416 E. W. MACBRIDE. 
sections showing this are all taken from a single series ; that in 
the case of the proboscis cavity the transverse section only 
shows a constriction of the gut; and that in the single longi- 
tudinal section figured which shows the anterior ceelom opening 
into the archenteron, there is an abrupt break in the character 
of the cells ; the gut-cells do not, he says, gradually pass into 
celomic cells, thus suggesting that the opening figured is an 
artefact. Now so little is the insinuation justified that Bateson 
founded his results on a single series, that he does not 
express complete certainty as to the original connection of the 
collar ceelom with the gut, because he found the openings of 
communication in ‘ very few” of the larve. Does Professor 
Spengel mean to demand that a zoologist should figure all 
the sections he has obtained which show a certain point? I 
imagine that few editors of scientific journals would relish the 
prospect. His objection to the longitudinal section can be 
met with a direct denial; the section appears to any one 
accustomed to the appearances presented by the developing 
celom of Echinoderms to be perfectly normal, a transition 
from gut-cell to coelomic cells can be made out. It is hardly 
needful to add that the constriction of an anterior cceelom from 
the gut, and a “constriction of the gut,’ are one and the 
same. To what miserably small dimensions the supposed 
“ trochophoral” peculiarities of the Tornaria reduce on 
examination we have shown above; that the principal ciliated 
ring of the trochosphere, the prototroch, is not represented in 
Tornaria, Spengel himself has admitted. The absence of those 
most characteristic organs of the trochosphere, the head 
kidneys, he regards as of little importance, as also the presence 
of a preoral ccelom totally unrepresented in the trochosphere. 
His calm assumption, in defiance of evidence to the contrary, 
that the esophagus and intestine are of ectodermal origin, I 
have dealt with above. In this connection also it should be 
remarked that he mistakenly attributes to Professor Huxley 
the terms stomodzeum and proctodeum, which we owe to 
Professor Lankester. 
In justice, however, to Professor Spengel, we ought to add 
