VOL. XXII.] PHILOSOPHICAL TRANSACTIONS. 521 



The use of these muscles seem to me very particular, for the same muscles 

 which flutter the wings serve also to move the legs ; the upper tendons of the 

 muscles enter into the wings, the same I believe which the fibres compose, 

 and the lower enter a good way into the legs; yet the contrary motions of these 

 organs are not at all hindered ; for as long as the wings play, the feet lie still, 

 and serve for a prop to the muscles which move the wings. And when the feet 

 are in action, the wings are quiet, and in their turn serve to support the ten- 

 dons which direct the feet. 



The eyes are like two thick oblong pearls, which begin at the fore part of 

 the head, and end in the hinder part. Their outer membrane is dry, thin, trans- 

 parent, and incloses a small soft ball, filled with a very black liquor ; two small 

 canals, filled with air, enter into each of these eyes, and run along to the great 

 channel, also furnished with air, which accompanies the intestine from the 

 head to the tail. This stricture made me at first think that the libella could 

 drive the air contained in these canals into the eyes, to give it a greater 

 convexity, to behold objects that are very near ; and on the contrary, the air 

 is forced out of the eyes again, to flatten them when they look at remote objects; 

 and this conjecture is not altogether frivolous, for having blown into the thick 

 canals, which are about the middle of the body, the eyes became considerably 

 tumefied, and by letting the air return, they became flat again. 



On the Use of the Numeral Figures in England in the Year lOQO. Bt/ Dr. 



IVallis. N°266, p. 677. 

 I now send you, from Mr. Thomas LuffTcin of Colchester, a draught of the 

 window in Colchester, mentioned in the Transactions N° 255, whereby it ap- 

 pears that the numeral figures were here in use in the year IO90. 



On the Fossil Shells and Fishes in Lincolnshire. By the Rev. Mr. Abr. de la 



Pryme. N° 266, p. 677- 



Broughton in Lincolnshire lies near that Roman way, which I gave you an 

 account of in my former letter.* The town is small, but ancient, apparently of 

 Roman origin, being situated near one of their highways, and to have taken its 

 name from some ancient burrow or barrow there. 



In this parish are two stone-pits, or quarries, very remarkable. The first is 

 at the east end of the town, the other in the field, on the south of the town. 

 The stones of the first are not much used for building, being soft, but v\hat 

 they dig them chiefly for, is to get a clayey substance, or earth, that lies under 

 them, to cement and lay the stones of the second quarry in, of vvliich they 



* Page 494 of this volume. 

 VOL. IV. 3 X 



