Johnston, Morphology of the Head. 



195 



the center for fibers supplyinp^ end buds in teleosts. As has 

 been pointed out in numerous places (42, 73, 65. 6^ , 68, 70, 

 71, 63, 49) this assumption is based merely on the misapplica- 

 tion of the term "lobus trigemini" by Mayser (90) to the an- 



TABLE A. 



9- 



COMPARING CUTANEOUS SENSE ORGANS IN LOWER 

 VERTEBRATES. 



End buds 



Sense cells slender, 

 rod-shaped, reaching 

 full depth of epidermis 



Neu7-omasts 



Pit and canal organs, 

 Ear. 



Ampullae, 

 nerve sacs. 



Vesicles 

 of Savi. 



Sense cells pear-shaped, not reaching full depth 

 of epidermis. Supporting cells rod- 

 shaped. 

 Merkel (91, comparative), Maurer (89, teleosts), Herrick (48, teleosts), 



Johnston (68, Petromyzon). 

 Innervated by com- 

 munis components. 

 Herrick (49) and 



others. 

 Fibers slender. 



Innervated by various rami of "lateral line 



nerves." 

 Many authors ; see review in (70) and (49) . 



Fibers characteristically thick. 



Strong (114), Herrick (46), and others. 



Central endings in lobi 

 facialis (and vagi). 

 Herrick (47, 48, 49), 



and others. 

 Secondary tract is the 

 secondary vagus tract. 

 Uncrossed (67). 

 This tract ends in the 

 secondary vagus nu- 

 cleus beneath the cere- 

 bellum (67). 

 Function is taste ; re- 

 spond only to chemical 

 stimuli. 

 Herrick (49). 



Distributed in mouth 

 and branchial cavities, 

 and over head, body 

 and fins; in most forms 

 without regular ar- 

 rangement. 

 Always superficial. 



Central endings in acusticum, lobus lineae later- 

 alis, cerebellum, and nuc. acust. spinalis. 

 Many authors; see (70) and (49); Strong (ii:;). 



Secondary tract is the tr. bulbo-tectalis, formed 

 by internal arcuate fibers. Crossed. (47, 

 67,68). 



This tract ends in the tectum opticum (47, 67, 

 68). 



Function of equilibration and hearing. 

 Respond to changes Probably Probably 



of pressure in sur- . the same. the same. 



rounding fluid. 



Many authors, see (70); Parker (ioi, ,102). 

 In canals or rows of 



pits. Regular ar- 

 rangement in 



forms. 



all 



Appear in 

 rows related 

 to canals and 

 pits. Sink in, 

 long tubes, 

 collected in 

 groups. 



Always depressed below the surface. 

 (One exception, 48). 



Separated 

 from the 

 surface. 



