Br. F. A. Bather — Notes on Yiinnan Cystidea. 515 



of classificatory importance or as individual peculiarities due to 

 accident or as resulting from some extraneous cause". He is right 

 in regarding the last interpretation as the "most probable"; the 

 structures are in fact the root attachments of some other Pelmatozoon, 

 and similar appearances are familiar enough to those who have 

 studied Ordovician cystids in the field. In II, 3, there is a small 

 one near the base, and this, as drawn in fig. 3, has a circular lumen. 

 In II, 4, there is near the base a rather large one, 4 mm. high, 

 4-7 mm. wide at its summit, and 6*7 mm. wide where it rests on the 

 theca ; it is divided by a stellate lumen into irregular pentameres. 

 By removing the thecal plate on which this rests and examining its 

 inner surface it is seen that the encrusting root covers several 

 diplopores. That the covering up of the diplopores took place 

 gradually as the root extended appears from a few incipient roots on 

 the better preserved face of the same specimen, for in them the pores 

 still pierce the outer extensions of the incrustation. This face of 

 the theca bears five such roots, and two of them, which also are 

 quite small, have a sub-pentagonal cup-like excavation, reminiscent 

 of the Liassic Cotylecrintis. IS^ear the lower end of II, 6, there is a 

 relatively large root-base which rises sharply from the test like 

 a broken volcanic cone (Text-fig. 7); its diameter below is 8 mm., 

 and above about 4-5 mm. In II, 8, a somewhat similar root covers 

 tlie anal pyramid. On the anterior face of II, 10, which is the less 

 flattened face and presumably lay upwards, there are three, perhaps 

 four, root-bases, more or less merged in the test. The object which 

 in II, 5, covers the hydropore [v. srtpra, p. 513, line 7 from end) may 

 or may not be such a root. 



The preceding facts prove that the roots were independent of the 

 cystid on which they grew, that in some cases they must have 

 established themselves on the theca after the death of the cystid, 

 but that in other cases they settled on it and continued to grow, at 

 least for a time, during the life of the cystid. When in the last- 

 mentioned case the cystid deposited its own stereom round and 

 partly over the stereom of its unbidden guest, then a difficulty was 

 created for the modern palaeontologist. 



All the points of supposed difference between Ovocystis and 

 Smocystis have now been discussed and shown to be non-existent or 

 unimportant. It follows that Ovocystis is a synonym of Sinocystis, 

 which now contains the three species S. loczyi, S. yimnanensis, and 

 S. mansuyi. The nomen nudum Sinocystis piroides Reed (in Coggin 

 Brown, 1913, Rec. Geol. Surv. India, xliii, p. 332) is said in the 

 1917 memoir (p. 60) to be a synonym of I'yrocystts (?) orientalis 

 Heed; it was provisionally attached to the larger of. the two 

 specimens from locality K 15/302. 



Since Dr. Heed has not named a Genotype for Sinocystis, the 

 species S. loczyi is hereby selected. 



Before the systematic position of Sinocystis is discussed, further 

 notes on the specimens will be given. 



