646 



ON THE CIRCULATORY SYSTEM OF THE GRASS-SNAKE. 



O.A.R 



Right Ovarian Artery. 



Oc.A. 



Occipital Artery. 



Od.A. 



Oviducal Artery. 



Od.A.P 



Posterior Oviduoal Artery 



Od.S.L 



Left Oviducal Sinus. 



Od.S.R 



Right Oviducal Sinus. 



Od. V.L. 



Lett Oviducal Vein. 



Od. V.L.F 



Left Posterior Oviducal 





Vein. 



Od.V.R. 



Right Oviducal Vein. 



Od. V.R.R. 



Right Posterior Oviducal 





Vein. 



Oe.A. 



Q<]sophageal Artery. 



Oe. V. 



(Esophageal Vein. 



OLA. 



Olfactory Artery. 



Olf. lo. 



Olfactory Lobe. 



Op. A. 



Ophthalmic Artery. 



O-pt. lo. 



Optic Lobe. 



Opt. Ner. 



Optic Nerve. 



O.P.V. 



Oblique Palatine Vein. 



Orb. 



Orbit. 



O.S. 



Orbital Sinus. 



O.S.A. 



Anastomosis between the 





Orbital Sinus and the 





Maxillary Vein. 



Ov.A. 



Smaller Ovarian Arterj'. 



Ovar. Zi. 



Left Ovarj'. 



Ovar. B. 



Right Ovary. 



P.A. 



Parietal Artery. 



Fan. 



Pancreas. 



Par. 



Parotid Gland. 



Par. A. 



Anastomosis between a 





branch of the Anterior 





and a branch of the 





Posterior Parotid Gland 





Arteries. 



Par. A.A. 



Anterior Parotid Gland 





Artery. 



Par. P.A. 



Posterior Parotid Gland 





and Superior Maxillary 





Artery. 



Par. V. 



Vein from Parotid Gland 





and also from neigh- 





bouring muscles. 



P.O. 



Primary Carotid Artery. 



P.C.V. 



Post-Caval Vein. 



Pel.V. Vein probably corres- 

 ponding to the Pelvic 

 Vein of Lacertilia. 

 Fit. Fos. Pituitary Fossa. 

 Pl.C.V. Palato-cerebral Vein. 

 Pl.P.V. Palato-pterygoid Vein. 

 Pul. A. Pulmonary Artery. 

 Pul. V. Pulmonarjf Vein. 

 P.V. Parietal Vein. 

 R.A. Right Auricle. 

 Ret. A. Retinal Artery. 

 R.P.L. Left Renal Portal Vein. 

 R.P.R. Right Renal Portal Vein, 

 R.R.A. Anterior Right Renal 



Artery. 

 R.R.M. Median Right Renal 



Artery. 

 R.R.P. Posterior Right Renal 



Artery. 

 Rt. A. Rectal Artery, 



R.V. Rostral Vein. 

 S.C.A. Short Ciliary Artery. 

 S.M.A. Superior Mesenteric 



Artery. 

 S.N. A. Anastomosis of the Sub- 

 nasal Sinuses. 

 S.N.V. Sub-nasal Vein. 

 Sp. A. First Spinal Artery, 

 Sp. V. Spinal Vein. 

 Spin. Cor. Spinal Cord. 

 Spl. Spleen. 

 S.P.L. Lett Supra-renal Portal 



Vein. 

 S.P.R. Right Supra-renal Portal 



Vein. 

 S.R.L. Left Supra-renal Vein. 

 S.R.R. Right Supra-renal Vein, 

 Sup. Lab. Ql. Superior Labial Gland. 

 Sup. Ren. L. Left Supra-renal body. 

 Sup. Ren. R. Right Supra-renal body. 

 Th. A. Thyroid Artery. 

 TJu/. ai. Thyroid Gland. 

 Ton. Mns. Tongue Muscle. 

 Ton. Sh. Tongue Sheath. 

 V. Ventricle. 

 V.A. Vertebral Artery, 



Pip 



Pis 



PiAXE LXX. 



1. Diagram of the Heart and Blood-vessels in the anterior part of Tropidonotus 



natrix. The two main arteries and veins on the ventral side of the head 

 are indicated, but their precise distribution is dealt with on Plate LXXII. 

 Between the lines X.X. and Y.Y. a portion of the circulatory system is 

 omitted, as the relations of the Hepatic and Pulmonary Vessels and the 

 Dorsal Aorta are similar throughout the whole length «f the liver. The 

 part omitted is about the same length as the distance from the thyroid 

 gland to the line X.X. For the purposes of diagram the liver is repre- 

 sented as pulled out to the right of the animal. The positions of the Liver 

 and Lungs are indicated by simple outline and those of the Gall-bladder, 

 Spleen, and Pancreas by shaded areas. 



2. Diagram of the posterior Blood-vessels in a female Tropidonotus natrix. 



The positions of the kidneys and ovaries are indicated by simple outline 

 and those of the supra-renal bodies by shaded areas. For the purposes of 

 diagram the intestine is represented as pulled out to the right of the 

 animal, the fat-bodies as external to the oviducts, and the oviducts as 

 external to the ureters. Owing to the fact that the anterior end of the 

 Fat-body is supplied from the right ovarian arter^^, while a little further 



