No. 388.] CORRESPONDENCE. 369 
skeleton of Limulus” (Fig. 5 A). The diagrams do resemble each 
other very much no doubt, but the Limulus diagram can hardly be 
regarded as an accurate representation of the cartilages of that 
animal, as may be seen by comparing it with a drawing made directly 
from the object itself (Fig. 6). This figure is copied from one in a 
paper about to be published by Mr. Redenbaugh and myself, on the 
cartilages of Limulus, Apus, and Mygale. It is not easy to account 
for the construction of Mr. Gaskell’s extraordinary diagram, since 
the endosternite of am adult Limulus is, roughly, two inches wide by 
three inches long, and several millimeters in thickness, a single heavy 
plate of tough cartilage, not readily broken or distorted. It has, 
moreover, been repeatedly figured and described, and Gaskell has 
himself dissected it and studied its histological characters. 
Papers like the ones we have just reviewed are unfortunate. They 
are not a credit to the science of comparative morphology, and the 
interest in the whole subject of the origin of vertebrates suffers from 
the reaction induced by such efforts. 
WILLIAM PATTEN. 
HANOVER, N. H. 
