438 The American Naturalist. [May, 
It seems possible to take another view of the homology of the 
temporary or embryonic tentacles in the former stage of Acaulis 
than that suggested above. In the first place, we ufay regard 
them as the same as the temporary tentacles of the young Myrio- 
thela. They are in point of fact not unlike similar appendages 
in Actinula, with which they may be readily homologized. Some- 
what similar temporary appendages appear in the young Glos- 
socodon on the side of the bell, as have been described by others, 
and as I have figured in my paper on the Tortugas Acalephe. 
If we regard the Actinula as represented by the young Glos- 
socodon it seems possible that the temporary appendages in both 
may be homologous. It seems to me probable that there is a 
close likeness between the young Myriothela, as represented by 
Allman, and an Actinula in the smaller of the two kinds of 
specimens which are here figured. 
It is on account of the embryonic likeness of Myriothela that 
in my plates of the Hydrozoa in the Embryological Monographs 
(Memoirs Museum Comp. Zoology, Vol. IX; No. 3.) I placed 
Myriothela in close proximity with Hydra among the lowest 
forms of these animals. Still, in certain features, Myriothela has 
a high organization which is shared also by Acaulis. It would 
be interesting and valuable from a morphological standpoint to 
know more of the ultimate form of the body and appendages of 
Acaulis, and some of the early stages in growth which lie between- 
the ovum and the young with temporary tentacles. 

