Affinities of the Genus Parkeria, Carp. 11 



7. Relations to Extinct Organisms. 



There are various extinct organisms which have, or have 

 been supposed to have, relationships with Parkeria which 

 may be briefly glanced at here. Foremost amongst these 

 may be placed the singular spheroidal fossils from the Trias- 

 sic rocks of Kashmir, which Prof. P. Martin Duncan described 

 under the family name of the Syringospha^ridge (' Scientific 

 Kesults of the Second Yarkand Mission,' 1879). By the 

 great kindness of Mr. Medlicott, the Director of the Geolo- 

 gical Survey of India, and of Dr. Henry Woodward, I have 

 been supplied with specimens of Syringosphoira^ of which I 

 have made a careful examination by means of thin sections. 

 In their general aspect the fossils of the genus Sgringosphcera 

 present an exceedingly close resemblance to Parkeria, with 

 which they also agree in the possession of a tubulated coeno- 

 steal tissue. On the other hand, the coenosteum in Sgringo- 

 sphcera does not increase by the formation of successive con- 

 centric lamellffi with intervening rows of chamberlets, and I 

 have been able to demonstrate the presence of well-marked 

 zooidal tubes (" gastropores ") occupied by reticulate styles 

 or columellse. I shall be able, in fiict, to show that the genus 

 Sgringosjiha^ra, Duncan, is referable to the Hydrocorallines 

 and is nearly related to the recent genera Allopora and Spo- 

 radopora ; but I need not enter further into this point on the 

 present occasion, as I purpose treating of the genus more 

 fully in a separate memoir. 



The genus Porosphcera^ Steinmann, was referred by its 

 author (' Pala^ontographica,' N. F. Bd. iii.) to the Hydrozoa, 

 and was looked upon as related to Parkeria^ a view which 

 had previously been put forward by Mr. Carter (Ann. & Mag. 

 Nat. Hist. 1877). I have prepared and examined a number 

 of thin sections of Porosphcera glohularis, Phill. sp., from the 

 White Chalk of Britain, and do not feel able to coincide in 

 the above view. Without expressing any dogmatic opinion 

 on the subject^ I am disposed to tliink that PorospJuer a WiW be 

 found to be truly referable to the group of the Lithistid 

 sponges, and to be related to the genus Hindia, Dune. It is, 

 at any rate, certain that the genus has no special relationship 

 with Parkeria^ and the minute structure of its skeleton does 

 not resemble that of any Hydrozoon with which I am ac- 

 quainted. Bradya tergestina of Staclie is unknown to me, 

 and I am unable to express any opinion as to its afliuities. 



The genus Loftusia, H. B. Brady (Phil. Trans. 1869), has 

 been regarded by Steinmann, Carter, and others as likewise 

 referable to the Hydrozoa, and as more or less nearly related 



