686 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
/3. Paratomy without regeneration of complete parts of the body ; 
(3) With precocious formation of organs and resorption, 
e. g. P. fissipara. 
(4) With precocious formation of organs, but no resorption, 
e. g. Microstoma, Stenostoma, Catenula. 
The strobilation of the allied Cestoda must be regarded as a mode 
of division greatly reduced by parasitism. The brain of fissiparous 
Turbellaria is solely regenerated by trunk cells ( = unbranched connec- 
tive tissue-cells). The olfactory pits of the Stenostomidse are formed by 
the conversion of epidermis cells into olfactory cells, and by invagina- 
tion of the dermal parts into the anterior lobes of the cerebral ganglion ; 
on the other hand, the olfactory pits of Microstoma do not sink into the 
brain. The eye of Stenostoma (key-like organ) is regenerated by stem- 
cells cut off from the brain ; in Microstoma the eye is formed by conver- 
sion of the epidermal cells into retinal cells. 
The simple pharynx of the Steno- and Microstomidse as well as the 
plicated pharynx of Planarians are regenerated solely by stem-cells. 
The dermal glands are also formed afresh from stem-cells. The regene- 
ration of the protonephridium is effected by cells of the longitudinal 
canal ; there is here .no new formation of a complete organ, but only 
reproduction of part of an organ. The “ intense growth ” of the zooids 
during the process of division is due to frequent karyokinetic cell- 
division in the epidermis as w r ell as in the parenchyma and enteric 
epithelium. The genesis of the different organs during asexual propa- 
gation is exactly the same as in the development of the embryonic 
Planarian. The function of the stem-cell is twofold — to enable the 
Turbellarian to undergo regeneration, and at a definite time to form the 
generative organs. 
Notes on Land Planarians.* — Prof. L. Graff gives a short account 
of the Land Planarians collected by A. Borelli in the Argentine 
Kepublic and in Paraguay. The Bipaliidas are absent from the neo- 
tropical region, while the Geoplanidae there reach their highest develop- 
ment. Of the six species of Geoplana found by Borelli G. langi is new, 
as are the two species of Bliynchodemus , B. Stenopus and B. Borellii. 
The same author f describes two new species of Bipalium from 
Sumatra, and one from Tonkin.* 
Temnocephala chilensis.§ — Dr. L. Plate remarks that, while our 
knowledge of the Eastern form of this interesting non-parasitic Trematode 
has been considerably increased, the Chilian form requires further 
investigation. A basal membrane is so well developed beneath the epi- 
dermis that it cannot be overlooked. The protoplasm of the epidermis 
either forms a homogeneous layer not divided into cells, in which there 
are a large number of vacuoles filled with a clear fluid, or the vacuoles 
form large, labyrinthine canals, between which the protoplasm forms 
delicate bands. We have here, therefore, to do with a syncytium traversed 
by vacuoles or canals. A number of proportionately large nuclei are to 
be seen in the protoplasm. 
* Bull. Mus. Zool. Torino, ix. (1894) 4 pp. 
t Ann. Mus. Civ. Genova, xiv. (1894) pp. 524 and 5. 
t Bull. Soc. Zool. Fiance, xix. (1894) p. 100 (1 fig.). 
§ SB. Akad. Wiss. Berlin, 1894, pp. 527-31. 
