Apeil 30, 1909] 



SCIENCE 



711 



botany or agriculture in the botanical instruction ; 

 (3) the biological grouping of subjects; (4) the 

 holding of the interest of the students, i. e., the 

 finding of the eifective point of contact for botany 

 with students who are looking for practical values. 

 No formulation of the value of botany can be 

 made until these problems have been settled. The 

 time is now ripe for a well-organized investiga- 

 tion, to be followed by a statement of well-estab- 

 lished conclusions. 



A full report of the meeting will be issued in 

 pamplet form early in May. This will be sent to 

 the members of the federation. Any one may 

 obtain copies by applying to the secretary. 



C. R. Mann, 



Secretary 



The University of Chicago 



THE AMERICAN ASSOCIATION FOR THE 



ADVANCEMENT OF SCIENCE 



SECTION F (ZOOLOGY) 



The vice-presidential address at the Baltimore 

 meeting was delivered by Professor E. B. Wilson. 

 It was published in Science, January 8, 1909. 



The secretary has received abstracts of papers 

 read as follows: 

 Brood-protection mid Sexual Dimorphism among 



Echinoderms : Hubert Lyman Claek, Harvard 



University. 



The large number of echinoderms now known 

 (about fifty) which protect or care for their 

 young in some way show great diversity in the 

 method used. The eggs may develop outside the 

 body of the parent or more rarely within the body- 

 cavity or in special reproductive cavities. If de- 

 veloped outside the body, the young may become 

 attached to some part of the parent, or be shel- 

 tered among her spines or covering plates, or 

 simply be brooded beneath her ventral surface. 

 If developed within the parent, the young may 

 swim about freely in the body-cavity, or more 

 rarely undergo their development in the repro- 

 ductive organs, which are thus practically uteri. 



Among all these brood-protecting species, how- 

 ever, there seem to be only half a dozen (about 

 twelve per cent.) which occur in tropical waters, 

 while more than sixty per cent, are found in 

 Antarctic or South Temperate seas. 



Only four species, and these all from between 

 30° and 60° S. latitude, show any marked sexual 

 dimorphism. In one, an ophiuran, the male has 

 only five arms, the female, six to eight (Koehler). 

 In another, a holothurian, the development of a 

 peculiar brood-chamber in the dorsal integument 



distinguishes the female. The third is a spatan- 

 goid in which the lateral petals of the female are 

 much broader and deeper than those of the male 

 and serve as brood-pouches. The fourth is a 

 olypeastroid, recently discovered in the Australian 

 collections of the " Thetis," in which the abactinal 

 area of the female is deeply depressed to form a 

 horseshoe-shaped brood-chamber, wholly wanting 

 in the male. 



Notes on the Eggs of the Anura of Ithaca, N. Y. : 



Albert H. Wrioht, Cornell University. 



Eight species of Anura are found at Ithaca, 

 N. Y., namely: Bana sylvatica, Hyla pickeringii, 

 Rana pipiens, Bufo lentiginosus americanus, Rana 

 palustris, Eyla versicolor, Rana clamitans and 

 Rana catesbiana. 



The first five species appear from hibernation 

 and spawn under a maximum air temperature of 

 43-50° F. ; the last three delay until the maximum 

 reaches 70° F. or more. The first five usually 

 breed from the last of March until the middle of 

 June; the last three, from the last of May into 

 August. All but two species, Bufo I. americanus 

 and Retna clamitans, occupy four or five weeks 

 for the spawning period. The exceptions may 

 require two or three months. The numoer of eggs 

 may vary from 800 in Hyla pickeringii to 20,000 

 in Rana catesMana. 



The eggs of three species, Hyla versicolor, Rana 

 clamitans and Rana catesiiana, float more or less 

 at the surface of the water; the eggs of the other 

 five are submerged. The five species with sub- 

 merged eggs are the first to breed. They deposit 

 eggs with firm jelly envelopes, several eggs ap- 

 pearing at an emission except in Hyla pickeringii, 

 where only one appears at an emission. The three 

 with buoyant eggs breed after May 25. They 

 deposit at the surface masses or films of eggs with 

 loose jelly envelopes, several eggs being deposited 

 at an emission. The best diflferential egg char- 

 acters are: the manner of deposition, the nature 

 of the jelly envelopes, the color of the vitellus, 

 the diameters of the vitellus and jelly envelopes, 

 the number of eggs and the season of deposition. 



Factors Determining the Movement of Melwnin 

 Pigment Granules: Oscar Riddle, University 

 of Chicago. 



Movement of these particles from one part of 

 the cell plasma to another, and from one cell 

 to another, is probably determined eitfter by the 

 solubility properties or by the electrical state of 

 the granules. Author obtained no evidence of 

 solubility. The granules are, however, definitely 

 proven to be colloidal bodies bearing a negative 



