18 ARKIV FÖR ZOOLOGI. BAND 1. N:0 25. 



lateral veins. At the same point, or in some specimens close 

 to it, but from the vessel that goes to the right lateral vein 

 a vein arises that continues in the portal vein. The poste- 

 rior Cardinal vein runs for a long distance unpaired along 

 the dorsal wall of the body cavity, then it divides in two 

 short branches entering the kidneys (PJ. I), where they form 

 a renal portal system. Several veins from the body wall en- 

 ter also into the capillary system of the kidney (Pl. I, 1 — 4). 

 The blood from the kidney is collected by a vein that forms 

 the anterior part of the posterior cardinal vein and joins the 

 anterior cardinal vein of the same side. 



V ena hepatica {v. h.). In Spheroides this vein is single. 

 It joins the right Cuvierian duct near its entrance into sinus 

 venosus. Just before its junction with the named duct it 

 receives a large vessel that forms the united part of the both 

 vessels conveying the blood from the gonads (vg). 



V ena portae (v. p.) originates as already mentioned from 

 the posterior cardinal vein or from its anastomose with the 

 right lateral vein. It receives several branches from different 

 parts of the alimentary canal (Pl. I, ö, 6, 8, 9, 10) and from 

 the air-bladder (Pl. I, 7). It enters the liver, where it breaks up. 



The specimens of Balistes, Lactophrys and Diodon that 

 I have had at my disposal for dissection have allowed me 

 to make only a few observations on the venous system. Of 

 course, a statement about the occurrence of lateral veins 

 would be of greatest interest. In Balistes and Lactophrys this 

 has been impossible, but in Diodon I have succeeded in find- 

 ing the anterior part of this vein. As Fig. 2 {v. 1. d. and 

 v. 1. s.) shows there is on each side a vein entering sinus 

 venosus in the same way as the lateral veins do in Sphe- 

 roides. I have also found veins arising from the posterior 

 cardinal vein and continuing on the lateral side of the body. 

 as in Spheroides. I have foUowed them to about the pectoral 

 region but from there to their probable entrance into sinus 

 venosus the preservation of the specimen w^as too bad to 

 allow a dissection of veins. I think, however, quite certain 

 that the named veins represent the lateral veins. In Balistes 

 and Diodon there is as in Spheroides only one inferior jugular 

 vein. The hepatic vein is single in Diodon, but according to 

 the existence of a well-developed liver Balistes has three 

 hepatic veins. 



