ON BUDDING IN ANIMALS. 13 



accomplished quickly) the eggs or other elements rapidly 

 augment in bulk, the natatory bristles develop, the bud soon 

 arrives at a certain degree of maturity, evinces energetic move- 

 ments, breaks off, and swims freely. The nurse- stock then shows 

 regeneration posteriorly. 



In other cases, before the bud is detached, the proliferating 

 zone in front of the tail (pygidium) of the nurse-stock gives rise 

 to new segments, which considerably increase the length, so 

 that on separation of the bud it is ready to proceed with a new 

 bud posteriorly. 



In a third form the head of the bud is found as before at the 

 forty-first setigerous segment. Thereafter two indifferent seg- 

 ments (formative zone) in front of the head are formed, and a 

 new bud is developed. The posterior bud, as in the previous 

 cases, is formed out of certain of the older segments of the 

 nurse-stock, and is thus more or less scissiparous in origin. 



Again, a nurse-stock of forty or forty-two segments* is 

 followed by a chain of buds (generally male, more rarely female), 

 all formed at once by active proliferation. The terminal bud 

 soon becomes free. Another of forty segments, with ovaries 

 from the twenty-fifth to the fortieth (fifteen), then several young 

 segments (four) with cirri and minute bristles, a formative zone, 

 and a tail (pygidium). It becomes a female bud, with its head 

 at the forty-first segment. 



As a rule in examining such forms, Malaquin is of opinion 

 that if the segments of the bud are of the same or larger 

 diameter than those of the nurse-stock, then it is probably 

 a case of fission ; whereas in budding the segments have a 

 smaller diameter than those of the parent or nurse-stock. In 

 certain Syllidians, again — for example, Autolytus longiferiens 

 and Exogone gemmifera — both direct development (epigamy) and 

 budding (schizogamy) are present. 



De Saint Joseph! thinks that, when the bud in Autolytus has 

 considerable length, and consists of three regions, it is probably 

 the result of fission. On the other hand, if short and of two 

 regions, it is probably due to budding. While Myrianida has a 



* In others the nurse-stock in front of the buds has only twenty-eight 

 setigerous segments. 



f ' Ann. des Sc. Nat.' 1886, p. 256. 



