MYXINE. 311 
A small cartilage near the cesophageo-cutaneous duct 
represents a complex branchial basket found in the lampreys. 
Lastly, a large Zingual cartilage supports the tongue. 
Myxine is unique amongst the Vertebrata in having no 
trace of vertebree. 
The coelom is spacious, and consists of a pericardium 
around the heart 
Ceelom. Fig. 224. —VENTRAL DISSECTION 
- and an abdominal OF Myxi1NE GLUTINOSA TO 
cavity surrounding the intes- SHOW THE GILI,- POUCHES 
tine which communicates x4. (Ad nat.) 
with the exterior by an 
abdominal pore. BuccalCirri 
The Heart is like that of 
a fish. It is two-chambered, 
with one auricle and a 
ventricle. It lies on the 
ventral surface 
of the cesoph- 
agus, and drives 
blood by a branchial artery 
diverging to the six gill- 
pouches by six afferent 
branchials. Six efferent 
branchials unite dorsally to 
form a dorsal aorta. These 
branchials pass between the 
gill-pouches and each sup- 
plies blood to the adjacent 
surfaces of two gill-pouches. 
Blood- 
Vascular, 
Gill-Pouches. 
Efferent Ducts of Gill-Pouches. 
The venous system con- g 
sists of paired jugulars and og 
cardinals uniting in a sinus Bog 
venosus and thence to the raga 
heart. xg & 
The éraiz is small and a 
simple. There are paired 
cerebral hemi- 
spheres, the cere- 
bellum is very small and the 
optic nerves do not cross. There are zen cranial nerves, as 
in fishes, but there is no sympathetic system. 
Nervous, 
CEsophageo-cutaneous Duct. 
