1890.] HELODERMA SUSPKCTUM. 201 



In my larger specimen the ovaries are very much atrophied, while 

 the oviducts have very much more the form of those in Lacerta 

 viridis, as drawn for us by Parker in his ' Zootomy,' than they 

 have in L. muralis as seen by Parker (W. N.), and figured in his 

 translation of Wiedersheim's ' Comparative Anatomy of Vertebrates ' 

 (p. 318). In other words, their anterior ends are rather split-leaf 

 like than elongo-folded tubule-like. A comparison of the two 

 figures in question will make my meaning clear. 



The kidney is large and several-lobed rather than two-lobed as it is 

 in Lacerta viridis, and its posterior slender part equals in length the 

 anterior or enlarged part. The ureters open in the usual way in the 

 cloaca. In Helodenna the kidneys are of about an equal size, and 

 each one extends about as far forwards as the other. Standing 

 between the anterior aperture of the oviduct and the atrophied ovary 

 in my larger specimen, I make out a parovarium, which is thin and 

 subcircular and about as large as my index-finger-nail. Leading 

 backwards from it, I can with ease trace the rudimentary duet of 

 Gartner. Upon either side, at the sites of the penes in the male, 

 I iind present a papilla which possibly represents a clitoris in this 

 lizard. 



V. Notes upon the Thoracic Organs. 



Upon opening the cavity of the chest we find a very firm pleuritic 

 membrane, continuous with the serous membrane covering the liver, 

 spreading across the heart from lung to lung and enveloping those 

 organs, as well as enclosing the structures about the heart's base. 

 Dividing this down the median line we observe that the last-named 

 organ is likewise contained in its own serous sac, the pericardium, 

 while our dissections further show that the outer membrane closely 

 ensheaths the lobulus cardiacus of the liver and the thyroid gland at 

 the ventro-posterior end of the trachea (see figure 3 of Plate XVI., 



I.C., t.ff.). 



Opening next the pericardium the heart is brought fully into view, 

 with its ventricle and two large auricles. 



The Thyroid Gland. — This structure is quite large in our present 

 subject (fig. 3, t.ff.), and occupies a very different position from the 

 thyroid in such a reptile as Lacerta viridis. In Heloderma I find 

 it at the root of the trachea overlying the great vessels at the base of 

 the heart. This is more in accord with what we find in Birds, 

 where in some forms of them it lies upon the origin of the carotid 

 artery ; there is, however, a gland upon either side at the base of 

 the thyroid in a young Stork ^ 



As in the Crocodiles, the thyroid of Heloderma is bilobed ; the 

 transverse, basic portion lies across the trachea next the base of the 

 heart, and connects the two lobes. These are subcylindrical in form, 

 with pointed apices, each passing forwards by the windpipe, on either 

 side. 



^ See Wiedersheim's ' Comparative Auatoiuy of Vertebrates,' Engl. ed. by 

 W. N. Parker, p. -121, fig. 185 (fr.). 



