Reviews—Dr. G. Lindstrom—Silurian Corals from China. 87 
occupied in the living state by rudimentary or imperfect polypes.” 
_ Prof. Moseley ! has also recently made a similar statement respecting 
the interstitial tubules in the existing Heliopora, that it is ‘‘ by no 
means improbable that the coenenchyma here is composed of the 
tubes of aborted zooids (siphonozooids).” We may here, en paren- 
thése, reiterate our opinion that there is no true relationship between 
Heliolites and Heliopora; the true distinct septa of the former genus 
cannot be compared with the pseudo-septa of the latter. Professor 
Lindstrém is totally opposed to the views of Nicholson, and believes 
that the tubules in Heliolites are produced by the extension outwards 
of the ends of the septa of the coral. In his view the tubules con- 
sist of the intergrowth of the borders of the individual corallites, 
and from these extended borders new corallites are produced by 
budding. Lindstrom regards the structure of Heliolites as homo- 
logous with that of Acervularia ; so that the cylindrical corallites of 
Heliolites ave equivalent to the central portion of the corallites of 
Acervularia, and the tubules are merely the exterior borders of the 
corallites. It may, however, be stated that, altogether apart from the 
correctness of Nicholson’s views as to the tenants of the interstitial 
tubules, the walls of the cylindrical corallite in Heliolites are too 
distinct and well defined to be compared with the pseudo-walls of 
the interior portion of the corallites in Acervularia. In the beautiful 
representations of the microscopic structure of Heliolites and its 
allied genera Propora, Lyellia, and Plasmopora given by Nicholson 
in plates xi. and xii. of his “ Paleozoic Tabulate Corals,” we fail to 
see any indication that the coenenchyma of these genera, whether 
tubular or cellular, has been produced by an outward extension of 
the septa of the individual corallites. 
Prof. Lindstrém also proposes to abolish the genus Séreptelasma, 
Hall, on account of the insufficient and unsatisfactory definition of 
its characters by its author, and the various interpretations of the 
genus introduced by subsequent writers, and he places the species 
usually included in the genus under Ptychophyllum, Ed. and H., and 
he also embraces therein the genera Strephodes, M‘Coy, Polycclia, 
Dybowski, and Grewingia, Dybowski. 
Our space only allows us to refer to one other subject, touching 
the authorship of the dissertation ‘“Corallia Baltica,” in which 
several of the Silurian corals are mentioned for the first time. It 
is a question which is very desirable to clear up, and therefore we 
cannot do better than give the explanation of Lindstrém in full. 
He says: “It is generally believed by non-Swedish authors that 
Henric Fougt composed this treatise. It is, however, positively 
certain that Linneeus is himself the author of it. The circumstance 
that Fougt’s name, though not as author, is upon the title-page, 
has given rise to this belief. Now it was, till very recently, the 
custom in the Swedish Universities, that candidates for the degree 
of Doctor, or, as it was then styled, Master of Philosophy, should 
publicly defend a Treatise or Dissertation—therefore the words on 
1 Report of the Scientific Results of the “ Challenger,”’ p. 123. 
