304 



neiglihoiirliQod of this species, and lo judge I'lom lius author's description of 

 Sijsteiiopora contractu ', I must also refer this form to the family Sclerodomidde. It 

 agrees with Sclerodomus denliciihilns 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 descrihed hy Waters under the generic name of Cellcirin- 

 e//a ' should also he referred to this family, and the author himself is also almost 

 inclined to place them in the neighbourhood of .Sys/e/jopora. To this familv, lastly, 

 I must also refer Tessaradomci tn>rc(dis, which consists of a (juite similar, hard and 

 solid, finely striated calcareous mass as is found in Scterodomns denlicid(dus, with 

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

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

 the name of Porina prolwscided. 



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

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

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

 but even to another family than Sclcrodamm dentictdaliis. The thick -walled 

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

 seems to be somewhat brittle. The separating wall between the two zoa-cial 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 ocecia seems lo indicate, that these are transformed zod-- 

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

 description of them is very necessary. 



Family Tubucellariidae Busk. 

 The zonrcia, 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 zoo^cia are provided with a number of, as a rule scattered, multiporous 

 rosette-plates. AvicLdariu may be present. The ocvcia* are at the end open spaces, 

 formed by a strong expansion of the i)eristome (perislomial oa-cia), and in the 

 hitherto known members of this small family an ascoi)ore is found. The col- 

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

 expansions. 



' 115, p. 56—57. - 115, p. 3i). ^ 110, p. 15. ' IIG. 



