430 ZOOPHYTES. 



The characteristics of the coralla in the several genera, are as fol- 

 lows : 



FAMILY I. MADREPORID.E. 

 Cells deep and without cross septa. 



GENUS 1. MADREPORA. Branches with an apical calicle, and distinct lateral caliclcs 

 upon the branchlets. Cells deep, 6-12 radiating points within, which are sometimes 

 obsolete. 



GENUS 2. MANOPORA. No apical calicle ; calicles all obsolete, or irregular ; coralla 

 quite porous ; cells as in the Madreporae. 



FAMILY II. FAVOSITID.E. 

 Cells with cross septa within the coralla ; rarely, solid below. 



SUBFAMILY 1. ALVEOPORIN^E. Coralla very light porous; cells deep, and with 

 radiating points within, as in the Madreporae. 



GENUS 1. ALVEOPORA. Cells contiguous, with very thin cribrate parietes. 



SUBFAMILY 2. FAVOSITIN^E. Cells with radiating entire lamellos, often becoming 

 obsolete; contiguous, at least at the summits of the coralla. 



GENUS 2. SIDEROPORA. Coralla with obtuse branches ; cells containing a distinct 

 star of six rays, meeting in a short columella at centre not seriate, distinctly traceable 

 within the coral lum. 



GENUS 3. SERIATOPORA. Coralla with very slender terete branches, often pointed : 

 cells seriate ; texture very solid, and cells, therefore, not traceable within the coralla. 



GENUS 4. POCILLOPOHA. Coralla with the branches never terete ; surface usually 

 verrucose, and cells traceable within, except when quite slender ; texture mostly very com- 

 pact ; lamellae nearly obsolete. 



GENUS 5. FAVOSITES. Coralla consisting of agglomerated prismatic cells. 



GENUS 6. CATENIPORA. Coralla consisting of single lines of cells, forming mean- 

 dering vertical plates, which plates often intersect one another. 



SUBFAMILY 3. HELIOPORINjE. Cells circular, not contiguous. 



GENUS 7. HELIOPORA. Cells with narrow radiating lamellse; texture of the inter- 

 stices minute tubular. 



GENUS 8. HELIOLITES. Cells with narrow lamellse ; interstices irregularly cellular. 



GENUS 9. MILLEPORA. Cells very minute ; rays obsolete ; texture of the interstices 

 quite compact or sparingly porous. 



FAMILY III. PORITID^. 



Cells shallow, hardly traceable within the coralla, which are throughout fine-porous. 



GENUS 1. POHITES. Coralla glomerate or furcato- ramose ; cells not over a line in 

 diameter ; (polyps with twelve short tentacles.) 



GENUS 2. GONIOPORA. Coralla glomerate or columnar ; cells over a line in diame- 

 ter; (polyps with sixteen to twenty-four tentacles.) 



