260 EXPLANATION OF THE PLATES. 



Ohs. In reference to Figure 6, it is to be remarked, that in only some 

 specimens could such an appearance of vessels, as is there shown 

 be seen, and the appearance 7n(i>j have been produced by folds 

 occasioned by the pressure between the plates of glass to which the 

 specimen was subjected. Of Algae, the Hon. W. H. Harvey 

 says, — " All consist of simple cellular tissue, or of its elements, 

 gelatine, membrane, and endochrome, variously elaborated and 

 perfected. No vessels or ducts have been discovered in any." — 

 Man. Brit, Algae, Introd. p. xvii. 

 PLATE XXIII. Fig. 1, A tuft of Jania rubens, natural size. Fig. 2, 

 A portion highly magnified to show the cellular structure of the axis, for 

 the calcareous crust has been removed by an acid j the tubercles con- 

 taining granules ; and the seminal capsules in the axils of the extreme 

 branchlets. Fig. 3, Is another portion from -another specimen from 

 which the crust has been likewise removed, highly magnified. 

 PLATE XXIV. Fig. 1, 2, 3, Nullipora polymorpha, all of the na- 

 tural size. Fig. 4, 5, NuL. calcarea. Fig. 6, Nul. fascicu- 

 LATA. The specimen had been originally of greater size, but consi- 

 derably broken in the carriage. 

 PLATE XXV. Fig. 1, Millepora lichenoides of Ellis and Solander. 

 Fig. 2, 3, Varieties, solid and amorphous, of Nullipora poly- 

 morpha. Fig. 4, The mass from which this figure was taken had 

 the texture and consistency of Nullipora fasciculata, and it 

 may be considered as representing a state of a coralline intermediate 

 between that species and Nul. agariciformis. I was unwilling to 

 describe it as a species, for there is in fact no end to the varieties which 

 these abortive productions assume, originating as they do in the pecu- 

 liarities of their seminal beds : 



" — . we find 



" It matters much with what first seeds are join'd ; 

 " What site, and what position they maintain, 

 " What motion give, and what receive again." 



Lucretius, trans, by Creech, 



