Description of a New Genus and some JVew Species. 127 



lire slightl}^ raised; from six to eight tube oritices oeeup}- the space of 

 one Hue. Intertubular space about oue third as thick as the width of 

 the tube mouths, and minutely tubular. 



Longitudinal sections of the branches present the tubes as proceed- 

 ing in a gentle curve from the middle or axis of the branch to the sur- 

 face, and as they approach the surface and have arrived to within one 

 line of the same, they bud off one or two more slender tubes; the 

 tubes before they have been thus multiplied are traversed by complete 

 and close tabulae, a little more than one tube diameter apart. Near 

 the surface the tubes are of two kinds, smaller and larger ones; the 

 former are at intervals collected into groups, which represent the 

 stellate maculae on the surface; between these the remaining tubes are 

 placed alternatel}', oue larger and one or two smaller; the large tubes 

 repi'csenting the true cells, while the smaller ones represent the mi- 

 nute tubuli in the intercellular spaces. The diaphragms in both kinds 

 of tubes are close set, about two thirds of a tube diameter distant from 

 each other. 



In transverse sections the tubes near the margin are seen to be cut 

 longitudinally, while in the center they are divided transversely, and 

 here they are thin-walled and generally with an hexagonal outline. 



In sections taken parallel with and close to the surface, the stellate 

 spaces are seen to be occupied b}^ a net-work of sub-angular cells. 

 Tlie tubules are circular, and fill up the space not occupied by the ma- 

 culae; they are separated bj' a similar net- work of minute colls as those 

 composing the maculae. 



This species in its external characters approximates closel}' to Fis- 

 tvlipoi'a, McCo}', since the stellate and intertubular spaces in their 

 structure are essentially the same as the cellulose tissue, of which the 

 intertubular spaces and macuhie, in most of the species of that genus, 

 are composed. Fistulipora [Callopora) incrassata, Nicholson, has star- 

 like spaces, occupied b^^ very minute tubuli, but these spaces have no 

 radiating ridges surrounding them. In S. limitaris there are also 

 none of these ridges, and in these two species the resemblance is very 

 manifest. On the other hand, in sections of S. limitaris, taken paral- 

 lel with and close to the surface, we find a striking similarity to sec- 

 tions of the same kind of Chattetes decipiens, Rominger, and C.fron- 

 dosus, D'Orbign^r, while in longitudinal sections much aflfinity is pre 

 sented to several ramose species of Choitetes. The species of Stelli- 

 pora and their numerous A'arieties, in fact, are connecting links be- 

 tween CluHetes and Fistulipora. Stellipora ayitheloidea, Hall, is dis- 

 tinguished from this species, exteriorly, by its sub-frondescent growth. 



