FLORIDAN BRYOZOA. 47 



Celleporine constitution, what especially will occur in the young layers of zooecia over- 

 growing the older ones of the colony, in connexion with the more irregular arrange- 

 ment, the more the avieularia also become indepentlent in their development. In this 

 respect, among the' Floridan Bryozoa, the Hippothoa biaperta is one of the best ex- 

 amples of variability. 



Through almost the same degree of affinity combined with the Hippothoa biaperta 

 and Avith the Hipp. Isabelleana, in the Floridan sea, a species, which seems me to be new, 

 presents the manner of divergence of this type towards the colonial conformation, which 

 formerly constituted the genus Hippothoa. 



Hippothoa divergens (Pl. IX, figs. 177 and 179). 



Char.: Zooecia rhombica vel ovalia frontem convexam, vulgo imperforatam, valde 

 calcaream prsebent. Apertura zocecii rotunda proximaliter aperte sinuatur, aviculariis 

 parvis, rotundis, ad latera positis munitur. Avicularium majus, acutum, extus vergens, 

 ad partem lateralem frontis zooecii erigitur. 



1. Forma typica: Zooecia rhombica, quorum apertura latitudine 0,n — 0,12 mm. 

 fere sequat, coloniam crustiformem contiguam exstruunt. — Fig. 179. 



2. Forma läxa: Zooecia ovalia, quorum apertura latitudine 0,09 mm. fere aequat, 

 coloniam laxam, Mollice vel Hippothoa; (auctt.) forma?, exstruunt. — Fig. 177. 



Hab.: Formam typicam testa? mortua? insidentem e prof. 135 orgyarum, formam 

 laxam lapillo insidentem e prof. 120 orgyarum sustulit Pourtales. 



Through the zooecial aperture most alike the Hippothoa Isabelleana, and with the 

 same lateral avicularium as that species, except that it is placed more laterally and 

 that its mandible, here, in its outer half is narrowed, almost linear, it combines, there- 

 with, the oral avieularia of Hippothoa biaperta, with what species it shares, also, the 

 harder clegree of calcification, usually with an imperforate front side, though, some- 

 times, the pores raay be observed at the margins of the zooecia. With the härd calci- 

 fication, in the thickening of the shining, bluish-white zooecial wall, the primary aperture 

 becomes deeply sunken, and the oral avieularia, sometimes, enclosed in the secondary 

 aperture, thus formed. 



In the genus Hippothoa I place the Floridan form of another species, which seems 

 me yet to be undescribed, although that form, as will be seen by its definition, wants 

 the most essential character of this genus. 



Hippothoa fenestrata (Pl. VI, fig. 142). 



Char.: Zoascia ovata, modice ventricosa, fronte porösa, aperturam primariam (cujus 

 latitudo circ. = 0,12 mm.) quadrato-rotundatam (in forma e mari pacifico Hippothoa; 

 modo sinuatam eam vidi) secundarie in tubum erectum producunt, qui proximaliter 

 fenestra rotunda apertus aviculariis ad latera acutis munitur. 



