834 



SYSTEMATIC HISTORY OF THE INFUSORIA. 



marked genus. Its confusion has arisen from Professor Kiitzing's retention 

 in it of some species of Actinoptychus, and the application of its name 

 by Professor Smith to the latter genus. The disc is not undulated; and 

 the rays, which are often very indistinct, are dotted or interrupted, not 

 continuous lines. From the minute size and close arrangement of the puncta, 

 the frustules, when mounted in Canada balsam, never appear hyaline, but of 

 a brownish or, more frequently, of a beautiful purplish colour. The disc is 

 furnished with an intramarginal pseudo-nodule, which simulates an orifice. 

 Ehrenberg in this, as in other genera of Diatomaceee, distinguished his species 

 solely by the number of their rays ; but we cannot retain them, as we con- 

 sider species foimded on such characters altogether unscientific and erroneous. 

 In general, names once bestowed ought to be retained, even when somewhat 

 inappropriate or defective, because less injury is done by their retention than 

 by burdening the science with synonyms ; still we believe it far better to 

 bestow a new name when, as in this genus, numerous species are reduced to 

 one to which the original names would be inapplicable. 



AcTiNOCYCLUS moniliformis(\\. sp.). — 

 Disc divided into compartments by three 

 or more rays, formed of single series of 

 dots, in a moniliform arrangement. = ^. 

 ^erwarmSjEM. pl.22. f. 9. Fossil. Europe, 

 Africa, and America. This species in- 

 cludes most of Ehrenberg's figures of 

 Actinocycli from the deposits of Greece, 

 Oran, Sicily, and Virginia (pis. 18, 19, 21 

 & 22). We have seen no specimens ; but 

 in Ehrenberg's figures the single monili- 

 form rays difier so greatly from what we 

 find in the following species that we 

 must consider them distinct, although 

 Ehrenberg, in consequence of his regard- 

 ing the number of the rays as the essen- 

 tial character, has mixed up its forms 

 with those of the following species under 

 the same names. 



A. Ehrenherfiil (n. sp.). — Disc gene- 

 rally iridescent, closely punctated, so as 

 under a low power to appear waved, 

 divided by regular equidistant rays 

 formed of interrupted double lines, which 

 terminate at the margm in minute teeth. 

 Common, both recent and fossil. Very 

 fine in Icliaboe guano. Under this name 

 we include all Ehrenberg's species with 

 rays composed of double lines. The rim 

 is narrow, but generally distinct ; pseudo- 

 nodule minute. In fluid, A. Hhrenhergii 

 is colourless ; but when momited in bal- 

 sam, it, like the next species, varies with 

 different shades of brown, green, blue, 

 purple, and red. The rays are formed 

 by lines composed of linear or subidate 

 hyaline spaces, which, more frequently 

 than in A. Rcdfsii, are in pairs, though 

 sometimes alternate ; they are often in- 

 distinct, especially in smaller specimens. 

 This species is best recognized by the 

 waved appearance of its puncta. 



We subjoin a list of forms included in 



A. Ehrenhergii, but by Ehrenberg re- 

 garded as distinct species. Most of them 

 may be obtained from Ichaboe guano. 

 We imite them all in this species : — 

 A. ternariiis, 3 rays ; A. quatejmarius, 4 ; 

 A. quinarius, 5 5 A. hiternarins, 6 ; A. 

 septeyiarius, 7 ; A, octonarius, 8 ; A. no- 

 narius, 9 ; A. denarius, 10 ; A. undena- 

 rius, 11 ; A. bisenariuSf 12 ; A. tt'edena- 

 rius, IS; A. hiseptenarms, 14; A. quin- 

 deuanus, 15 ; A. hioctonarius, 16 ; A. 

 septemdenariiis, 17 ; A. hinonarius, 18 ; 

 A. tioi'emdenarius, 19 ; A. vicenarius, 20 ; 

 A. Lima, 21 : A. Ceres, 22 ; A. Juno, 23 ; 

 A. Jupiter, 24 ; A. 3fars, 25 ; A. Mer- 

 curius, 26 ; A. Pallas, 27 ; A. Saturnus, 

 28; A. Terra, 29; A. Venus, 30; A. 

 Vesta, 31; A. Uranus, 32; A. Achar- 

 neus, 33 ; A. Aldeharan, 34 ; A. Antares, 

 35 ; A. Aquila, 36 ; A. Arcturus, 37 ; A. 

 Bet-el-c/ose, 38 ; A. Canopus, 39 : A. Ca- 

 pella, 40 ; A. Fom-el-hot, 41 ; A. Lyra, 

 42 ; A. Procyon, 43 ; A. Requlus, 44 ; A. 

 Rigl, 45 ; A. Sirius, 46 ; A. Sol, 47 ; A. 

 A. Spica, 48; A. Stella 2)olaris, 49; A. 

 Ninus, 50; A. Alexander, 51; A. Ptole- 

 mcsus, 52; A. Davides, 53; A. Numa, 

 54 ; A. Croesus, 55 ; A. Dux, 56 ; A. Rex, 

 57 ; A. Imperator, 58 ; A. Plutus, 59 ; 

 A. Proserpina, 60 ; A. ahundans, 61 ; A. 

 luxuriosus, 62 ; A. prodigus, 63 ; A. for- 

 tunatus, 64 ; A. locuples, 65 ; A. opiparus, 

 66 ; A. pretiosus, 67 ; A. poly act is, 68 ; 

 A. magmyicus, 69 ; A. Zoroaster, 70 ; A. 

 Solon, 71 ; A. Cleohulus, 72 ; A. Chilo, 

 73 ; A. Pittacvs, 74 ; A. Thales, 75 ; A, 

 Bias, 76 ; A. Periander, 77 ; A. Socrates, 

 78; A. Salomo}!, 79; A. Homerus, 80; 

 A. Hesiodus, 81; A. Tyrtmis, 82; A. 

 Anacreon, 83; A. Sappho, 84; A. Pin- 

 darus, 85 ; A. JEschylus, 86 ; A. Sophocles, 

 87; A. Euripides, 88: A. Virgilius, 89; 

 A. Horafius, 90 : A. Tuhehain, 91 ; A. 



