130 BULLETIN : MUSEUM OF COMPARATIVE ZOOLOGY. 



That of the third stage, 



2 (4) T, + (4) 2 To + (4) ?>h + (4) 6^, = 48 T, 

 the same as the second stage, with au additional tentacle of the t^ 

 order intercalated on each side of the t^ tentacles, making 1 1 tentacles 

 in each quadrant, or three between each of the three primary divisions 

 of the quarter. 



The fourth stage, 



2 (4) T, + (4) 2 To + (4) Zty + (4) Gu + (4) 12^3 = 96 T, 

 or a tentacle of the third order, ^3, intercalated on each side of U^ thus 

 making 7 tentacles in each of the primary divisions of the quarter. 



The fifth stage, with 192 tentacles, would have for its formula, 



2 (4) T, + (4) 2 To + (4) 2,h + (4) &t, + (4) 12^3 + (4) 24^,= 192 T, 

 or a tentacle of the fourth order, #4, intercalated on each side of ^3, 

 thus making 15 tentacles in each of the primary divisions of the quarter. 

 The theoretical formula for the sixth stage, with 384 tentacles, 

 would be, 



2 (4) T, + (4) 2 To + (4) Zt, + (4) 6<, + (4) 1 2^3 + (4) 24^^ .+ (4) 48^5 = 

 384 T, 



a tentacle of the fifth order, t^, having been intei'calated on each side 

 of the tentacles of the t^ order, thus making 41 tentacles in each of 

 the primary divisions of the quarter. 



It is not necessary to carry these stages any further, ab the largest 

 number of tentacles observed in any primary division of each quadrant 

 is not greater than thirteen, which would limit it to a modified stage of 

 192 marginal tentacles. 



Tlie accompanying tables have been arranged so as to indicate the 

 association, whatever their number may be, with the highest number of 

 marginal tentacles occurring in any primary quadrant. This number 

 may be a normal number between any T^ and To, or between any To and 

 To, and may be due to the absence of one of the To tentacles, or of both, 

 in the quadrant. 



A glance at the tables shows how few of the specimens examined 

 possessed the normal number of tentacles. AVe should have as the 

 normal stages of each quadrant for the four stages up to 192 tentacles. 



T„ To, To, Te, first stage, with 12 marginal tentacles. 



Tc, h, To, ti, To, ti, T„ second stage, with 24 marginal tentacles ; or, 

 as in the tables, 1, 1, 1 ; 1, 1, 1 ; 1, 1, 1 ; 1, 1, 1; of which eleven speci- 

 mens were seen from the number tabulated fur numerical variations. 



