52 



SCIENCE 



[N. S. Vol. XXXIV. No. 863 



gulfing a certain number of nettles, meta- 

 morphose directly into cnidocysts. 



On page 2Y5 Professor Kepner quotes Gros- 

 venor througii me, and adds " likewise no one 

 can have witnessed the discharge of nema- 

 tocysts of Microstoma when stimulated by 

 pressure or acetic acid without looking upon 

 them as organs of defense." Yet both Cuenot' 

 and I proved that the defensive value of the 

 nettles is slight if not negligible, whereas in 

 1909' I showed that under certain conditions 

 (pressure, acetic acid) the discharge of net- 

 tles, even when enclosed in mother tissues or 

 in eolids, may be no more the outcome of 

 physiological stimulation than the explosion 

 of a pistol is the result of a " stimulated " 

 trigger. 



In conclusion. Professor Kepner raises the 

 question whether eolids have " acquired their 

 method of dealing with nematocysts of ccelen- 

 terates through flatworm ancestry." To any 

 one acquainted with the relationships, not 

 only of molluscs, but of the particular ones 

 under discussion, this question is a bit sur- 

 prising, for not only is the supposed flatworm 

 ancestry of the mollusca exceedingly prob- 

 lematical, but gastropods are not primitive 

 molluscs, nor are nudibranchs primitive gas- 

 tropods. One would certainly expect indica- 

 tions of the " nematocyst-habit " in primitive 

 forms if there were any reasonableness in the 

 phylogenetic point of view as applied to this 

 problem. Otto C. Glaser 



Maeine Biological Laboeatoey, 

 Woods Hole, Mass., 

 June 22, 1911 



DOUBLE MUTANTS IN SILKWORMS 



To THE Editor of Science: Eeferring to 

 Professor Kellogg's interesting report on 

 " Double Mutants in Silkworms," in 

 Science of May 19, 1911, I would call atten- 

 tion to the fact that in his original publica- 

 tion the puzzling data regarding the inherit- 

 ance of the white cocoon character is made 

 clear by the assumption of two kinds of 

 white, one dominant to color, the other reces- 



•< Arch, de Zool. Exp., 46 S., T. 6. 



' Journal of Experimental Zoology, Vol. IV. 



sive to color. In some of his original data 

 certain individuals were evidently heterozy- 

 gote for these two kinds of color. The recog- 

 nition of both a dominant and a recessive 

 white will also explain some of the puzzling 

 phenomena reported in the more recent data. 

 W. J. Spillman 



EXPLODED theories AND THEOLOGICAL PREJUDICE 



These are expressions used in Professor 

 White's review of the new edition of " The 

 Ice Age in North America." The exploded 

 theories mentioned are " the Calaveras skull," 

 " the Lansing man " and " the Nampa fig- 

 urine." The error concerning the Calaveras 

 skull figured by Whitney is freely granted in 

 the book. But that there was a skull found 

 as described, and other remains of man, in the 

 auriferous gravels is still supported by a sufS- 

 cient amount of convincing evidence to com- 

 mand attention. 



As to the Nampa figurine, I am not aware 

 that any one has brought anything but the- 

 oretical considerations to bear against the 

 evidence originally collected by Charles 

 Francis Adams and his associates immedi- 

 ately after its purported discovery; while the 

 theoretical considerations are based, as I have 

 shown, upon misunderstanding of the geolog- 

 ical conditions. The cataclysm connected 

 with the bursting of the upper barriers of 

 Lake Bonneville, and the pouring of its 

 waters into the Snake River valley must be 

 reckoned with before the conditions reported 

 at Nampa are set down as incredible. 



The facts relating to the Lansing man are, 

 I think, sufficiently set forth in the book to, 

 at least, merit attention. If we are to accept 

 every attempt to explode a theory as success- 

 ful we shall soon come to a standstill in our 

 discussions. 



As to theological prepossessions, I only 

 remark that it is as easy to impute anti- 

 theological prepossessions, as to suspect the- 

 ological bias. In any event the facts them- 

 selves should not be overlooked. Let us have 

 fair play. G. Frederick Wright 



Obeklin, O., 

 June 17, 1911 



