102 Prof. G. Lindstrém on the 
enormously long birotulates of Mr. Potts’s Heteromeyenia angy- 
rosperma (‘ American Naturalist,’ Dec. 1883, p. 1296, fig. 13, 
e, f), in which one set are very long indeed and the other 
comparatively short; thus the former project much beyond the 
latter on the statoblast, which renders its surface correspond- 
ingly irregular. Nor is the size alone of the cells of the par- 
enchymatous structure of any use specifically, as I find from 
a variety of Spongilla fragilis just (12th January) received 
from Mr. Potts, in which there are all sizes mixed together 
like the bubbles in froth. 
XIL—A Reply to the Remarks of Prof. Duncan on a Paper 
entitled ‘* Contributions to the Actinology of the Atlantic 
Ocean.” By G. LINDSTROM. 
Tn the ‘ Annals and Magazine of Natural History’ for De- 
cember 1883, Prof. Duncan has thought proper to criticise 
a paper of mine which was published in 1877. Prof. Duncan, 
who during the interval of seven years “ felt no disposition ” 
to “reply” to me, now finds it necessary not only to “re- 
consider’’ my paper, but to use language by no means con- 
sistent with the quiet tone that ought to prevail in scientific 
discussions. 
Prof. Duncan seems to think* that I, convinced of my 
errors, especially through his writings, ought to have re- 
canted my statements long ago, and admitted that they were 
erroneous. I have not done so—first, because I am not con- 
vinced that I am wrong to the extent Prof. Duncan supposes ; 
secondly, because I could not admit facts solely upon the 
dictum even of Prof. Duncan himself; thirdly, because I have 
not had occasion to revert to this matter specially until now, 
when I am compelled by Prof. Duncan’s uncalled-for attack, 
much against my will, to turn from more urgent occupations. 
Premising that a great part of his criticism consists of a 
recapitulation of remarks already made by Pourtalés and 
Moseley, and with which zoophytologists have been long 
conversant, I shall now try to reply to the points put forward as 
Prof. Duncan’s own animadversions. 
Caryophyllia Pourialesii, Duncan.—I was led to give this 
* “JT hoped that time would bring some remarks from him..... . 
These researches [of Duncan, Pourtalés, and Moseley] might have 
modified Prof, Lindstrém’s views; but as theydo not appear to have done 
so,” &e, (Ann. & Mag. Nat. Hist. Dec. 1883, pp. 361, 362). 
