36 



Ein ab Lönnberg, 



grown comparatively most, which is quite natural as its functions shall 

 begin first. If the relative dimensions of the different portions of the 

 ventricle of this foetus are compared with the corresponding ones of 

 the adult it is apparent that the psalterium of the latter is compara- 

 tively much smaller than in the foetus. This is made evident by the 

 following statements: in stage a. the longest diameter of the psalterium 

 is 70 °/o of the longest diameter of the reticulum; in stage b. the same 

 relation is 60 °,o; in stage g. 55 °/o, hut in the adult only 35 %. The 

 psalterium of the adult is by this proved to be a reduced organ, which 

 fact no doubt stands in connection with the changed diet as has been 

 said above. 



The general arrangement of the intestine is about the same as 

 in the adult. The centripetal coils are two in number, and the cen- 

 trifugal ones 1 72. The rectum is quite filled by faecal matter and 

 this may at least to same extent account for the fact that the trans- 

 verse coil of the rectum behind the right kidney which seemed redu- 

 ced in the foregoing stages is well developed in this specimen. This 

 explanation is. however, not quite satisfactory, for in stage f. the rectum 

 is expanded as well, without forming a coil but only a very short 

 curve. It seems consequently to prevail some variability with regard 

 to this. 



The kidneys are quite simple without any trace of exterior 

 lobulation and have only one longitudinal mamilla. 



With regard to the development of the teeth in Gephalophus melano- 

 rhoeus the following notes may be made. In the earliest stages represen- 

 ted in the collection there are, of course, no teeth developed as yet. In 

 stage b. for instance a low and even ridge-like prominence in the incisive 

 tract of the mandible includes the rudiments of the future teeth. This 

 edge is at the lateral and posterior end bordered by a rather large termi- 

 nal papilla (see fig. 8) which already may be traced in stage a. In stage 

 c. the ridgelike prominence is beginning to divide into separate papillae 

 corresponding to the different teeth, but the large posterior papilla is 

 unaltered. In stage d. (see fig. 9) this division into papillae is complete, 

 and on either side of the median line five papillae may be counted, 

 four of these are derived from the continuous edge and the fifth is the 

 posterior terminal papillae. All five papillae of either side sit close to 

 each other and have quite the same appearance. It could therefore 

 be supposed in this stage that they were homologous all of them and 

 that the fifth posterior papilla contained the rudiment of same premolar 



