DEVELOPMENT OF BALANOGLOSSUS KOWALEVSKII. 511 
Continued Account of the Later Stages in the 
Development of Balanoglossus Kowalev- 
skii, and of the Morphology of the Enterop- 
neusta. 
By 
William Bateson, M.A., 
Fellow of St. John’s College, Cambridge. 
With Plates XXVIII, XXIX, XXX, XXXI, XXXII, and XXXIII. 
PREFACE. 
Tue following paper is descriptive of the figures which 
illustrate my concluding account of the morphology of the 
Enteropneusta. 
As an abstract of some of these facts was given with the first 
paper on “ Later Stages,” &c., a certain amount of repetition 
has become unavoidable. 
Owing to the relation of the parts described in that paper to 
other parts which were not then described, it has unfortunately 
become necessary to refer to figures in that paper on the 
present occasion ; for this reason, the figures of the two papers 
have been numbered consecutively. 
In the ‘ Quarterly Journal of Microscopical Science’ for 
April, 1884, and April, 1885 (Supplement), I gave an account 
of the general development of B. Kowalevskii. The second 
of these papers contained a description of the later develop- 
ment of the notochord of this species, and a comparative 
account of that organ as found in other species. On the 
present occasion the remaining organs will be similarly dealt 
with. 
