62 Prof. Allman on the Hydroida. 



bearing the name oi Heteradis, should be designated by that of 

 Heterostephanus {erepo^, dissimilar, and arejyavo^, a crown), a 

 name which will entirely express the character which originally 

 suggested that of Heteradis. 



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 Eudendridse. 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 medusae. If so, it is most probable that the medusa is of the 

 Ohelia type, and the two species will then go into the genus 

 Ohelia 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 Lafoea plicatilis. It must 

 therefore be enumerated among the species included under the 

 genus Calycella, while the subsequently described Lafoea plicatilis 

 of Sars must be removed from the genus Lafoea, 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. 



