7(16 SCIENTIFIC RECOKD FOR 1885. 



also considered. {Jenaische Zeitschr.f. Natiirwiss., v. 18, pp. 713-750 (1 

 pi.); J. B. M. S. (2), V. 5, p. 665.) 



Infiisorians. 



Artificial multiplication of Infusorians. — With a view to determine the 

 behavior of Infnsorians when vivisected, A. Griiber experimented on 

 the Stentor ccer ulcus. (1) First, an individual was bisected transversely, 

 and on the following day each of the parts had become a perfect indi- 

 vidual ; (2) one of these was likewise bisected, and again on the follow- 

 ing day the two sections had developed into perfect animalcules ; (3) 

 one of the second bisection was also cut transversely, and again (4) one 

 of the third bisection. In both instances the sectionized parts became 

 perfect individuals on the day of their division. The result of the ex- 

 periments thus noticed, and others, further served to show also that the 

 sections without a nucleus, although they did well, " never grew up into 

 complete animals," as did those with a nucleus. The presence of a 

 nucleus, in fact, is perhaps a necessary element for complete regenera- 

 tion. {Biol. Centralblatt, v. 5, p. 137 ; J. B. M. S. (2), v. 5, pp. 658, 659.) 



PORIFERS. 



Sponges. 



Beproduction of the frcsh-iraier sponge. — The reproductive process has 

 been investigated by Dr. W. Marshall in one of the common European 

 fresh-water sponges, Spongilla lacusfris. The gemmules or winter em- 

 bryos are formed in the neuter autumn sponge from wandering nutri- 

 tive amoeboid cells, known as trophophores, which accumulate in the 

 inhalent corals or in the ciliated chambers. The embryo is at first a 

 " morulalike mass of round uniform cells." It escapes from the cap- 

 sule in which it is invested in April or early in May. In about a nionth 

 after the escape of the embryo from the capsule, maturity and comi)lete 

 sexuality are attained. " It seems probable that the males are desti- 

 tute of enteric cavity and mouth," while the females are " usually pro- 

 vided" with such. After fulfilling their sexual functions the "males 

 seem to i)erish." The females bear "neuter forms" and then increase 

 in size, but the " enteric cavities and mouth-openings are reduced in 

 size, and not unfrequently disappear." In fine, there is " a seasonal 

 alternation of generations ;. the winter gemraulpe form spring sexual 

 spongillae which produce sexual forms in which arise the winter gem- 

 mulse." {Sitzungsber. Katiirf Gesellsch. Leipzig, 1884, pp. 22-29; J. E. 

 3L S. (2), V. 5, pp. 1011, 1012). 



CCELENTRATES. 



Polyps. 



A new family of Pennatulids. — The interesting group of Pennatulids, 

 which was named by Kolliker the " Junciformes," has received an inter- 

 esting addition during the past year, in the shape of a new species, rep- 



