132 Scott and Mas ten . — The Structure of Trigonocarpus. 
Stopes (’04) : Miss M. C. Stopes, Beitrage zur Kenntnis d. Fortpflanzungsorgane der Cycadeen. 
Flora, Bd. IV. 
(’05) : On the Double Nature of the Cycadean Integument. Ann. Bot., vol. xix. 
Wild (’00) : G. Wild, On new and interesting features in Trigonocarpon olivaeforme. Trans. 
Manchester Geol. Soc., Part xv, vol. xxvi. 
Williamson (’77): W. C. Williamson, On the Organization of the Fossil Plants of the Coal 
Measures. Part viii. Phil. Trans. Roy. Soc., vol. clxvii. 
EXPLANATION OF PLATES XI-XIV. 
Illustrating Messrs. Scott and Maslen’s paper on Trigonocarpus. 
PLATE XI. 
Fig. 1. First of a series of transverse sections across a seed of Trigonocarpus Parkinsoni , This 
section is the lowest of the series and is cut across the base of the seed some considerable distance 
below the chalaza. Slide 627 (S) 1 . Magnification between 6 and 7 times. 
b. triangular space containing main supply bundle of the seed and surrounded by a zone of 
dark-coloured sclerotic tissue continuous with the sclerotesta ; /. limiting layers of sarcotesta. 
Fig. 2. The central portion of the same slide as shown in Fig. 1 more highly magnified. 
Magnification 100. 
s. t. sclerotic tissue continuous with sclerotesta ; b. main supply bundle of seed ; s. triangular space 
enclosing bundle. 
Fig. 3. Transverse section of same specimen at a higher level across the base of the seed. Inner 
part of sarcotesta preserved with about six sarcotestal bundles. Slide 626 (S). Magnification 6. 
b. main supply bundle of seed ; s.t. sclerotestal core surrounding bundle ; s.b. six sarcotestal 
bundles embedded in compact sarcotesta ; l. limiting layers of the sarcotesta. 
Fig. 4. Central part of same more highly magnified, s.t. part of core of sclerotesta ; b. main 
supply bundle of seed ; a. cells surrounding bundle. 
Fig. 5. Transverse section across the central part of the body of the same seed as shown in 
Figs. 1-4, showing general form and three principal and nine secondary sclerotestal ridges. Slide 
325 (S). Magnification 6. 
m. megaspore membrane (contracted) ; n. nucellus ; s'.t'. one of the principal ridges of the 
sclerotesta ; s.t. one of the secondary ridges of the sclerotesta ; sa. sarcotesta ; l. limiting layers of 
sarcotesta ; s.b. position of one of the sarcotestal bundles (shown more magnified in PI. XIV, 
Fig. 28). 
Fig. 6. Transverse section across the upper part of the body of the seed probably passing across 
the pollen-chamber. The central cavity is beginning to assume a triangular form and the sclerotesta 
shows the differentiation into two zones. Slide 1470 (W). Magnification 6. 
p. wall of pollen-chamber ; s.t. inner zone of sclerotesta ; s'.t'. outer zone of sclerotesta ; sa. 
sarcotesta ; /. limiting layers. 
Fig. 7. Transverse section near base of micropyle showing triangular form of micropyle and 
‘wing’ of sarcotesta. Slide Q. 585 (M). Magnification 6£. 
t. m. triangular micropyle ; s.t. sclerotesta of micropylar beak ; sa. sarcotesta ; l. limiting layers 
of sarcotesta. 
Fig. 8. Transverse section across micropylar beak at a higher level than Fig. 7. From same 
specimen as Fig. 7. Slide 487 (S). Magnification 6. 
t.m. triangular micropyle ; s.t. sclerotesta of micropylar beak ; sa. sarcotesta ; l. limiting 
layers of sarcotesta. 
1 [The reference letters after the number of the slide refer to the collections to which the slides 
belong. 0 = in the collection of Prof. Oliver, F.R.S. M = in the Manchester Museum. B = the 
Binney Collection at Cambridge University. S = Dr. Scott’s Collection. W = Williamson Collection 
at the Natural History Museum.] 
