ANATOMY OF THE TEREBRATULA. 17 



the facts whicli have recently misled some otherwise valuable labourers in that field, into 

 phlebenteric notions. 



" In the winged insects, which have but one heart, as also but one circulation, there is 

 this heart answering both purposes, (viz., the corporeal and pulmonary circulations)." 

 (Hunter on the 'Blood and Inflammation,' 4to, 1796, p. 134.) "When the veins 

 entering into the heart are small, in comparison with the quantity of blood which is 

 wanted in the ventricles, there we have an auricle ; but where the veins near the heart are 

 large, there is no auricle, as in the lobster, and generally in insects. In the snail, where 

 the veins in common are large, yet as they are small where they enter the heart, there is 

 an auricle." (Op. cit., p. 138.) But what, it may be asked, did Hunter mean by "large 

 veins" in insects, the lobster, and the snail. He has left us the explanation of his 

 meaning in his observations ' On the Circulation in Insects,' where he writes : — 



" OF THE VEINS." 



" The veins of the insect would appear to be simply the cellular membrane ; but they 

 are regularly formed canals, although not so distinctly cylindrical canals, as in the 

 quadruped, &c., nor branching with that regularity. They would appear to be, or to fill 

 up, the interstices of the flakes of fat, air-cells, muscles, &c., and, therefore, might be 

 called, in some measure, the cellular membrane of the parts." (' Hunterian MS. Cata- 

 logue,' printed in the ' Physiological Catalogue,' tom. ii, p. 31, (1834.) 



Baron Cuvier, as is well known, entertained with regard to the vascular system of 

 Insects, ideas closely akin to those which some of his pupils have more recently expressed 

 by 'phlebenterism,' after modifying M. Quatrefage's original meaning of the term ; for Cuvier 

 supposed that the whole of the blood of Insects stagnated in the lacunar or cellular inter- 

 spaces of the several organs -. he was consequently led to deny that insects possessed a 

 true circulation, or that the dorsal tube — " heart, extending through the whole length of 

 the animal," (Hunter, op. cit., 1793, p. 137,) acted as a heart. The more truthful views 

 of Hunter, based on the analogy of the already commencing irregularity and extent of the 

 venous sinuses in the lobster and snail, have been amply confirmed by the researches of 

 Professor Carus, on the 'Circulation of the Blood in the larvae of Ephemerides andLibellulae.'' 



With regard to the Crustacea, Hunter, who left preparations, and a beautiful series of 

 drawings, illustrative of the circulating system in the Lobster {Astacus marinus), thus 

 describes the latter : — 



"or THE VEINS IN THE LOBSTER. 



" The veins in this class of animals, as in the winged Insect, &c., are principally in the 

 form of large irregular cells, as if the cellular or investing membrane of the animal con- 

 tained the venal blood; and, when injected, we find the injection prhicipally in large 



^ Blutkreislaufes in den Larven netzfliiglicher Insekten, 4to, 1827. 



