ZOOI.OGY HOWARD, MARK. 245 



however, are to be drawn as rapidly as is consistent with the extreme care 

 required. 



It is hoped to submit the whole work for publication by January i, 1910, 

 but of course it is possible, through delays at present unforeseen, that the 

 time may be extended. 



Mark, E. L., Harvard University, Cambridge, Massachusetts. Grant No. 



564. Study of maturation and early stages in the development of the 



ova of mice and rats. (For previous reports see Year Books Nos. 5, 



6, and 7.) $100. 



The paper prepared in conjunction with Dr. Long has not yet received its 



final revision ; but this is not owing to any deficiency on the part of Dr. Long ; 



it is due solely to my inability to find time during the college year to do more 



than carry on the work on parasitism in insects. The revised paper will, 



however, be submitted for publication in the course of a few weeks. 



The attempt to produce hybrids between rats and mice by means of arti- 

 ficial insemination, to which I referred in my last report, has not proved 

 successful. The work was undertaken by Mr. S. Morgulis. After some 

 preliminary trials with artificial insemination of mice with the seminal fluid 

 of mice, attempts were made to fertilize the ova of white mice with the 

 spermatic fluid of white rats. About twenty-five such experiments were 

 made with suitable precautions to exclude the possibility of previous or sub- 

 sequent fertilization in the normal way. In no one of these experiments 

 were there any signs of fertilized ova. From the constantly negative results 

 obtained it seemed undesirable to continue the experiments further. The 

 surviving animals of the stock have, however, been kept for the purpose of 

 carrying on other studies connected with problems contemplated in the origi- 

 nal grant. 



Naples Zoological Station, Naples, Italy. Grant No. 553. Maintenance of 

 two tables for American biologists. (For previous reports see Year 

 Books Nos. 2, 3, 4, 5, 6, and 7.) $1,000. 



The privilege to make use of the facilities offered by the Zoological Station 

 have been duly granted to Dr. Harold S. Colton, of Philadelphia, who worked 

 from October 26, 1908, to April i, 1909; Dr. S. Paton, from October 31, 

 1908, to April 29, 1909; Dr. Shigio Yamanouchi, of the University of Chi- 

 cago, from December 25, 1908, to February 27, 1909. 



Dr. Stewart Paton has now, after a sojourn of several years at the Naples 

 Zoological Station, returned to the United States. 



As already reported on a former occasion, I am not able to summarize the 

 aforesaid scientists' investigations after their recent sojourn at the Zoological 

 Station and repeat that an abstract of their work would best be given by 

 themselves. 



