222 CLASS VII. 
Phalanx I. Rhabdocela. Intestine simple, cylindrical, not ex- 
sertile from the mouth. Body elongate, roundish or depressed. 
Prostoma OErst. (not Ducks), Gyrator EHRENB. Oral aperture 
anterior terminal. 
Sp. Prostoma lineare Onrst., Gyrator hermaphroditus EuRens., Abhandl. 
der Akad. der Wissensch, zw Berlin, 1835, Tab. I. fig. 2. 
Vortex EHRENB. 
Sp. Vortex truncatus, Planaria truncata, Zool. danic. Tab. 106, fig. 1, a, 6, 
EHRENB. 1. |. figs. 3, &c. 
Derostoma OERST. (DUGES in part). 
Mesostoma Duans, Orrst. Body depressed, transparent; oral 
aperture annular, rotund, situated a little in front of or in the middle 
of the body. Eyes two anterior. 
Sp. Mesostoma Ehrenbergii, Planaria tetragona MUELL., Fasciola quadrangu- 
laris Pauu., Spicil. Zool. x. Tab. 1 fig. 12; Zool. danic. Tab. 106, 
figs. I—5 ; FoxKE, Ann. des Wiener Museums, 1. 1836, pp. 191—206, Tab. 
xvi. This species has been elaborately investigated by the last-named 
writer ; it undergoes various changes of form ; from the flat form a quad- 
rangular arises, as though the animal were about to divide itself in the 
length. Pattas had already observed this Planaria more than 70 years 
earlier at Sorgzliet, and it has lately been found again at Leyden by HERR 
HERKLOTS. 
Strongylostoma OERST. 
Typhloplana KHRENB. 
Macrostoma OERST. 
Microstoma Orrst. (Vid. SCHULTZE quoted p. 203.) 
Convoluta OERST. 
Phalanx II. Dendrocela. Nutrient tube branched. Body 
depressed. (Dendroceela and Cryptocela OERST.) 
a) Appendages numerous, tubular or papille on the back. 
Thysanozoon GRUBE, Holidiceros QUATREF. Eyes sessile, nu- 
merous ; body excised anteriorly and cloven into two tentacles. 
Sp. Zhysanozoon Brocchit, Eolid. Brocchiti QUATREF. 1.1. Pl. 5, fig. 1, (perhaps 
the same species as Thysanozoon Diesingit GRUBE, Actinien, Echinodermen 
u. Wiirmer, fig. 9); in the Mediterranean. The intestinal canal has here a 
retiform division, 
