16-1 AKISTOTLE S ANHOMCBOMEEIA 



Aristotle says that Buccinnm and Murex or Purpura 

 have a tongue-like proboscis which is hard and can bore 

 through the shells of animals used as baits.* The last part 

 of this statement is incorrect, for these molluscs bore mainly 

 by means of their radulas. 



The Kocliloi which appear to have comprised the snails, 

 HelicidcB, are said by him to have a stomach close to the 

 mouth and like the crop of a bird ; beneath it, he adds, are 

 two hard, white bodies, like nipples, and from it a simple 

 long stomachos extends to the mecon in the spiral of the 

 shell, t What he calls the stomach seems to be the crop, 

 and the hard, white bodies seem to be the dart sacs of the 

 Helicidce. 



After describing the five teeth, constituting the chief part 

 of what is still called &quot;Aristotle s lantern,&quot; he says that the 

 oesophagus of the sea-urchin leads to the stomach, with 

 its five loops full of excreta.! He had evidently examined 

 the internal organs of a sea-urchin, in which the gastro 

 intestinal canal is suspended, in the form of a coil with 

 loops, from the inner sides of the shell. 



According to Aristotle, most of his Entoma have an 

 alimentary canal which passes directly and without divisions 

 from the mouth to the anus, but a few have a coiled alimen 

 tary canal, and in some, e.g., the locust, there is a stomach 

 succeeded by a straight or coiled intestine. 



This is a very general description, and is not a good one. 

 Many larvae, myriapods, centipedes, and some others of his 

 Entoma have a fairly straight, simple alimentary canal, but 

 many of his Entoma, e.g., beetles, bees, &c., have a com 

 plicated alimentary canal and intestinal caeca, the existence 

 of which Aristotle does not appear to have known. 



F. THE UBINOGENITAL OEGANS. 



It has already been shown that Aristotle believed that 

 the blood, having left the heart, never returned, but was 

 used up or dissipated in various ways. It is well-known 

 that a part of the blood is removed by the action of the 

 urinary organs, but he believed that the essential organ for 

 the performance of this function was the bladder, and that 



* H. A. iv. c. 4, s. 8. f Ibid. iv. c. 4, ss. 8 and 9. 

 | H. A. iv. c. 5, s. 5 ; P. A. iv. c. 5, 680a. 

 H. A. iv. c. 7, s. 7 ; P. A. iv. c. 5, C82a. 



