52 University of California Publications. [Zoology 



niately to be males. It is also highly probable that other species 

 of Aglaophenia, and other genera, may exhibit in their phylacto- 

 carps peculiar sex characters corresponding to the foregoing 

 types or to some other type or types not yet discovered. 



Zoological Laboratory, 



University of California, 



Berkeley, Cal., Fehruary 23, 1906. 



BIBLIOGRAPHY. 



AUman, G. J. 



1877. Keport on the Hydroida collected during the Exploration of the 

 Gulf Stream, etc. Mem. Mus. Comp. Zool. V, No. 2, pp. 1-66, 

 34 plates. 



1883. Keport on the Hydroida dredged by H. M. S. Challenger, etc. 

 Chall. Kep. Zool. VII, No. 3, pp. 1-55, 20 plates. 



Nutting, C. C. 



1900. American Hydroids. Part I. The Plumularidae. Special BiUletin 

 4, U. S. Nat. Mus., pp. 1-285, 34 plates. 



Torrey. 



1902. The Hydroida of the Pacific Coast of North America. Univ. of 



Cal. Publ., Zool. I, pp. 1-104, 11 plates. 

 1904. The Hydroids of the San Diego Region. Univ. of Cal. Publ., Zool. 

 II, pp. 1-43, 23 text figures. 



