364 PHILOSOPHICAL TRANSACTIONS. [aNNO I/IO. 



because of the spines of the first four vertebrae of the back, which are 4 inches 

 broad; whence the tax-wax, running forward (where the spines are narrow, or 

 where there are no spines at all, as in the first three vertebrae of the neck) in a 

 straight line to the skull, the space below it for the muscles to move in must 

 be the same at the neck as at the spina, where the epiphyses keep their upper 

 sides at such a distance. Above this tax-wax in the neck arise two muscles, 

 thinner and narrower at first, but thicker and broader as they go to the skull, 

 where they firmly adhere to the sides of a large sinus in its back part (b, fig. l) 

 whence ascending, being lodged in the depression on the top of the head, and 

 between the eminences (dd) they descend till they come over against the hole 

 for the root of the trunk, a, and become thicker and round, and in their whole 

 descent form the fore part of the trunk with the extremity. 



Thus then the proboscis is composed of two pair of muscles, one pair form- 

 ing its back part, which arises from the sternum, and passes with straight fibres 

 in below the os zygomaticum ; and from thence forward, till it forms the body 

 of the trunk itself: another pair which, arising from the neck, pass over the 

 head, and descending forms its fore part. The fibres of this muscle descend in 

 a straight line, till they form the body of the trunk, and then begins a strong 

 tendinous interstice, by which they are separated from their copartners; whence 

 their fibres descend obliquely to another strong interstice, by which on each 

 side they are separated from their antagonist, where the same oblique course of 

 fibres is again to be observed, that is, that the erectores proboscidis (for so we 

 may call these which make up the fore part of the proboscis) {ggj fig. 22) unite 

 in a tendinous interstice, h, from whence the fibres on each side obliquely de- 

 scend: so likewise the retractores proboscidis, for so we may call those which 

 form the back part of the proboscis, have their tendinous interstices running 

 down the middle of its back part; from whence the fibres obliquely descend, 

 almost making an angle of a demi-rhombus on each side in another longitudinal 

 tendinous interstice, by which the fibres of the antagonist muscles are conjoined. 

 Thus we see a wonderful contexture of four muscles, so contrived as to per- 

 form all kinds of motion. 



These muscles surround two large cavities, about the middle of the proboscis, 

 2 inches diameter from the right to the left, and 3 inches, each from above to 

 below ; for as they proceed from the skull they are very wide, according to the 

 capacity of the hole in the fore part of the skull, whence the proboscis proceeds. 

 They are divided by a strong cartilaginous septum, which runs straight from 

 before to behind, along the middle of the proboscis; and into this septum the 

 muscles situated in the fore and back part are inserted: these holes are cartila- 

 ginous, all round obduced with several nerves, and endued with a great many 



