FLORIDAN BEYOZOA. 5 



development, it attains the same form as the aperture of the zocecion, though it is 

 much smaller, and I never saw the denticles of the zooecial aperture in it. The zooecia 

 have the well-known cellarian form; they undergo the same changes with age and pre- 

 sent the same variations in consequence with the more robust or slender form of the 

 stem, as those differences that are already known concerning the C. fistulosa: yet they 

 are smaller — I have measured the crescent-shaped apertures about 0,08 mm. broad — 

 generally more elongated and hyaline with slighter and more scattered granulations; but 

 the lateral rib on each side of the area is very conspicuous. 



Now, if we try to discuss the relations, that exist between this form and the C. 

 fistulosa, we need only to point to the justly median form, that is described by Busk 

 under the narne of Cellaria Johnsoni x ). Thus, in C. fistulosa, the avicularia develop 

 themselves in the same manner and position as do the ooscia; these two organs there 

 constituting a secondary budding; when they are present together, above the same 

 zooecion, the avicularium keeps the higher position. In the C. Johnsoni, the avicula- 

 rium (Busk, 1. c, vol. VIII, pl. XXVIII, fig. 5) retains the same form as that of C. 

 fistulosa, but seems to appertain to the primary budding, thus replacing a zooecion, in 

 the same manner as that of C. tenuirostris. These differences, concerning the form and 

 position of the avicularia, have their full analogy in many of the bryozoan genera, 

 and very often they appear within the limits of the variability of a species 2 ). It is 

 a general rule, that where we do not find any real difference in the form of the zooe- 

 cia, there the other differences, also, lose the greatest part of their value as specifical 

 characters. Now, the C. tenuirostris really differs from C. fistulosa in the size of the 

 zooecia as well as in their granulation; but these differences are slight and can not be 

 judged as of high value; and it seems me rather preferable to regard them as varie- 

 ties from the same origin. Of course it is a matter of agreement, how to express the 

 different degrees of affinity; in accordance with many other bryozoan series, I should 

 like to conjoin the above-named three forms into the limits of one species; and, indeed, 

 it will be very difflcult, if not impossible, with certainty to distinguish small fragments 

 of these forms, in their highest degree of calcification, if they want their avicularia. 



The Cellaria tenuirostris is brought up from 52 fathoms, off Carysfort reef, and 

 from 68 fath, W. off Tortugas. As it was first described by Busk from Bass-strait, it 

 is now to be registered among the interesting forms, which are common for the Au- 

 stralian and Caribbean seas. 



After this account of the three genera of Floridan bryozoa, which, according to 

 the hitherto prevalent opinions of the systematical arrangement of this group, should 

 be arranged together in the family Cellariece (Salicornariadce), it is very easy to show 

 the true relations between them. The great differences, in the form as well as in the 

 developmental changes of the zooecia, in these genera, throw them long away from each 

 other. The only reason for bringing them together in one family, would be the arti- 



l ) Quart. Journ. Micr. Se, vol. VI, p. 125, Zooph. pl. XIX, fig. 2; vol. VII, p. 65, Zooph. pl. XXII, figs. 



4, 5; vol. VIII, Zooph. pl. XXVIII, figs. 4, 5. 

 -) See: Kritisk Förteckning of ver Skandinaviens Hafs-Bryozoer, Ofvers. Vet. Akad. Förh. 1867, p. 397 and 



410; Bit., p. 60 etc. 



