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Show 258 MR. F. E. BEDDARD ON THE ANATOMY [June 6, mented area in the male Gerrhosaurus is distinctly greater than in the female example of that lizard, and there is no conspicuous fold of membrane continued forward from the gonad duct to serve as a demarcation between the two areas in the latter. The suspensory ligaments o f the liver offer, as is well known, characteristic differences of arrangement in various Lacertilia. In both examples of Gerrhosaurus the falciform ligament of the liver is double posteriorly for about the last ^ of the total length of the liver. This double region of the umbilical or falciform ligament is a tent-like structure; that is, the two separate membranes converge ventrally to be inserted in common on to the ventral median line of the parietes. A partial duplication of the umbilical ligament of this kind is not uncommon in the Lacertilia. It occurs, for example, in Lacerta ocellata. The double condition of the umbilical ligament in the Scincidse, originally discovered by John Hunter * and subsequently more fully dealt with by myself t and Prof. Cope +, seems to be merely an exaggeration of this, the union of the two, posteriorly separate, umbilical ligaments being deferred until at or near the anterior extremity of the liver. Furthermore, all of the members of the family Scincidae are not thus characterised ; for in Macroscinus cocteaui the arrangement of the umbilical ligament is much like that of Gerrhosaurus. In the question of affinity, therefore, the disposition of these mesenteries is not decisive. There are, however, one or two other points to be noted. In the first place, in Eumeces algeriensis both the umbilical ligaments are thickly invaded by muscular tissue, especially the left-hand ligament. This is also noticeable in Macroscincus, though to a much less extent; and it will be remembered that Macroscincus cocteaui is a much larger lizard than is Eumeces algeriensis, so that size in this case has nothing to do with the development of thickness and muscularity in the umbilical ligaments. It is plainly therefore of importance to note that in Gerrhosaurus these ligaments are not obviously muscular at all. In the accompanying figures (text-figs. 33, 34) of the ventral surface of the liver in Gerrhosaurus two other facts may be pointed out. In the first place, there are traces of a membrane which runs obliquely forward and ends in a notch in the left border of the liver. As this white seam (b in text-figs. 33, 34) is much better developed in one example than in the other, I take it to represent a rudimentary structure, and it may represent the original course of the umbilical vein and thus correspond to a similar trace which Hochstetter has lately described § in] the Blind Worm (Anguis fragilis). * Essays and Observations, revised by Richard Owen, London, 1861, vol. ii. p. 369. " The liver [o f Tiliqua] is attached forwards by two membranes, one to each lobe, which unite at top." "(" P Z S 1888, p. 98. X Proc. Acad. Sci. Philadelphia, 1896, p. 308. § Morph. Jahrb. xix. Taf. xvi. fig. 18; but the course o f the seam is different in the two cases. |
