ZOOLOGY AND BOTANY, MICllOSCOPY, ETC. 
187 
New and little-known Rotifers.* — In continuation of his previous 
notes Dr. W. B. Burn gives, first, a description of Furcularia tenuiseta 
found in a pool at Tooting Common ; it is one-fortieth of an inch long ; 
the body has a loose glassy integument which is extremely flexible. 
Though delicate in appearance it burrows through dense flocculent 
masses with ease, for the purpose of hiding itself in the dark. He adds 
some notes to Mr. Gosse’s account of Diplois propatula which was found 
in a pool on Esher Common, where many rare rotifers are to be taken. 
The Gastrotricha.t — Dr. C. Zelinka monographs the enigmatical 
Gastrotricha. His diagnosis is as follows: — There is no retractile 
wheel-apparatus at the anterior end ; there are two ciliated bands along 
the entire ventral surface ; two coiled water- vascular canals, each 
bearing long rod-like ciliated lobes, open separately in the middle of the 
ventral surface; a simple brain-ganglion lies in part still within the 
ectoderm ; the muscle-cells are simple ; the ovaries are paired ; the fore- 
gut is muscular, without jaw-apparatus, and like that of Nematodes ; the 
mid-gut is straight and without glands ; the hind-gut is pear-shaped, 
with a rectum and dorsal anus ; there is a primary body-cavity. 
After a discussion of the numerous opinions as to the systematic 
position of the Gastrotricha, Dr. Zelinka concludes that they have 
diverged from the ancestral line of the Rotatoria, and that they have 
developed parallel to the latter, but at a lower level. From the 
ancestors of Gastrotricha, Echinoderes and the Nematodes may also have 
arisen, but the Gastrotricha are further from Echinoderes than from the 
Rotifers. As the nearest descendants of the Trochophora, they may be 
ranked as Trochelminthes, among the Protonephridozoa, and before the 
Rotifers, 
The size of these organisms varies on either side of the limit of 
naked-eye vision. Many are about 0 * 2 mm. in length, while Chsetonotus 
schnitzel measures 0*4 mm., and dwarf forms as little as 0*07 mm. 
They feed on small plants and animals, or on their remains. They 
swim by means of the two ventral bands of cilia, unlike Infusorians in 
never going backwards. One form, Dasydytes saltitans Stokes, is able to 
jump forcibly forwards by the aid of four long bristles on the ventral 
surface. They seem to occur in all fresh-water basins, especially in 
those with such aquatic plants as duckweed, Potamogeton, and Characesa, 
most abundantly in sunny ponds, but not in rapidly flowing water. 
The different forms of Gastrotricha are classified as follows : — 
I. Sub-order. Euichthydina, with a forked tail. 
1. Family. Ichthydidse, without spines. 
Ichihydium Ehrbg., 2 sp. 
Lepidoderma n.g., 4 sp. 
2. Family. Chsetonotidae, with spines. 
Chsetonotus Ehrbg., 18 sp. 
Chsetura Metschn., I sp. 
II. Sub-order. Apodina, without a forked tail. 
Dasydytes Gosse, 3 sp. 
Gossea n. g., 8 sp. 
* Science-Gossip, 1890, pp. 34-6 (4 figs.). 
t Zeitschr. f. Wiss. Zool, xlix. (1889) pp. 209-384 (5 pis. and 10 figs.). 
