Kingsbury, Brain of Nectmus. 



203 



dc. — diacoele. 



d. comtn. — " dorsal " commissure of 

 the text. 



d. e. — ductus endolymphaticus. 

 Dien. — diencephal. 



dplx. — diaplexus. 

 dt. — diatela. 



e. h. c. — external horizontal canal, 

 Epen. — epencephal. 



epiph. — epiphysis. 



/. c. — fasciculus communis. 



gl, — glomerule. 



gin. — ganglion. 



hb. — habena. 



hyph. — hypophysis. 



infd. — infundibulum. 



/. — lemniscus. 



/. r. — lateral recess. 



mb. — Meynert's bundle. 



m. c. — Mauthner cell. 



mc. — mesoccele. 



Mesen. — mesencephal. 



Meten. — metencephal. 



on. — optic nerve. 



or. — optic recess. 



/. — porta (foramen of Monro). 



paraph. — paraphysis. 



pc. — paraccele ('lateral ventricle'). 



psc. — postcommissure. 



plf. — posterior longitudinal fasciculus. 



par. — preoptic recess. 



pplx. — prosoplexus. 



pre. — prosoccele (entire cavity of pros- 



encephal. 

 prcs. — precommissure. 

 /'r^j^w.— prosencephal. 

 re. — rhinocoele. 

 Rhinen. — rhinencephal. 

 s. e. — saccus endolymphaticus. 

 sp. — spinal. 



spcs. — supracommissure. 

 splx. — supraplexus. 

 t. — terma. 



tr. a. — tract a. (text) 

 tr. b. — tract b. (text) 

 vel. — velum (transversum). 



PLATE IX. 



Fig. I. The brain of Neeturus maculatus, dorsal aspect, x 5.4. 



Fig. 2. The same from the ventral aspect, x 5.4. 



Fig. J. The same, lateral aspect, x 5.4. The cranial nerves are shown but 

 diagrammatically, as is to a less extent their representation in Fig. i and 2. 



Fig. 4. The mesal aspect of the brain as reconstructed from sagittal sec- 

 tions. X 9. 



Fig. 5. Latero-ventral aspect of the oblongata to show the roots of the 

 cranial nerves. This is a reconstruction from transections and is diagrammatic ; 

 the roots of the seventh and eighth nerves are, for the sake of clearness, separ- 

 ated somewhat more widely than is actually the case. (See Fig. 19.) 



Fig. 6. The metaplexus from the ental aspect to show the arrangement 

 of the folds. 



Fig. 7. Transection through the brain of a larval Neeturus, 6-8 weeks old, 

 at the level of the "dorsal" commissure. The precommissure appears a few 

 sections farther cephalad. x 31.5. 



Fig. 8. Transection of the brain of a just hatched larva, at the portas, to 

 show the paraphysis. x 31.5. 



