HYDROIDA J, 



thelidai\ whereas in the Tiihiilanidar it has disappeared. It forms a striking contrast to the proboscis 

 of the Eudoidriidac^ the outer oral portion of which is more abounding in indifferent endodermal 

 cells and more nearly approaching the state of things in the BougainviUudai\ in which, however, also 

 the indifferent endodermal cells aj^pear in larger numbers. As is mentioned before, this oral zone is 

 wanting both in the Clavidac and the Stylasteridae. 



The Corynidac, like their near relations the Myriotliclidac^ are distinguished by a vigorously 

 developed polype musculation, and in connection with this show an astonishing power of changing 

 appearance and volume. It is easy for them to swallow a comparatively large copepode, and in my 

 material I have found several shapeless-looking Corync-^oXy^^s which were digesting rather large 

 crustaceans. Thus they are very greedy animals, frequently feeding on organisms larger than the 

 polype of normal size. Series of sections show how the food half dissolved also is led direct into the 

 gonophores and is absorbed by their endodermal spadix. The endodermal cells of the spadi.x then are 

 filled with some granulous contents, which are greedily absorbing and tenaciously keeping the liaema- 

 toxyline of Delafield, wdiile they are rather indifferent to both the haematoxyline of Bohmer and 

 to cosine. However, the cells also contain several eosinojjhile grains. 



Gen. Coryne Gaertner. 



^'•Corynidac forming colonies, with solitary capitate tentacles spread all over the hydranth. The 

 colony is formed by the ramification of an upright hydrocaulus, whose tubes do not communicate 

 through secondary canals. The gonophores are developed on the proximal portion of the polypes". 



Many investigators place the species productive of medusae in a separate genus, Syncoryne. 

 This criterion, however, is of merely biological nature, and thus of less importance to systematists. 

 And apart from this, it is evident that some species of Coryne produce more strongly reduced eume- 

 dusoids which are only quite exceptionally detached from the mother colony. The species have not 

 yet been sufficiently examined. Therefore, it is obvious that, for instance, the species Coryne Lovcni 

 (M. Sars) must have been several times confounded with Coryne Sarsi (Loven). In the medusoid 

 gonophores of the former species the tentacles are wholly reduced, while Coryne Sarsi has complete 

 medusoid gonophores with tentacles. The opinion maintained by L. Agassiz (i860) and Hincks 

 (1868), based on the observations of L. Agassiz (I.e.) and Clark (1865), that some .species of Coryne 

 at one time of their lives produce free-swimming medusae, at other times, on the contrary, sessile 

 eumedu-soids, has not yet been refuted, but, quite the contrary, been strengthened by the observation 

 of a parallel condition of things in species of Caiiipaniilaria (Giard 1899, Behner 1914). It is 

 not impossible that Coryne Sarsi should be one of these species of Coryne. In Coryne Loveni the 

 eumedusoid gonophore has lost its tentacles, and at the same time the development of the generative 

 cells shows us that the gonophores are not here normally disengaged from the colon)-. Other species, 

 such as Coryne Hincksi Bonne vie and Coryne brevicornis Bonne vie, seem to have gonophores 

 somewhat more reduced, still, however, keeping the medusoid structure strongly defined. These 

 species, then, exhibit stages forming the transition to Coryne pusilla Gartner with its strongly 

 reduced styloid gonophores. 



