THE ANNALS 



-^n 



AND 



MAGAZINE OF NATURAL HISTORY. 



[FOURTH SERIES.] 

 No. 41. MAY 1871. 



XXXIX. — On a Sjjechnen o/" Diplograpsus pristis with Hepro'- 

 ductive Cajysuhs. By JoHN HoPKiNSON, F.G.S., F.E.M.S. 



In looking over a few Graptolites which had recently been 

 received by Mr. Etlieridge at the Geological Museum, I detected 

 a specimen wliich appeared to be a Dlj^ilorjvapsus bearing re- 

 productive capsules. About half of the graptolite as it is now 

 seen was visible ; and this portion showed the reproductive 

 organs, but no hydrotheca3, the proximal end being imbedded 

 in the shale. On clearing away the shale, the specimen, which 

 Mr. Etlieridge kindly lent me for examination, proved to be a 

 tolerably well-preserved impression of Diplograpsus ijristis. 



The graptolite appears as a silvery pyritous impression on 

 the sm-face of the shale. The proximal termination is indi- 

 stinct. A slender radicular process, continuous with the solid 

 axis, can just be made out. At the distal end the shale is 

 broken riglit 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 hydrothec^e, 

 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 par- 

 tially hidden. There are twenty-four in the space of an inch. 

 Towards the distal end the apertures only of a few of the 

 hydrotheca3 are seen ; they appear as " scalariform impres- 

 sions " on the surface of the polypary. 



The reproductive organs, wliich I consider to represent the 

 gonothecaj 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 rela- 

 tion to the hydrothec^e, there being ten to the inch. They 

 appear to have budded from the periderm at right angles to 



Ann. & Mag. N. Hist. Ser.4. Fo?. vii. ' 23 



