108 BULLETIN 76, UNITED STATES NATIONAL MUSEUM 



differentiated carinals. Differing from alaslcensis in having a long scries of actinals, 

 a narrow dorsolateral area, conspicuous carinal series, superomarginals higher on side 

 of ray, and in Lacking conspicuous bivalved pedicellariae. 



Heretofore the name Itexactis has been applied to almost any small 6-rayed 

 / , ptasti rim with slender rays and relatively few spinelets. Verrill reproduced Stimp- 

 son's original description but his own published observations were confined to speci- 

 mens of L. pusilla from Monterey. What his "numerous specimens from Puget 

 Sound and (lie Queen Charlotte Islands" may have been I have no way of knowing, 

 since they can not be located. Certainly duplicates of Stimpson's puzzling types 

 are not common in that region. 



It is necessary to repeat that among the numerous small 6-rayed sea stars of the 

 northwest cast of America specific lines are exceedingly difiicult to draw; but nowhere 

 is there such a confusion and intermingling of forms as in the sounds of Washington 

 and British Columbia. Specific lines which are fairly distinct elsewhere here break 

 down and one of the reasons is probably hybridization, as suggested by the presence 

 of a minority of intermediate and freakishly aberrant specimens. Hybridization 

 would be likely and simple enough if the breeding seasons coincide; but it is difficult 

 to prove that it takes place. 



I have used hexactis in a different and much broader sense than has Verrill, to 

 include the common 6-rayed Leptasterias of the Puget Sound region having irregular 

 abactinal spinulation, a fairly regular and narrow carinal band of spinelets, and usually 

 monacanthid or diplacanthid superomarginals (forma regularis). This ranges from 

 Cape Flattery to Eodiak Island, while an intergrading paucispinous variation {aspera) 

 can be traced as far as the Shumagin Islands. A multispinous form (plena) appears 

 to intcrgrade with both forma regularis and hexactis in the Puget Sound region; 

 while its northern counterpart, forma siderea, intergrades with regularis and probably 

 also with L. camtschatica dispar (through forma nitida at Kodiak). 



1 have studied Stimpson's type and type series. Probably if an attempt had 

 been made to find the most puzzling specimens in the Puget Sound region no better 

 selection could have been made. The type series, No. 1368, contains three examples 

 of forma hexactis with K 32 to 40 mm. (pi. 51, figs. 2, 3), a small relatively stouter- 

 rayed specimen with 11 20 mm., and monacanthid superomarginals, referable to 

 forma regularis (pi. 51, fig. 1) and 14 equally small, stout-rayed examples of a sub- 

 form of plena (figs. 5-9). Whether these were collected together is not known, but it 

 is very probable. 



In the original description, reproduced by Verrill, Stimpson has incorporated 

 some of the characters of these small plena, as, for instance: "In some specimens the 

 lateral spines are distinct from the ventrals, being separated from them by a channel, 

 and forming a crowded row of confluent clusteis like the dorsals. Dorsal spines small 

 and numerous, in little heaps, which being confluent in a longitudinal direction form 

 three or five (according to the distance from the disk) rows, separated from each other 

 by corresponding rows of papuliferous depressions." This refers to small plena 

 having K about 20 mm. such as Plate 51, Figures 6, 8; Figure 5 is somewhat inter- 

 mediate with regularis. In the following sentence he says: "These spines in some 

 specimens, however, are fewer and do not form heaps." This refers to the type and 

 twocotypes; Figures 2, 3. 



