6 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I40 



tem makes connection with the stomatogastric, or "sympathetic," 

 nervous system. A pair of lateral roots emerges from the tritocere- 

 brum and enters what appears to be the central center of the stomato- 

 gastric system, the unpaired frontal ganglion. It is from this ganglion 

 that the median recurrent nerve emerges. 



The subesophageal ganglion innervates the mouth parts and con- 

 tains both motor and sensory components. There are often present in 

 this ganglion "giant cells," which are specialized nerve cells with 

 neurosecretory significance. The subesophageal ganglion communi- 

 cates with the supraesophageal ganglion by means of the circum- 

 esophageal connectives, which circumvent the esophagus and may 

 be notably long or almost nonexistent. In the latter case the brain 

 appears to adjoin the subesophageal ganglion directly. 



ACKNOWLEDGMENTS 



The author wishes to express his gratitude to Dr. Calvin A. Richins 

 of Saint Louis University School of Medicine, with whose encourage- 

 ment this research was completed ; to Dr. R. E. Snodgrass for suggest- 

 ing several changes in the original draft ; and to Dr. Ralph E. Crabill, 

 Jr., under whose influence my interest in centipedes was born, for 

 reading the manuscript. 



II. REVIEW OF THE LITERATURE 



Investigations of the chilopod nervous system began early in the 

 19th century (Treviranus, 1817; Leon-Dufour, 1824). Until methods 

 of microtomy were introduced in the second half of that century, 

 studies were confined to gross dissections and a few in toto staining 

 procedures. The smaller species of centipedes and the Geophilomorpha 

 were given very little attention. 



Newport (1843) was the first worker to study the nervous system 

 of a geophilomorph (Geophilus '^ suhterraneus Leach) . Having recog- 

 nized the importance of a comparative invertebrate neurology as "an 

 aid in resolving problems of life in higher animals," Newport studied 

 the abdominal ganglia of three chilopod types : a lithobiid, a scolo- 

 pendrid, and a geophilid. He described the pedal nerves and the 

 manner in which they emerged from the central ganglion. More 

 noteworthy, however, is the footnote which appeared on page 245. He 

 remarked that in the embryo of the geophilomorph Necrophloeophagus 

 longicornis (Leach) — 



"^ ■= Stigmatogaster suhterraneus (Leach). 



