28 EUCRATIID.E. 



terminal, larye, with the oral valve at the upper extremity ; 

 margin armed with spines. OECIA unknown. 



FROM Scruparia this genus is distinguished by its mode 

 of branching and its constantly uniserial habit, by its sub- 

 tubular cell, and large spinous aperture. From Huxley a it 

 is separated by the shape and structure of the aperture 

 and by its elongate subcylindrical cell. 



BRETTIA PELLUCIDA, Dyster. 

 Plate IV. figs. 6, 7. 



BKBTTIA PBLLUCIDA, Dyster, Quart. Journ. Micr. Sc. vi. (1858), 260, pi. xii. 

 figs. 3-5. 



Zoarium perfectly transparent, about half an inch high. 

 Zooecia much elongated, subcylindrical, slightly ex- 

 panded towards the aperture ; aperture placed on the 

 front of the cell, at its upper extremity, oval, rounded 

 above, pointed below, with five to nine marginal spines, 

 irregularly arranged. Ooecia unknown. 



Polypide with 10 tentacles. 



HABITAT. On stone between tide-marks. 

 LOCALITY. Tenby (Mrs. Brett: Dyster). 



Nothing is known of this minute but characteristic 

 form beyond what we learn from Mr. Dyster's brief de- 

 scription and Mr. Busk's excellent figure, which I am 

 permitted to copy for this work. 



BRETTIA TUB^EFORMIS, 



Plate II. fig. 2 ; Plate V. fig. 1. 

 BKETTIA PELLUCIDA, Norman, Rep. Brit. ASBOC. I860, 196 & 199. 



Zoarium minute, transparent, dichotomously branched, 

 surface smooth, attached by a number of tubular fibres. 



