ox THE VEKOUS SVSTEM OF VARAN US. 4bV 



25. On the Venous S3'steni of the Lizard Varanus hengal- 

 ensis (Daud.). By GoBiND Singh Thapar, M.Sc, 

 Professor of Zoology, Canning (College, Lucknow*. 



[Received April 5, 1921 : Read May 10, 1921.J 

 (Text-figures 1-4.) 



The only data we possess concerning the venous system of the 

 genus Varanus appear to be contained in the work of Corti, 

 ' De Systemate Vasorum Psammosauri grisei,' 1847 (which I have 

 not seen ; the observations ax-e reproduced in Bronn's Thierreicb, 

 voL vi. Abt. iii. Reptilien, by C. K. Hoft'mann, p. 1010); Hoch- 

 stetter, ''Beitriige zur Entwickelungsgeschichte desVenensystems 

 der Amnioten, II. Reptilien {Lacerta, Iropidonotus)," Morph. 

 Jahrb. xix. 1893, p. 464 (mainiy the renal and hepatic portal 

 systems of V. arenarius, according to Beddard a synonym of 

 V. griseus) ; Beddard, " On the Venous System in certain Lizards," 

 P. Z. S. 1905, i. p. 447 ( F. griseus), and Beddai-d, '''On the Vas- 

 cular System of Heloderma, with Notes on that of the Monitor? 

 and Crocodiles," P. Z. S. 1906, ii. p. 610 {V. griseus, niloticus, 

 and exanthematicus) . 



These descriptions, however, do not completely apply to the 

 present species, V. hengalensis, common in and near Lucknow, 

 and it seems desirable, therefore, to record the results of my 

 investigation. 



Besides ordinary dissections, injections were made through 

 the anterior abdominal vein, using a thick solution of gum arable 

 to which a little colouring matter — carmine or methyl blue — 

 was added. The iluid passes completely into the system, and it 

 is easy then to dissect out even the finer vessels. I have used 

 this fluid in preference to gelatine, as it can be employed cold, 

 and sets satisfactorily after being placed for a short time in 

 alcohol, swelling the vessels. I have to thank Prof. H. C. Ahuja, 

 of the Central Hindu College, Benares, for supplying me with 

 the necessary literatiu^e ; and my grateful acknowledgments are 

 due to my friend Mr. S. K. Zibbu, of the Lucknow Christian 

 College, for the assistance he has given me in the course of my 

 work. 



I. The System of the Anterior Vena Cava (text-fig. 1). 



(1) The External Jugular Vein (e.j.). It is stated that this 

 vein is ordinarily absent on the left side in Lacertilia ; in the 

 present species, however, it occurs on both sides, the vessels 

 running parallel on each side of the trachea. It joins the internal 

 jugular at the base of the neck. The external jugulars com- 

 municate with each other by four transverse connections, the 

 plexuses. The first plexus is situated at the level of the thyroid 

 gland, close to the place of union of the external with the internal 



* Communicated by Dr. J. Stephensok, F.Z.S. 



