MOTOR RESPONSES IN INVERTEBRATES 623 



215. Welsh, J. H. The nature and movement of the reflecting pigment in the eyes 

 of crustaceans. Jour. Exp. Zool. 62 : 173-183. 1932. 



216. Welsh, J. H. Temperature and light as factors influencing the rate of swim- 

 ming of larvae of the mussel crab. Pinnotheres macuhita Say. Biol. Bull. 63: 

 310-326. 1932. 



217. Welsh, J. H. Photokinesis and tonic effect of light in Unionicola. Jour. Gen. 

 Physiol. 16 : 349-355. 1932. 



218. Welsh, J. H. Light intensity and the extent of activity of locomotor muscles as 

 opposed to cilia. Biol. Bull. 65: 168-174. 1933. 



219. Wenrich, D. H. Notes on the reactions of bivalve mollusks to changes in light 

 intensity: image formation in Pecten. Jour. Animal Behav. 6: 297-318. 1916. 



220. Weyraxtch, W. K. Untersuchungen und Gedanken zur Lichtorientierung von 

 Arthropoden (1. Teil). Zool. Jahrb. 47: 291-328. 1930. 



221. White, Gertrude M. Reactions of the larvae of the shrimp, Paleomonetes 

 vulgaris, and the squid, Loligo pealii, to monochromatic light. Biol. Bull. 47 : 

 265-273. 1924. 



222. WiLLRiCH, Ursula. Beitrage zur Kenntnis der Lichtkompassbewegung und 

 des Farbensinnes der Insekten. Zool. Jahrb. 49: 157-204. 1931. 



223. Wilson, E. B. The heliotropism of Hydra. Amer. Nat. 25: 413-433. 1891. 



224. Wolf, E. Uber das Heimkehrvermogen der Bienen. Zeitsch. Vergl. Physiol. 

 3:615-691. 1926. 



225. Wolf, E. ITber das Heimkehrvermogen der Bienen. 2. Mitt. Zeitsch. Vergl. 

 Physiol. 6: 221-254. 1927. 



226. Wolf, E. Sehscharfepriifung an Bienen im Freilandversuch. Zeitsch. Vergl. 

 Physiol. 14 : 746-762. 1931. 



227. Wolf, E. The visual intensity discrimination of the honey bee. Jour. Gen. 

 Physiol. 16 : 407-422. 1933. 



228. Wolf, E. On the relation between measurements of intensity discrimination 

 and visual acuity in the honey bee. Jour. Gen. Physiol. 16: 773-786. 1933. 



229. Wolf, E. Critical frequency of flicker as a function of intensity of illumination 

 for the eye of the bee. Jour. Gen. Physiol. 17 : 7-20. 1933. 



230. Wolf, E., and W. J. Crozier. Orientation in compound fields of excitation; 

 Photic adaptation in phototropism. Jour. Gen. Physiol. 11: 7-24. 1927. 



231. Wolf, E., and W. J. Crozier. The variability of intensity discrimination by 

 the honey bee in relation to the visual acuity. Jour. Gen. Physiol. 16 : 787-793. 

 1933. 



232. Yagi, N. Phototropism of Dixippus morosus. Jour. Gen. Physiol. 11 : 297-300. 



1928. 



233. Yerkes, Ada W. Modifiability of behavior in Hydroides dianthus. Jour. 

 Comp. Neur. and Psych. 16: 441-449. 1906. 



234. Yerkes, R. M. The intelligence of earthworms. Jour. Animal Behav. 2: 

 332-353. 1912. 



235. Zerrahn, Gertrud. Formdressur und Formunterscheidung bei der Honig- 

 biene. Zeitsch. Vergl. Physiol. 20: 117-150. 1933. 



Manuscript received by the editor April, 1934. 



