CONTENTS OF No. 173.-New Series. 



MEMOIRS 



The "Sexual Season" of Mammals and the Relation of the "Pro- 

 cestrum" to Menstruation. By Walter Heape, M.A., Trinity 

 College, Cambridge ......... 1 



A Description of Ephydatia blembingia, with an Account of the 

 Tormation and Structure of the Gemmuie. By Richakd Evans, 

 B.A. (With Plates 1—4) 71 



On a Collection of Nemerteaus from Singapore. By R. C. Punnett, 

 B.A. (With Plates 5—8) . . ' Ill 



On the Protostigmata of Molgula manhattensis (De Kay). By 

 Arthur Willey. (With Plate 9) ...... 141 



