210 



AUTOLYTUS. 



Grube, in his ' Familien der Anneliden ' (1851), made a new Family, the Amytidea, 

 to include Polybostrichus longisetosus of (Ersted, Nereis prismatica of 0. F. Muller, Nereis 

 bifrons of 0. F. Midler, Photocharis cirrigera of Bhrenberg, Nereis corniculata of 0. F. 

 Muller, and Nereis clavicomis of Sars — all sexual forms connected with Autolytus prolifer 

 and its immediate allies. 



Malaquin (1893) takes Autolytus Edwardsi, De St. Joseph, as the type of reproduction 

 in the group, and describes various phases in separate individuals. In the first instance 

 an adult develops genital glands in the posterior segments, this region subsequently 

 separating by fission and having an independent existence for a time. A segment in front 

 of the genital region, between the fortieth and forty-fifth segment, is thickened and becomes 

 the formative segment — the head of the bud being developed from it and subsequent 

 additional segments in the bud. In some cases a number of segments in front of the head 

 of the bud bear genital glands. After the separation of the bud the nurse-stock develops 

 new segments. 



In the second case the stolons of twenty to twenty-two segments have in front of them 



Fig. 56. — Transverse section of Autolytus prolifer to show the arrangement of the muscles. Letters as "before. 



a certain number of segments in process of development. The bud separates as usual, 

 regeneration of the posterior segments of the nurse-stock ensuing. 



In the third case the genital segments posteriorly are separated as a bud with head 

 and appendages. A formative zone in front of the bud actively develops segments which 

 have genital products in front of them and the bud and its genital organs behind. 



In the fourth case several buds, generally males, are attached to the posterior end 

 of the nurse-stock, the last separating as a bud as in the case of Myrianida. It is an 

 example of rapid stolonization. 



The fifth case resembles the first and second. In a nurse-stock of forty segments 

 the last fifteen, viz., from the twenty-fifth to the fortieth, are observed to have ovaries, 

 a bud of four segments with cirri and small bristles, a formative zone, and a pygidium, 

 the head being at the forty-first setigerous segment of the stock. 



In the sixth case the condition is the same as in the first, only the head of the bud is 

 between the twenty-fifth and thirtieth segments. 



