62 Prof. Allman on the Hydroida. 
bearing the name of Heteractis, should be designated by that of 
Heterostephanus (€repos, dissimilar, and oréhavos, a crown), a 
name which will entirely express the character which originally 
suggested that of Heteractis. 
I find also that I have, by an oversight, omitted from the 
Synopsis the genus Cionistes of Dr. T. S. Wright. This is a 
genus of Tubularian Hydroids discovered by Dr. Wright on the 
Scottish coast. I have never seen a specimen; but Dr. Wright 
gives the following diagnosis of the genus :— 
“ Polypidom retiform; alimentary polypes sessile, minute, 
white, with a single row of short tentacles ; reproductive polypes 
columnar, thickened towards the apex, not terminated by a clus- 
ter of thread-cells bearing many generative capsules ”’*. 
Though the above diagnosis contains some characters which 
I cannot consider as of higher than specific value, there are still 
a sufficient number on which to found a valid genus, which will 
take its place in the. family of the Eudendride. Dr. Wright 
records, though without description, a single species of the genus, 
namely, C. reticulata, Wright. 
Under the genus Diplura, Greene, I have also inadvertently 
omitted to give the only species which has been traced to its 
trophosome, namely, 
Diplura fritillaria, Steenstrup (sp.), = Coryne fritillaria, 
Steenst. ° 
Mr. Alder, in a letter which I have received from him, reminds 
me that I have omitted to enumerate among the species of Cam- 
panularian Hydroids the Sertularia gelatinosa of Pallas, and the 
Sertularia longissima of the same author, both of which are 
placed by subsequent authors under the genus Laomedea. The 
omission of these species from my Synopsis was entirely acci- 
dental. I have no personal knowledge of their gonosomes ; but 
Mr. Alder informs me that it is his belief that both species give 
off medusze. If so, it is most probable that the medusa is of the 
Obelia type, and the two species will then go into the genus 
Obelia as defined in the Synopsis. 
I have also accidentally omitted the Campanularia fastigiata 
of Alder, which is, in all probability, a Calycella. Mr. Alder is 
himself of this opinion, and is moreover convinced that his C. 
fastigiata is identical with Sars’s Lafoéa plicatiis. It must 
therefore be enumerated among the species included under the 
genus Calycella, while the subsequently described Lafoéa plicatilis 
of Sars must be removed from the genus Lafoéa, and must take 
the place of a synonym of Calycella fastigiata. 
In introducing Sars’s genus Myriothela into my Synopsis, I 
* T.S. Wright in Ann. Nat. Hist. for August 1861, p. 123, 
