l8 HYDROIDA 



be characterized as southern boreal; it mainly occurs along the coasts of the North Sea and round 

 the British Isles; how far it advances to the north on the coast of Norway, we do not as yet know 

 with certainty; but a any rate it does not push forward as far as into the Arctic seas. 



Coryne sp. aff. Hincksi Bonnevie. 

 Material : 



"Ingolf" St. 44. 6i42' Lat. N., g^6' Long. W., 545 met. 4.8. 



A small colony of young individuals of a species of Coryne is attached to the stalk of a Tu- 

 bularia sp. The hydrocaulus is irregularly wrinkled and attains a height of up to 6 mm. with polyps 

 i 2 mm. long. There occur 4 8 small, apparently medusoid, gonophores at the base of the polyp 

 closely below the tentacles. The tentacles are short. The stolon of the colony is reptant, the stalks 

 of the polyp are unbranched. On account of the bad state of preservation it is impossible to furnish 

 a proper design of the individuals. 



It is possible that the individuals belong to the species Coryne Hincksi Bonnevie, which 

 has previously been recorded only from a depth of 100 fathoms near Hammerfest (Bonnevie 1899). 



Family Myriothelidae. 



"Large solitary hydroid polyps with stratified ectoderm, in which occur two kinds of nemato- 

 cysts. Besides the typical oviform nematocysts of Capitata are found in somewhat smaller numbers 

 narrowly oval or nearly cylindrical, rather large nematocysts which are especially frequently occur- 

 ring in the ectoderm of the gonophores. The tentacles are capitate with a central cavity which does 

 not communicate with the gastral cavity of the polyp, and which is distally broader. The vigorously 

 developed distal portion of the tentacles is shored up by a particularly developed portion of the supp- 

 orting lamella, here showing a fibrillary structure with fibres radiarily arranged. The supporting 

 lamella is vigorously developed in the wall of the polyp and provided with bilamellae. The endoderm 

 exhibits a dense circle of mucous glands at the mouth of the animal. No calcareous skeleton is 

 developed". 



The Myriothelidae seem to be nearly related to the Corynidae, and also to the Milleporidae, 

 which latter form calcareous skeletons. The last mentioned family presents in its dimorphically 

 developed nematocysts a strong resemblance to the Myriothelidae. However, only a character as the 

 peculiarly developed supporting lamella in the thickened distal portion of the tentacles, as well as 

 the dimorphic development of the nematocysts, justifies the distinction of the Myriothelidae as a parti- 

 cular family beside the Corynidae. Already Bonnevie (1899) has pointed out the near rela- 

 tion between Myriothelidae and Corynidae and the bridge between them suggested by the species Mo- 

 nocoryne gigantea (Bonnevie). The arrangement by groups of the tentacles and the attachment of 

 the gonophores to these groups are very likely to form the base of the development of the blasto- 

 styles of Alyriothela. But on account of the peculiar direction in which the structure of the tentacles 



