NOTES ON THE NAIDIFORM OLIGOOH^TA. 339 



A is a primary zooid developed from the egg. A will give 

 rise to two secondary zooids, B and C^ in the following manner : 

 — after its nM^ segment {n is a number characteristic probably 

 of each species) a bud, Z, will form; this will divide into two 

 regions, z and z' : z will consist of an indefinite number of 

 segments, and form the tail of B ; while z' will consist of a 

 definite number of segments (a number characteristic of each 

 genus), and will become the head of C. 



B and C may now separate, or may remain joined together 

 until two new budding regions have appeared. 



In either case, after the ri^^ segment of B another bud, Z, 

 may form, which will behave iu the same way as the first bud 

 behaved, and divide into z and z' ; and z will become the tail of 

 a tertiary zooid b ; and z' the head of another tertiary zooid, c j 

 and a similar process will take place after the n^^ segment of 

 C, giving rise to two other tertiary zooids, c^ and c^. The chain 

 of four zooids represented by the letters b, c, c^, c^, may now 

 separate into two chains of two zooids each, bc and c^c^, or so 

 far as we know may remain joined together until, by the 

 formation of four new budding regions, a chain of eight 

 zooids, b, c, c^, c^, c^, c*, c^, c^, has developed. As a matter 

 of fact I believe that in no Naid do more than four zooids 

 hang together in a chain. 



Among a mass of Naids where asexual reproduction was rife, 

 specimens might occur which could be represented thus : — A, B, 

 C, BC, B, c, c^, c^, bc, c^c^, b, c, c^ c^, c^, c*, c^ c^, bc, c^c^, 

 c^c^ c^c^, bcc^c^, c»c*c5c6, &c. 



I am inclined to believe that the forms which do occur are 

 A, BC, BC, c^c2, Bcc^c^, bcc^c^ c^c^^c^, &c. ; and among these 

 we may theoretically recognise three types : — (1) forms A, 

 developed from the egg ; (2) forms BC, bcc^c^, bcc^c^, &c., in 

 which the original head end is retained ; and (3) forms c^c^, 

 cMc^c^, &c., in which the head is a budded region; and it is 

 possible that there are forms C, which must be distinguished 

 from c^c^, c'^c^c^c^, &c., as they possess the tail end of a form 

 A, while c^c^ and c^c'^^c^c^ must consist entirely of segments 

 formed by budding. 



