NOTES AND OBSERVATIONS ON BOARD H.M.S. RATTLESNAKE 8/ 



spherical, spheroidal or oval bodies are imbedded, from which the ap- 

 pearance of dots arises. These are held together merely by the 

 gelatinous substance, and have no other connexion with one another. 

 Each " spheroid " is a cell, with a thin but dense membrane, ^wo^^ to 

 ■n-iu-th of an inch in diameter, and contains a clear, fatty-looking 

 nucleus nVirth to sTXjth of an inch in diameter, surrounded by a mass 

 of granules which sometimes appeared cellseform. 



This fundamental structure — a mass of cells united by jelly — like 

 an animal Palmella, was subject to many and important varieties. 



Very commonly the central part of each mass, instead of containing 

 a single large cavity, consisted of an aggregation of clear, large, 

 closely-appressed spaces, like the " vacuolae " of Dujardin (figs. 2, 3, 

 2 a, 3 a). 



Very frequently also each cell was surrounded by a zone of peculiar 

 crystals somewhat like the stellate spicula of sponge, consisting of a 

 short cylinder, from each end of which three or four conical spicula 

 radiated, each of these again bearing small lateral processes (figs. 3 a, 

 2 U). 



In another kind, much more rarely met with, the spherical cell 

 contained a few prismatic crystals about ^J^y^th of an inch in length ; 

 it was of a bluish colour, and enveloped in a layer of densely packed 

 minute granules not more than xTTTnT^h of an inch in diameter. Out- 

 side these there was a number of spherical bright yellow cells xTinrth 

 of an inch in diameter, and inclosing the whole a clear, transparent 

 brittle shell perforated by numerous rounded apertures, so as to have 

 a fenestrated appearance (fig. 6). There were no spicula in this kind. 



In a single specimen I found a similar shell, but its apertures were 

 prolonged into short tubules (fig. 5). 



Frequently the connecting substance in which the cells were im- 

 bedded appeared to be quite structureless, but in some specimens 

 delicate, branching, minutely granular fibrils were to be seen radiating 

 from each cell into the connecting substance (fig. 2 h). 



I have mentioned certain minute bright yellow spherical cells con- 

 tained within the shell of the fenestrated kind ; such coloured cells are 

 contained in all kinds either diffused through the connecting substance 

 or more or less concentrated round each large cell (figs. 3 a, 2 b). 



Th. nucleata. (PL XVI. [Plate iij fig. 4.) 



This form consists of a spherical mass of jelly as large as the 

 middle-sized specimens of the last variety, with an irregular blackish 

 central mass. Enveloping this and forming a zone about half the 



