ANIMAL NATURE OF DIATOMEjE. 473 



together, not laterally, but the head of one to that of 

 another ; or, in the direction of breadth instead of length, 

 we shall form the most just idea of the only species of 

 this genus, (T. musica). And though I could not study 

 it in the very small fragment with which Kiitzing favoured 

 me, 1 still think I can assert that here also, as well as 

 in the preceding genus, the canals run without interrup- 

 tion along the attachment and the free margin of the 

 diaphragms ; and the apparently capitate vittae are 

 produced either by animal matter, or an open space in 

 those imprisoned canals. 



^Fragments, similar in appearance to what is seen 

 laterally in the margins of the frustules of Terpsinoe, are 

 met with in the fossil flour of Santa Fiore. 



57. Grammatophora. — Bacilli oblongata tabulati, 

 adnati demum semisoluti et isthmo .concatenati ; vittcB 

 longitudinales semper bines, medio interrupt(S,plus minusvts 

 curvatcjB. 



Kiitzing, treating of G. marina, the most common, 

 remai'ks that by calcination the exterior inflexions of the 

 vittse disappear, and that, on this account, a greater 

 distinctness is acquired by the canals, in which these 

 vittse are situated, and which extend uninterruptedly the 

 entire length of the frustules. He represents these 

 canals, by two delicate lines, one external, the other 

 internal, to each vitta, as well in this species as in 

 all the others. I see the external line clearly, and 

 to me it seems to indicate the conjimction of the secon- 

 dary valves with the primary. The striated margins, 

 seen in many species {tropica, gihba, gibherula, serpen- 

 tina) belong to the lateral surfaces; and when, as in 

 G. marina, they are smooth, they turn yellow by the 

 action of heat, like the remainder of these secondary 

 surfaces. On account of this colouring, it is difficult 

 to see the external arches of the vittae, for these lines 

 run at a tangent to them. I suspect that along this 

 suture there runs a fine canal, hollowed out in the 



