312 The Allif^ator and Its Allies 



Figure ijd is in the region of the posterior end 

 of the heart (/z/), which is cut through the tip of 

 the ventricle, and the anterior end of the liver 

 (//) , which has the appearance of a mass of darkly 

 stained cords or strands of cells surrounding a 

 large blood-vessel (mz')- This blood-vessel may 

 be called the meatus venosiis, though it is not sepa- 

 rated by any line of demarcation from the auricle. 

 A few sections anterior to this region the meatus 

 venosiis opens dorsally into a large vessel on each 

 side {dc), which at first glance seems a part of the 

 body cavity, but which is in reality the ductus 

 Cuvieri, formed by the union of the anterior and 

 posterior cardinal veins. An irregular, crescentic 

 cleft {be), lying medial and parallel to each of the 

 Cuvierian vessels, is the body cavity. In the upper 

 angle of this cavity is a granular mass, the glomeru- 

 lus, that of the left side being accompanied b}^ 

 the extreme anterior end of the Wolffian duct. In 

 the rounded mass of mesoblast, between the cleft- 

 like regions of the body cavity, the lung rudiments 

 {hi), and the oesophagus {oc) are seen as three 

 small, circular openings; that of the oesophagus is 

 somewhat smaller than the other two. The noto- 

 chord {nt) , spinal cord {sc) , and muscle plates {mp) 

 have almost the same appearance as in the preced- 

 ing section. A spinal ganglion {sg) is seen on 

 each side of the spinal cord; the one on the left 

 shows a well-defined spinal nerve {su), which may 

 be traced ventrally as far as the end of the muscle 



