PHYSIOLOGY OF SYNAPTULA HYDRIFORMIS 377 



chains of neurones so arranged as to permit only one type of 

 response — viz., a total reaction (the swimming movement) — 

 from all possible forms of stimulation, and that in successive 

 later stages this generalized type is gradually replaced by a 

 series of special reflexes involving more diversified movements. 

 . . . . The simple reflex arc . . . . , which is adapted 

 for the execution of a single movement in response to a particu- 

 lar stimulus, is the final stage in the developmental process, 

 whose initial stages are much more complex and diffuse arrange- 

 ments of neurones adapted for total reactions of a more general 

 sort" (Herrick, '15, p. 66). 



BIBLIOGRAPHY 



Baur, A. 1804 Beitrage zur Naturgeschichte der Synapta digitata. Drei Ab- 



handlungen. Nova acta. acad. Leop. Carol., Bd. 31, 



1864 a 4, 51 p. 



1864 b 3, 60 p. 



1864 c 3, 119 p. 

 Becher, S. 1907 Rhabdomologus ruber Keferstein und die Stammform der 



Holothurien. Zeitschr. wiss. Zool., Bd. 88, pp. 545-689. 



1909 Die "Horblaschen" der Leptosynapta bergensis. Ein Beitrag 



zur Kenntniss der statische Organe. Biol. Centralbl., Bd, 29, pp. 413— 



425. 

 Buddenbrock, W. v. 1912 Ueber die Funktion der Statozysten im Sande gra- 



bender Meerestiere (Arenicola und Synapta). Biol. Centralbl., Bd. 



32, pp. 564-585. 

 Chick, H. 1913 The factors concerned in the solution and precipitation of 



euglobulin. Biochem. Jour., vol. 7, pp. 318-340. 

 Clark, H. L. 1898 Synapta vivipara: a contribution to the morphology of 



Echinoderms. Mem. Bost. Soc. Nat. Hist., vol. 5, pp, 53-88. 



1899 The synaptas of the New Englarfd coast. Bull. U. S. Fish. 



Comm., vol. 19, pp. 21-31. 



1907 The Apodous Holothurians: a monograph of the synaptidae an i 



molpladidae. Smiths. Contrib. Knowl., vol. 35, No. 1723, 231 pp. 

 Copelaxd, M. 1917 The olfactory reactions of snails. Anat. Rec, vol. 11, 



pp. 520 521 . 

 Crozier, W. J. 1014 a The sensory reactions of Hol'othuria surinamensis Lud- 



wig. Zool. Jahrb., Abt. f. Physiol., vol. 35, pp. 233-297. 



1914 b The orientation of a holothurian to Light. Amer. Jour. 



Physiol., vol. 36, pp. 8-20. 



1916 a The rhythmic pulsation of the cloaca of holothurians. Jour. 



Exp. Zool. vol. 20, pp. 297-356. 



1916 b The taste of acids. Jour. Comp. Neur., vol. 26, pp. 453-462. 



1!'17 The photoreceptors of Amphioxus. Anat: Rec, vol. 11, p. 520. 



