168 Prof. All man on the Hydroid Zoophytes. 



comparison, in the ' Mikrogeologie/ pi. 37. 10. fig. 1 «-/, under 

 the name of Borelis (Melonia) Melo. 



All the Alveolina, recent and fossil, that we have yet seen 

 present but one specific characterization in their structure, how- 

 ever much their external form may vary in shape from round to 

 cylindrical, or in size from the dimensions of a grain of sand to 

 one or more inches in length. For nomenclatorial purposes the 

 first-established specific appellation, accompanied by varietal 

 names, will serve well — Alveolina Melo, varr. sabulosa, elon- 

 gata, &c. For particulars as to its structure we refer the reader 

 to Dr. Carpenter's Monograph on Alveolina in Phil. Trans. 1856. 



XVIII. — Notes on the Hydroid Zoophytes. By Prof. Allman. 

 1, On the Locomotive Sexual Zooid o/ Dicoryne conferta. 



In the f Annals of Natural History' for November 1859 I 

 described, under the name of Dicoryne, a new genus of Tubu- 

 laridan Zoophytes, assigning to the species on which I founded 

 the genus the name of stricta. 



Since then, Mr. Alder has obtained perfect specimens of a 

 zoophyte which in his valuable " Catalogue of the Zoophytes of 

 Northumberland and Durham " he had previously described 

 under the name of Eudendrium confertum, and has satisfied 

 himself that my Dicoryne stricta is identical with the Euden- 

 drium confertum of that work. 



Having recently seen, in the possession of Dr. Strethill Wright, 

 specimens of the Eudendrium confertum sent to him by Mr. 

 Alder, I have no hesitation in assenting to Mr. Alder's view of 

 the identity of the two animals — an identity which I did not 

 before recognize in consequence of the original description and 

 figure of Eudendrium confertum having been apparently given 

 from imperfect specimens, as no notice is taken in them of the 

 very characteristic proliferous polypes [Gonoblastidia, Huxley). 



While, however, there can be no question as to the validity of 

 the genus Dicoryne, the specific name of stricta which I gave to 

 the zoophyte must be abandoned, and that of conferta, which 

 had been assigned to it by Mr. Alder, its discoverer and original 

 describer, retained. 



When I published an account of this remarkable genus, I had 

 seen only male specimens ; since then, however, female indi- 

 viduals have fallen into my hands, and I have been enabled to 

 make a more complete investigation of the structure of the 

 gonophotvs and of the phenomena connected with the sexual 

 reproduction of the zoophvte. 



