266 SELECTED NOTES FROM 



Fig. 2. — One of the "Peridia" enlarged, viewed from above, x 25. 



3. — Portion of the celluhir structure of "ectoderm" of leaf, 

 X 100. 



4. — Another portion, showing supposed "spermatium" (male 

 organ of fructification), x 100. 



5. — Sphseraphides exposed by accidental removal of part of the 

 outer skin (" ectoderm "), x 100. 



6. — Diagrammatic section of SjyJueria. 



7. — Diagrammatic section of ^cidhnn. The same letters indi- 

 cate corresponding parts of each. 

 8 p. , spermatium. 



Stg., sterigmata, pollen in the higher plants. 

 Fer., peridiurn ; receptacle for sp., spores — seeds in the 

 higher plants — which are contained in little transparent 

 cases, called asci, as., in the figures. 



>3 



J) 



jj 



3J 



,, 8. — Portion of leaf of Onosma tauriciim, probably the under- 

 surface, x 25. 



0. — Part of one of the large hairs, more magnified to show the 

 roughness of the surface, x 100. 



10. — Base of a hair, showing the cluster of cells forming the 

 support, and sectional view of the jjrominences, x 100. 



>; 



3J 



JJ 



5J 



)J 



11. — One of the smaller spines of Amphidotus cordatus; the 

 smaller connected figures at the side are to show outlines of 

 sections at their respective places. 



12. — Base of a larger spine, showing the powerful ridge for 

 attachment of levator and depressor muscles, and the part of 

 its broken extremity, whence the enlarged view (Fig. 13) is 

 obtained. 



14. — Diagrammatic section of part of a spine. 



,, 15. — Calcareous plates from skin of Holofhuria. 



a.a.a.a. — Plates in form of a calcified network, supposed 

 to be situated at and parallel with the surface. 

 h.b. — Arched pieces supposed to be articulated by their 

 extremities with processes arising from the centre of the 

 former. From the middle of the arch, on its convex border, 

 arise two short colinnns, united at their free extremities, 

 where they bear two or three dentations. These double 

 colunnis are supposed to represent the anchors of Synapta, 

 and to be for the same purpose — viz., to enable their posses- 

 sor to hold on more firmly to the sea-bottom. 



Drawn by Tufien West. 



Plate XIX. 

 Fig. 1. — Represents the male Cheijletus eruditus, x 50. 

 ,, 2. — Represents the female ditto, x 50. 



