Lymphatics and Enteric Epitheli^im of Ainia Calva 371 



line," or mucous canals. (Huxley, Anat. Vert. p. 79). The 

 lateral lymph vessel is essentially different from the lateral 

 canal, which has the same direction. If one raises the scales 

 with the lateral canal situated under them, and if the skin 

 be cut, there is found in the subcutaneous connective tissue 

 a small vessel, with delicate walls, lying in the groove which 

 separates the long lateral muscles of the vertebral column 

 and so closely connected to the surrounding parts that it is im- 

 possible to separate them. (Hyrtl, Annales des Sci. Nat. Vol. 

 20 (2' serie), p. 222). This canal is the lateral lymph vessel. 

 Unlike the preceding it has no openings upon the surface of 

 the skin. 



The main subcutaneous lymphatic vessels of Amia calva 

 are four in number and are situated, one on each side of the 

 body, entad of the lateral line, one on the ventri-meson and 

 one on the dorsi-meson. From the large lateral lymph vessels 

 many small branches are given off in a penniform manner. 

 At the base of each pectoral fin is a large lymph sinus. The 

 branches joining these to the lateral lymph vessel extend dor- 

 sad and join the latter at the caudal edge of the shoulder- 

 girdle ; another branch extends from the pectoral to the peri- 

 cardial sinus. After receiving the branch from the pectoral 

 sinus, the lateral lymphatic passes under the pectoral arch 

 and opens into a large lymph sinus (Fig. 10), extending from 

 the dorsal end of the clavicle* along the dorso-lateral portion 

 of the cephalic edge of the arch, to which it is closely joined, 

 and into the base of the cranium. In the cranium the sinus 

 could be traced readily only to about opposite the base of the 

 orbit. The opening from this sinus into the veins is at a point 

 about I c. m. cephalad, and a very little ventrad, of the dor- 

 sal end of the clavicle (Fig. 10). The orifice is guarded by a 

 valve which opens toward the vein. Near the edge of the 

 clavicle, a little ventrad of the level of the lateral lymph ves- 

 sel, is another orifice opening from this sinus into the peri- 



* The clavicle is the large curved bone vpith a thick cephalic and thin 

 caudal border. It extends ventrad and then cephalo-mesad so as nearly 

 to meet its fellow of the opposite side at the ventri-meson of the throat. 

 (Parker's Zootomy, p. 100). 



