MORPHOLOGY OF BATHYNELLA AND ALLIED CRUSTACEA. 489 
Notes on the Morphology of Bathynella and 
some Allied Crustacea. 
By 
W. T. Caiman, D.Sc. 
(Published by permission of the Trustees of the British Museum.) 
With 14 Text-figures. 
Contents. 
page 
I. Introductory ..... 489 
II. External Characters of Bathynella . . 490 
III. Internal Anatomy of Bathynella . . 500 
IY. Development of Bathynella . . . 502 
Y. The First Thoracic Somite in the Syncarida and 
other Malacostraca .... 502 
YI. The Mandibular Groove in the Syncarida . 506 
YII. The Degeneracy of Bathynella . . . 508 
YIII. The Classification of the Syncarida . . 509 
IX. The Affinities of the Syncarida . . 512 
X. List of Papers referred to . . 513 
I. Introductory. 
The recent re-discovery of Bathynella natans by P. A. 
Chappuis (1914a, 1915) 1 throws welcome light on one of the 
most remarkable of living Crustacea. In the thirty years 
that had elapsed since its first description by Vejdovsky 
(1882), from two specimens found in a well in Prague, this 
1 The numbers in brackets after names of authors refer to the list 
of papers on p. 513. 
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