TPiE SPLEEN IN MONOTREMES. 



at the cephalic margin between the two, and the actual 

 width of attachment may be less than 2 cm. One or two 

 small notches may be noted at the caudal border near the 

 termination of the lesser process, and a notch directed 

 towards the body between the right and left process. It 

 is interesting to note that in an Agama (Reptilia) measur- 

 ing 30 cm. snout to vent and abdominal width of 7 cm. the 

 spleen was 1.5 cm. long and .4 cm. wide, while the snout to 

 vent measurement of the Platypus is 37 cm. and width 

 13 cm. 



Echidna (Echidna aculeata), 



As in the Platypus, three main portions of the spleen 

 may be recognised (p. 136), viz., body and two processes; 

 but while uniformity is characteristic of the spleen of the 

 Platypus, although conforming to the general character 

 it is rare in the Echidna to find two spleens alike. 



(1) Body. — This is better defined than in Platypus 

 and is in relation to the stomach fundus, being directed 

 towards the oesophagus. It is suspended in the great 

 omentum, the width of which, even in a male adult, only 

 equals 1 cm. ; and so at this early stage we obtain the 

 definition of a gastro-splenic omentum. Its length varies 

 from 3 to 5 cm. and the width .5 to 1 cm. 



(2) The right ventral process is the longer of the 

 two and is also suspended in the great omentum (lesser 

 sac), the width of which at its anterior extremity is 7 

 cm. ; so that it is more mobile than the body. Its average 

 length is 5 to 7 cm. and width .5 to 1.5 cm. 



i ^' 



(3) Left Dorsal Process. — This is shorter than the 

 anterior, and two portions may be recognised, viz., a stem 

 terminating in a pear-shaped body, which may be smooth 

 or (especially in smaller specimens) corrugated. The 



187 



