48 Mr Taylor on the Respiratory Organs and Air-bladder 



second and third arches, after supplying the lamina? of the 

 former and the semitransparent tissue of the latter with small 

 twigs, are also continued to the bladders ; where they are mi- 

 nutely ramified, forming an indistinct net-work of vessels upon 

 their internal surface. Fine vermilion injection, thrown in at 

 the root of the branchial artery, penetrates these minute ves- 

 sels distributed upon the second and third arches and the in- 

 ternal surface of the bladders, while at the same time it fills 

 the aorta and its branches as far as the tail. The aerated 

 blood is returned by small vessels, forming, at the posterior 

 part of the bladders, two short trunks, which join the branches 

 of the branchial artery before they are reflected backwards, 

 and unite to constitute the aorta. 



The Cuchia, it is obvious from this account of its anatomi- 

 cal structure, possesses the circulation of reptiles, and the re- 

 spiration, partly of that class of animals, and partly of fishes. 

 Of the whole volume of blood contained in the branchial ar- 

 tery, one-third passes through the gills and respiratory blad- 

 ders, while the other two are conveyed directly from the heart 

 to the aorta, without being exposed to the action of the air. 

 This fluid, therefore, undergoes a partial oxygenation, present- 

 ing, as may be inferred, a dark purple culour in both divisions 

 of the vascular system, the arteries as well as the veins. Hence 

 the obtuscness of the external senses, and want of activity ob- 

 servable in the Cuchia. It is of a dull and languid nature, 

 exhibiting in all its movements a degree of sluggishness that 

 forms a striking contrast to the vivacity of the eel. A few in- 

 dividuals, which I kept in water for upwards of two months, 

 during the last rainy season, were observed to lie at the bot- 

 tom of the vessel in a very weak and apparently torpid state, 

 without taking any food : and seldom moved about, except oc- 

 casionally to rise to the surface for the purpose of inhaling air. 

 The respiratory bladders, although individually of a small size, 

 afford, in conjunction with the branchial structure of the second 

 and third arches, a sufficient extent of surface for the oxygena- 

 tion of the small portion of the blood transmitted to them. They 

 do not approach either in configuration or texture to any known 

 modification of branchiae, but on the contrary have a close simi- 

 litude, in both these particulars, to the posterior portion of the 



