FLORIDAN BRYOZOA. 53 



rying depth of from 15 to about 300 fathoms. Its most peculiar property, in the Flo- 

 ridan sea, distinguishing it from the well-known European variety, is the less degree 

 or raising or entirely wanting of the avicularian rostrum (tubercle) at the zooecial 

 rnouth. 



The zooecia are in a härd degree of calcification, in this respect almost resemb- 

 li«g the Cellepor a gigas. Their front side, uniformly thickened, wants pores; and the 

 oral avicularium, with a rounded or blunt triangulär mandible, is totally inclosed in 

 the secondary zooecial aperture, whose varying breadth I have measured to be about 

 0,14 or 0,15 mm. When the rounded, perforated ooscion is developed, the margin of 

 the secondary zooecial aperture is growing up from each side on its front. The great 

 spathulate avicularia, which are dispersed among the zocecia, morphologically belong 

 to the same order as these, with almost the same construction and size; their aper- 

 ture, in its varying length, can be measured up to 0,3 mm. On their front side, some- 

 times, I have seen a small lateral avicularium, in the same position as on the zooecia 

 of the two preceding species. 



Cellepora avicularis x ) (Pl. IX, tigs. 193 — 198). 



Of this form Pourtales has taken well-grown colonies, although of small size, 

 growing on Serialaria and on pieces of any undeterminible Zoophyte, at a varying 

 depth of from 9 to 111 fathoms. 



With almost all the characters of the preceding form, it differs therefrom, prin- 

 cipally, by the smaller size of the colonial organs, their less degree of calcification, 

 proceeding also in a little differing manner, and by the different colonial form. The 

 breadth of a primary zooecial aperture I have measured to about 0,o<> mm.; the breadth 

 of a secondary one to about 0,13 mm. In the tips of the branches the zooecia, of a 

 shining hyaline colour, are cylindrical and well-marked from each other. Lower down 

 on the stem, a common layer of calcification fills up the furrows between the zooecia, 

 and, from the base of the ooecia, it grows up över the front of these. This layer of 

 calcification attains a still greater development on the elongated and slender form ot 

 this group, 



Cellepora margaritacea (Pl. IX, figs. 187 — 192), 



which is described by Pourtales 2 ) and seems to be one of the most common Bryo- 

 zoa of the Floridan Sea, as, in a great richness of specimens, it was taken by him, at 

 22 different localities, in a varying depth of from 15 to 270 fathoms. 



In the zooecial construction, as well as in the form of the other colonial organs, 

 it most nearly approaches the above-described Cellepora tuberosa. This at once will be 

 obvious in comparing its ovate rhomboidal zooecia, in the tips of the branches, with 

 the cylindrical ones of the corresponding age of the Cellepora avicularis. Furthermore, 

 the avicularian rostrum, at the side of the zooecial aperture, just as usual in the 'Flo- 



') Synonyma vide in Ofvers. Vet. Akad. lörh. 1867, Bih., p. 32. 



-) Vincularia margaritacea, Podrt.. B ull; Mus. Comp. Zool. Cambridge, N:o 6, p. 110. 



