156 Dr. J. E. Gray on Chinese Mud- Tortoises. 



all the American species, even those with only one apical 

 spine to the elytra, by the spine (or sharp tooth) being a pro- 

 longation (a little divergent) of the sutural angle, and not 

 distant from it ; from the spine the apex is gradually rounded 

 to the sides. The punctation of the elytra is scanty and in 

 lines. The thorax is rather wider than usual in the middle, 

 and the discoidal tubercles are very obtuse. The head is 

 tumid behind the eyes, more distinctly so in the <$ than in 

 the ? . The scape of the antennae is roughly punctured. 

 There is no long pubescence on body or limbs. 



[To be continued.] 



XXII. — Notes on Chinese Mud- Tortoises (Trionychidse), wiVA 

 the Description of a new Species sent to the British Museum 

 by Mr. Sivinhoe, and Observations on the Male Organ of this 

 Family. By Dr. J. E. Geay, F.R.S. &c. 



[Plate V.] 



Mr. Swinhoe has most kindly sent to the British Museum 

 several specimens, preserved in spirits, of Mud-Tortoises from 

 the neighbourhood of Shanghai . 



The collection contains : — a large specimen of the most 

 beautiful species of Mud-Tortoise which I have yet observed 

 from any country ; and I believe it to be new to science ; 

 three specimens of a very plain olive Mud-Tortoise, which 

 are peculiar for having the crown of the head and nose covered 

 with a hard very thin skin, somewhat like the skin which 

 covers the head of the Terrapins ; and several specimens of 

 different ages, but all young, of Landemania perocellata ) 

 showing the change of colour in the young animals of this 

 species as they increase in age. . 



This collection is also interesting as showing the form of 

 the male organ and the external sexual character of the males 

 of this group of Chelonians. The specimens having been killed 

 by being placed in spirit, the male organ has been exserted in 

 two of the specimens. It is expanded and fan-shaped, wit) 

 the urethral grooves on the lower side forked and ending ii 

 conical claw-like terminations. In both specimens the tail is 

 short, tapering to a very fine point, and ending in a hard spine ; 

 while the tails of the other specimens are all without points, 

 soft, and rather blunt at the end. The armed tail is the cha- 

 racter that Leconte gives of the males of Kinosternon. 



The Reptiles have been divided into : — those which have 

 a single male organ for intromission, as the Tortoises, the 

 Crocodiles, &c. ; and those which have a pair of organs for the 



