NOTE ON ACALYPT08PORA. 43 



To this species belong some of the earlier species of Surivella, 

 viz. : — 



S. Craticula, Eh. = C. Ehrenbergii, Grim. 

 S. megaloptera, Eh. = C. megaloptera, Grim. 

 S. procera, Eh. = C. procera, Grun. 



C. Perrotettii is distinguished from the above by its distinct 

 longitudinal striae. S. Craticula has already been figured with a 

 distinct central nodule, as a variety, Greg. Mic. Jour. vol. ii., pi. 4, 

 f. G. With careful examination it may always be observed, my 

 figure of Navicula rhyncocephala, var. a and /3. in Vcrh. Wien, 

 zool.-bot. Gesellsch, 1860, t. 4, f. 31, a and c are outer? valves of 

 C. Ehrenbergii. The position of the genus Craticula still requires 

 consideration. 



(Prof. H. L. Smith, in his new Conspectus of the families and 

 genera of Diatomacese deletes the genus Craticula, and unites it with 

 Greville's genus, Stictodesmis. F. K.) 



Figures 23 and 24, although occurring in the original plate, do 

 not represent diatoms, but are two species of Oscillaria. 



NOTE ON ACALYPTOSPORA. 



Acalyptospoxa nervisequia. — In the 10th volume of the " Ann. 

 Sc. Nat.," at page 343, an elaborate description is furnished by 

 Desmazieres of an original structure found on the leaf of the elm, 

 which he regards as a fungus of the Family Coniomycetes, and has 

 named Acalyptospora nervisequia. Berkeley and Broome, in the 

 15th vol. of the " Annals of Natural History," record it as occur- 

 ring at Apethorpe, in Northamptonshire, and remark that it looks 

 like a short obtuse Puccinia, and that it closely resembles a gland. 

 In the " Handbook of British Fungi " it is stated to be inter- 

 mediate between Torulacei and Puccinia^, and to appear to be more 

 closely allied to the former than the latter. A diligent examina- 

 tion of the leaves of the common elm has left me without any 

 doubt that this so-called Fungus is simply a glandular hair. It 

 occurs on every leaf of the common elm in all stages of its growth, 

 from its first expansion to its fall. By macerating the leaf in liquor 

 potassaa, and subsequent washing with water, the tissues are ren- 

 dered transparent, when the object is seen plainly to be a process of 

 the cuticle as much as any other hair on the surface of the leaf, and 

 to have none of the characters of a fungal growth. I am 

 strengthened in this view of the matter by finding on the leaves of 

 Viciafaba, Agrimonia Eupatoria, Sambucus nigra, Anagallis arvensis, 

 and Solanum Dulcamara, similar growths, which are, I presume, 

 regarded without dispute as glandular hairs. C. J. Muller. 



[N.B. — Has our correspondent examined specimens of Acalypto- 

 spora, published by Desmazieres himself, and compared them 

 with his glandular hairs ? — Ed. Grev.~\ 



