204 



On a Specimen of Diplograpsus pristis with Reproductive 



Capsules. 



By John Hopkinson, F.G.S., F.R.M.S. 



(Read March 2Uh, 1871.J 



In looking over a few Graptolites which had recently been received 

 by Mr. Etheridge at the Geological Museum, I detected a specimen 

 which appeared to be a Diplograpsus bearing reproductive capsules. 

 About half the graptolite as it is now seen was visible ; and this 

 portion showed the reproductive organs, but no hydrothecaa, the 

 proximal end being imbedded in the shale. On clearing away the 

 shale, the specimen, which Mr. Etheridge kindly lent me for 

 examination, proved to be a tolerably well-preserved impression of 

 Diplograpsus pristis. 



The graptolite appears as a silvery pyritous impression on the 

 surface of the shale. The proximal termination is indistinct. A 

 slender radicular process, continuous with the solid axis, can just be 

 made out. At the distal end the shale is broken right across the 

 polypary, which here shows no signs of coming to a termination. 

 One inch only is exposed. 



The solid axis is clearly seen throughout. The hydrothecae, 

 towards the proximal end, are very distinct ; the apertures of those 

 on the left-hand side are clearly seen, extending partly over the 

 periderm, while those on the right-hand side are partially hid. 

 There are twenty- four in the space of an inch. Towards the distal 

 end the apertures only of a few of the hydrothecee are seen ; they 

 appear as " scalariform impressions " on the surface of the poly- 

 pary. 



The reproductive organs, which I consider to represent the 

 gonothecae of the recent Sertularian zoophyte, are developed almost 

 immediately opposite each other from each side of the periderm and 

 throughout its whole length. Though at equal intervals from each 

 other, they are in no even numerical relation to the hydrothecas, 



