518 
PROFESSOR W. C. WILLIAMSON ON THE ORGANIZATION 
surface of the testa, whilst the rest of its substance is made up of others, a, less 
regular in size and form. Within this portion of the seed the layer, fig. 61, a, is seen 
on both sides of the seed, intervening between the sclerenchyma just described, and the 
prosenchymatous folds of the canopy, and which layer obviously corresponds with the 
similar one shown in figs. 65 and 66 of my memoir, Part VIII., and probably also with 
the layer a of fig. 69 of the same memoir. Fig. 63 represents a portion of this tissue 
as seen in fig. 61. It consists of extremely delicate prosenchymatous, barred or spiral 
cells, such as are seen in so many living seeds. When writing my previous description 
of Lagenostoma ovoides, I was not aware of the extreme distinctness of this layer as a 
differentiated portion of the testa. I presume it may be regarded as the endotesta, 
though the exact identification of these subdivisions of the testa in recent and fossil 
Gymnospermic seeds is necessarily difficult and somewhat uncertain. 
Fig. 64 is a vertical section through the shorter axis of Ccirdiocarpon anomalum. The 
memoir, Part VIII., fig. 119, showed the aspects of this seed when cut through in 
the plane of its maximum diameter. The present figure exhibits the appearance of 
the same seed when intersected in the plane vertical to that of the above figure. We 
find the exotesta at a —the delicate prosenchymatous endotesta at b ; the prolonged 
micropylar canal at d ; the Chalaza, with the prolonged funiculus at i, i', and what in 
the previous memoir I have designated the perispermic membrane at g. 
At a very early stage of my researches my attention was arrested by the circum¬ 
stance that the fragments of wood and bark found in the calcareous modules, both of 
the Oldham and Halifax districts, were frequently drilled through by numerous circular 
canals. It soon became obvious to me that these passages had been produced by 
Zylophagous animals. Similar borings have been described by Dr. Dawson in his 
Triassic Dadoxylons from Prince Edward Island,* and still later by M. Charles 
Brongniart from some of the French carboniferous strata.! 
Fig. 65 represents a specimen of some prosenchymatous bark, which has been per¬ 
forated by animals of diameters varying from about ‘0066 to •0011. The creatures 
have not merely pushed the prosenchymatous cells aside, but have eaten their way 
through them. I was long perplexed by the occurrence of many specimens like 
that represented in fig. 66. I found numerous groups of small, round, or oval 
spore-like bodies, like those seen at a, b. They usually occurred in clusters, those 
composing each cluster being generally of very uniform size. Under high powers 
they exhibited a somewhat granulated structure. At length the truth dawned upon 
me that these were the copros of vegetable feeders—probably the same as those that 
had drilled the round holes in fig. 66. I noticed that these objects were invariably 
lodged in cavities from which the tissues had been extracted. Thus in both, 66 a and b, 
the cellular parenchymas, a' and b', have been eaten away, and the copros, a and b, 
* 1 Report on the Geological Structure and Mineral Resources of Prince Edward Island,’ bj .T. W. 
Dawson, LL.D., assisted by B. T. Harrington, B.A., 1871, plate 3, fig. 27. 
-j- ‘ Annales do la Societe Entomologique de France.’ Seance du 12 Avril,1876, 
