1913] Proceedings of the Cleveland Meeting 133 



and in particular from Hansen, Heymons, Borner, Verhoeff, and Esch- 

 erich, none of whom however have progressed far toward a satisfactory 

 solution of the problem. In general it has been accepted that the 

 stipes and mentum correspond to the thoracic and abdominal coxas 

 while the maxillary and labial palpi were equivalent to the trochanter, 

 femur, etc., or the functional leg. 



Studies on Rhyparobia maderice the "giant cockroach " from Panama, 

 particularly of 10 mm. and 12 mm. embryos, as well as other investiga- 

 tions in connection with the appendages of the Thysanura, make it 

 evident that the typical appendage (mouth-parts, thoracic, abdominal, 

 caudal) of the Hexapoda consists of seven definite areas best represented 

 by the maxillas with the galea, lacina, ectostipe,^ endostipe, ectocardo, 

 endocardo, and palpus. Futhermore the palpus should be homologized 

 with the stylus of the thoracic and abdominal coxas and not with the 

 functional leg, inasmuch as both palpus and stylus are appendages of 

 homodynamous areas (ectostipe, ectomentum, meron) while the leg is 

 an appendage of the area (endocoxa) corresponding to the endostipes. 



The facts noted suggest the origin of the biramose appendage of the 

 Hexapoda directly from the parapodium of the Polychaeta, the noto- 

 podium and neuropodium arising in connection with the dorsal and 

 ventral bundles of setae and corresponding to the outer (ectal) and inner 

 (endal) groups of sclerites as outlined above. It would thus appear that 

 the Arthropoda are a polyphyletic group, and that the relationship 

 between the appendages of the Hexapoda and Crustacea is a more 

 remote one than generally accepted in connection with the studies of 

 Hansen and Borner. 



The historical development of the problem as well as the presenta- 

 tion of the facts which would seem to establish the views here advanced, 

 will appear in the completed paper of which this is a partial summary. 



Discussion: W. A. Riley — I have been especially inter- 

 ested to learn that Dr. Walton is swinging away from his earlier 

 belief in the double nature of the insect segment. It has 

 seemed to me that embryological data afforded no evidence in 

 support of the theory though there are indications of the 

 biramous nature of the appendages. The theory of the origin 

 of the insect appendages from the pleuropodes receives much 

 additional support from the work here presented. 



The President announced the following committees : 



Committee on Resolutions — S. J. Hunter, W. A. Riley, and 

 L. B. Walton. 



Committee on Nominations— Herbert Osbom, R. A. Cooley, and 

 Cornelius Betten. 



Auditing Committee — P. J. Parrot, A. F. Burgess, and W. E. Britton. 



1. The prefixes " ecto " and " endo " have been utilized in an attempt to 

 establish a better nomenclature while minor changes have been made in the 

 terminology of older parts, e. g. " ectostipes " is a more cumbersome term than 

 " ectostipe." 



