1774 HINGED-SHELL TORTOISES 265 



see as perfect as possible. I wish you may catch a curvi- 

 Cauda before the autumn is over; you will at once be 

 convinced that it is an (Estrus — os nullum^ pundis tribus, 

 &c. It sometimes haunts upland fields, and teazes the 

 horses at plow ; but is more frequently found in swampy 

 wet places, and is probably aquatic in its larva state. The 

 nits laid on my horses at Meon-stoke Aug. 19th stick 

 on their legs and flanks still. Skinner can, if he pleases, 

 send several queries and pertinent enquiries relative to 

 ' Syst. Nat.' which he well understands with its comparative 

 merits, and defects, as far as the Author has borrowed from 

 or imitated Mr. Ray. Next summer I will if possible get 

 a grasshopper lark ; but they are not easily procured : they 

 skulk in the hedges like mice. 



When you write to Linn, next, pray talk to him about 

 tortoises. There are tortoises whose shells are always open 

 behind and before " apertura testae anterior," as he says him- 

 self, " pro capite et brachiis ; posterior pro caud^ et femori- 

 bus." These apertures are supported, as it were, by pillars 

 on each side and can never be closed. Of such construction 

 is the shell of Mrs. Snooke's present living tortoise, Timothy. 

 But then there are tortoises whose under shell has a cardo, 

 an hinge, about the middle of their bellies, commanding one 

 lid or flap forward, and one lid backward (like the double 

 lidded snuff-boxes) which when shut conceal the head and 

 legs and tail of the reptile entirely, and keep out all 

 annoyances. Two such (very small they were) Mrs. Snooke 

 had formerly; and the shells lie still in her room over the 

 hall. Now concerning shells of this construction Linn, 

 makes no mention at all ; and this construction is certainly 

 the most curious and perhaps the most uncommon. But 

 what I would infer from all this is, that in his genus of 

 Testudo express mention should be made of this diversity; 

 and the genus should be divided into testis clausis, cardinatis; 

 and testis apertis, or by some such expressions. He loves, you 



