| OCR Text |
Show 1890.] HELODERMA SUSPECTUM. 195 adiposum strongly impinges upon its right lobe. Composed of the usual hepatic tissue, the liver of Heloderma is, during life, of a deep brownish-red colour, but this turns paler after the organ has been placed in spirit, and it becomes tinged with a greenish hue. Ventrally, as a whole, this gland is convex over its surface, it being behind more or less concaved. Primarily, it is divided into two principal lobes ; the right lobe has a length of about 7'5 centimetres and a width of 2-5 centimetres, while the left lobe is something like a centimetre less in both of these dimensions. Its borders are rounded, and it measures through its thick part, which is near its centre, about a centimetre. Regarding it upon its ventral aspect (Plate XVI. fig. 1), we are to observe that the right lobe exhibits near its posterior apex one or two small fissures, while a small teat-like process of the glandular substance issues from the same lobe to cross towards the left behind the gall-bladder. This right lobe is likewise indented in such a manner that the gall-bladder is exposed to some considerable extent through an oblong aperture. Between the lobes, behind, issue the bile-ducts, and the portal vein makes its entrance. Viewed upon its dorsal aspect (Plate XVI. fig. 2), the liver of this Lizard presents us with a number of interesting points for our examination . Chief among these is a small supplementary lobe which comes off from the anterior part of the right lobe near its mesial border. It projects freely, being subcylindrical in form with rounded apex, and in direction it is oblique, passing up close to the outer side of the heart. From this latter fact I propose to call it, in those specimens wherein it is present, the lobulus cardiacus. Other very much smaller lobuli are to be seen upon this aspect of the liver in the specimen before us, whether these are constant or not, I cannot at this writing say. Several of these occur at the apical extremity of the right lobe; two overlapping ones are seen at the hinder part of the fossa cystidis fellece. In this latter fissure obliquely lies the gall-bladder, an organ which we will describe further along. The pons hepatis, or the ligature that binds the right and left lobes of the liver, in Heloderma is very extensive and very thick, extending as it does from the fissure of the gall-bladder to a point anteriorly where the two lobes meet the apex of the heart. The portal vein enters the left lobe of the liver at its lower part, as a single trunk. Its branchings take place after the vessel passes into the hepatic substance. At about 4 centimetres behind the liver the anterior abdominal vein joins the portal as its main tributary. Beddard figures the portal vein of Varanus salvator as entering the right lobe of the liver (P. Z. S. 1888, p. 104); but this does not agree with a specimen of Varanus niloticus before me, wherein the portal vein distinctly enters the left lobe of the liver, branching just as it does so \ 1 I am indebted to Professor Alexander Agassiz for the specimen of V. niloticus to which I refer, and to Professor Samuel Garman for his kindness in selecting it from the collections of the Museum of Comparative Zoology of Harvard College, and forwarding it to me. |
