HYDROIDA 



extended polyp; they are without rings; at most there is some faint and irregular wrinkling here 

 and there. The polyp is fusiform with the tentacles irregularly distributed all over the surface; the 

 polyp may be retracted into the broader distal portion of the hydrocaulus. 



The structure of the gonophores seems to be strongly reduced. They are developed at the 

 upper part of blastostyles without tentacles, at most i mm. high. 



Material : 



The Faroe Islands: 13 miles West to South of Munken, depth 150 fath. (on Cardium sp.). 

 9 East South East of Bispeu, 70 ( - - ). 



. boom. 



Text-fig. L. Localities of Merona cornucopiae and Monobrachium parasitum A in the Northern Atlantic. 



Merona cornucopiae was first described as a Tubiclava by Norman (1864). But as the latter 

 genus is characterized by the gonophores being borne on the polyps, he thought he had better set 

 up a new genus Merona (1865) for the species in hand, bearing its gonophores on polyps strongly 

 reduced or on blastostyles. This criterion, however, is of subordinate importance and would by no 

 means justify the separation of two genera. However, from the drawings occurring in literature, a 

 much essential point of difference urges itself. The perisarc of the species of Tubiclava is not so wide 

 that the polyp can be retracted into it, while this is the case with Merona. The division, therefore, 

 seems well founded. But at any rate a renewed examination of the two genera is needed. 



Merona cornucopiae seems only to occur attached to shells of living mollusks, and has been 

 found on species of the genera Cardium, Astarte, and Dentalium. The species does not seem to be 

 very frequent; it has previously been recorded from the sea to the north of the Shetlands at the 

 depth of 80-100 fathoms, and from the coast of Northumberland. To these localities are now to be 



6 



The Ingolf-Expedition. V. 6. 



