DISTRIBUTION OF SUBCUTANEOUS VESSEI.S IN GANOIDS II9 



The positions of the cephalic sinuses and their points of ter- 

 mination in the jugulars are about the same as in Scorpceiiicht/iys, 

 but their connections and positions in yi?/i/a, Polyodon and 

 Salmo are very different. Hence these somewhat dissimilar 

 sinuses may be only analogous. I take the term cephalic sinus 

 to be nothing more than an arbitrary name given to a dorso- 

 cephalic sinus that is in connection with all the subcutaneous 

 vessels and which terminates directly in the jugular vein, or 

 possibly the precava in some species. 



Branchial Lymphatic Trunks {Nutrient Veins P).^ — These 

 vessels in Lepisosteus have not been worked out with anything 

 like the detail that they were in Polyodon. Each arch pos- 

 sessed a dorsal and a ventral trunk that traversed between the 

 two rows of filaments, parallel with, but distad of, the afferent 

 branchial artery, and which so far as could be ascertained had 

 no connection with one another. No effort was made to trace 

 out the origin of these vessels from the filaments, and nothing 

 more was attempted than to follow these canals to their ultimate 

 termination. In Lepisosteus the branchial arches are round and 

 only miniature when compared with Polyodon. They are sur- 

 rounded by a spare amount of spongy connective tissue, con- 

 taining only a few corpuscles in its meshes and a small number 

 of blood vessels. 



The first dorsal branchial trunk (Figs. 8 and 9, D.Br.- 

 Z'.(i)) takes its origin a little above the center of the arch 

 from between the two rows of filaments. Upon leaving the 

 most dorsal pair of filaments it travels along the anterior 

 margin of the first branchial levator muscle, receives a fork 

 (Fig. 8) from the second branchial trunk ; then curving to the 

 mesal side of the muscle, penetrates the floor of the anterior 

 part of the branchial sinus, through an opening (Figs. 11 and 

 12, Br.L.T.[i)0.) about opposite the first branchial levator 

 muscle. The second dorsal branchial trunk (Figs. 8 and 9, 

 Br.L.T.{2)) arises in like manner from the dorsal filaments of 

 the second arch, and after leaving the arch it forks between the 



'As in the case of the branchial trunks of Polyodon the method of forcing 

 water through these trunks and noting the points of its exit was resorted to with 

 advantage in Lefisosteus. 



