74 ZOOPHYTES. 



Plate XXIII. Fig. 4. Hydra;, profile. 



5. Hydrae protruding from their cells. 



6. Hydra fallen from its cell. 



7. Increment of the Flusira membranacea. 



All the figures, except the first, are enlarged. 



§ 2. Lepralia. — Sea Scurf, Dr Johnston. — Berenicea, Dr Fleming. — 

 Plates XXIV., XXV. — On this section, treating of the Calcareous Zoo- 

 phytes, I can offer but a few of the most general observations ; nor, perhaps, 

 will they prove very satisfactory to those in quest of minute and special 

 information. None of the race, I am induced to believe, has yet undergone 

 such accurate and permanent investigation as is indispensable for illus- 

 trating the subject. Hitherto the skeleton alone having been the princi- 

 pal object of consideration, more remains to be said of the Lepralia by 

 those enjoying favourable opportunity, than perhaps of the majority of 

 zoophytes. 



We shall be somewhat aided in this obscure branch, by recurring to 

 the preceding paragraph regarding the Flustra membranacea. 



If I rightly comprehend what naturalists understand by the Lepralia, 

 its formation in the living state seems equally indistinct and indefinite ; it 

 is neither clearly seen, nor of determinate figure. This may probably re- 

 sult from its increment advancing in unequal rate and proportions from 

 different parts, at different times, but not from all the circumference at 

 the same time. Farther, it is generally after increment of a specimen has 

 ceased, and after its hydra 1 , the authors of it, have perished, that the 

 actual shape is sufficiently exposed to view. 



I do not infer from the substance of this remark, however, that the 

 hydra is the actual fabricator of the substance of the Lepralia, more than 

 that the hydra of the fistulous zoophyte fabricates its own cell. 



Possibly in the Lepralia, as in some of the preceding, which partake 

 more or less of calcareous nature, the polyparium results from an animal 

 secretion. 



While a specimen appears as an orange or a carnation patch, with a 

 kind of fullness, as viewed by the naked eye, the surface proves rugged, 



