Nasal Aperture 
312 CHORDATA. 
The median olfactory sac has been noted. The paired 
eyes are present but scarcely functional, whilst 
the paired auditory sacs are small and contain 
only one semicircular canal. 
The &édneys are paired organs lying in the dorsal part of 
the ceelom. They consist of coiled tubules communicating 
cowenttul: with the exterior by paired ureters beside the 
anus. The gonad is simple and produces 
sperms in the young individual and eggs at a later period. 
Hence M@yxine is a protandric hermaphrodite. There are 
no genital ducts. 
Sensory. 
Fig. 225.—MEDIAN SAGITTAL SECTION THROUGH MYXINE 
Guutinosa x 4. (dd nat.) 
Nasal Sac. Internal Nas. Opening of 
Brain. | Gill-Pouch. Nerve Cord. Notochord. 
(Esophagus. h / 
ff : 
To 
Heart. Liver. Intestine. 
ngue, 
Gill-Pouch. | 
Branchial Artery. 
The eggs are large, oval, and have much yolk. They 
are enveloped in capsules which have hooks at 
each end and are usually found embedded in 
slime. The development is unknown. 
Myxine shows a number of very primitive vertebrate 
features, of which we may specially note the absence of 
paired fins, vertebral column, pancreas, spleen, sympathetic 
nerves and genital ducts. The unpaired nasal sac, the 
peculiar pituitary pouch with its internal aperture, the ear 
with a single semi-circular canal, and the hermaphrodite 
condition are also unique characters amongst Vertebrata. 
With the lampreys it constitutes the class Cyclostomata, a 
name emphasising the suctorial condition of the mouth. 
Development. 
