5. Entwicklungslehre. 77 



136) Smith, G., Studios in tlie Experimental Analysis of Sex. 



(Quart. Journ. Micr. Sei. Vol. 54,4. p. 577—604. Febr. 1910.) 

 1. The author discusses Mendeliau Theories of Sex, and those depending 

 on „heterochromosomes". He shortly reviews the hypotheses of Castle, M'Clung, 

 Wilson, Bateson and Correns and indicates the bearing on these of the 

 Pacta of castration and parthenogenesis. 2. The relation hetween Primary and 

 Secondary Sexual Characters. In some cases secondary sexual characters are 

 dependent upon the presence of a functional gonad, in others (cf. the experi- 

 ments of Meisen heim er 011 Lepidoptera) there is no such dependence. The 

 author describes Ins observations on the effects of Sacculina on Inachus. 

 On males the parasite causes the host to approach the feraale form, all stages 

 being found from slightly modified males to speeimens differing from normal 

 females only in the presence of copulatory styles, which may be much reduced. 

 On females the sacculina only causes a reduetion of the distinctively female 

 characters, but 110 approach to those of the male. On recovery, males may 

 produoe ova in the testis. Potts has obtained similar results in Eupagurus 

 parasitised by Peltogaster. These facts suggest that the male is hetero- 

 zygons in respect of sex (<5 2), but in Cladocera the facts of parthenogenetic 

 reproduetion show that the female is heterozygons. 



Since the change of a male to the female type oecurs in the absence of 

 a functional gonad, the author suggests the existence of a „sexual formative 

 substance" which stimulates the produetion not only of the gonad but also of 

 the secondary sexual characters. Doncaster (Cambridge). 



137) Coyentry, A. F., The Application of M. G. W. Smiths Theory 

 of Dwarf Males to Myzostoma. 



(Ann. & Mag. of Nat. Hist. Ser. 8. 5,28. p. 378—380. 1910.) 

 The author points out that the facts known about the sexual relations 

 of Myzostoma are in agreement with Smiths hypothesis that the „comple- 

 mental males" of Cirripedes are potential hermaphrodites in which the de- 

 velopment of the female organs is arrested. The descriptions of Myzostoma 

 of Beard and Wheeler, while not agreement with each other, are both expli- 

 cable on the assumption that „dorsicolous" individuals with only male organs 

 are in reality protandrous hermaphrodites: while in speeimens attached to the 

 disc of Comatula both testes and ovaries develop. 



Doncaster (Cambridge). 



138) Gey, F., Ein Gambusenbastard? 



(Blätter f. Aquarien- u. Terrarienkunde 21,2. p. 23. 1910.) 

 Vielleicht Bastard zwischen einem 8 von Gambusia und einem o von 

 Girardinus. Wolterstorff (Magdeburg). 



5. Entwicklungslehre. 



(Siehe auch Nr. 70, 114, 117, 124, 128, 132, 198—200.) 



139) Marre, E., Die Inkubationsdauer des Fischeies. 



(Blätter f. Aquarien- u. Terrarienkunde 21,8. p. 120—122. 

 Marre macht hier die Aquarienfreunde mit den wichtigen Untersnehunge 1 

 von Reibisch u. a. über den Einfluß der Temperatur aui die Entwickelung 

 von Fischeiern bekannt und regt zu entsprechenden Untersuchungen auch bei 

 der Zucht von Zierfischen an. Aber auch andere Umstände Bind in Betracht 

 zu ziehen. Je größer das Ei, je länger dauert die Inkubation. 



Wolterstorff (Magdeburg). 

 G* 



