80 Mr. A. W. Waters on 



now ready, dealing witli species growing in a cupuliform 

 sliape, including Seleuariadie and Conescliarellinidie, as the 

 consequences of war may cause delay. 



The re-examination of some specimens of what Haswell 

 described as SpJucrophora fossa show the importance of this 

 tpccies in throwing light on certain fossils. The zoaria are 

 small, and were described as subspherical " with a circular 

 pit; at the upper pole/^ but it does not seem that we must 

 t^pi'ak of the pit being at the upper pole. The growth is 

 towards the pit, a fact correctly shown by Haswell, although 

 he does not allude to it (PI. VJ. fig. 1). Another form 

 with zoaria about the same size, described by Reuss* as 

 Dijilotuxis ploceiiiala, now changed by Gregory f to Biselen- 

 aria, as the name Diplotaxis was preoccupied, grows on one 

 surface to the border and then turns over to the other 

 growing towards the centre. Although the growth in the 

 two forms considered is not quite identical, they partially 

 explain one another. Canu % in describing Biselenurin offo, 

 (ireg., says the zooscia radiate from a "grande ancestrule," 

 which, however, is not shown in Canu's figure, and, as the 

 zo(Kcia are Membraniporidan, it is difficult to understand. 



The importance of the pit was appreciated by Haswell, 

 who did not attempt any explanation in his first {>aper, but 

 in a subsequent one § he mentions a Cellepora with minute 

 Aetinids lodged in cylindrical pits, excavated in the substance 

 of the polyzoarium. He thinks this may throw some light 

 on the pits of Sp/uerop/wra fossa, and described it as a case of 

 symbiosis of Actinid with CeUepora. However, as regards 

 fS. fossa, the definite position of this pit in recent species 

 from various localities, as well as in fossils fi'om many 

 localities, makes this very improbable; nor is this all, for it 

 is clear that what was described as " aufrecht stehende 

 Zelle'^ or "primoidial Zelle^^ by Reuss and others in Batopora 

 and some allied genera is a similar pit, though much smaller. 

 In both cases there is a raised ridge sitrrouuding the border 

 (PI. VI. fig. 6), and there are in the pits lai-ge pores leading 

 to the surrounding zooecia. Reuss, who had seen the tubes 

 from these pores, spoke of them as a hydrostatic system, but 

 hov.' he considered that the system functioned is not clear. 

 Canu II and Bassler also refer to a hydrostatic system. 



* ]Jiv. des deutsch. Unterolig. Sitz. d. k. Akad. Wissen. Wien, Iv. 

 p. ■ril,'}^. ii. tigs. 5-7 (186-4). 



t '■ Brit. Pal. Biy.," Trans. Zook Soc. London, vol. xiii. p. 234 (1893J. 



I " Brv. Tert.," Ann, de Paleou. vol. ii. p. 30 (1907). 

 § ProL*. Linn. Soc. N.S. Wak-s, vol. vii. p. G08 (1882). 



II Early Tert. Cheil. Brv. p. 7-3; Smithsonian lust. U.S. Nat. Mus. 

 Bull m (lUi7). 



