'68 



STSTEITATIC HISTORY OF THE INFUSORIA. 



fonning a mucous browii stratum on 

 leaves, stones, &c., in sliallow waters. 

 /3, France, (ix. 177, 178- xiii. 21, M. 

 Zinckeni.) In both the primary and in- 

 ternal cells the lateral margins have a 

 beaded appearance, produced by the 

 ends of the lateral costae. 



]M. comtrictum ( Ralfs). — Lateral valves 

 constricted beneath the apex, other^dse 

 as in 31. circulare, SBD. vol. ii. pi. 32. 

 f. 278. = Eiimeridion constriction, KSA. 

 p. 11. Common. Europe. Internal cells 

 as in 31. circulare. We have received 

 very perfect specimens from Mr. Okeden, 

 gathered in Wales. 



Doiihtfid Species. 

 M. ? panduriforme (E.). — Lateral 

 valves constricted near the ends, the 



capitate extremity acuminated. E Infus. 

 pi. 16. f. 3. 1-430". Form that of Gom- 

 phonema acumincdum. 



M. ? ovutmn (Ag.). — Frustules ovate, 

 combined into a celUdose lamina. KSA. 

 p. 10. Sweden. 



M. ? coccocanipyla, EM. pi. 14. f. 79. 

 Berlin. Perhaps a bad tigure of one of 

 the preceding species with internal 

 cells. 



M. marimim (Greg.). — Front view 

 sublinear, with coarse marginal puncta ; 

 valves clavate, with 16 coarse marginal 

 strife in -001", and a blank longitudinal 

 median line. Greg D Clyde, p. 25, pi. 2. 

 f. 41. Marine. Scotland. Frustules 

 two to four together. Certainly not a 

 true species of this genus, as its costte 

 are not pervious. 



Genus ONCOSPHENIA (E.). — Frustules quadrangular, cuneate, not con- 

 catenate ; valves without an umbilicus, and also destitute of lateral apertui^es ; 

 and internal septa equal, but their apices unequal on account of their cuneate 

 and uncinate form. Oncospheniae apj^roach nearest to Podospheniae by the 

 absence of pedicels in the latter, but are peculiar in theii' uncinate form. 

 We are unacquainted with this genus, and ignorant of the reasons which 

 induced Professor Kiitzing to place it among the Meridieae. 



nules 11. Probably a distorted state 



Oncosphenia Carpathica (E.). — La- 

 teral valves cuneate, laxly striated ; one 

 end turgid, rounded, straight, the other 

 attenuated and uncinate. KSA. p. 11. 

 Cai*pathian Mountains. 1-792" : pin- 



of some other species similar to the 

 variety of Diatoma elonycdum figured by 

 Professor Smith in BD. pi. 60. f. 311. 



FAMILY III.— LICMOPHORE^. 



Frustules cuneate, longitudinally bivittate, attached or stipitate, solitary 

 or united in a fan-like manner ; lateral surfaces striated or smooth, but not 

 costate. The fmstules in the front view are cuneate, and have, like the 

 generality of the Diatomaceae, two puncta at each end, the upper ones, how- 

 ever, being most conspicuous. Most frequently two longitudinal sutiu^e-like 

 lines, corresponding to the puncta, are more strongly marked in the Licmo- 

 phoreae than in most other families ; these Kutzing caUs " vittae," and has 

 formed a tribe which from them he calls '^ Diatomeae vittatae." The vittae, 

 however, are not peculiar to this tribe ; for, as Meneghini justly remarks, 

 *^ they are merely the same longitudinal lines which run along the primary 

 surfaces of almost all the Diatomaceae" (MeD. p. 462). Professor Smith 

 describes them as '' modifications in the outline of the valve, which in Podo- 

 sphenia is slightly inflected at its larger extremity, causing, on a front view, 

 the appearance of notches at the spot where the valves unite with the con- 

 necting membrane (central portion) and the foramina exist. The apparent 

 prolongation of this notch to the lower extremity of the frustule is nothing 

 more than the valvular suture which is seen in all the Diatomaceaj " (SBD. 

 vol. i. p. 82). 



The cuneate shape of the frustules in the front view, and the dissimilar 

 ends of the lateral surfaces, distinguish the Licmophorcae from Synedra, the 

 species of which often resemble them in habit. 



