384 Mr. W. D. Lang—Revision of the 
plane; avicularia directed inwards; cost 
15-22 Oo es Chobe its a ach tee oe ee, a See eee 
b. Apertural bar somewhat flattened and sloping 
proximally ; avicularia directed outwards ; 
costee 14-15, 
AS Garidze BiOrb Tx...-.5- 2 -rsieto'e ster Pere barca 6. A. linearis. 
2, ‘Candas lone” 20a. ces non ee eee 7. A. porrecta. 
ce. Apertural bar very slightly flattened and 
produced vertically in a median ie 
costes 1G-1S Seeker cients a ieee , 
B. Apertural spines decidedly thickened. 
I. G&cia stout ; caude short or none. 
1. Coste slightly fused; apertural bar with 
5. A. homunculus. 
8. A. imax. 
median process ; coste about 12.......... 9. A. gastert. 
2. Coste firmly fused; apertural bar not 
specially modified ; costee about 20 ...... 10. A. frequens. 
II. Cicia meagre ; candie long. 
1. Costze slightly fused; about O Fan Jos teats 11. A. levinsent. 
2. Coste firmly fused ; about 18............ 12, A. aggregata. 
1. A. | Hippothoa] brevis (Reuss.), 1872, Palaeontographica, 
vol. xx. part 1, p. 100, pl. xxiv. fig. 1 ; Cenomanian ; 
Saxony. 
2. A. méckleri, sp. n. 
Type-specimen. British Museum, D. 23020 ; Chalk Mar! ; 
Cambridge. 
3. A. artion, sp. Nn. 
Type-specimen. British Museum, D. 25544; low in 
cortestudinarium-zone ; S.E. of Boxmoor, Herts. 
4. A. gallica, sp. n. 
Type-specimen. British Museum, D. 28480; Coniacian ; 
Fécamp, France. 
5. A. homunculus, sp. n. 
Type-specimen. British Museum. D. 8212 ; Holaster planus- 
zone ; Borstal, S.W. of Chatham, Kent. 
6. A. [ Cribrilina] linearis (Vine), 1893, Rep. Brit. Ass. for 
1892, Edinburgh, p. 316.  Type-specimen. British 
Museum, D. 2638; Lower Senonian; Chatham, Kent. 
7, A. porrecta, sp. 0. 
Type-specimen. British Museum, D. 7308 ; coranguinum- 
zone ; Charlton, Kent. 
