5-'<S rK(K;REi)iN(;s ok tiik acadkmv ok I--^"?;"-, 



This suggestion springs from various facts: The extent of the 

 ''growth color" in comets, the apparent absence of disk in single rays, 

 and the constant place of breaking in the pyloric caeca. 



The breaking place in the skeleton may occiu- near the disk, IVom 

 f)-12 nun. fVom tlie angle of th(^ ray, or at almost any |)oint on the i-ay. 

 I have never seen a break tliat was decidedly inside the disk. 



In 18 S]:)ecimens with '20 regenerating rays, 4 were less than 3 mm., 

 20 wci-c from .T-G mm., and 2 wci'e Hf) and 4") mm. from angle. 



The cause of breaking is obscure. Tnlike Ophiurians th(\y are 

 exceedingly tougli. At touch Phatariti becomes hard, tough and 

 rigid, and wlien it is thus contracted it. requires considerable strength 

 to pull it asunder, :ind it is ;i (ntiiriill mnlter ^^\■^']\ to cut among the 

 ossicles. 



If :iny cxleiiial force br.-irs n pnii in hrcnking the nnimal it is prob- 

 able that the (-reature is surprised when lim)) and relaxed, but 1 am 

 inclined to think that Phdlarid always breaks itself, no matter 

 what may b(^ the im])ulse. They may break wlien conditions are 

 changed, somcd-imes within a few hours after being placed in jars, 

 or a few days, or even not for months. Some never In-eak, but stand 

 all kinds of inconvenience of heat and cold and stagnant water. 



Ther(^ is no season for the breaking, for they are found newly broken 

 in the sea in all seasons of the year. The sensitiveness of this species 

 to our cold spells in winter and hot spells in sununer has put an end 

 to many promising experiments. Whatever may be the stimulus the 

 aninud can and does break of itself. 



Dm'ing the years 1901-04 1 have watche<l more tlian fifty stai'Iish 

 disunite. There is a regulai'ity about the matter that indicates that 

 the breaking is not an accident, or the fancy of a day, l)ut a habit of 

 the species. The breaking is automatic. Exjjeriment confirms the 

 inference that naturally arises on seeing a large number of specimens 

 together that the irregularity is due to an inherent character of this 

 species of Phatarin. The process is deliberate. It is not a breaking in 

 the proper sense of the word, but a drawing or pulling asunder. It 

 requires from half an hour to three or four hours, with resting spells, 

 and the motions arc perceptible. 



The ordinary method is for the main portion of the starfish to remain 

 fixed and passive with the tube feet set on the side opposite the 

 departing ray, and for this ray to walk slowdy away at right angles to 



time for its withdrawal were avoided and after a number of months the ray liad 

 reached the comet stage. In one case two arms started to grow from the "place 

 from which one had been cut. The pliotograpli and statement of facts appeared 

 in Proc. Acad. Nat. Sci. Phila., Mav. 1904. 



