748 THE AMERICAN NATURALIST. [VoL. XXXIII. 
There has also been observed in Trichoplax a most interesting 
process of conjugation, in which two individuals become joined so 
completely as to leave no trace of the point of fusion. This process 
is preparatory to mechanical fission or architomy. That it always 
precedes this reproduction is yet to be proved. No other method of 
generation has been observed. 
From the above facts is drawn the conclusion that Trichoplax can- 
not, as has been claimed by the advocates of Haeckel’s Gastraa 
theory, be considered as a flattened gastrula. Neither is it related 
to the Plathelmintha, as stated by Bohmig, since the accelous condi- 
tion of certain Turbellaria is secondary, but that of Trichoplax is 
evidently ancestral. 
The author considers it unnatural to place Trichoplax and the 
closely allied Treptoplax in a special group, the Placulzadz, and to 
set them as the simplest type of the multicellular animals, Protaccelia, 
at the foot of the metazoan stem. It is claimed that the mere fact 
that the Protaccelia are not hypothetical, like the Gastraea, but really 
exist, is in itself disproof of Haeckel’s gastreal phylogeny; that 
there is danger that the advocates of this theory, in their zeal for 
proof of the minutiz may neglect the broader facts of development, 
which point so evidently to a varied origin of the Metazoa. 
Trichoplax then, while it does not support the Gastraa theory, may 
yet serve as an important factor in the development of the true 
theory of metazoan embryology. Viaweioe &. ALEN 
Notes. — Gephyrea, collected at Christmas Island, Indian Ocean, 
are described by Shipley (Proc. Zoöl. Soc., London, Jan. 17, 1899). 
Of the six species listed only one, Thalassema baronii Greef, is rare. 
In the same paper, Physcosoma japonicum Grube is reported from the 
coast of British Columbia, though previously known only from the 
western shores of the Pacific Ocean. 
The supposed occurrence of Synganus trachealis, the gape worm, 
in the domestic duck, as recorded by various authors, has been 
definitely shown by Railliet (Arch. Parasit., Vol. I, No. 4, pp. 626, 
627) to be due to the mistranslation of an English letter! 
Recent work on the Myxosporidia is the subject of a comprehen- 
sive review by Doflein (Zod/. Centralbl., Vol. I., pp. 361-379). Of 
great general importance is noted the opinion of the author that with 
better knowledge of both groups this order is approaching the 
Rhizopoda. 
