304 



neighbourhood of this species, and to judge from this author's description of 

 Systenopora contracta\ I must also refer this form to the family Sderodomidae. It 

 agrees with Sderodomus denticulatas in the numerous, scattered pore-canals, the cov- 

 ered-over ooecia and in the possession of an avicularium on the inner surface of the 

 peristome. The species described by Waters under the generic name oi Cellarin- 

 ella^ should also be referred to this family, and the author himself is also almost 

 inclined to place them in the neighbourhood of Systenopora. To this familv, lastly, 

 I must also refer Tessaradoma borealis, which consists of a quite similar, hard and 

 solid, finely striated calcareous mass as is found in Sclerodomns denticulatas, with 

 which species it further agrees in the covered-over ooecia and in the structure of 

 the rosette-plates. Another species of this genus is described by Waters^ under 

 the name of Porina proboscidea. 



Of the remaining species which Busk refers to the genus Bifaxaria I have 

 only been able to examine an extremely small fragment of Bif. corrugata, and 

 there can be no doubt that this species belongs not only to another genus 

 but even to another family than Sderodomus denticulatas. The thick-walled 

 calcareous mass, which is only perforated by some extremely fine, slit-like poi-es, 

 seems to be somewhat brittle. The separating wall between the two zooecial rows 

 has a row of small, uniporous rosette-plates within each lateral margin, the avi- 

 cularia seem to have no transverse bar etc. The slight information given by 

 Waters' concerning the ooecia seems to indicate, that these are transformed zooe- 

 cia. All seems to show, that these forms take up a special position and a new 

 description of them is very necessary. 



Family Tubucell^riidae Busk. 



The zocecia, which are covered by a membrane and have no spines, are more 

 or less thick-walled and provided with densely placed pits or areas separated by 

 ridges, each surrounding a pore. The lateral walls which are common to the 

 adjoining zooecia are provided with a number of, as a rule scattered, multiporous 

 rosette-plates. Avicularia may be present. The ooecia''- are at the end open spaces, 

 formed by a strong expansion of the peristome (peristomial ooecia), and in the 

 hitherto known members of this small family an ascopore is found. The col- 

 onies form either richly branched, jointed tufts or free, foliaceous one-layered 

 expansions. 



^ 115, p. 56—57. 2 115, p. 39. ' 110, p. 15. * 116. 



