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PROFESSOR W. C. WILLIAMSON ON THE ORGANIZATION

we have an outer membrane at b , which appears to be a continuation of b". At theupper part of the seed we have an arrangement which appears to correspond approxi-mately with that of fig. 79. Thus the membrane f divides above the apex of theperisperm into the two layers f & f'. At first I regarded f as the perispermic mem-brane ; hut the transverse portion f distinctly exhibits a coarsely cellular structure, asat f" we have an equally distinct prosenchymafous one,—conditions that differ from allthe unmistakable perispermic membranes of other examples. I find at h a small massof cellular tissue which appears to me to be part of the parenchyma of the interior ofthe nucleus. If this is so, it follows that the true perispermic membrane is here blendedwith the nucular one throughout the greater part of its course, as in fig. 86. Since theseed thus appears to occupy an intermediate position between Conostoma oblonga andC. ovalis, it may be provisionally recognized as Conostoma intermedia. Its length isabout T3 and its diameter ‘07.

Fig. 85 represents the external aspect of a small seed obtained by Mr. Aitken,of Bacup , from the Ganister bed near Oldham, in which such objects are very rare. Ibelieve it will prove to be a distinct species of Conostoma; but unfortunately its internalstructures are imperfectly preserved, but enough remains to show that it is distinct fromall those which I have described.

Figs. 88-93 represent five sections of another remarkable seed w T hich is very distinctfrom those already described, but of which I have only found one solitary specimen.Hence I have adopted the plan which I have followed in several other cases. I begangrinding at the exterior of the seed, where I first obtained the appearances representedin fig. 89; and as I ground deeper into the seed I sketched the structures which succes-sively presented themselves until I reached what appeared to be nearly the centre of theseed, as seen in fig. 93. I believe that the centre of the apex of the seed is approachedin fig. 92, but I was nearer the centre of the chalazal extremity in fig. 93. The irregu-larities in the outline of this seed demonstrate that the outer layer (a) was a fleshysarcotesta, capable of being irregularly shrivelled up. It consisted, as is seen in figs. 88& 93, of parenchyma composed of very minute cells. The greater part of fig. 89 is atangential section made in the plane of this sarcotesta, with a small projection (k) at itschalazal base, which, I presume, has been part of a funiculus. Near the apex thetissues of the sarcotesta open out to form a wide micropyle, terminating, in this section,in two thin and converging margins (ai a!)*. Within these margins there is a ring (li)of delicate parenchymatous tissue. The opening in its centre obviously shows that thesection has here intersected a cylindrical canal. In fig. 90 we find that the sectionhas not only reached, but partly passed through a thin and delicate prosenchymatousstructure (/), which is apparently the nucular membrane. At the micropyle we stillhave the upper ring (7i), but we now find a similar one (h 1 ) at the lower end of the

* Dr. Dawsox has figured a seed from the Devonian . Beds of New Brunswick, under the name of Cardiocarponcornutum (“The Fossil Plants of the Devonian and Upper Silurian Formations of Canada,” Geological Surveyof Canada , 1871, p. 60, pi. xix. fig. 214), in which the testa “divides into two indexed processes at top.”