10 McMURRICH 



uals and is, in some cases, after the individuals have obtained a 

 considerable size, replaced by salmon color or by white. In sup- 

 port of this idea it may be stated that individuals are frequently 

 found whose color is chiefly salmon or white, but whose column 

 is splashed with irregular bands, spots or dots of brown. This 

 fact seems to be true also of the Puget Sound forms according 

 to the description given by Verrill ('69). Of course all individ- 

 uals do not necessarily undergo a change from the brown color 

 with advancing age, since brown forms may frequently be found 

 quite as large as the individuals of the other colors. 



The second point to which I wish to call attention receives a 

 simple explanation from the conclusion just stated. Salmon- 

 colored individuals blotched with brown are not uncommon and 

 white individuals similarly marked are also found, but, never as 

 far as I have seen, do individuals of a salmon color blotched 

 with white, or vice versa, occur. In other words the salmon- 

 colored and white varieties never merge into one another while 

 both merge into the brown variety. 



2. As to dimensions the specimens which I have collected at 

 Woods Holl agree in size fairly well with those of the present 

 collection, except that I have never found any East Coast speci- 

 men as large as the largest Puget Sound specimen. Verrill, how- 

 ever, states ('64) that the more northern forms, especially those 

 from the Bay of Fundy, are larger than those from more south- 

 erly localities. 



3. As to external form I have not been able to distinguish 

 any constant differences in the external form of the individuals 

 from the two localities. The differences which Verrill con- 

 sidered to exist in the slenderness of the tentacles and the dis- 

 tance of the collar from the margin cannot be regarded as of 

 much importance since they are apt to be due to contraction ; I 

 find indeed as much difference in both these respects between 

 different specimens from Puget Sound or Woods Holl as be- 

 tween specimens from the two localities. 



As to internal structure. Making due allowance for the vari- 

 ability in the details of the internal structure shown to exist in 

 the Puget Sound specimens, and for the similar variability occur- 



