28 THE VOYAGE OF H.M.S. CHALLENGER. 



The properties of this genus have already been discussed in such a detailed manner 

 that no further explanatory remarks are necessary. I ascribe to the genus Leucilla 

 the following species : — 



Leucilla connexiva, n. sp. 

 uter, n. sp. 

 amphora, H. 



Leucilla capsula, H. 



(?) Crustacea, H. 

 (?) echinus, H. 



Leuconia, Bowerbank. 1 



Leuconidse with the spicules of the parenchyma, irregularly disposed throughout and 

 with flagellated chambers of more or less regularly rounded contour. 



The connecting link between the genera Leucilla and Leuconia I see in Leuconia 

 multiformis, n. sp., the relationship resting upon grounds quite analogous to those which 

 induced me to associate my genus Anamixilla with the genus Amphoriscus. But if the 

 phylogenetic affinities of some species of Leuconia are clear, this is by no means the case 

 with respect to many other forms, which for want of detailed comparative investigations 

 are to be temporarily referred to the same genus. Moreover, I feel certain that, in the 

 course of time, my Leuconia will be subdivided at least into four, possibly even into more, 

 quite independent genera. I say this with reference, for instance, to the species Leuconia 

 alcicornis, G., Leuconia elongata, Sch., Leuconia cataphracta, H., which I am quite sure 

 will be sooner or later elevated to be the representatives each of a special genus. The 

 same will probably take place with respect to the species Leuconia johnstonii, C, Leuconia 

 stilifera, S., Leuconia saccharata, H., Leuconia ochotensis, MM.; and, on the other hand, 

 with regard to the species Leuconia fistulosa, Bk., Leuconia pumila, Bk., Leuconia levis, 

 n. sp. At present, however, the realisation of these subdivisions would be scarcely season 

 able ; it will be well to await further and more detailed comparative investigations, and 

 provisionally I group in the genus Leuconia all the Leuconidse which do not belong either 

 to the genus Leucilla, to the genus Leucetta, or to the genus Pericharax. 



Leucetta, Hasckel 2 (sensu mutato). 



Leuconidse, the skeleton of whose strongly developed cortex is quite different from 

 that of the parenchyma. 



The peculiarities of this genus, which has an analogue amongst the Syconidse in 

 Heteropegrna, consist in the possession of a strongly developed cortex and of two quite 

 different skeletons, that of the cortical layer being characterised by large spicules, that of 

 1 Brit. Spoiigiad., i. p. 164, 1864. 2 Kalkschwamme, Bd. ii. p. 110. 



