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mation of a single sexual individual; the development of the head of 

 the stolon taking place on the 14th or 15th segment. After the sepa- 

 ration of the stolon from the parent stock it is likely that this process 

 may repeat itself by the outgrowth of an embryonic tissue by which 

 the parent stock regains its former length, thus according with the 

 phenomena observed in Auiolytus longicirris by De St. -Joseph 

 (Ann. des Sciences Nat. 7® S. I). Whether however such a growth takes 

 place sufficient to form a second stolon I have not been able to ascer- 

 tain for Autolytus ornatus. In this species the embryonic tissue does 

 not become plainly visible until after the separation of the stolon, and 

 in no instance have I observed a chain of stolons such as is found in 

 Autolytus varians Verrill, a form quite common on the New England 

 coast, or as has been described for Autolytus Edwardsi by De S t.- Jo- 

 seph and Malaquin. The positien of the stolon in A. ornatus is very 

 constant, the development of the head invariably taking place on the 

 14th or 15th segment, usually on the 14th or with rare exceptions on 

 the 15th. 



The presence of ovules and sperm cells anterior to the 14th seg- 

 ment can therefore be accounted for in but two ways: 1) Either after 

 the separation of the stolon, and subsequently after the parent stock 

 has again regained its length there must be a production of a second 

 stolon taking its origin anterior to the 14th segment so as to include 

 the 12th and 13th segments; or 2) The so-called asexual individual 

 or parent stock must at a certain stage of its existence develop into a 

 sexual individual. 



Examples of budding anterior to the primitive budding segment 

 may occasionally be observed in A. varians where , for example , after 

 the formation of a primitive budding zone posterior to the 43rd seg- 

 ment from which is developed a chain of stolons, a second zone may 

 make its appearance beetwen the 40tli and 41st segments. In this 

 species however the position of the zone of budding is situated not 

 only more posteriorily but the position of the segment upon which 

 is to be developed the head of the oldest individual of the chain of 

 stolons also varies and the position of the stolon cannot be accurately 

 indicated as it can be in A. ornatus. In A. variatis just as in A. Edwardsi 

 described by Malaquin (Recherches sur les Syllidiens) the posi- 

 tion of the budding zone may vary so as to reduce the length of the 

 parent stock to from 42 to 29 or even as low as 23 segments. Since 

 in A. ornatus I have not been able to find parent stocks with fewer 

 than 13 setigerous segments, and as the formation of a stolon is not 

 likely to occur so close to the region occupied by the stomach , which 

 is usually found in segments 6 to 11, it is improbable that the pheno- 



