REVIEW OF SPENGEL’S MONOGRAPH ON BALANOGLOSSUS. 385 
A Review of Professor Spengel’s Monograph on 
Balanoglossus.! 
By 
E. W. MacBride, B.A., 
Fellow of St. John’s College; Demonstrator in Animal Morphology to the 
University of Cambridge. 
With Plates 29 and 30. 
Tue eighteenth monograph of the Naples series lies at 
length before us. As a monument of patient industry and a 
mine of anatomical facts it stands in the foremost rank of 
zoological treatises. It contains minute descriptions of all the 
known species of Balanoglossus, as well as complete dis- 
cussions, not only as to the relationship of this interesting 
form to various phyla of the animal kingdom, but also as 
to the special morphology of every organ in the body of 
Balanoglossus. 
As the conclusions at which Professor Spengel has arrived 
are at variance with the views as to the relationship of the 
Enteropneusta which have been widely held in England for 
the last ten years, it seemed to me that a short account of the 
principal additions to our knowledge contained in the mono- 
graph might be useful to zoological students who lack the time 
necessary to peruse so huge a tome as the one before us. 
I shall append to the account of the new facts brought to 
light a short discussion on Professor Spengel’s views as to the 
phylogenetic position of the Enteropneusta, as it seems to me 
that he has adduced nothing which militates in the slightest 
1 «Die Enteropneusten des Golfes von Neapel und der angrenzenden 
Meeresabschnitte,” J. W. Spengel, ‘Series of Naples Monographs,’ No. 18. 
