94 
Dr. Beale, on Sarcolemma. 
4i acute angles, aiid concave sides, the angles thickened and 
bearing a claw-like process ; granules or cellulation radiating, 
the cellules becoming larger as they approach the margin. 
Distance between the angles '0050"'. (Fig. 12.) 
Hab. Barbadoes deposit, Cambridge estate; C. Johnson, 
Esq. 
All the valves I have seen are 4-anglecl, and sharply acute ; 
colour pale; cellules near the margin 7 in '001''. The 
margin itself slender, with a row of darker cellules. This is 
a most distinct species. 
Triceratium oculatum, n. sp., Grev. — Small ; valve with 4 
angles and nearly straight sides, the angles much rounded, 
with large transversely oval pseudo-nodules; surface filled 
with minute, radiating puncta. Distance between the angles 
•0018". (Fig. 20.) 
Hab. Barbadoes deposit, Cambridge estate ; very rare ; 
in slides communicated by C. Johnson, Esq. 
Whether this be the normal condition of the species it is 
impossible at the present moment to say, as only a single 
specimen has been observed. 
On the Structure and Formation of the Sarcolemma of 
Striped Muscle, and of the exact relation of the 
Nerves, Vessels, and Air-tubes (m the case of Insects) 
to the Contractile Tissue of Muscle. By Lionel S. 
Beale, M.B., F.R.S., Fellow of the Royal College of 
Physicians ; Professor of Physiology and of General and 
Morbid Anatomy in King^s College, London ; Physician 
to King^s College Hospital. 
(Read June 8Ui, 1864.) 
(Plates XIV & XV.) 
The apparently structureless and perfectly transparent 
membranous tube called the sarcolemma contains the con- 
tractile material of striped or voluntary muscle, which may be 
split up in a longitudinal direction to form " filarillge,^^ and in 
a transverse direction to form " discs.^' The precise relation 
of the sarcolemma to the contractile material of the muscle 
on the one hand, and to the nerve-fibres and capillaries on 
the other, and the mode of its formation, have long been 
questions of the utmost interest to anatomists and physio- 
