ACALEPH&. 123 
Sp. Geryonia proboscidalis, Medusa proboscidalis Forsx. Icon. rer. nat. Tab. 
36, fig. 1; GuErin Iconogr., Zooph. Pl. 16, fig. 2; Cuvimr, R. Anim., édit. 
dlustr., Zooph., Pl. 52, fig. 3. This species from the Mediterranean, with 
six threads or tentacles at the margin of the disc, may be considered as 
the type of this division. 
Family VII. 2hizostomide. Arms ramose, with many suc- 
torial oscules. Margin of the body without tentacles. Disc with 
four ovaria or testes, sometimes (in Casstopea) eight. 
Ltlizostoma Cuv. Tentacles amongst the arms none; arms 
confluent into one pedicle inserted in the disc. 
Sp. Rhizostoma Cuviertit, Réaumur Mém. de Acad. des se. de Paris, 1710, 
Pl. x1. fig. 27, 28; Cuvier Journ. de Physique Tom. xurx. p- 436; Cuv. 
R. Anim. édit, ill. Zooph. PI. 49- This species sometimes attains to 
a great size. The Rhizostoma has four pairs of suctorial arms, which are 
provided with absorbent vessels ; by these it receives its nutriment, which 
consequently consists of minute animalcules, or of animal matters in 
solution, These absorbent vessels and their branches coalesce into four 
stems, which run along the pedicle and end in the stomach. From the 
stomach run laterally vessels through the hood. Surrounding the stomach 
are four cavities, with very wide opening below, in which the organs 
of propagation are seated. The uppermost portion of the hood consists of 
a substance more firm than the rest of the body. See K. W. Eysrnnarpr, 
Ziir Anatomie und Naturgeschichte der Quallen, Nov. Act. Acad. Ces, 
Leop. Carol. Nat. Curios. T. x. pp- 375, &c. with figures. Rhizostoma 
Aldrovandi Peron, GuERIN Iconogr., Zooph. Pl. 15, fig. 1, &e. 
Cassiopea Pinon. Tentacles amongst the arms none. Arms 
eight or ten, very much branched, not conjoined at the base into a 
peduncle, furnished with vesicular appendages, 
Sp. Cassiopea frondosa, Medusa frondosa Pau., Spice, Zool. x. Tab. 1. fig, 
I—3; Cassiopea borbonica DutuE Cutasn, Mémorie sulla storia e notomia 
degli Animali senza vertebre del Regno di Napoli, 1. 1823. Tab. 11. ; Guirin 
Leon, Zooph., Pl. 15, fig. 2; Cuv. R. Anim. édit. dlustr., Zooph. Pl. 51, 
fig. 2, &e. (See other figures of Tinestus Nov. Act. Acad. Ces. Leop. Car. 
Natur. Curios. Tom. xv. 2. 1831, pp. 247—288, Tab. 69—73. 
Cephea Péron. Large cirri amongst the arms. 
Sp. Cephea cyclophora Péron. Medusa cephea Forsx. Icon. rer. nat. Tab. 
XXIX, fig. (copied in Cuv. R. Anim. édit. illustr., Zooph. Pl. 51, fig. 4) &e. 
B) Mouth single central. 
Family VIII. Medusidea. Mouth tetragonal central. Arms 
four, mostly very distinct, very rarely none. Four lateral cavities 
in the disc, open beneath, inclosing the genital organs. 
