766 



SYSTEMATIC HISTOET OF THE INFUSORIA. 



11. tnojus (S.). — Valves linear, arcuate, 

 witli rounded, subcapitate extremities : 

 stripe 27 in -001". SBD. vol. ii. p. 14, 

 pi. 33. f. 286. Britain. Dillers little 

 from H. gracile, save in its greater size 

 and elevated dorsum, and is probably a 

 sporangial form of it or some other 

 species, S. It scarcely differs from some 

 of Ehrenberg's figures of H. paralleltan, 

 except in its more inflated ends. 



H. exiguiwi (Breb.). — Valves slender, 

 narrow-linear, arcuate, with obtuse re- 

 cm'ved extremities, and 42 very delicate 

 striae in -001". KSA. p. 8. Eunotia 

 (jraciUs, SBD. vol. i. p. 16, pi. 30. f. 249. 

 Europe. 



H. Veneris (K.). — Valves smooth, 

 plano-convex, vdth acute apices. KB. 

 p. 39, t. 30. f. 7. Eunotia IcBvis, EM. 

 pi. 39. 3. f. 41. Trinidad. 



2 * Valves with crenate or toothed 

 dorsum. 



H. bidens (E.). — Valves with plane or 

 slightly concave venter, biundulated 

 dorsum, and dilated, truncate apices. 

 EA. p. 9, & M, several figm-es. = Eu- 

 notia bidens, EA. p. 125, & M. pi. 2. 1. 

 f. 2 ; Eunotia bigibba, KSA. p. 6 ? Eu- 

 rope, Asia, and America. The dorsum 

 has a notch-like depression near each 

 end. 



H. Guiancnse (E.). — Valves dilated at 

 the middle, with two dorsal undulations, 

 and tapering, slightlv reflexed ends. 

 EA. p. 129, t. 2. l.'f. 4. Cayenne, 

 (xii. 54.) 



H. Papilio (E.). — Valves subquadrate, 

 with a much dilated bicrenate dorsum, 

 constricted near the obtuse apices. EA. 

 p. 129, t. 2. 1. f. 2. Asia and America, 

 (xn. 45, 49-62.) 



H. undulatum (S.). — Valves linear, 

 with gibbous venter, three or more 

 slight dorsal midulations, and obtuse, 

 somewhat recurved apices. SBD. vol. 

 ii. p. 12, pi. 33. f. 281. Europe. Distin- 

 guished fi'om the other British species 

 by its gibbous venter. 



H. denticulatum (Breb.). — Valves very 

 naiTow, arcuate, with denticulated dor- 

 sum and slightly recurved apices. 

 KSA. p. 10. France. Dorsum mar- 



gined with minute teeth, constricted 

 near the rounded apices. 



H. triodon (Perty). — Valves smooth, 

 ■udth concave venter, convex triundu- 

 lated dorsum, and broadl}^ rounded ends. 

 Perty, Inf p. 198, t. 17. f. 5. Switzer- 

 land. Very like Eunotia diodon j but 

 striie have never been observed. Frus- 

 tules mostly clear as crvstal. Pertv. 



H. ternarium, EM. pi. 34. 6 a.' f. 5. 

 Florida. Valves arcuate, with slightly 

 concave venter, three dorsal undulations, 

 and obtuse apices. 



H. quaternarium (E.). — Valves nar- 

 row, very finely striated ; dorsum a little 

 convex, deeply fom'-toothed ; venter 

 slightly concave, with attenuated and 

 recurved apices. ERBA. 1852, p. 235. 

 California. Joints of the chain 4 to 7, 

 three times as broad as long, E. 



H. quinarium (E.). — Valves as in H. 

 quaternarium, but with five dorsal teeth. 

 E. /. c. p. 535. California, Asia, and 

 Africa. Joints of the chain 14, five times 

 as broad as long. The frustules of H. 

 quaternarium and II. quinarium are very 

 similar to those of Eunotia quaternaria 

 and E. quinaria, but are distinguished 

 by forming chains and by the attenuated 

 ends of the valves, E. 



Douhtfid Species. 



H. carinatum, EM. pi. 34. 6 a. f. 6. 

 Florida. Frustiiles rectangular, smooth, 

 with a transverse median band. 



H. ? marinum (S.). — Filaments tena- 

 cious ; valves costate, slightly and regu- 

 larlv arcuate, mth acute apices ; costse 

 10 in -001". S Aimals, Jan. 1857, p. 10, 

 pi. 2. f. 14. Marine. France. Distin- 

 guished by its marine habitat and costate 

 valves. 



Species known to us only by name : 

 probably several of them are merely 

 concatenated states of Eunotia and 

 Epithemia. 

 H. AustralicE, E., Australia ; H. Ca- 



melus, E., Asia ; H. Textrictda, E., Asia ; 



K.Zebra,^., Asia; H. venirale, E.,Asia; 



H. amphioxys, E., Asia ; H. umbilicatum, 



E., Asia ; H. JEthiopicuin, E., Asia j H. 



Falklandii, E.; Falkland Islands. 



FAMILY II.— MERIDIEM. 



Frustules prismatic, attenuated at the base, attached, at least when young, 

 to a gelatinous cushion; in front view cuneate, in lateral view clavate or 

 obovate, with pervious transverse costae or striae. Ktitzing places the MeridieaB 



between the Eunotieae and Fragilariece 



and Meneghini would unite them 



