876 Prof. AUman on the Construction and 



The genus Campanulina was constructed by Van Beneden (Bull. 

 Ac. Roy. Brux. 1847) for a delicate Campanularian Hydroid whose 

 most striking character- appeared to the Belgian naturaHst to be the 

 broad membranous web by which the bases of the tentacles were 

 united to one another. He named the Hydroid which he thus took 

 as the type-species of the genus Campanulina tenuis. 



Mr. Alder, from an examination of authentic specimens of Van 

 Beneden's Hydroid, has since determined its identity with the spe- 

 cies which had been described by himself under the name of Lao- 

 medea acuminata. As Van Beneden, however, has given us no de- 

 finite specific diagnosis, while Alder has given us a very full and 

 complete one, and as Alder's specific name has thereby become ge- 

 nerally adopted, it will be more convenient to retain the name of 

 acuminata rather than that of tenuis, and the rules of priority will 

 hardly be so stringently interpreted as to offer any valid objection to 

 this course. 



In drawing up the diagnosis which I have given above for the 

 genus Campanulina, I have deemed it better to make it sufiiciently 

 comprehensive to include Campanulina repens, Allm., a Hydroid 

 discovered by myself, and which, with undoubted affinities to Campa- 

 nularia acuminata, may possibly be regai'ded as presenting a separate 

 generic form. It differs from G. acuminata in the fact of the hydro- 

 thecae being provided with a true operculum formed of converging 

 lanceolate segments, instead of having the undivided membranous 

 termination which these receptacles exhibit in C. acuminata, and in 

 the web which connects the bases of the tentacles being so shghtly 

 developed as to be nearly obsolete. 



Besides this, the Medusa escapes from the gonangium with four 

 well-developed marginal tentacles — a feature, however, which may 

 only indicate a more advanced stage of development at the time of 

 liberation, and not such as can be employed as a generic character, 

 unless the difference in this respect between the two Medusae can, 

 by further observation, be shown to be permanent. I have recorded 

 this Hydroid in my note-book under the generic name of Hypsoro- 

 phus (vyJA6po(f)os, high-rGofed), in allusion to the high conical operculum 

 by which the hydrotheca is closed on the retreat of the polypite ; 

 but I prefer to keep this name as provisional, dependent on further 

 observation proving that the difference between the Medusae at the 

 time of their liberation is persistent — a character which may then, 

 when combined with the difference between the hydrothecae, be re- 

 garded as truly generic. 



Campanulina acuminata, Alder (sp.), = Campanulina tenuis, 

 Van Ben., =:Laomedea acuminata, Alder, = Wrightia acuminata, 

 Agass, 



Campanulina! repens, Allm. 



iEquoridaB. 

 1. Zygodactyla, Brandt. 

 Trophosome. — Plydrocaulus simple (or branched ?), rooted by 



