394 Mr. W. D. Lang—Revision of the 
B. No secondary aperture, but apertural bar 
sharply bent proximally, and bearing no 
median process like that in A; avicularia 
TATC: OP AVSCDE a; ce asi elope as eee ene b. Leptochetloporine. 
a. Lagyvoporryva, subfam. nov. 
Tabular Diagnoses of the Genera. 
A. Apertural spines always6 ............00:: I. Hexvacanthopora. 
B. Apertural spines primitively 6, as shown in 
the neanastic cecia, but finally 4. 
I. Costee widely separate; median process of 
apertural: bar Lim Fons teitag sy 3 = ooo Il. Prodromopora. 
II. Costze more or less closely juxtaposed ; 
median process of apertural bar strongly 
developed *p4/ Gis oxi ois chnorte et erence Ill. Lagynopora. 
I. HexacaNTHOPORA, gen. nov. 
Genotype. H. sexspinosa. 
Tabular Diagnoses of the Species. 
A. Cécia smaller (about § mm.); costa 18-20 .. 1. H. sexspinosa. 
B. Cécia larger (more than 2 mm.). 
LO Oot ee era, Se eR nee eae 2. H. kintburiensis. 
TE COstee ee oo sais nicl aoe cima Arron 3. H. brightonensis. 
1. H. sexspinosa, sp. un. 
Type-specimen. British Museum, D. 21205; Marsupites- 
zone; Odiham, Hants. 
2. H. kintburiensis, sp. n. 
Type-specimen. British Museum, D. 21204; guadratus- 
zone; Kintbury, Berks. 
3. H. brightonensis, sp. u. 
Type-specimen. British Museum, D. 28890 ; Marsupites- 
zone; Brighton, Sussex. 
II. PropRomorora, gen. nov. 
Genotype. P. precursor, sp. n. Type-specimen. British 
Museum, D. 8351 ; coranguinum-zone ; Gillingham, N.E. of 
Chatham, Kent. 
