XOETH-ITALIAX BRYOZOA. d 



have mostly been collected many years ago, and, when returning to the 

 work, it has often been possible to further clean them by soaking in 

 water, then brushing with a camel-hair pencil, drying, and repeating 

 the process. Eecently, however, I have obtained very much better 

 results by placing the fossils in a saturated solution of sulphate of 

 soda and allowing it to crystallize. When this is washed out it 

 loosens the matrix within the apertures, and they are thus more 

 thoroughly cleaned than would be possible by ordinary means. 



Although all of Eeuss's works were beautifully illustrated, the 

 figures were rather the artist's than the naturalist's figures, one 

 zooecium being drawn and then identically repeated several times ; 

 but this geometrical regularity does not often occur in nature. The 

 figures now given are supplementary, to show the characters to 

 which I allude. 



Though considering a revision now required, I would point out 

 how great an advance Eeuss's work was upon what had been done 

 before ; and that he gave more attention to zooecial characters than 

 his predecessors had, often forming groups according to the nature 

 of the surface and the presence of oral spines or avicularia. It is 

 true that very few of these groups will now stand, but in this way 

 the study of the value of the characters has been made possible 

 without adding to the number of generic names. 



There are many cases of a species occurring in both the incrusting 

 and erect form ; some show considerable difference in zoarial shape, 

 and there are interesting instances of great range, so that different 

 parts of the same colony have widely divergent appearance. 



Perhaps the most noticeable case is OeXlepora proteiformis, which 

 commences in a flat Escliara-foim., on which, however, single zooecia 

 may be raised (figure 14) ; but in later stages the zooecia are piled 

 up irregularly, often several layers thick. Lepralia hisulca varies 

 much in appearance ; and Porina coronata may either have the 

 zooecia distinct or scarcely distinguishable. There may be more or 

 less of a peristome in front, and the number of large pores or avicu- 

 laria around the aperture is very variable ; further, the central 

 avicularium may be absent, may be moderately large, or developed 

 into a gigantic raised spatulate avicularium, "When the aperture 

 has a closure the appearance is further modified. Porina papillosa^ 

 with or without avicularia or prolonged zooecia, also has a very 

 variable appearance. There are forms with Lumdites-m.ode of growth 

 with the zooecia of Memhranipo^ri, Oellepora, and Lepralia. 



As we thus obtain more exact acquaintance with the Bryozoa of 

 past times, we shall in some cases be enabled to check the correct- 

 ness of the principles of present classification and gain new ideas as 

 to relationship ; but fresh difficulties are brought before us. 



Among the points brought forward, the discovery of Catenicella 

 is of special interest as bearing upon the relationship of this genus. 



Fedora excelsa is interesting, from the way in which it grows from 

 the apex of the colony, — from occurring on both sides of the Alps, 

 — and from the genus being represented by one recent form dredged 

 by the ' Travailleur.' 



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