
590 THE AMERICAN NATURALIST. [VoL. XXXVI, 
If the cut edges of a split oral end are permitted to reunite, new 
tentacles develop at the regions of union. Polyps with fourteen 
tentacles were thus produced, but the repetition of the operation on a 
fourteen-tentacled hydra resulted in no further increase of tentacles. 
Attempts were made to secure heteromorphosis, or reversal of 
* polarity," by grafting. In several cases tentacles were developed 
upon an aboral cut surface or a foot upon an oral cut surface, but 
in all these cases (which the author interprets as heteromorphosis) 
the pieces whose polarity appeared to be reversed were very small 
parts of the trunk. In the case of a graft of any considerable length, 
the free cut end reproduced parts similar to those which had been 
cut away from it. In the cases of apparent heteromorphosis exhib- 
ited by very small fragments of the trunk, can it be proved that 
there is not a shifting about of the tissues or a migration of cells, so 
that the regeneration does not really involve a reversal of polarity ? 
H. Wa R 
A Revised Classification of the Enteropneusta. — It is nine years 
since Spengel's great monograph of this group was published. 
A number of important additions to our knowledge have been 
made in the meantime, and the author now returns to the subject! 
for the purpose of recasting the systematic arrangement of the 
species, and rectifying certain violations of nomenclature which the 
monograph contained. 
The total number of species has been increased by thirteen, and 
information about one of the old species, viz., Ptychodera flava 
Eschscholtz, has been largely extended since the publication of the 
monograph. 
A total of twenty-nine species is now recognized by the author. 
The arrangement of these into families and genera is as follows: 
FAMILY I. HARRIMANIIDE SPENGEL, I9oI. 
Genus 1. Harrimania Ritter, 1900. 
“2. Dolichoglossus Spengel, 1893. 
"o 3. Stereobalanus Spengel, 1901. 
N 
FawiLY II. GLANDICIPITIDÆ SPENGEL, IQOI. 
‘Genus 1. Glandiceps Spengel, 1901. 
"s 2. Spengelia Willey, 1898. 
“3. Schizocardium Spengel, 1891: 
oe 1 Die Benennung der Enteropneusten-Gattungen, Zoo/. Jahrbuch, Abth. fiir 
Systematik, Geographie, und Biologie der Thiere, Bd. xv, Heft 2, 1gol. 



