ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 67 



are the " ectoderm " and " endoderm " of tlie cystid. An invagination at 

 the anterior pole forms the polypide. The " ectoderm " forms the intestinal 

 epithelium, and from it the ganglion is separated off. The alimentary- 

 canal is a simple invagination of the cystid wall. An upward curvature 

 precedes the rupture into the tentacle disc, and with this is associated the 

 formation of three dorsal invaginations, into the cavity of the two-layered 

 polypide-bud. Of these the two lateral form the lophophore, while a 

 median represents the sharp twist of the hind-gut towards the oesophagus. 



Herr Krapelin would regard the hypoblast of the gastrula as mesoderm. 

 The archenteron is thus an enterocoel, and the intestinal epithelium of the 

 polypide-bud is the true endoderm arisen by gastrulation. The theory of 

 the double character of the Polyzoon (cystid and polypide) is thus gratui- 

 tous, and the Polyzoa form a welcome connecting link between Coelenterata 

 and Enterocoelia. 



The ciliated embryo leaves the maternal body-cavity through a " pro- 

 lapsus uteri " in the dead polypide. He confirms Nitsche's account of 

 the development of statoblasts. They too arise from both layers of the 

 funiculus. One portion of the " ectoderm " forms the chitinous shell, 

 while the other developes directly into the outer layer of the body-wall 

 of the statoblast embryo. The development of the sessile statoblasts is 

 essentially similar to that of the free forms with the ring of air-cells. 



Blastogenesis in the Bryozoa-* — M. A. A. Ostrooumoff has some re- 

 marks on M. L. Joliet's recent paper on blastogenesis in the Bryozoa ; 

 the " rudiment of the digestive canal " is, M. Ostrooumoff thinks, nothing 

 more than a mass of lymphatic cells ; on this subject reference is made to 

 Kiikenthal's observations on the lymphoid cells of Annelids. The figures 

 of Nitsche are defended against Joliet's criticisms. 



Life-history of Pedicellina.j^ — Mr. S. F. Harmer, from a personal study 

 of the metamorphosis of Pedicellina, has been led to confirm Barrels' 

 account, and to withdraw his previous opinion ; he now concludes that the 

 postlarval changes consist in a remarkable metamorphosis, and that the 

 first bud is formed after the primary individual has acquired its adult 

 characters. The author thinks that the metamorphosis of Pedicellina is a 

 simple modification of a more archaic process, due to abbreviation of 

 development, that the oral groove persists partly as the adult lophophore, 

 and that the vestibule closes at fixation and undergoes the whole of its 

 alterations in the interior of the larva; a secondary opening is effected 

 when the adult condition is practically attained. 



It is probable that the growing point of a stolon of Pedicellina consists 

 solely of an ectodermic layer secreting a cuticle, and a mass of indifferent 

 connective-tissue cells, imbedded in a structureless jelly. With regard 

 to the so-called brown bodies of the Ectoprocta, Mr. Harmer cannot doubt 

 but that they are degenerated polypides ; in "Pedicellina degeneration is too 

 slight to give rise to a characteristic brown body. 



Recent Marine Polyzoa. J — Mr. G. E. Vine has drawn up for the British 

 Association a report on recent Cheilostomatous and Cyclostomatous Polyzoa, 

 in continuation of his reports on the fossil forms ; especial attention is 

 given to the recent works of Mr. Busk and the Eev. T. Hincks, and their 

 terminology is explained. The present notice deals more with the home 

 of than with the animal itself; for the study of the latter the author 



* Zool. Anzeig., ix. (1886) pp. 618-9. ' 



t Quart. Journ. Mier. Sci., xxvii. (1886) pp. 239-63 (2 pis.). 



X Report. Brit. Assoc. Adv. Sci. for 1885 (1886) pp. 481-680. 



F 2 



