E. LÖNNBERG, MAMMALOGY OF ECUADOR. ^ 89 



this opening a small portion of the gall-bladder was visible. 

 It is thus so deeply sunk in the tissue, that it just is visible 

 on the frontside, biit fissura cystica has completely disap- 

 peared. The right lateral lobe is like the left by a complete 

 fissure divided from the adjacent central lobe. It extends 

 also on the abdominal side in a median direction, so that it 

 to great extent covers the right central lobe, although not 

 completely as is the case on the left side (ef. above), but a 

 triangulär portion (with the base at the ventral margin of 

 the liver) of the right central lobe can be seen between the 

 median margins of the left and right lateral lobes. The 

 caudate lobe is large and covers the right kidney, to the 

 posterior end of which it reaehes with the tip of its appendix. 

 The Spigelian lobe appears to be absent. 



In a small Marmosa the liver is rather thick (unlike in 

 Didelphys and Metachirus). The left lateral lobe is large 

 and reaehes on the abdominal surface to the median line. 

 The central lobes are completely fused, so that only a shallow 

 longitudinal groove (as in Caenolestes) indicates the position 

 of fissura umbilicalis. The gall-bladder lies in an emargina- 

 tion, which represents /. cystica and which it entirely fills. 

 It is visible also on the front-side to some extent. The right 

 lateral lobe is smaller than the left lateral and does not 

 extend so far mesially on the abdominal side. The caudate 

 lobe is large. It caps the kidney and extends with its ap- 

 pendix far down on its lateral side. I could not see any 

 Spigelian lobe. 



The liver of Caenolestes has thus no great resemblance 

 to any of the Didelphyidae. 



But the different genera of that family differ also inter 

 se with regard to the shape and structure of the liver. 



I have also extended the comparison to a Sminthopsis 

 crassicaudata. In this animal as well the left lateral lobe is 

 large and reaehes nearly to the median line. There is no 

 fissura umbilicalis. The gall-bladder lies in a fissura cystica 

 near the free margin of the liver, so that it is partly visible 

 from the frontside, but the fissure extends also some distance 

 on that side, about as in Caenolestes. The right lateral lobe 

 is considerably smaller than the left and the caudate lobe 

 extends backwards över the kidney on its mesial side, not 

 laterally. A Spigelian lobe appears to be present but not 



