be eminently " crystals"? 

 In our example the aciculse are so plainly represented and 

 designated that it is unaccountable how the author of ' The 

 Dawn of Life ' could allow himself to apply a misleading epi- 

 thet to them, and to speak otherwise of those belonging to his 

 so-called "curious organisms." 



The next new figure to be refen-ed to (fig. 31, J), although 

 it does not represent a decalcified specimen, affords any thing 

 but a proof in favour of Eozoonism, inasmuch as it represents 

 a foraminiferal impossibility — " tubuli " passing off" obliquely 

 and tangentially from the chamber-casts, to the exclusion of the 

 "canal-system" and the "intermediate skeleton." Dr. Dawson 

 himself seems to have little faith in this " anomaly," as it has 

 been called by Dr. Carpenter, since it is not introduced into 

 his " restoration oi Eozoon. '''' 



The last figure requiring notice (top one in fig. 49, h, p. 176) 

 represents another kind of " anomaly," and equally a forami- 

 niferal impossibility — the under side as well as the upper side 

 of the " intermediate skeleton " furnished each with a " proper 

 wall" {a and a'), thereby making the pseudopods of the wall a 

 to project into the skeleton instead of the surrounding water ! 



6. ^^ Stromatoporoid successors of Eozoon " f. 



Dr. Dawson frequently introduces these fossils in a way to 

 produce the impression that they form important evidences in 

 his favour : this will be observed in the " short answer " he 

 has offered to one of our " objections " (the 21st, p. 191). 



In order to justify himself Dr. Dawson nowhere counte- 

 nances the idea that the Stromatoporids are either sponges, as 

 entertained by some, or corals, as believed by others ; but he 

 regards them as Rhizopods, " nearly akin to Foraminifers." 

 Our respected opponent even goes so far as to declare in regard 

 to two species (or their " canals ") that he has " no doubt they 



• Proc. Kuy. Irish Acad. vol. x. pi. xliv. fifr. 10. 



t The Strom atoporas, representod by the common S. concetitrica, form 

 a family, appropriately termed iStromatuporida. 



