210 



first, the duodenum, descends straight down and thus turns slightly 

 towards the right with its apex. The second loop lies on the right 

 side, near the back, its distal third is bent upwards ; the whole 

 loop is a closed one, and is retrograde with reference to the course 

 of the duodenum. The third principal loop takes up the space 

 between the first and the second loops, it is likewise retrograde, 

 but open ; the middle portion of both its branches is irregularly- 

 kinked ; its ascending branch is accompanied by the two well 

 developed cteca. The intestinal convolutions of Pedionomus are 

 certainly different from those of either Turnices or Rasores. There 

 is no indication of a horseshoe-shaped doubling of the second loop, 

 nor do the convolutions of Pedio^iomus agree in numbers and 

 other characters with those of the groups mentioned above. The 

 convolutions of Pedionoimis exhibit characters which are inter- 

 mediate between those of Ralli, Turnices and Rasores, and which 

 are at the same time peculiarly modified. 



Measurements : Absolute length of the intestine from the pylorus 

 to the anus 47 cm. 



Relative length of the intestine 6-5 cm. 



Absolute length of the rectum 4 -2 cm. 



Absolute length of one ccecum 5-5 and 7"0 cm. 

 The liver of Pedionomus consists apparently of three almost 

 equally sized lobes, owing to the left original lobe being split in 

 half. In this respect Pedio7iomus agrees only with the Turnices 

 and with the Rasores, it differs however from the latter and agrees 

 with the former by the small size of the right lobe, which is 

 scarcely half the size of the double left lobe. 



Skeleton. 



The number of cervical vertebrte is fifteen in Pedionomus and 

 in the Turnices, sixteen in the Rasores. The last two of these 

 vertebra} carry long dorsal ribs but without sternal portions. 

 Although Pedionomus agrees with the Turnices in the number of 

 cervical vertebrae, it differs from the Turnices (at least from Heini- 

 podius jJugna.c, of Fuerbringer, oji. cit. p. 240) in the composition 

 of the brachial nerve plexus. The latter is formed in Hemipodius 

 by the eleventh to foureeenth spinal nerves, in Pedionomios by the 

 twelfth to fifteenth, in the Rasores by the thirteenth to sixteenth 

 or thirteenth to seventeenth spinal nerves. In Pedionomus five, 

 almost six ribs, belonging to the sixteenth to twentieth or twenty- 

 first vertebrjie are attached to the sternum ; in the Turnices only 

 three or seven, rarely five ; in the Rasores almost always four, 

 very rarely only three. The greater number of these sternal ribs 

 is a more primitive, Ralline character. The sternum of Pedio- 

 nomus is decidedly like that of the Turnices and differs in every 

 essential point from that of the Rasores. The posterior margin 

 of the sternum possesses only one notch of moderate depth on 

 each side, only the Processus lateralis posterior but no Proc. 



