tOLYZOA FROM THE LIAS. 



635 



in the Spiroporaz * or the Tubuliporce ; yet, notwithstanding this, 

 I think the species finds best, though insecure, place with the latter 

 group. It has the long and partly free zooecia of Tubuliporce, and 

 an inconstant habit of growth common to the genus. As a 

 provisional name therefore seems to be necessary, I would suggest 

 that of Tubulipora inconstans. The transverse line or septum 

 formed by the two layers of cells when back to back, as in the 

 foliaceous forms (fig. 12), has somewhat of a Diastoporoid look. 



Through the courtesy of Mr. Newton I have been enabled to 

 examine the type specimens of Tate's Spiropora liassica at the 

 Jermyn- Street Museum, and it appears to me that the Spiropora- 

 like branches of Tubulipora inconstans are not only provided with a 

 smaller number of zocecia to form an average-sized zoarium, but the 

 zooecia are also much longer and somewhat broader. Their dispo- 

 sition is irregular, whereas S. liassica has a regular arrangement of 

 the peristomes in each annulation and, moreover, the ordinary 

 erect colonial growth of the Spiroporas. 



Horizon and Locality. From the Marlstone Rock-bed, zone of 

 Ammonites spinatus, of the Middle Lias, King's Sutton, Northampton- 

 shire, also from the Transition bed between the Middle and Upper 

 Lias at Appletree, near Banbury, and at Badby, near Daventry. 



Associated with the species above described are two others in which, 

 though the colonial and zooecia! forms are essentially different from 

 it, the structural details are so closely mimicked as to make their 

 reference to other genera a matter of doubt. I have therefore 

 described and figured them, but have left the nomenclature until 

 further evidence shall show their precise relationship. 



Zoarium erect, uniserial, commencing as a straight or slightly 

 undulating and often flattened simple tube, then dilating and 

 throwing off a branch right and left, without, however, any cell- 

 opening at the node, though a faint line of fusion is visible in the 

 primary stem. The secondary branches or zocecia dilate also at 

 each succeeding node where the single cell opens and a fresh zooecium 

 begins. The branches diverge at an angle of from 45 Q to 50°, and 

 the cell opens at a little distance above the point whence the new 

 one has sprung. Peristomes circular, in diameter of the normal 

 width of the zooecium. The surface pores and subsidiary tubes are of 

 the same character as in Tubulipora inconstans. (PI. XXV. fig. 11.) 



Though out of the few examples collected some are erect, others, 

 on the contrary, show some portion of the zooecium to be flattened 

 as if the colony was partially adherent, and between this and the 

 next group there seem to be connecting links. 



Horizon and Locality. Prom the Middle Lias, zone of Am- 

 monites spinatus, King's Sutton. 



Similar forms occur in the Inferior Oolite of Dorsetshire. 



* Mr. Waters (Quart. Journ. Geol. Soc. vol. xliii. p. 340, 1887) describes 

 and figures Entalophora wanganuiensis with closures, and I have now Inferior 

 Oolite species similarly provided. 



2x2 



