MICHIGAN ACADEMY OF SCIENCE. 15 



A Hydra with Branched Tentacles. Peter Okkelberg. 



Length of the Life Cycle in the Brook Lamprey. Peter Okkelberg. 



Notes on the Late History of the Germinal Vesicle in the Egg of Crypto- 



branchus. Bertram G. Smith. 

 Notes on the Proportion of the Sexes in the Whitefish. Raymond Pearl. 

 The Development of the Albino Rat From the End of the First to the End of 



the Tenth Day of Insemination. G. Carl Huber. 

 Sex-limited and Sex-linked Inheritance. Hansford MacCurdy. 

 A Peculiar Type of Brachydactyly. Hansford MacCurdy. 

 Records of Mastodon in Gratiot County, Michigan. Hansford MacCurdy. 

 A Problem in Distribution. Bryant Walker. 



The Preparation of Serial Sections of Frog Embryos. Bertram G. Smith. 

 The Porifera, Oligochaeta, and certain other Groups of Invertebrates in 



the vicinity of Douglas Lake, Michigan. Frank Smith and Bessie R. 



Green. 



