Kingsbury, Oblongata in Fishes. 19 



this level. The lateral line nerve is small, but yet unexpectedly- 

 large when it is remembered that the lateral canal of the lateral 

 line system is short ; doubtless neuromasts in the epidermis oc- 

 cur. Cephalad of this root, one of medium size springs from 

 the fasciculus communis system (IX?). Vllaa is very small; 

 Vllb rather large. 



Eventognathi. In the Cyprinidae we encounter forms al- 

 ready well known from the monograph of Mayser ^ and in them 

 and the Catostomidae there exists so far as known to me, the 

 greatest complexity of the oblongatal region among teleosts. 

 The secondary fusion of the oblongata, involving in the two or- 

 ders last mentioned the acusticum only, here includes also the 

 preauditory portion of the fasciculus communis system and 

 there is produced the tuberculum impar of earlier authors. For 

 this fusion the great development of the fasciculus communis 

 system and the nerves issuing from it, seems probably, in a de- 

 gree, responsible ; an increasing growth of this system under 

 the limitations which the fusion of its cephalic portion imposes, 

 produces apparently the monstrosity of the carp and sucker 

 brain. A displacement of the acustic systems is also a neces- 

 sary accompaniment of the growth and eversion of this inner 

 region, and instead of being dorsal, it has been crowded cephal- 

 ad, although when other things are considered, this may be 

 shown to be more apparent than real. In the brains examined, 

 however, a series of increasing complexity may be easily formed, 

 which further studies will undoubtedly make more complete. 



To Mayser's account of the cyprinoid brain little more can 

 be added than to speak of the different modifications of the re- 

 gions and their relations to the cranial nerves. No microscop- 

 ical study of the carp brain has been made and Mayser's ac- 

 count has been taken as the source of information. Notemigonus 

 is the simplest of the cyprinoid brains examined by the writer. 

 The caudal beginning of the fasciculus communis systems is 



* Mayser examined many teleosts besides cyprinoids, and in the absence of 

 any comparison or statement to the contrary, it has been assumed by some (and 

 naturally) that the conditions described by him were typical of teleosts 

 generally. 



