PKOGEESS OP MICROSCOPICAL SCIENCE. 41 



unaided observations, however numerous) as " conclusive proof," and 

 trusting, tlierefore, that these researches will lead others to investi- 

 gate the subject and correct or confii'm his results, he concludes his 

 observations. 



A Specimen of Diplograpsus pristis icith Beproduciive Capsules. — Mr. 

 John Hopkinson, F.E.M.S., has recently described a curious grajito- 

 lite. The chief peculiarity seems to be the presence of reproductive 

 organs. These, which Mr. Hopkinson considers to be representations 

 of the gonothecfe of the recent Sertularian zooj)hyte, are developed 

 almost immediately oj^posite each othei', from each side of the peri- 

 derm and throughout its whole length. Though at equal intervals 

 from each other, they are in no even numerical relation to the hydro- 

 thecfe, there being ten to the inch. They appear to have budded from 

 the periderm at right angles to the hydrothecse, and thus have caused 

 the polypary to be imevenly comj)ressed. The most j^erfect are pear- 

 shaped in form, ^th of an inch long ; and at their narrow end, by 

 which they are attached, about gVth of an inch wide. They have 

 apparently been bounded by a single marginal fibre, which is slightly 

 thickened at its edges, and, where the pyrites are removed, has im- 

 pressed a fine double groove on the surface of the shale. If the fibres 

 were slender tubes, this appearance would naturally be presented ; for 

 their outer margins would oifer the greatest resistance to compression. 

 The so-called solid axis of the graptolite frequently jDresents a similar 

 appearance. At the proximal end of the polypary these fibres only 

 are preserved, the oldest or first-formed gonothecfe having fulfilled 

 their function and perished. The distal extremity of even the most 

 perfect is not clearly defined, the impression of the capsule in most 

 cases becoming gradually less perceptible from the proximal to the 

 distal end. Sometimes the capsules are irregularly ruj)tm'ed, their 

 torn jagged edges being distinctly seen, while one has split along its 

 marginal limit, along the line of the marginal fibre, which apj^ears to 

 have parted abruptly near the distal end of the capsule at one side, 

 and split acutely for some distance along the other side. This would 

 appear to indicate that the capsule may be composed of two mem- 

 branes joined together at their edges, through which the fibre, if it be 

 not merely a tube formed by a kind of double marginal seam, has rim. 

 In no case can a distinct unruptiu-ed distal orifice be traced. The 

 gonothecfe present other peculiar appearances. Towards their prox- 

 imal end they are sometimes longitudinally corrugated or crumjjled, 

 or traversed by fibres which extend for some distance into the body of 

 the polypary. Some are much twisted and bent about, occasionally 

 overlapping each other. Between two which thus overlap, or perhaps 

 only come into contact with each other, just at the point of contact 

 and apparently within one of the capsules, are two minute young 

 graptolites, one lying across the other. Each consists of a thin mem- 

 brane, probably forming the first partially developed pair of hydro- 

 thecfe, a minute radicle, and a slender solid axis which is prolonged 

 beyond the membrane. They are similar in form and proportions; 

 but one is a little larger than the other. Its length, from the extreme 

 point of the radicle to the distal end of the axis, is gV^^ ^^ ^^ inch. 



