60 NOTES ON THE AGRICULTURE, BOTANY 



countries have been little studied but it is probable that the 

 indicated forms would be found there. Certainly a further 

 exploration will show a clearer picture of the origin and 

 composition of these insects. 



VI. — Observations on the Eiver Soft Tortoise 

 in North Manchuria. 



In the Far East in the Amur basin and other rivers in 

 this district is often seen a particular tortoise — Amy da Maackii 

 Brandt. It belongs to the family of soft river tortoises 

 (Trionyehidae), which is now confined only to the warmer 

 regions of South and East Asia, North America and Africa. 

 During the middle portion of the Tertiary period they were 

 extremely abundant in all parts of Asia and Europe, but at 

 the present time are extinct in Europe and in North Asia. 

 It is specially interesting to find that of the 25 existing kinds 

 of soft tortoises, 15 are in the South and East of Asia, 7 in 

 North America and 6 in 'Africa. The Amy da Maackii 

 resembles the American form — T. ferox — and also at times 

 reaches the same size. This tortoise is characterised by 

 having its shells covered with a thin greenish-olive skin and 

 by a long snake-like neck, which together with the head can 

 be completely withdrawn. The young specimens have a 

 back of a light colour and are covered with longitudinal lines 

 of small knobs which disappear when they are full grown. 

 Sometimes this tortoise grows to the weight of 60 pounds in 

 North Manchuria, and once in 1917 such a tortoise was 

 caught at Harbin. The Amyda appears at the end of March 

 and in April, lays its eggs on the sandy shore of islands and 

 sand banks, buries its eggs in the sand to a depth of ten 

 inches; when the small tortoises are hatched, they strive to< 

 swim from the river into the water courses and ancient beds 

 of rivers covered with stagnent water, where they feel them- 

 selves safe, and stay a long time. The tortoises are about 

 10 to 20 cm. in size and are usualy found in rivers, they are 

 very timid. During the day they are rarely seen on the 

 shore but commonly on the surface of the water especially 

 towards evening and in calm weather : when they hear a 

 noise they put their heads and long necks out of the water. 

 In some places in North Manchuria the Chinese soft tortoise 

 is so abundant that their eggs are eaten and serve as an 

 article in the local Chinese trade. The Chinese adroitly seek 

 their nests by following the tracks of the tortoise. The 

 Chinese do not much use it as food on account of popular 

 superstition. The larger specimens are dangerous; their bite 

 is very severe and the local Chinese are not infrequently 



