486 
EEVIEWS. 
a specimen without abrading the slender, irregular spicula, whose 
points form the horizon over which the soft walls of the animal 
stretch in a uniform, smooth film. It is, therefore, necessary to study 
perfectly fresh specimens, in order to form a correct idea of the rela¬ 
tions of the superficial, spiculate deposits of the animal basis.” 
Of Hydroids referable to the very natural division of Sertularina , 
Professor Agassiz figures and describes the following eight species— 
a. Glytia pot erium. 
b. Glytia bicophora. 
c. Clytia intermedia. 
d. Glytia cylindrica. 
e. Laomedea amphora. 
f. Obelia commissuralis. 
g. Eucope diaphana. 
h. Dynaniena pumila. 
All of these, excepting the last (A), belong to that section of 
Sertularina in which the polypites are stalked, that is, to the Cam- 
panularians. This group Professor Agassiz proposes to divide into 
no less than three distinct families,— Oeeanidce , Eucopidce , and Lao- 
dieeidce. As in the case of the Gorynidce , a number of Naked-eyed 
Medusae, wdiose structure is akin to that of the medusoids known to 
originate from the several Hydroids described, are placed with them 
in the same families and genera. 
The first family contains those creeping Campanularians, re¬ 
ferred by Johnston to the genus Gampanularia proper. Glytia 
poterium is referred to a new genus, Orthopyxis; G. bicophora and 
G. intermedia to Trochopyxis , or Glytia proper; and C. cylindrica to 
Elatypyxis, the medusoids of which are free. These, like others of 
the same family, have “ free eyes between their tentacles,” and 
closely resemble the young of Tiaropsis diademata , one of the Aca- 
lephs described with so much detail in the author’s former essay 
on the Naked-eyed Medusae of Massachusetts. Some additional 
observations on the marginal bodies and immature condition of this 
species are here inserted in a special section. 
The three Campanularians which follow are members of the 
family Eucopidce , the eye-specks of their medusoids being “at¬ 
tached to the base of the tentacles.” The medusoids of Laomedea 
amphora never emerge from the reproductive calicle ( £ gonotheca,’ or 
‘ gonangium’ of Allman) within which they are developed. Both 
Obelia and Eucope , however, possess free medusoids, the names of 
these genera having been originally given to what w T ere looked upon 
as independent forms of Eiscophora. The free zooids of Eucope 
are very nearly related to most of the Naked-eyed Medusse usually 
referred to Thaumantias. So close is this resemblance, that the 
adult medusoid of E. diaphana was formerly described as a Thau¬ 
mantias by Professor Agassiz himself, in the memoir mentioned 
above. 
