OF TUE MELOSIRE-E. 



817 



tral ridge and crossed by fainter lines at 

 each end. Professor Kiitzing describes 

 it as of a golden coloiu* wlien dry ; oiu* 

 specimens are gi-eenish. Sporangial frus- 

 tules larger, concatenated, originating 

 from tlie temiinal frustule only. Ac- 

 cording to Kiitzing, the friistules in this 

 species are ternately, and in the next bi- 

 nately conjoined ; this does not coincide 

 with our experience. The only species 

 likely to be confounded \v4th it is the 

 following. 



M. salina (K.). — Smaller; valves of 

 the binate frustules achromatic, smooth -, 

 keels very fine. KB. p. 52, pi. 3. f. 4. = 

 GalUonella nwiunuloides, El. p. 167. 

 /3. concatenata, more distinctly stipitate ; 

 frustules concatenated by a distinct isth- 

 mus, KB. pi. 3. f. 5. Brackish waters. 

 Europe. This species difters from 31. 

 nmnmuloides by its less conspicuous 

 keels and more distinct stipes. Pro- 

 fessor Smith imites them ; for " forms 

 aberrant in these respects are so fre- 

 quently intermixed with the ordinarj^ 

 frustules that " he ^' cannot regard such 

 pecidiarities as of specific importance." 



M. Westii (S.). — Frustules sub- 

 globidar ; valves conical, with truncated 

 apices and a sutural and median sili- 

 cious ring. SBD. ii. p. 59, pi. 52. f. 333. 

 Stomach of Pecten, coast of Sussex. 

 This species seems distinct in the 

 strongly marked central and lateral 

 ridges. 



2 * Joints hinately or ternately conjoined ; 

 valves with rounded ends, neither cari- 

 nated nor denticulated, GallioneUa. 



M. moniliformis (Mlill., Ag,). — Joints 

 rather longer than broad, finely punc- 

 tated, binately conjoined, with rounded 

 ends. KB. pi. 3, f. 2. =31. Borreri, Gr. ; 

 GallioneUa 7nonilifor7nis, E. Common in 

 brackish and marine waters. Diam. 

 1-860". Kutzing describes this species 

 as having ternately conjoined frustules 

 concatenated by a distinct isthmus. 

 Sporangial frustules larger, concatenated, 

 and, according to Professor Smith, origi- 

 nating only in the terminal frustides of 

 the filament, (v. 71.) 



M. lineata (Dillw^Ti, Ag.). — Joints 

 cylindrical, smooth, binately conjoined, 

 with rounded ends ; pairs closely adnate. 

 KB. p. 53, pi. 3. f. 1= GallioneUa lineata, 

 E. Marine. Europe. A single filament 

 sometimes consists of from 1200 to 4000 

 frustules, forming a chain 2 or 3 inches 

 in length. Length of ioint 1-1400" to 

 1-430"? " ^ 



^i, duhia (Kiitz,). — Smaller; articu- 



lations depressed, spheroidal, smootli. 

 KB. p. 53, pi. 3. f. 6, Marine, neai* Cux- 

 haven. Diam. 1-1200". 



M. Jurr/ensii (Ag.). — Slender; joints 

 smooth, elongated, with two slight con- 



[ strictions beneath the silicious sheath ; 



j junction-surfaces convex, hemispherical, 



j closely concatenate. KB. p. 54, pi. 2. 



I f. 15. = i)/. suhjlexilis, SBD. pi. 51, f. 331. 

 Brackisli waters. Em*ope. Diam. 1-800" 

 to 1-1200". There is only one sutural 

 line, having usually on each side of it a 

 slight constriction. As in 31. varians, 

 the inflated joints are interstitial, and 

 closely united to the parent frustule. 

 M. Jurgensii differs from 31. suhjlexilis 

 in its marine habitat and more closely 

 connected joints ; but we find it difficidt 

 always to discriminate them. The joints 

 are more miiform than in 31. varians, 

 usually longer in proportion to theii* 

 breadth, and with more-rounded ends, 

 especially in the new-formed valves. 

 (V.63.) 



M. suhJlexdis(K.). — F'rustules cylindri- 

 cal, smooth, binately conjoined, yoimger 

 ones elongated, adult shorter, depressed 

 ends slio-htlv convex ; pairs united bv a 

 short is'thnius. ICB. p. 53, pi. 2. f. 13. 

 Rividets. Em-ope. Diam. 1-560". Re- 

 sembles 31. varians with the binate frus- 

 tules connected by short interstitial pro- 

 cesses. Professor Smith thinks this 

 species identical with Conferva lineata, 

 Dill. Sporangial frustules as in 31. mo- 

 niliformis. 



M. varians (Ag.). — Joints cylindrical, 

 irregidarly binately conjoined; ends flat 

 with rounded angles, closely adnate; 

 disc with verv delicate, radiating mar- 

 ginal stride. SBD. pi. 51. f. 332= Gallio- 

 neUa varians, Ehr. Fresh water ; every- 

 where common, ^.(pqualis, all the joints 

 quadrate ; 31. cequalis, Ag. This species 

 varies much, both in size and length of 

 joints; the margins of the filament are 

 more or less interrupted ; but the ge- 

 minate arrangement of the frustules is 

 often very obscure ; the valves, although, 

 as in most other Diatoms, they are really 

 dotted, appear smooth unless magnified. 

 The sporangial cells are inflated and in- 

 terstitial; Professor Smith describes 

 them as at first globular, but afterwards 

 dividing (as in the preceding species) and 

 becoming cylindrical, whilst liabenhorst 

 gives a completely different account of 

 them. The latter says " that on forma- 

 tion of the inflated cell, its gi-anules, at 

 first irregularly formed, become oblongo- 

 ovate. Motion takes place as in ordinary 

 zoospores. The cell opens, the granules 

 3g 



