5Q8 PHILOSOPHICAL TRANSACTIONS. [aNNO 1683. 



times shoot out a considerable length; at others retract it in again, and so very 



much alter its figure, by becoming broader.* But whilst I was doing this, by 



its riggling its body it happened to fall off my finger ; it presently took hold 



again, and gave me as much trouble to free it a second time from its adhesion 



as at the first. For the present I put it into spirit of wine, that I might more 



carefully view it with a microscope at home. And in doing this, making use 



of some extraordinary good ones, it very plainly appeared as is represented in 



my 8th fig. thick beset with two orders of spikes, or hooks, whereof the larger 



rose from the middle, spreading themselves over the edges of the circumference; 



the other, which were less, issuing out about the midway, and were shorter, 



as is seen in this figure, and are represented sideways in^ the gth fig. I could 



not on the strictest inquiry, -and with extraordinary glasses too, perceive any 



orifice here, which we may suppose to be the mouth ; only a little indenting in 



the centre, occasioned by the issuing out of the spikes there. This end was 



not perfectly flat, but a little globous ; and I could perceive by the swelling a 



little below on the neck, and wrinkling of the skin, how it shot out, and 



contracted its neck, as I observed it when alive: for some little space here, I could 



not observe with the glasses any joints at all ; but after, very thick set and 



small, and gradually increasing in length, as they descended towards the tail. 



The heads of the other two worms exactly appeared the same in the microscope, 



as this. And afterwards by carefully viewing them by my naked eye, I could 



observe these hairs or spikes. 



It was objected by some ingenious persons, who had been acquainted with 

 what I observed concerning this head, whether these spikes or hairs might not 

 be like the small feet of the tick or recinus, for its fastening itself the better to 

 help its suction. And indeed were it blood it lived on, the case were plain; but 

 since it is chyle, I do not see what service they could do it in this, for when 

 they fasten, the head is deep immerged in the inward coat of the intestine, and 

 so may be thought for that time to get but a very inconsiderable soop, if any, 

 and nothing in proportion to what is requisite for so vast a long body ; and 

 what it is often observed to be turgid with. On the whole, what seems most 



* It is remarkable that Linnaeus, who does not appear to have examined the taenia with much ac- 

 curacy, denies the existence of the head. ' Caput serpentiforme ad extremitatem crassiorem fmxerunt 

 Tyson, Andry, Tulpius, sed fallunt, cum omnis articulus propria vita gandeat, nee ullus vennis capite 

 instruatur, quod canicidiis constat." Syst. Nat. p. 1323. — ^The real structure of the head is now well 

 known: it is surrounded by a double row of claspers or hooked processes, as truly described by 

 Tyson, and with four round orifices for suction, which Tyson does not appear to have discovered. 

 The species of tlie taenia are very numerous, and they chiefly inhabit the intestines of quadrupeds^ 

 birds, or fishes. 



