190 HYDROID^. Part IV. 



of the budding brood usually observed (PI. XVIII. Fie/. 14). Some had tentacles, 

 while others were destitute of them or had mere papillae in their places. But 

 the most remarkable phenomenon connected with these modifications was, that they 

 all had eggs or spermatozoa, in various stages of development. Some of them 

 were casting their eggs, others had apparently finished laying, while some had just 

 begun to develop them. So it was with the degree of development of the sper- 

 matozoa. In the section on the development of the medusoid form, the details 

 of these peculiarities will be given in a more extended form.^ 



SECTION III. 



THE REPRODUCTION OF CORYNE MIRABILIS. 



We have never been so fortunate as to see the development of Coryne mira- 

 bilis, from the egg. Since, however, we know that the medusoid form produces 

 eggs, it can safely be affirmed that Coryne originates, primarily, from an egg. 

 Including this mode of reproduction, we may say that there are three ways in 

 which Coryne develops its young, namely: first, from the egg, whence a hydroid 

 is produced by direct growth; secondly, from the stem of this hydroid other 

 hydroids bud, and, remaining attached, build up a branching community ; and, lastly, 

 MedusfB-buds arise from the head of the Hydroid. 



The Budding of hjdroids. — Nothing can be more simple than the manner in 

 which the stem of the Hydroids pushes out, sideways, its double wall, and forms 

 a hollow, semi-globular bud, and thus lays the foundation of a young Hydroid 

 (PI. XX. Fig. 3, a b). It is very rare, however, that true buds are formed opposite 

 to each other, as seen in the figure to which Ave have just referred. The bud 

 being hollow is supplied directly with nourishment, by the circulating currents 

 from the stem. As the bud grows larger and longer, it swells near the end, 

 becoming club-shaped (PI. XX. Fig. 4) ; and soon the walls at the apex are per- 

 forated. The perforation is the mouth {Fig. 4, d^), and the swollen part the head. 

 Synchronically Avith the formation of the mouth, two broad swellings or knobs 



^ In the Memoirs of the Royal Swedish Acad- species. His investigations were made in June, but 



emy, 1835, transhited in Wiegman's Archiv fur had he seen Syncoryna in the previous months, in 



Naturgeschiehte, 1839, p. 321-326, Tab. VI. Figs. May, for instance, as did Sars, in 1838, according 



19-28, Loven describes the same peculiarities as to his remarks published in his Fauna Norvegia;, 



occurring in Syncoryna (Coryne) ramosa Ehr. and in 1846, he would have also observed the earlier 



S. Sarsii Loven ; but he considers them as apper- and usual mode of reproduction. S. Sarsii is no 



taining to the usual mode of reproduction of these doubt identical with S. ramosa. 



