Zoological Society. 391 



June ]4. — Richard Owen, Esq., Vice-President, in the Chair. 



The following paper, by George Gulliver, Esq., F.R.S., entitled 

 " Observations on the Muscular Fibres of the OEsophagus and Heart 

 in some of the Vertebrate Animals," was read. 



The present communication is a continuation of the observations 

 on the muscular fibres of the oesophagus and heart published in the 

 ' Annals Nat. Hist.' vol. v. p. 349. 



The author applies the term voluntary to the striated muscular 

 fascicles — extending along the entire length of the gullet, and even 

 on the commencement of the cardiac extremity of the stomach in 

 several animals, along more or less only of the tube in man and 

 some other mammals, and wholly absent from it in many of the 

 lower Vertebrata — because this fibre has all the anatomical charac- 

 ters of the muscular fibre of animal life, which no completely in- 

 voluntary muscle has hitherto been found to possess. " If we are 

 to judge of the office of the fibre in question from its structure, it 

 must be concluded that in many Vertebrata the whole length of the 

 gullet is capable of voluntary motion, in some the lower or poste- 

 rior portion is not obedient to the will, while in others the motions 

 of the entire gullet must be quite involuntaiy. 



" That the muscular coat of the gullet should differ in animals of 

 different orders will not a])pear surprising ; but it was hardly to be 

 supposed that a difference in the oesophageal sheath would be found 

 in some genera of the same order. Yet such is the fact in the Ferae ; 

 and it is probable that further research into the anatomy of this 

 order will disclose more differences in their minute structure, espe- 

 cially as my observations on the blood have shown that there is a 

 i-emarkable diversity in the size of the blood-corpuscles or red par- 

 ticles of some of the subdivisions of the Carnivora*. 



" Perhaps the extent of the muscular coat of the gullet may vary 

 in the same subject at different periods of life. In young and middle- 

 aged mares and geldings some of the muscular fibre of animal life 

 may be generally traced on the gullet four or five inches from the 

 stomach ; but in a gelding twenty- five years old this fibre could not 

 be found on the last ten inches of the gullet ; and in an aged rabbit 

 I found the striated muscular fascicles but sparingly on the last inch 

 of the gullet, although in this animal generally they are most abun- 

 dant in this situation. 



" A summar)'^ of my inquiry concerning the extent of the voluntary 

 muscular fibre on the gullet is subjoined. Some of the results 

 may be modified by more facts, which are yet required to furnish 

 a satisfactory view of the subject. I have had no opportunity of 

 becoming acquainted with the researches of M. Ficinus and M, Va- 

 lentin, referred to by Dr. Baly in his translation of Professor Mul- 

 ler's 'Physiology,' vol. ii. p. 851. 



QUADRUMANA. 



In this order, as in the human subject, the muscular fibre of 

 animal life does not invest the lowest portion of the gullet. 



* See Ann. Nat. Hist. vol. vii. p. 577 ; vol. viii. p. 533 ; and Appendix to 

 Gevher's General Anatomy, p. 6-7. 



