68 THE ACALEPHAE. $ 64. 
§ 64, 
With the Otenophora, this respiratory system consists of an infundibuli- 
form cavity, communicating with the stomach by two orifices, situated at its 
base and surrounded by sphincters. h 
Numerous aquiferous canals pass out of this cavity, traverse the body in 
a longitudinal direction, and finally anastomose with an annular vessel 
surrounding the mouth; but, beside these, there are two short canals which. 
pass directly to the posterior extremity of the body, where they open 
externally. ; oo 
With Eucharis and Cydippe, these canals are differently distributed ; 
thus, two go to the tentacles, two to the sides of the stomach, and four to 
the sides of the body. The same is true with Beroé, excepting that those 
to the tentacles are wanting. The lateral canals divide, at a short distance 
from the cavity, into as many branches as there are sides. With Cydippe, 
the excretory canals are simple; with Eucharis they are provided with 
vibratile lamellae, and with Beroé with branching appendages.” 
With the Discophora, numerous aquiferous canals pass from the stomach 
or its appendages, traverse the disc in a radiating manner, sometimes bifur- 
cating, and terminate at the borders of the disc in an annular vessel which 
opens externally by numerous orifices. 
In Cytaeis, Geryonia and Thaumantias, there are four of these canals, 
arranged in a crucial manner; and in Aequorea there are seventy-four 
disposed in a ray-like way. 
In Medusa aurita, there pass from the four folds of the stomach six- 
teen of these canals, eight of which are simple, and eight bifurcating 
numerously before reaching the marginal vessel of the disc.” With Sthe- 
nonia and Aurelia® they are very numerous and widely branched. 
With Medusa aurita, the terminal openings of the annular vessel are 
eight, and regularly alternate with the organs of hearing there situated. 
But in Cephea these openings are said to be directly beneath these last- 
named organs, : . 
With the Siphonophora, an aqueous system has not yet been well made 
out. There is, however, with some, an elongated cavity which is perhaps 
respiratory, and which, in some species, opens into the stomach, and in others. 
directly upon the outer surface. i 
1 Will (Hore tergest. p. 30, Taf. I.) has made 
very minute researches upon the aquiferous sys- 
tem of Eucharis, Cydippe and Beroé. That of 
Beroé ovatus, Forskalii, and of Lesueuria vi- 
trea, has been carefully described and figured by 
Milne Edwards as a circulatory system (Ann. 
d. Sc. Nat. XIE. p. 320; XVI. p. 203, 213, Pl. 
1.-VI.). 
2 Will, loo. cit. Taf. LI. fig. 5, 7, 8, 14, 16. 
8 Milne Edwards, Ann. d. Sc. Nat. XVI. p. 
197, Pl. I. fig. 1. 
4 Rosenthal, Zeitsch. f. Physiol. I. Hft. 2, Taf. 
XI. ; also, Ehrenberg, Abhandl. d. Berl. Akad. 
1835, Taf. I. bis. III. 
5 Eschscholtz, loc. cit. Taf. IV.; also Brandt, 
Meém. del’Acad. d. Sc. de St. Petersburg, IV. 1838, 
Pl. IX. X. XI. 
6 Ehrenberg, Miuiller’s Arch. 1834, p. 566; 
also, Abhandl. &c. loc. cit. p. 188, Taf. I. fig. 1, 
w. and Taf. IV. fig. 2, z. 
7 Will, loc. cit. p. 60. 
8 In Diphyes, this canal terminates in this way 
by an oval dilatation, lined with ciliated epithelium, 
and has perhaps properly been regarded by Wilé 
(loc. cit. p. 78, Taf. II. fig. 22, a.) as a respiratory 
organ. A similar cavity, with a coecal appendage, 
is found in Ersaea (Will, loc. cit. p. 81, Taf. IL 
fig. 27-31,d.e.). If the arms provided with open- 
ings, of the Physophorae, are really stomachs, then 
the cavity beneath them, which has a canal 
passing along the axis of the animal, should be 
taken as belonging to the aquiferous system, for it 
receives water by an opening at the base of the 
anus. This same opening has been taken for a 
mouth by Philippi (Miller's Arch. 1843, p. 63, 
Taf. V. fig. 10). According to Lesson (Duper 
rey, Voyage. loc. cit. No. 6, fig. B.), there is be- 
tween the suckers of Ve/ed/a an orifice which leads 
from before backward into a large branching canal. 
This structure, hitherto regarded as a digestive 
