868 Prof. Allman on the Construction and 
2. Ecrortzevra, Agassiz, 
Trophosome.—Ccenosare invested by a chitinous periderm, 
and consisting of a simple or branched hydrocaulus springing 
from a filiform (?) hydrorhiza. Polypites flask-shaped, with 
filiform tentacula arranged in two verticils, the proximal verticil 
composed of tentacles which are longer than those forming the 
distal verticil. 
Gonosome.—Gonophores phanerocodonic, on branched pedun- 
cles, which are borne upon the body of the polypite, between the 
proximal and distal verticils of tentacles. Medusa, at the time of 
liberation, with a nearly spherical umbrella; a manubrium with a 
simple mouth, and shorter than the height of the umbrella- 
cavity; four radiating canals, and four marginal tentacles ; no 
distinct ocelli; the umbrella furnished with eight prominent 
longitudinal ribs formed of linear series of thread-cells. 
To his genus Ectopleura Agassiz, as has been already said, refers 
the Tubularia Dumortiert of Van Beneden. In thus separating 
Van Beneden’s Tubularidan from the true Tubularie, Agassiz seems 
to me to be fully justified ; but I cannot so easily assent to the cor- 
rectness of associating with it in the same genus the Sarsia pulchella 
of Forbes, the Sarsia turricula of M‘Crady, and the Sarsia nodosa 
of Busch. (See Contr. Nat. Hist..U. 8. vol. iv. p. 343.) These 
naked-eyed Medusze are very different from the Medusz of Van 
Beneden’s Tubularia Dumortieri, while one of them (Sarsia turricula) 
has been traced by M‘Crady, if not with absolute certainty, at least 
with high probability, to a Coryniform trophosome. 
Ectopleura Dumortiert, Van Ben. (sp.), = Tubularia Dumor- 
tierit, Van Ben. 
3. Hysocopon, Agassiz. 
Trophosome.—Ccenosare invested by a chitinous periderm, 
and consisting of a simple (or branched ?) hydrocaulus rooted 
by a filiform hydrorhiza. Polypites flask-shaped, with the ten- 
tacles arranged in two sets,—the proximal set long, and forming 
a single verticil, the distal short, and arranged in two verticils. 
Gonosome.—Gonophores phanerocodonic, springing directly 
from the body of the polypite between the proximal and distal 
sets of tentacles*. Medusa, at the time of liberation, with a- 
deep-belled umbrella, a moderate-sized, simple-mouthed manu- 
brium, four radiating canals, and with the distal extremity of 
* In Hybocodon prolifer, the only described species, “the first Medusa 
arises directly from the actinal area of the disc, while from the marginal 
termination of one of the radiating tubes of this Medusa numerous similar 
Medusz are developed, the latter again giving rise to other Medusz in the 
same manner, and from a corresponding place on their margin.” (Agassiz.) 
ee ee a ee ee. — 
fan ay 
ah. 
