480 
KEYIEWS. 
i. Tkamnocnidia spectabilis. 
j. Tkamnocnidia tenclla. 
Jc. Corymorpha pcndula. 
1. Feoinaria gibbosa. 
on. Fudendriuon dispar, 
n. Fougainvillea superciliaris. 
a. — Coo'yne mirabilis is very like one of our own British forms of 
this genus; we fea.r to say which, lest by so doing we should provoke 
the criticism of some over discriminative Zobphytologist. In a note 
on a future page of his father’s monograph, Mr. Alexander Agassiz 
describes the medusoid of a second species, C. rosaria, from the Grulf 
of Georgia, which “resembles the English C.pusilla very closely.” 
In fact, Sarsia tubulosa (the medusiform zooid of C. pusilla ), is 
scarcely, if at all, to be distinguished from the free gonophores of 
either of the two American species. Professor Agassiz enters with 
great minuteness into the general structure and histology of this 
Hydroid, giving ample details as to its modes of budding, with special 
reference to the formation of its reproductive zooids. 
b. — Clava leptostyla is a minute zoophyte, somewhat akin to 
C. multicornis. Dwelling in colonies on Fucus vesiculosus, its mode 
of life differs much from that of the other American Hydroids, for it 
alone, “ though much less protected by a natural covering than 
several of the Tubularians, is subjected to the dashing of the breaking 
surf.” It is also more active. “ Erom the mouth at the tip of the 
head, to the attachment of the slender base of the stem, the whole 
upright body is highly contractile, and capable of assuming a variety 
of shapes. When very lively it is stretched to the utmost, with elon¬ 
gated head, and extremely attenuated tentacles ; at other times, 
every thing remaining as in the first instance, the head is depressed to 
a flat-topped disk, from which the tentacles radiate nearly in one 
plane, like the spokes of a wheel.” In the beautiful drawing by 
Clark and Sonrel which illustrates this portion of the text, these two 
diverse aspects of the tentacular crown are represented in a highly 
characteristic manner. 
c. —The next species, Fliizogeton fusiforniis, belongs to a new genus, 
of which only male colonies have hitherto been noticed. Fliizogeton 
is, in some degree, intermediate between Clava and Hydractinia; 
but is readily discriminated from the former by the position of its re¬ 
productive buds, which arise from the creeping base and not from 
the bodies of the polypites. These buds, ‘medusae’ or ‘medusa- 
buds ’ of Professor Agassiz, were fixed. “ In other genera (he writes) 
we have been accustomed to see the medusa wither and decompose, 
after it had matured and discharged its reproductive contents ; but 
here an unusual and unexpected phenomenon takes place; one and 
the same individual medusa , after discharging its reproductive organs , 
is metamorphozed into a hydra; the same wall which formed the disk 
of the medusa grows upward, and forms a long, cylindrical body, 
within which an inner wall develops, from the base of the still per- 
