16 F. A. SMITT, 



mens, in a higher degree of development, the C. pusilla will, perhaps, once come near- 

 er to C. cornigera; but at present all the three forms are very well distinguished 

 species. 



The fourth Cellularian form amongst the Floridan Bryozoa belongs to that group, 

 for which in my former papers, in following Busk, I have retained the name Caberea, 

 although the name Canda could, with the same right, be applied to it x ). The distinc- 

 tion between these genera, pointed out by D'Orbigny, viz. the number of rows of zo- 

 oecia, here becomes of less weight, as being only a secondavy alteration following the 

 above-named divergence of the whole group towards the Membraniporidan type. 



Caberea retiformis 2 ) (Pl. V, tigs. 43—46), 



such as I have reeeived it from Count de Pourtales, in very good specimens, shows 

 the most intimate afnnity with the Can<l<i orachnoides, Lmrx. I need only refer to a 

 comparison between my ligures 43 — 46 with those of the Australian form given by 

 Busk 3 ), and the identical form of the zooecia as Avell as the great resemblanee between 

 the vibracularia will at once be obvious, except that the Floridan form seems to be a 

 little more elongated. The only reason for retaining the Caberea retiformis as a dis- 

 tinct species, we lind in its want of avicularia but possessing an elongate quadrangular 

 fornix with the inner-upper and inner-lower angles commonly rounded and bent in- 

 wards a little. In other respects the description and ligures given by Busk suit as 

 well the Floridan as the Australian form: and when the latter wants its avicularia (cfr. 

 Busk, 1. c, pl. XXXIII lig. 2) or the former löses its fornix, the two forms will almost 

 exactly agree with each other. 



The form of the vibracularium (hg. 45), that reminds us of Cellularia scabra, 

 shows the connexion of Caberea with the other Cellularian forms. After the differences 

 in this respect within the Caberean series to fonnd consistently generical distinctions, 

 would lead us to the most arbitrary distinctions as depending only on the degree of 

 morphological development, not on a true distinctiveness of typical form. 



The ooicia present almost the same form as that of the Caberea Ellisii, although 

 they are a little incurved towards the median line of the front of the stem, and the 

 calcinaton of their wall not only leaves the semieircular field above their aperture 

 more membranous, but also a smaller, more circular field at their top remains in that 

 sta te. 



Even this species very clearly shows, in the form and calcination of its zooecia, 

 its tendency towards the configuration of the Membraniporidan type. The primary 

 apertural area occupies almost the whole front side of the zooecion, closed by a thin 

 meinbrane, beneath which it is partially filled up, at its proximal end, by a granular 

 calcination sloping a little inwards, just in the same way as that we more commonly 

 lind within the serial development of some Membraniporidan types. The plate thus 



1 ) Cfr. COrbigny, Pal. Franc, Terr. Uret., vol. V, p. 332! 



2 ) An Canda patagonica,^J)'OvLB., Voy. d. VAmer. mer., Zooph., pag. 9, tab. II fig. 5 — 9; id., Pal. Franc. 

 1. c, pag. 331? 



Canda retiformis, Pourt., Bull. Mus. Corap. Zoöl. Harv. Coll. Oambr., N:o 6, p. 11<» 



3 ) Cat. Polyz. Brit. Mus., tab. XXXIII. 



