3o8 



DISCOVERY REPORTS 



The subsequent branching does not proceed at absolutely the same rate in all of the 

 main canals, but there are some specimens, 4-5 mm. wide, with four branches to each 

 main canal and with thirty tentacles, and one in which every main canal has six branches ; 

 this specimen is 5 mm. wide and has forty-two tentacles. The largest specimen of this 

 group (Fig. 8) is 6 mm. in diameter and has fifty-four tentacles, the largest number 

 observed in the whole collection; the number of branches to each main radial canal 

 varies from six to ten (8, 8, 8, 6, 8, 10). 



(3) Irregular specimens (twenty-two examined). Some of the variations observed 

 are seen in Figs. 9-12. The variability of all the irregular specimens is given in 

 the accompanying table, to which only a few remarks need be added. If the number 

 of main radial canals is larger than the number of stomachal lobes, it means that 

 two or more canals issue from one or more of the lobes; three of the specimens 

 with ten main canals are very regular in shape, two canals issuing from each of the five 

 stomachal lobes ; in one of these specimens the thirty-five tentacles are distinctly seen 

 to belong to four different stages in development: 5 + 5 + 10+15. 



Willia mutabilis. Table showing variation in the number of radial canals, etc. 



