86 ON THE MORPHOLOGICAL RELATIONS 



Again, the sclerome of a mammal consists of a number of 

 sclerotomes, grouped into the cephalic, cervical, thoracic, lum- 

 bar, sacral, and caudal syssclerotomes. 



For the muscular system I employ the terms myome, myo- 

 tome, symmyotome ; for the nervous system, neurome, neuro- 

 tome, synneurotome ; for the vascular system, hcemome, hcema- 

 tome, synhcematome ; for the morphologically as well as physio- 

 logically important digestive system, with its segments, and 

 gi'oups of segments, peptome, jyeptatome, and synjjeptatome, etc. 



Till very lately, I had not met with any indication of the 

 actual morphological character of the so-called supra-oeso- 

 phageal ganglion in the works of British or foreign physiolo- 

 gists. I have now found, in an obscure corner of Von Baer's 

 works, sufficient evidence that he had recognised its pre-stomal 

 character. His statements are contained in a single paragraph, 

 which forms an episode in the middle of the second corollary 

 of the fifth scholium of his work on the development of the 

 chick in ovo. Von Baer hold-s, with E. H. AVeber and Trevi- 

 ranus, that the nervous axis of the neuropod is homologous 

 with the series of ganglions on the posterior roots of the 

 spinal nerves of the hsemapod ; and he considers the " supra- 

 cesophageal" ganglion to be the homologue of the Gasserian 

 o'anslion ; but he adds, " Peculiar stress is laid on this, that 

 it (the supra-oesophageal ganglion) lies above (iiber) the 

 mouth. This appears to me to be a false view of the matter ; 

 it lies, in fact, in front of (vor) the mouth." He gives a 

 diagram of the arrangement, and proceeds : " The following 

 sketch will make it evident that the so-called brain of the 

 insect has the same signification as the posterior ganglions ; 

 and the oesophageal ring is only a secondary formation, 

 dependent on the breaking through of the mouth, permitted 

 by the symmetry of the structure, and the necessary con- 

 nection of the ganglions." 



It is somewhat remarkable that no one even of Von 



