REVIEW OF SPENGEL’S MONOGRAPH ON BALANOGLOSSUS. 405 
examined. Spengel states also that he has proved that the 
pericardium originates from the dorsal ectoderm. Here again, 
however, his main proof is one thick section, and again his 
results have been contradicted by Morgan. It throws con- 
siderable light on the prejudice with which Spengel has 
approached the discussion of the results obtained by other 
workers, that on this meagre evidence, and the assumption that 
the intestine is a proctodeum, he should maintain as probable, 
not only the ectodermic origin of the pericardium, but also 
of all the other celomic cavities in the animal. His theory 
of their method of formation is illustrated in Pl. 29, fig. 7. He 
assumes because they are ciliated and separated by constric- 
tions from the stomach that both cesophagus and intestine are 
of ectodermal origin. The trunk ccelom arises from the latter, 
and he supposes the collar celom to be segmented from it—a 
process which he compares to the segmentation of the meso- 
dermic band of an Annelid. He supposes the proboscis cavity 
to arise as an ectodermal ingrowth, and that the pericardium is 
its fellow, in spite of the fact that the probocis cavity is (apart 
from the pore) a bilaterally symmetrical structure, and that 
the pericardium is a median one. 
Bateson, without definitely committing himself, suggested 
as probable that the gonads were derived from the ectoderm. 
Spengel, by the examination of young adults, has shown that 
their connection with the ectoderm is secondary, and supposes 
that they are derived from mesenchyme cells. Morgan has 
proved them to originate, as in all other Ceelomata, from the 
peritoneum. 
Affinities of Enteropneusta with Chordata. 
We have now reached the section of the monograph dealing 
with Professor Spengel’s views on the relationships of the En- 
teropneusta and the morphology oftheir organs. These views 
may be briefly summarised thus: he denies utterly their rela- 
tionship to the Chordata, and suggests, instead, distant Annelid 
affinities. 
I shall briefly recapitulate the arguments for the Chordate 
