554 B. r. Kingsbury and II. 1). Reed. 



tion of the ear capsule associated with the outpocketing of the peri- 

 lymphatic space we employ the name Prominentia perilymphatica. 

 Without going into a discussion of homologies, we designate as Os 

 squamosum the Os paraquadratum of Gaupp, hut in the use of other 

 names we adhere.to the terms used by him. The term j^rotoji is used 

 as the equivalent of the German word Anlage. 



We depart from the usages of the preliminaiy paper' in substi- 

 tuting Vena petroso-lateralis for Ve7ia jugidaris interna of which it 

 is a direct continuation, employing the name used by Driiner, like- 

 wise using his term, Muscidus cephalo-dorso-nmndlbularis for Mus- 

 cularis depressor mandibuli. Palatoquadratum is substituted for 

 Quadratum. 



AchnoivledgmentS. We have received material for study and help- 

 ful criticism from many sources and wish especially to express our 

 indebtedness to Professors Wilder and Gage and Dr. W. A. Hilton of 

 Cornell University, Professor Robert Wiedershemi of the University 

 of Freiburg and Mr. B. G. Smith of Syracuse University. Aside 

 from personal obligations we wish to express our appreciation of the 

 works of Wiedershcim and Gaupp in this field of research.^ 



AmBYSTOMIDxIE. 



Amhystomd^ punctatum. Two reasons determined the choice of 

 this form as one of the species in which to work out quite thoroughly 

 the development of the ear region: (a) the ease with which a large 

 number of stages, larval, transforming and adult, could be procured ; 

 (b) its systematic rank as a typical urodele. In all, some forty 

 series were examined and four models prepared. In this way was 

 obtained a complete history of the transformations through which 



^Errata. At this point we desire to correct errors that were allowed to 

 creep into manuscript and proof in the earlier paper : 



(1) p. 83, line 2. Hemidactylum should read Ileniidaetyliuni. 



(2) p. 83, line 11, 4-G mm. should read 12-14 mm. 



(3) p. 83, line 17, 1888 should read 1879. 



(4) p. SO. line 2. caudal should read dorso-oaudal. 



(5) p. 87, line 4, Hemidactj^lum should read Hemidactylium. 



(6) p. 87, Fig. 4, D.e. should read D.p. — Ductus perilymphaticus. 

 ^The same as Ambystoma accordins to older usage. 



