.1 X. I TOM Y OF CRYPTOBRANCH US 



317 



that the j^reatest difficulty was experienced in Kt'ttin}^ the injec- 

 tion fiuid into the smaller vessels, in fact, it was only by repeated 

 injections at various points that even the more important veins 

 of this region could be filled. The posterior end of the ])()stcrior 

 cardinal veins could not be filled with the injection i-vvn 

 after repeated attempts, so that the connection- of iIk-m' \t ins, 

 if any exist, with the other veins of the alxioininal iv^ion cnld 

 not be nuide out. 



The con.picuu,,., thin-u.,nnl .Inn. n no.us (Ficrs. 13 and 14, 

 S. ]\) into which the blood from the various parts of the body 

 is emptied, is formed mainly by the union of three large veins: 

 the two superior venie cava' {S. ('.), and the inferior vena cava 

 (/. ('.). The pulmonary veins (/..), bringing i)l()od back to the 

 heart from the lungs, as their luime would indicat(\ miite with 

 each other dorsal to the sinus venosus, and cmpt\ ituo the latter 

 at a point whose exact location is diliiciiir to determine on account 

 of the small size of these pulmonary ve»els. The >ni)eri()r vena 

 cava of the right side seemed in most, if not all caM'-, to be attached 

 to the apex of the ventricle. What the object of tlii-^ attachment 

 might be, was not determined. Macli snperior vena cava is formed 

 by the union of the followin- veins: the innominate iln.i which 

 is ])ractically nothing more than th(> lateral continuation of die 



Tile e\1<-rnal insular collects bloo.l clnelly fnmi the lower side 

 of the head, and is formnl by the union of two veins which proba- 

 bly correspond to the mandii.ular an.l lingual or laiyngeal, though 

 they could not be traced to their origin. 



The posterior cardinal {Car.) empties into the >u))en()r cava 

 at a point nearly opposite the opening of the external juunlar. 

 Throughout mo.st of its course it lies deeply btuied in the nmscles 

 of the dorsal bodv wall. and. as has been said, its .-xtrenie poste- 

 rior termination ('•ould not be determined, ouin- to die impo.si- 

 bilitv of obtaining a .-oinplete injection. It wa> tra.vd back- 

 wan! :,s far as thr anterior end of tlu- ki.lncy. but wla-tlicr beyoml 



