133 



descended to its lower or gastric extremity. The muscle was 

 enveloped in that cellulo-elastic tissue which abounds in almost 

 all parts of this animal, especially in the thorax, where it con- 

 nects the lungs to the ribs and diaphragm (there being no pleu- 

 ral membranes), and extends from the latter along the oesopha- 

 gus and trachea, connecting all parts intimately together. On 

 dissecting through this tissue, the muscle in question was ex- 

 posed : it may be described as an azygos muscle, placed hori- 

 zontally in the median line, about two inches in its long axis, — 

 that is from the trachea to the oesophagus, and about an inch 

 in its vertical diameter; its anterior end arises from the pos- 

 terior surface of the bifurcation of the trachea, by short tendi- 

 nous fibres; these soon end in fleshy fasciculi, and form a thick, 

 strong muscle, which passes backwards and bends a little down- 

 wards to the fore part of the oesophagus, along which the fibres 

 descend, expand, and become continuous with its longitudinal 

 and spiral fibres, and can be distinctly traced to the cardiac 

 orifice of the stomach ; the upper margin of the muscle is round, 

 thick, and well defined ; the lower margin is concave, and held 

 in connexion with the diaphragm, and with its oesophageal 

 opening, by the elastic tissue before mentioned. The pneumo- 

 gastric nerves descend one along each side of this muscle, and 

 give small branches to it. (See Plate). 



" Imperfectly acquainted as we are with the habits and func- 

 tions of this interesting group of the animal kingdom, in their 

 natural state of liberty and of health, we cannot speak wi^h 

 confidence as to the design or use of this peculiar structure. 

 We do know, however, that an intimate and a very peculiar 

 connexion exists between the mechanical apparatuses con- 

 cerned in the functions of respiration, of prehension of food, 

 and of deglutition ; and that the powerful and exquisitely 

 organized proboscis is not merely a weapon of defence and 

 of oifence, but that it also serves as a breathing tube, and in 

 a great measure as an instrument of voice ; while at the same 

 time it is the sole organ for the prehension of food, both solid 



