152 REPORT — 1869. 



Variety 4. The corallum and costae are like variety 3, but the septa arise 

 from the intercostal spaces. 

 Locality. Gault, Folkestone. 

 In the collection of the Rev. T. Wiltshire, F.G.S. 



Variety 5. The coraUum is rather more conical inferiorly than in varieties 

 3 and 4. The septa are exsert, and project slightly beyond the costal margin. 

 The costae are all rudimentary. The epitheca is well developed, and reaches 

 Tip to the septa. 



Locality. Gault, Folkestone. 



The forms may be distinguished as follows : — 



r The type. 

 With more or less ridged costae \ Variety 1. 



Yri'. ^' 

 With nearly equal flat costae \ '^ ,* 



Costae rudimentary „ 5. 



r The type. 

 Septa arising from the costal ends . . . . -^ Variety 1. 



[ ,, 3. 



Septa arising from the intercostal spaces -I ^ / 



All the forms have four cycles of septa and pali before the first, second, 

 and third orders. 



2. Trochoeyaihus Wiltshiri, Duncan. 



The corallum is straight, conical, and either cylindrical above or com- 

 pressed ; its base presents the trace of a peduncle for attachment. The 

 epitheca is scanty and in transverse masses. The costae are distinct and sub- 

 equal. The calice is very open and rather deep. The septa are unequal, 

 hardly exsert, and broad at the margin of the calice. There are four cycles 

 of septa, and six systems. The pali are large, and are placed before all the 

 cycles except the last. The columella is rudimentary. 



Height i^^y- inch. Breadth of calice y\^ inch. 



Locality. Gault, Folkestone. In the zone o? Ammonites dentatus. 



In the Eoyal School of Mines, and in the collection of the Eev.T. Wiltshire, 

 F.G.S. 



This species is closely allied to Troclwcyathus conidus, Phillips, sp. The 

 compressed calice, the rudimentary columella, and the shape of the corallum 

 distinguish the new species from Trochocyathus conidus. 



Genus Leptoctathus. 

 LeptocyatJms gracilis, Duncan. 



The corallum is small, flat, and circular in outline. The costae are very 

 prominent, and join exsert septa ; the primary and secondary costae are very 

 distinct, and the others less so. All the costae unite centrally at the base ; 

 many are slightly curved. The septa are thick externally, very unequal, thin 

 internally, and the largest are more exsert than the others. There are six 

 systems and four cycles of septa. The pali are small and exist before all the 

 septa. The columella is very rudimentary. The calicidar fossa is rather 

 wide and shallow. 



Height hardly -^ inch. Breadth -f^ inch. 



Loccdity. Gault, Folkestone. 



In the British Museum. 



