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R. HOEPPLI AND H. J. CHU.
Wen Ch'uan, west of Hei Lung Tang near Peiping.
Four samples were taken from a stone tank where thermal water was stored in the bath-house of Wen Ch'uan. The water temperature in the stone tank was 34° C. All four samples contained representatives of two nematode species.
Sozun, Taihoku, Formosa,
One sample out of two which were taken from the overflow of a sulphur spring at Sozan contained numerous larvæ of a Dorylaimus sp. and a new Monhystrella sp.; at the place of collection the water temperature was 35° C. We wish to thank Prof. Yokogawa of the Government Medical School of Formosa and Mr. T. Koshimura of the Department of Foreign Affairs of the Government of Formosa for facilitating the collection of the material. The thermal water of Sozan is very rich in sulphur. PHYSICAL CONDITIONS OF THERMAL WATER :
In his work on the fauna of hot springs in Yellowstone Park and in the Western United States, Brues (1924 and 1928) has discussed the physical conditions of thermal water. It is, therefore, sufficient to mention here only the most essential factors. It is evident that the temperature plays a very important role. From various observations and experiments, one is entitled to draw the conclusion that a temperature of 40-50° C. is about the maximum for most animals normally living in fresh water of atmospheric temperature. Animals which normally live in sea water are much less resistant to higher temperature; transferred into water which was gradually heated various marine animals with two exceptions according to Frenzel could stand only temperatures of 25-30° C. and this only for a few hours, For chlorophyll-bearing plants the upper temperature limit is at about 60° C. The highest temperature from which a free-living nematode has been re- ported is 53° C. (Dorylaimus therma, Hot Springs in Yellowstone Valley). Apart from this case, free-living nematodes have been found in thermal water of
temperatures ranging between 25° C. Ragaz and 40° C. Montegrotto. The species described in the present paper occurred in water of 34.5-51° C. It is interesting to note that in our present material there were only larval stages occurring in water of a temperature above 40° C. Why larvæ ap- parently stand higher temperatures better than adults is difficult to explain. We merely record our observations. Taken as a whole we find that for most nematodes as for most other fresh water animals a temperature of 40-50° C. is about the upper limit which they can stand.
CHEMICAL CONDITIONS:
Because we have no analysis of the thermal waters from which we made our collections, we mention only that the two examined springs in Changchow, Fukien, and the spring in Sozan, Formosa, contain sulphur; the latter spring is very rich in this mineral. Most of the thermal waters contain salts in larger or smaller quantities; in some cases, for example, in certain springs in Yellowstone Park, the mineral contents and not the tem- perature of the water make life impossible for free-living nematodes,
The Hong Kong Naturalist.
Free-Living Nematodes from Hot Springs in China and Formosa.
FOOD CONDITIONS :
19
They have been briefly discussed by the senior author with reference to hot sprogs in Yellowstone Park. From the work of Menzel, Steiner, and Micoletzky, we know that the kind of food of free-living nematodes and the way way they take it, is rather different in different groups. There is no reason to assume that the thermal environment produces changes in the way of feeding and, because most of the species in our present study were found living between alge we assume that alge are the food for those of our forms which have no specially developed large teeth indicating predacious habits.
Altogether we found nine different species of adults; among them one new species for which we created a new genus, Greenia orientalis n.g., n. sp.-four new species belonging to known genera: Plectus chengmoh- liangi, n. sp., Microlaimoides lingi n. sp., Cyatholaimus chungsani n. sp. and Monhystrella ginlingensis n. sp.-one new variety, Monhystera filiformis var. Jukienensis n. var. three previously described species, Diploscapter coronata (Cobb), 1893, Aphelenchus parietinus Bastian, 1865 and Trilobus aliophysis (Steiner), 1919. Furthermore there were diferent larval stages present in our collection; among them a Dorylaimus sp. and a Microlaimus
TECHNIQUE:
sp.
The collected material was preserved in 10% formalin and then transferred to a mixture of 5% acetic acid, 20% glycerin and 75% water. In order to mount the anterior end in frontal view, the specimens were transferred into glycerin jelly.
SPECIAL PART,
Greenia orientalis n.g., n. sp.
(Pl. 11, Fig. 17; Pl. 12, Figs. 21-24).
two lateral setæ at the anterior end. culticularised walls. subventral teeth.
Greenia generic diagnosis: Cuticle striated. Eight submedial and Pharynx very long with strongly Behind the mouth opening one dorsal tooth and two Oesophagus has a bulb without valves, Two straight ovaries. Two spicula of equal length. One testis. A long outlet tube of the spinnerct, Amphids oval.
Greenia orientalis n.g., n. sp. diagnosis: Characters of the genus. Two pairs of adanal papilla. Amphids at about the level of the proximal end of the pharynx.
Two males and eleven females collected from Changchow in two different wells 5 and 13 feet respectively above the surface of the water. Water temperature in the first case 39° C., in the second 48.5° C.
One adult female and three larva collected from Foochow, Fu Long Ch'uan (Blessing Dragon Spring) stone tank storing thermal water of 35° C. Twenty-nine females, Foochow, Tzü She Ch'uan (Gathering of Moisture Spring), wooden enclosure of the opening, frequently splashed with
Supplement No. 1, 1932,
97
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