368 carl vogt. 



Reproduction by Budding. 



Buds are produced on both sexes, and always in the same 

 position, at the sides of the ventral surface. They are developed 

 without any reference to the sexual reproduction, being found 

 on females laden with ova, and on males in which the seminal 

 vesicle is in full activity. It seems probable that the buds are 

 of the same sex as the individuals that bear them. There are 

 never more than two buds, and they are always unequally deve- 

 loped. Frequently there is only one, and in the month of July, 

 and at other seasons the great majority of the Loxosomas exhi- 

 bited no trace whatever of gemmation. The Author thinks that 

 the comparative scarcity of buds, in which this form differs from 

 all others, except the L. singulare, Keferstein, may be employed 

 as a specific distinction. 



The production of buds is the work of the hypodermic layer 

 alone. No other portion of the body is concerned with it ; the 

 entire structure is developed from the ectoderm of the parent. 



The first indication of the bud is an elevation of the hypo- 

 dermic layer, over which the cuticle arches. Tt is in some degree 

 separated from the rest of the envelope and from the other hypo- 

 dermic cells by a more or less marked cuticular fold. 



The arched cavity formed by this rising is soon filled by the 



stages of its development. He observed the growth of the tentacles 

 on the anterior (or inner) surface of the ciliated mantle or vehim, and the 

 subsequent disappearance of the cilia. He also noticed the formation of a 

 kind of pedicle at the base of the body — a prolongation of the caudal 

 appendage ; by which the larva attached itself, and actually witnessed the 

 attachment. At this time, he states, the digestive canal was completely 

 formed. These observations are conclusive, and show that it is not merely 

 " probable," but certain, that the dissolution of the tissues is not one of the 

 developmental changes through wliich the PediceUina larva passes. I have 

 m.yself met with the larva of P. echinata attached, retaining much the 

 same form as when free, exhibiting just the differences of aspect that one 

 might expect during the transition into the adult state, but no sign of any 

 further transformation {vide ' Micr. Journ,,' v. xiii, n. s., p. 33). Seeing 

 it in this condition, and knowing that its internal structure is already con- 

 formed even in detail to the type of the adult, it would seem almost im- 

 possible to doubt that the further course of development must be straight 

 onwards towards the perfect form ; Van Beneden's observations show that 

 it is so. 



When we consider the close affinity between PediceUina and Loxosoma, 

 and the general agreement of their embryonic states, it is certainly in the 

 highest degree probable that the cycle of development is the same in both. 



It appears from the observations of Vogt, that in the latter genus the 

 whole conformation of the embryo is more delicate, and the internal organs 

 are less strongly defined than in the former ; but at the same time the struc- 

 tural plan is sketched in its completeness, and it is equally difficult in bo h 

 cases to believe that it is afterwards obliterated merely to be renewed by a 

 different process. It may, I tiiink, be considered all but certain that the 

 larvai of the Entoprocla pass directly into the perfect animal. — Transl. 



