FLOEIDAN BRYOZOA. 35 



The form of the zooscial aperture, as I often have demonstrated, in most cases 

 will be our surest guide in searching for the natural affinities of the Escharines. Thus, 

 provisionally, for arranging together the nearest allied species, by marking out, system- 

 atically, the most pregnant differences, althongh, as in the following will be seen, no 

 true generical divisions, in the ordinaiy sense, here will be accepted, at the side of 

 the preceding genus I place another one, which, in the same manner, seems to be new. 

 It may be named • 



Gemellipora. 



Char. gen.: Apertura zooeciorum vestigii pedis equini formam ref ert, ad angulos 

 proximales pro articulatione operculi constringitur, marginem proximalem sinuatum 

 praäbet. 



The name of the genus is chosen in reference to the colonial form of one of the 

 Floridan species, which may be named 



Gemellipora eburnea (Pl. VII, tigs. 152—156; Pl. IX, figs. 177, a and 178). 



Char. spec: Zooecia eburnea, clavata, rare porösa, aperturam (cnjus latitudo in 

 parte coloniaa serpente circiter = 0,05 mm.) fere rotundam, margine proximali latissime 

 sinuatam prasbent, coloniarn primo serpentem (Hippothoiformem, au ett.) deinde erectam 

 (Gemellariiformem, ramis tamen monostichis in rectam lineam divergentibus) articu- 

 latam exstruunt. 



Hab.: Pouetales hujus speciei exempla haud rara e prof. 120- — 170 orgyarum 

 sustulit. ' 



This species, in its erected state (fig. 153), through its ivory colour and delicate 

 stem, for the naked eye very much resembles the Crisice. But a more close examina- 

 tion will show the zooecia arranged more like the Gemellarice, two and two, back to 

 the back, in two rows a little spirally contorted around the imaginary axis of the stem 

 and branches. This contortion, however, here is connected with an alternately opposite 

 direction of the zooecia of the same row, and the front of all the zooecia is tnrned either 

 to the right or to the left side of the stem, from the plane of the ramification. Further, 

 the stem and the branches of Gemellipora eburnea are articulated, the latter at least at 

 their base, which constantly is attached to the first (oldest) pair of the zooecia in the 

 internodes of the stem. The creeping part of the colony (fig- 152), from which this 

 stem is raised, has the appearance of a dwarfish Hippothoa divaricata; but the speci- 

 fical form of the zocecial aperture easily will distinguish it therefrom. In the barder 

 degrees of calcification, and when more outgrown, this creeping state acquires a totally 

 other aspect, by prolonging the proximal part of its zooecia into a narrow, tubiform 

 pediele (Pl. IX, figs. 177, a and 178). This form I met with on a stone from 120 

 fathoras, and at first, as the most of the zooecia, in connexion with the barder calci- 

 fication, had got the margin of their aperture secondarily raised, and, worn as they 

 were, presented it irregularly sinuated in its proximal end, I thought it to be of 

 another genus, until at last the one of the zooecia showed the primary aperture un- 



