[882.] Problems for Zoologists. 389 



PROBLEMS FOR ZOOLOGISTS. 



BY J. S. KINGSLEY. 



1WTR. S. II. Scuclder in his address before the Entomological 

 A" Section at the Boston meeting of the American Association 

 for the Advancement of Science, presented some of the problems 

 which the entomologist has yet to solve, and acting upon the hint 

 which his article affords, I would here state some of the questions 

 in other departments of zoology which arc as yet unanswered. 

 Throughout our land there are several hundred people who are 

 greatly interested in zoology, but the greater portion of them 

 through lack of guidance and through misdirected efforts, add 

 nothing to the stock of scientific knowledge which the world pos- 

 sesses. On the shoulders of a few falls all of the original investi- 

 gation done in America to-day. It is to that larger class who are 

 willing to work, but who do not know how to work, or what to 

 work upon, that this article is addressed. Some of the problems 

 are simple, needing only a slight amount of experience, and a 

 moderate amount of skill, while others require for their elucida- 

 tion the trained investigator. To state all the problems requiring 

 solution, would take more space than is contained in a volume of 

 this magazine ; a few only, therefore, are presented. 



Hermann Fol has recently described the effects produced upon 

 the eggs of star-fishes when two or more spermatozoa enter it at 

 the same time. An abnormal segmentation ensues, proceeding 

 from two or more centers, and resulting in a compound gastrula. 

 This would suggest a possible explanation of the cause of double 

 monsters, and assign an answer for a much vexed question in tera- 

 tology. A single fact is but a slender foundation for generaliza- 

 tions of this character, and hence observations are needed to 

 ascertain whether in other groups a multiple impregnation pro- 

 duces a compound gastrula, and if so, what the gastrula in turn 

 produces. 



The eggs of a few animals have been studied while becoming 

 mature, and when the impregnation was taking place, and with 

 wonderful results. Yet but a very few forms have thus been 

 studied, and detailed accounts of the phenomena of the matura- 



The eggs of the larger proportion of the animal kingdom in be- 

 coming mature form what are known as polar globules. With 

 the possible exception noted by Grobben, these polar globules 



