352 University of Califoruia Publications in Zoology. [Vol.8 



lid. In place of the simple hub bored as a sleeve in the old model, 

 the new model has a larger hub (fig. C), 40 mm. in diameter, 

 with a bore rather greater than the standard in diameter and 

 carrying between flanges on both the upper and lower surfaces of 

 the hub three equidistant steel rollers 8 mm. in length and the 

 same in diameter. These stand with their axis of revolution in 

 the horizontal plane and in such a position that the least tilting 

 of the lid in any direction brings one or more of them in contact 

 with the standard, and their rolling motion facilitates the im- 

 mediate descent of the lid. 



The key-faucet and its revolving seat which closes the outlet, 

 have both been constructed of bronze, which is more durable than 

 the brass used in the first model, and the diameter of the outlet 

 has been increased to hasten the emptying of the catch and thus 

 to make possible more rapid repetition of catches at sea. 



Zoological Laboratory, University of California. 

 Transmitted August 17, 1911. 



LITERATURE CITED 

 KOFOID, C. A. 



1905. A self-closing water-bucket for plankton investigations. Cons. 

 Perm. Intern. Expl. de la Mer. Publ. de Circonstance, no. 32, 

 10 pp., 4 figs, in text. 



1910. The biological stations of Europe. Bull. U. S. Bureau of Educa- 

 tion, 1910, no. 4, xiv, 360 pp., 55 pis., 48 figs in text. 



McEwEN, G. F. 



1910. A preliminary report on the hydrographic work carried on by 

 the Marine Biological Station of San Diego. Univ. Calif. 

 Publ. Zool.. 6, 189-204. 1 fig. in text and 1 map. 



