244 CALIFORNIA ACADEMY OF SCIENCES [Proc. 4th Ser. 



coloration, warm flesh and salmon tinting of the interior of the 

 shell, pale anterior lobe, nearly nude girdle, and the marginal 

 position of the setae. Further characters to be noted only on 

 dissection are the spongy eaves, curious rows of pores in the 

 anterior valve, open sinuses, and sharply cut teeth. This com- 

 bination of features should effectually prevent the confusion of 

 P. rufa with any of the described forms. It is an important 

 addition to our fauna. 



24. Katharina tunicata (Wood) 



The specimens seen by me were taken between tides at Sitka 

 and at Forrester Island, but Mr. Willett writes : "Have found 

 Katharina and Crypfochiton common everywhere I have been 

 in S. E. Alaska, both in smooth water and rough." 



25. Cryptochiton stelleri Middendorff 



Here again the specimens seen by me were taken between 

 tides at Sitka and Forrester Island, but as just noted, Mr. Wil- 

 lett reports it an abundant species at every locality visited by 

 him. The specimens seen run a good deal smaller than they do 

 farther to the south, e. g., at Monterey. 



Literature Cited 

 Balch, F. N. 



:06. Remarks on certain New England chitons with de- 

 scription of a new variety. Nautilus, v. 20, pp. 62-68, October, 

 1906. 



Sykes, E. R. 



'94. Notes on the British chitons. Proceedings Malaco- 

 logical Society, London, v. 1, pp. 35-37, pi. 3, March, 1894. 



Thiele, J. 



:10. Revision des Systems der Chitonen, II. Teil. Zoolo- 

 gica, Bd. 22, pp. 71-132, pis. 7-10, Stuttgart, 1910. 



