574 . PHILOSOPHICAL TRANSACTIONS. [aNNO 1682-3. 



sides those spines just mentioned, there were other processiises (c d) for the ad- 

 vantage of setting on of the ribs, and the articulation with each other; but 

 what was most remarkable is (what I have already hinted) that round ball (e) 

 in the lower part of the upper vertebrae, which enters a socket of the upper 

 part of the lower vertebrae, like as the head of the os femoris does the aceta- 

 bulum of the OS ischii; by which contrivance, as also the articulation with each 

 other, they have that free motion of winding their bodies any ways. The ribs 

 in the neck were small, but larger towards the middle of the body, where they 

 were about 2 inches long; but towards the tail they grew less and shorter again, 

 and did all terminate at the beginning of the scales of the belly. In the ver- 

 tebras of the tail inwards there were 2 spines, (fig. 9, bb) whereas in the other 

 vertebrae there was but 1 ; as likewise there were here transverse slender pro- 

 cessuses (cc) something analogous to ribs. 



To the last vertebra of the tail was fastened the rattle (fig. 11, 1 2) ; in our sub- 

 ject there were but 5, but some others seemed to be broken off. That next the 

 tail was of a lead-colour, the others of a cineritious. It is well described by (Mus. 

 Reg. Soc. p. 5 1 ) Dr. Grew, who says, " They are very hollow, thin, hard, and 

 dry bones, and therefore very brittle, almost like glass, and very sonorous. They 

 are all very nearly of the same bulk, and of the self-same figure, most like the 

 OS sacrum of a man ; for although the last of them only seems to have a rigid 

 tail, or epiphysis adjoined to it, yet have every one. of them the like: so that the 

 tail of every uppei most bone runs within two of the bones below it : by which 

 artifice they have not only a moveable coherence, but also make a more mul- 

 tiplied sound, each bone hitting against two others at the same time." 



The use of this rattle (since I know no other) I shall give in the words of 

 Piso, who tells us, Huic tam pernicioso colubro benigna natura cautionis quasi 

 gratia crepitaculum addidisse videtur, ut illius sonitu admonitus quilibet homo 

 non solum, sed et qualecunque pecus, vel jumentum, tempestive sibi caveat a 

 vicino hoste. Both he and Nierembergius and others assert, that every year 

 there is an addition of a new rattle, which Dr. Grew suspects, for then they 

 must live 16 years, for so many joints there are observed in some in our reposi- 

 tory. I have been told in some there have been above 20. These rattles are 

 placed with their broadest part perpendicular to the body, not horizontal. And 

 the one is fastened to the last vertebra of the tail by means of a thick mus- 

 cle under it, and by the membranes that conjoin it to the skin.* I have not 

 given the figure of the whole skeleton, since what is wanting may be sufficiently 

 understood by the description, and whoso pleases may view the skeleton 



* Piso de Indiae utriusque re Nat. et Med. 1. 5, c. 2, p. SZ-t.— Orig. 



