582 The American Naturalist. [July, 
il. 
In the article in the NATURALIST (p. 923), Dr. Ayers claims 
to “have ascertained that, taking all the Bdellostomids together, 
they form a series in which the gill variation runs between 
the minimum of 6 pairs and the maximum of 14 pairs, or a 
DIFFERENCE BETWEEN THE EXTREMES OF 8 PAIRS OF GILLS, 
AND YET ALL THESE INDIVIDUALS NOT ONLY BELONG TO THE 
SAME GENUS—THEY BELONG TO THE SAMESPECIES!” (Big type 
and exclamation mark are Dr. Ayers’ own). 
In “ Biological Lectures” delivered at Woods Holl in 1893, 
lately published, is reproduced (pp. 125-161) a lecture by Dr. 
Ayers on “ Bdellostoma dombeyi Lac.; A study from the Hop- 
kins Marine Laboratory.” Therein Dr. Ayers has urged at 
length the contention just cited and has categorically stated 
that “the number of gills of individuals from different localities 
varies from 6 on either side to 14 on either side, with the 
observed intermediate stages” (p. 137). 
Dr. Ayers’ own record of his observation (p. 140) and sum- 
mary of those of his own as well as of others (p. 156) will be 
an all-sufficient refutation of this claim. 
“Tn the material which [he] was able to collect at Monterey, 
the following proportions of the several variations prevailed : 
104 individuals had 11 gills on both sides. 
96 [11 [11 Tl ét [14 
one side. 
and 12 *  * the other side. 
+ 2U8 " had12 “  * both sides. 
11 e " ID "- * ooo Hae 
and 13 *  * theother side. 
8 T had13 *"  * both sides. 
354 total number of individmals counted.” 
In his summary of observations on the number of gills, he 
gives formulas for all observations as follows :— 
Ee tie HIN og eee Me gee TERES E MER Oak. DR OS T Aer aes Ve Re EE e enm 
