H. B. Woodward — A " Greyicethcr " at Baysicater. 1 19 



pentagonal in outline. The line separating this additional plate 

 from the madreporite is not one of fracture, but is a true suture- 

 line, and is marked by two pits precisely similar to those which are 

 present on nearly all the suture-lines of the aj)ical disc. In the 

 suture-line between this extra plate and the centro-dorsal there is 

 also a pit, but there are none in the suture-lines between it and the 

 left anterior basal on the one hand, and the right posterior basal on 

 the other. The plate in question is quite distinct from the peri- 

 proctal plates of the recent Salenia, as it is separated from the 

 periproct by the centrodorsal plate. 



The relative size and outline of the madreporite plate, and the 

 position of its pore, seem to indicate that the supplementary plate 

 has either been separated from the madreporite plate at some early 

 period of the life of this Echinoid, or that its pi-esence has caused 

 the madreporite plate to take the somewhat modified form described 

 above. 



The only abnormal form of Peltastes Wrightii which has hitherto 

 been recorded is that which is figured by Wright,' where the centro- 

 dorsal plate is stated to be wanting and the apical disc is described * 

 as being composed of ten plates. The absence of the centro-dorsal 

 plate in this specimen, however, is due to imperfect preservation, as 

 the notches on the inner edges of the right and left posterior basals ' 

 abutting against the centi'o-dorsal clearly prove the former existence 

 of a suture-line with the characteristic pittings ; consequently the 

 centro-dorsal plate must have been present at one time, but has since 

 dropped out. Further, the raised rim or border which invariably 

 surrounds the whole of the periproct in the normal specimen, is 

 absent on the anterior half of the periproct in the specimen figured 

 by Wright. 



The presence of a centro-dorsal and a supplementary plate in the 

 apical disc of the specimen under consideration, indicate a nearer 

 approach to that of Acrosalenia than is shown by the normal 

 examples, although the supplementary plate may not be homologous 

 with any of the supplemental plates in the apical disc of Acrosalenia. 



VI. — Note on a Greywether at Bayswater. 

 By Horace B. Woodward, F. G-. S. 



MY attention was directed last Christmas to the cellar of the 

 King's Head, in Moscow Road, Bayswater. Some enlarge- 

 ment of the premises was required, and the base of the cellar was 

 to be lowered. About a couple of feet beneath the old floor, the 

 "woi'kmen came upon a block of stone, which resisted all their efforts 

 to dislodge it : and no wonder ! The stone proved to be a huge 

 Greywether, of irregular quadrangular form, measuring 9 ft. 6 in. in 

 length and also in breadth, and as much as 2 ft. 8 in. (possibly more) 

 in thickness. A portion of one side appeared to be a joint-plane ; 

 otherwise the mass exhibited the ordinary contours of a concre- 



1 Cret Echin. pi. xxx. fig. 2. 2 Ibid. p. 151. 



•' I am indebted to Mr. Gregory of the British Museum of Natural History for 

 this information. 



