SHALLOW- WATER STARFISHES 213 



well enable us to distinguish sporadic forms from more fixed races, 

 even among hybrid forms. 



At present, we can only describe the apparently more important 

 forms, as they occur in our collections. Where so many forms 

 exist, it is not strange that each collection, of any great size, should 

 give diverse results, even could the " personal equation " be 

 eliminated. 



However, there are certain leading forms in that fauna that all 

 investigators agree upon, as well established species. 



Dr. Fisher has also described and figured several very distinct 

 species from the deeper water, that do not come within the bounds of 

 this report, such as H. polyacantha, H. clarki, H. aleutica, H. asthen- 

 actis. 



Aside from those, he recognizes (pp. 267, 303) eight principal 

 species and named varieties from the shallow waters. The large 

 collections that I have studied make it seem necessary to add to 

 those, four or five additional forms, worthy of names. 



Of the dozen or so of named forms, I believe that about five or six 

 represent genuine species, besides the four deep-water species men- 

 tioned above. But most of the shallow-water forms from south of 

 Puget Sound may be referred to H. leviuscula. 



In a few cases my own determinations differ from those of Pro- 

 fessor Fisher, especially in respect to the arctic forms; but in the 

 main I believe he has treated the forms very judiciously. His col- 

 lections from that coast were larger than mine. His descriptions 

 are detailed and his illustrations numerous and excellent. To dupli- 

 cate them would be superfluous. Therefore his work should be con- 

 sulted by everyone interested in the group, and especially for the 

 doubtful forms. The following details are, therefore, abbreviated 

 in many cases. 



It is not improbable that some of the notable variations are mere 

 individual variations of variable species, without any constancy. 

 Other variations may be due to seasonal changes in nutrition and 

 rapidity of growth. I am disposed to think that the marked differ- 

 ences frequently noted in the roughness or thorny character of the 

 tips of the spinules of all the species may be due to changes in the 

 rapidity of growth. Those that have the tips of the spinules spicu- 

 lose or thorny may be growing, as to their spines at least, more 

 rapidly than those individuals with more even or rounded tips, as in 

 those of typical leviuscula and var. lunula. Such differences of 

 growth may be due to the abundance or scarcity of food, or to 



