ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
479 
but to that of the bundles, or, more exactly, to the phloem-region of the 
bundles outside the group of sieve-elements. For the pericycle of the 
stem he proposes the term periphragm. 
In Gymnosperms * the number of cotyledons may vary even within 
the same species. When the number of cotyledons is either two or three, 
then the number of fibrovascular bundles in the root corresponds to the 
number of cotyledons, the xylem-bundles alternating with the phloem- 
bundles. But when the number of cotyledons is more than three the 
number of bundles in the root is only half that of the cotyledons. 
Unlignified Elements in the Xylem.j — Dr. R. Raimann states that 
unlignified thin-walled cells frequently occur near the primary vessels 
in Dicotyledons. They have been observed in JEsculus , Tilia , Aristo- 
lochia Sipho , and Fagus. He proposes for these elements the term 
interxylary cambiform , since they resemble the cambiform in the soft 
bast in their origin, form, and structure. Their function he has at 
present been unable to determine. 
The author further states that the formation of the innermost xylem- 
zone takes place at a later period than that of the outer zones which 
follow the protoxylem. The elements of the protoxvlem do not form a 
closed tissue, but proceed either without any definite order or in radial 
rows out of the inner portion of the protoxylem. It is the elements of 
the innermost xylem-zone immediately surrounding the first vessels, or 
lying in rows between the rays of protoxylem, which remain for a time 
unlignified, forming the interxylary cambiform ; and even if they sub- 
sequently become lignified, their walls remain thin and they retain their 
cambiform character. 
Growth of the Cystoliths of Ficus elastica.f — A careful examina- 
tion of the structures has led Herr C. Giesenhagen to the following con- 
clusions. The stalk of the cystoliths consists of cap-shaped lamellie of 
uniform structure which also cover one another on the sides. Their 
body is composed of homogeneous nearly concentric lamellae of cellulose, 
in and between which there is a deposition of calcium carbonate. The 
radial strings in the body are tubular cavities filled with lime. The 
stratification, both in the stalk and in the body, arises from the succes- 
sive deposition of homogeneous lamellae of cellulose formed from the cell- 
protoplasm. The lamellae of cellulose in their body continue to increase 
considerably in size and density after their deposition, this depending 
nearly or exclusively on the subsequent importation of calcium car- 
bonate. The calcium carbonate is believed by the author to be present, 
both in a state of combination with the cellulose and also free between 
the surfaces of contact. The growth of the cystoliths of Ficus elastica 
appears, therefore, to take place partly by apposition and partly by 
intercalation. 
Recent observations in Anatomy.§ — Dr. D. H. Scott gives a very 
useful resume of the most important publications since the appearance of 
De Bary’s ‘ Comparative Anatomy of Phanerogams and Ferns,’ published 
in 1877, which have added to our knowledge of the anatomy of plants. 
* Comptes Rendus, cx. (1890) pp. 253-4. 
t SB. K. Akad. Wiss. Wien, xcviii. (1889) pp. 40-75 (2 pis.). 
t Flora, lxxiii. (1890) pp. 1-30 (1 pi.). § Ann. of Bot., iv. (1890) pp. 147-61. 
