98 ENTOPROCTA. 



above described, has taken place, the vestibule develops a new 

 external aperture, its outer wall fusing with the inner surface of the 

 body-wall, and a slit-like fissure arising at the point of fusion. In 

 close proximity to this perforation of the wall, the rudiments of the 

 first tentacles (Fig. 46, t) appear as outgrowths of the vestibular 

 wall extending into the vestibular cavity. 



The stage in the development of Pedicellina attained by means of 

 these transformations recalls the appearance of certain species of 

 Loxosoma in the oblique position of the vestibular aperture, and the 

 presence of a pedal gland (p) which has arisen as an ectoderm al 

 thickening. Only later are these characters lost, the head becoming 

 more distinctly marked off from the peduncle and assuming an 

 upright position, the aperture of the vestibule being apical. During 

 the histolysis of the inner organs, many of the isolated cells pass 

 into the body-cavity ; these are gradually absorbed, and the cavity 

 then appears filled with star-shaped mesenchyme cells. 



The metamorphosis of the larva of Loxosoma still remains unknown. There 

 can, however, be no doubt that it is in essential agreement with that here 

 described for Pedicellina. 



Asexual Reproduction. 



Asexual reproduction through the formation of buds plays an 

 important part in the life-history of the Entoprocta. In Loxosoma 

 the buds arise in large numbers at the ventral side of the cup, on 

 either side of the parent-animal. The buds here seem to form 

 alternately, those of the right side alternating in age with those of 

 the left. When the buds have attained a certain grade of develop- 

 ment they become detached, and continue their lives as solitary 

 individuals. 



In Pedicellina echinata, the formation of new buds takes place 

 from a basal stolon ; since the buds retain their connection with the 

 parent, colonies of variable size develop. These colonies are essentially 

 bilaterally-symmetrical in their development. The stolon forms from 

 the lower end of the peduncle of the oldest individual, on its anal 

 side (SEELIGER). The buds are arranged on the stolon in such a way 

 that the median plane in them corresponds with that in the parent- 

 animal. The youngest buds are found at the growing end of the 

 stolon. Each bud develops on the oesophageal side of the bud next 

 older than itself. In rare cases a lateral branching of the stolon has 

 been observed in Pedicellina. echinata (SEELIGER, EHLERS). In other 

 forms (Ascopodaria), such branching is common. 



