BIHANG TILL K. SV. VET.-AKAD. HANDL. BAND 28. AFD. IV. N:0 8. 37 



or a coecum (depending npon the degree of development) is for- 

 med at the left side of the mesenteric attachment. In Fty- 

 cliozoon and GecJco the coecum is rather large. Its basal part 

 lies on the right bnt its blind end ou the left side of the 

 mesentery. The opening of the small intestine is situated ven- 

 trisinistrally, and the coecum is strongly fixed to the back 

 by means of a mesenteric band. In Py g 02)odidce as re^resenteÅ 

 by Delma a small coecal diverticle is present and the small 

 intestine opens on the left side. In the Agamid lizards a 

 coecum is, as it seems, always present althongh in different 

 stages of development; in some forms it is even recurved 

 from the large intestine. The opening of the small intestine 

 lies on the right side of the large intestine and retains the 

 corresponding situation even when the colon, is doubled up 

 backwards but it becomes then of course situated on the left 

 (morphologically right) side. In the Iguanids the coecum 

 is usually present and often well developed, but in some ca- 

 ses (Liohemus) it is only represented by a slight excentricity 

 of the ileal opening. The Zonurids and Anguids as repre- 

 sented by Zonurus and Ophisaurus have no coecum. In the 

 specimens of Varanus I have dissected there was no real 

 coecum, but only a colic dilatation at the opening of the 

 small intestine. Gegenbaur (1. c.) mentions, bowever, a coe- 

 cum for y>Hydrosaurus>^, so that the colic dilatation may some- 

 times assume such a shape. In Tejidce we meet the stränge 

 condition that in Tupinamhis a very long coecum is found 

 included into the mesentery and a short coecum is recorded in 

 Ophiognomon (conf. above), but otherwise a coecum seems to 

 be missing in this family. In a similar manner among the 

 Amphisbtenids Amphishcena has, but lihineura misses a coe- 

 cum. In Lacertidce the opening of the small intestine is 

 moved to the right of the large intestine so that a more or less 

 pronounced coecal diverticle is formed. In the Scincoid li- 

 zards there seems as a rule to be a coecum, but in some forms 

 it is missing. 



When, as has been demonstrated above, a coecum in dif- 

 ferent degrees of development is present in some lizards, but 

 entirely missing in others, the question may readily be rai- 

 sed which of these conditions is the primary one. Or, with 

 other words, is the absence of a coecum in the lizards due 

 to reduction or is it a primary characteristic. It is certainly 



