BEITISH PALAEOGENE BEYOZOA. 233 



Distribution. London Clay, Highgate. 



Ti/2)e. Brit. Mus. No. 69205. Wetherell Coll. Encrusting Hippochrenes ampla. 



Figures. PI. XXIX. figs. 9 a, h. Fig. 9 «, part of zoarium, magnified 4 diara., 

 showing radial growths ; fig. 9 5, X 12 diam. 



Affinities. The mode of growth in loose disconnected rows resembles that often 

 assumed by M. catenularia (Jameson) [No. i, p. 561, name only] [Pyripora of Mac- 

 gillivi-ay) [No. i, pt. xi. p. 24], but the much greater size of the opesia in this species 

 is quite distinctive. 



Genus Lunulites, Lamarck, 1816. 

 [Lamarck, No. i, ii. p. 194.] 



Diagnosis. A genus of Membraniporidse with a unilaminate, conical, or cup-shaped 

 zoarium. The zooecia are arranged in radial rows ; radial rows of vibracularia either 

 separate the zooecia or occur alternately. 



Type species. L. radiata, Lamk. [No. i, p. 195]. 



Species 1. Lunulites tbansiens ^, n. sp. 



Syn. Lunulites urceolata, Lonsdale, 1850, in Dixon's Geol. Suss. pp. 159, 160, pi. i. fig. 8; 1878, 

 do. ed. 2, pp. 201, 202, pi. i. fig. 8. 

 Lunulites "? radiata, Lonsdale, 1850, in Dixon's Geol. Suss. ed. 1, pi. i. fig. 8; 1878, do. ed. 2. 



Diagnosis. Zoarium of medium size, depressed, circular, thin, cup-shaped ; convex 

 margin curved. 



Zooecia. Opesia with the aperture large, orbicular, elongate ; a small lamina at the 

 lower end. The lateral margins are steep ; the inner margin slopes more gently. A 

 pair of small tubercles occur on some of the margins between the two zooecia. 



Vibracularia large, aperture clithridiate ; the radial series are connected by a groove ; 

 they increase in size towards the periphery, and gradually pass into normal zocecia (whence 

 the specific name). On the concave side the ridges are irregularly distributed and are 

 separated by deep grooves ; there are numerous large pores ; on the narrower parts of 

 the ridges there may be only a single line of pores. 



Dimensions. Diameter -5 mm. ; height 1"25 mm. Taken from a small complete 

 specimen. In some fragments the number of zocecia is from 18-20 ; number of 

 zooecia in a radial series 10. 



Distribution. Upper Eocene, Barton Beds, Barton. Middle Eocene, Bracklesham 

 Beds, Bracklesham, Bramshaw, Brook, WhiteclifiT Bay. 



Type. Brit. Mus. No. 49724. From Barton. Edwards Coll, 



Figiores. PI. XXIX. fig. 13. Part of zoarium showing back, X 24 diam. Fig. 14. 

 Several normal zocecia, X 24 diam. — PI. XXX. fig. 1. Another specimen, showing the 



^ Referring to th.e gradual passage from vibracularia to zooecia. 



