178 
POPULAR SCIENCE REVIEW. 
BOTANY. 
The Markings of Diatoms. — M. W. Pring has sent us a copy of a paper 
communicated by him to the Societe Beige de Microseopie {Mem. tome vii.), 
containing descriptions of some sections of Diatoms. He obtained his sec- 
tions by mating thin slices of a diatomaceous rock from Nykjobing, in 
Jutland, and his observations relate chiefly to three species, namely, Coscino- 
discus ocvdus-iridis , C. excentricus , and Trinacna regina. In the first and 
third of these he finds that the markings of the valves are true alveoli tra- 
versing the thickness of the outer layer, and terminating against the inner 
layer, which is also perforated by smaller apertures. 
Diongated Spiral Cells in the Leaves of Crinum . — M. Trecul finds that in 
the leaves of some forms of Crinum , especially C. americanum, there are 
large spiral cells with the aspect of spiral vessels, either isolated in the 
parenchyma, or collected into more or less numerous groups. The blade of 
the leaf shows numerous parallel fibrovascular bundles, which become thicker 
in the direction of the thickness of the leaf towards the middle of the blade ; 
between them are vacant spaces formed by the destruction of the parenchyma, 
but interrupted by transverse dissepiments of parenchyma uniting the neigh- 
bouring bundles. The spiral or tracheiform cells described by M. Trecul, 
occur in all parts of the parenchyma of the leaf, but nowhere else in the 
plant. They attain a considerable length, but in this respect vary greatly. 
M. Trecul indicates a range of length of from 0*50 to 13 - 40 millim., in the 
same species. Two of them were observed to be forked. The number 
of spiral cells is much greater in Crinum americanum than in C. taitense ; in 
fact, these two species may be distinguished by the characters furnished by 
these cells. C. africanum comes nearer to the American species. M. Tre- 
cul suggests the question whether the plants presenting the above-mentioned 
anatomical character, which is not shown by the other Crina , are to be 
regarded as having the same specific origin. If they had a common origin 
they have undergone considerable modifications ; the Tahitian plant, espe- 
cially, differing very widely from the American. On the other hand, 
C. taitense being identified by Herbert and Kunth with Rob. Brown’s 
C. pedunculatum , which they regard as the first variety of C. australe, and 
therefore allied to C. nibricaule, exaltatum, and canaliculatum, the three 
other varieties of C. australe , it would be interesting to ascertain if all these 
forms possess the same character of the presence of spiral cells in the 
parenchyma of the leaves. — Comptes Rendus , 4 February and 7 March , 1881. 
GEOLOGY AND PALAEONTOLOGY. 
South African Triassic Reptiles. — In a paper read before the Geological 
Society in April last, and since published in the Quarterly Journal of the 
Society (Yol. xxxvi. p. 414), Prof. Owen described the remains of a reptile 
of his order Anomodontia, from the trias of Graaf Reinet, in South Africa, 
which he considered to show strong resemblances to the lower forms of the 
Mammalia. The fossils consisted of some thoracic vertebrae, with portions 
