250 MESSRS. SCLATER AND SALVIN [Apr. 22, 
lessened by the discovery of this fibre on the whole alimentary canal 
of the Tench* (Tinca vulgaris), after I had observed that this is not 
the case in some other cyprinoid fishes. 
Such facts tend to weaken the value in systematic zoology of the 
character afforded by the muscular sheath of the cesophagus. But 
whatever structure proves constant cannot be devoid of importance, 
however difficult the explanation may be; and, so far as my limited 
observations have gone, it is always easy to distinguish between 
certain orders of Mammalia, and these from birds and reptiles; 
simply by the muscular fibre of the cesophagus. For example, in 
the Quadrumana the striped muscular fibre stops short of the cardia, 
while in the Rodentia this fibre extends quite to that part of the 
stomach, as has been more particularly described of these and other 
vertebrates in the ‘ Proceedings’ of this Society (1842, p. 63 e¢ seq.). 
Hence it seems desirable to add this character, for as much as it 
may be worth, to the descriptions already known respecting such 
Mammalia as may have a questionable position in systematic zoology. 
The Aye-Aye is one of these; for it has been alternately placed 
among the Rodentia and Quadrumana. And by the courtesy of 
Mr. Flower I have examined for striated muscle about an inch of 
the cardiac end of the cesophagus of this animal, preserved in spirit 
of wine. The results were entirely negative. Not a single striped 
muscular fibre appeared, although the whole thickness of the ceso- 
phagus was examined, from the outer part of the preparation to the 
plaster with which it had been artificially distended ; in short, nothing 
of muscular tissue but the smooth variety could be found. And 
thus, so far as regards this point, the cesophagus of the Aye-Aye is 
as unlike that of Rodentia as it is like that of Quadrumana—a fact 
which tends to support the latest and now general conclusion as to 
the affinities of this singular animal. 
2. On Venezuelan Birds collected by Mr. A. Goering. By 
P. L. Scuatrer, M.A., Ph.D., F.R.S., and ean SALVIN, 
M.A., F.L.S.—Part Til. t 
(Plate XVIII.) 
Mr. Anton Goering’s present collection was principally formed in 
the vicinity of the Lake of Valencia, into which district he has made 
* Since this fact first came to my knowledge, through the last edition of 
Professor Beale’s excellent work on the Microscope, in which Weber is quoted 
as the observer, I have examined the intestines of the Tench, and found the 
striated muscular fibre on the greater part of its alimentary canal. The primi- 
tive inuscular wen of the cesophagus, stomach, and intestines presented an 
average diameter of =; 5, of an inch, while those of the dorsal and ventral muscles 
measured as much as ; Thus the striated fibres of the hollow muscles are 
only about one-fourth = thickness of those of the ordinary voluntary muscles ; 
and this agrees with my old measurements in fishes and other vertebr. ates, tabu- 
lated in the ‘Proe. Zool. Soe.’ (1842, p. 68). 
t See Part I., P. Z. S. 1868, p. 165; Part II, P. Z. 8. 1868, p. 626, 
