DEVELOPMENT OF BALANOGLOSSUS KOWALEVSKII. 81 
The Later Stages in the Development of Bala- 
noglossus Kowalevskii, with a Suggestion 
as to the Affinities of the Enteropneusta.' 
By 
William Bateson, B.A., 
Scholar of St. John’s College, Cambridge. 
With Plates IV, V, VI, VII, VIII, and IX. 
In the ‘ Quart. Journ. Micr. Sci.’ for April, 1884, I described 
the early stages in the development of a species of Balano- 
glossus, common on the shores of the Chesapeake Bay. 
I am led from various reasons, which I hope to detail 
when an opportunity occurs for discussing the classification of 
the Enteropneusta, to regard this species as identical with 
that described by Alex. Agassiz, and called by him B. 
Kowalevskil. 
I was again enabled, during the summer of 1884, by the 
great kindness of my friend Dr. W. K. Brooks, to pursue my 
investigations into the morphology of the Enteropneusta. My 
warmest thanks are due to Dr. Brooks for once more 
_ affording me the hospitalities of the Chesapeake Zoological 
Laboratory, which was this year situated at Beaufort, North 
Carolina. While there I collected a number of specimens of 
a large undescribed species of Balanoglossus resembling B. 
salmoneus (Giard). This species, a description of which 
1 A note on the subject-matter of this paper appeared in the ‘ Proc. Roy. 
Soc.,’ No. 235, 1885. 
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