Walton, L. B.

The Ohio Journal of Science

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Jan., 1905.] Actinolophus minutus. 261ACTINOLOPHUS MINUTUS A NEW HELIOZOAN, WITH AREVIEW OF THE SPECIES ENUMERATED INTHE GENUS.*L. B. WALTON.While examining late in October some sediment in a jar con-taining Hydra fusca collected September 17, 1904, in the Koko-sing River, attention was attracted by a small stalked form ofheliozoan like appearance. This (Fig. 1), a single example ofwhich was observed, on more carefulstudy proved referable to the genusActinolophus (Heliozoa) the representa-tives of which are not met with fre-quently, none to the knowledge of^thepresent writer having thus far been notedin America.Although there is considerable uncer-tainty as to the exact relation of the spe-cies constituting the group to the otherProtozoa, the characteristics of the formin question appear to merit record, dif-fering as it does from A. capitatus Penardthrough the absence of knobbed pseu-dopodia as well as in its much smallersize, and from A. pedatus (Zach.) by thespherical form of the body which is ovoidin the latter and much larger than thebody of A. minutus.Schulze, 1874, formed the genusActinolophus for the reception of A.pedunculatus a marine form from theBaltic Sea described by him. Penard1890, described A. capitatus from a singleindividual suggesting its close relation-ship with the tentacliferous infusoria(Suctoria). Zacharias, 1893, in a briefdescription, called attention to a newHeliozoan, Actinosphceridium pedatuswhich Schaudinn, 1896, in his monographof the Heliozoa, placed provisionally inthe genus Actinolophus, recognizing forthat genus three species, two of which were of doubtful value. Pen-ard, 1904, in his valuable monograph of the fresh water Heliozoa,mentions both A. capitatus and A. pedatus among forms whoseposition is doubtful, suggesting possible affinities with Tokophryaand Nuclearia, noting at the same time the desirability for further* Read before the Ohio State Academy of Science. Nov. 26, 1904.Fig. 1. Actinolophus minutusn. sp. (x 1000), psd.—pseudopo-dia, c. v.—contractile vesicle (?),p.—pedicle, g. e.— gelatinousenvelope, n.—nucleus.162 The Ohio Naturalist. [Vol. V, No. 3,study. Until a better knowledge is obtained of their affinitieshowever, it seems advisable to consider them under the genusActinolophus.The following summarizes our present knowledge of the groupand indicates the position of A. minutus in respect to the otherspecies.Genus Actinolophus, Schulze.1874 Actinolophus, F. E. Schulze, Arch. mikr. Anat. v. 10, p. 392.?1893 Actinosphceridium, O. Zacharias, Forschungber Plon, v. 1, p. 15.1896 Actinolophus, Schaudinn, Das Tierreich, Heliozoa, Berlin.Body spherical or oval, provided with a pedicle the length ofwhich is usually much greater than the diameter of the body.Body generally (always?) provided with a gelatinous envelopethrough which the fine pseudopodia are extended. Nucleusexcentric. contractile vacuole (?).The following table will serve to separate the forms:A1 Pseudopodia not knobbed at the extremity.B1 Pedicle 3—4/x in diameter, marine forms, A. pedunculatusB2 Pedicle not more than 2//, in diameter, fresh water forms,C1 Body ovoid, diameter 18/x, length 23/*, A. pedatusC2 Body spherical, diameter 12//. A. minutusA1 Pseudopodia knobbed at extremity, diameter 30//., freshwater forms, A. capitatus1. A. pedunculatus, Schulze, 1874 A. p. F. E. Schulze, Arch. mikr.Anat., v. 10 p. 392 f. 1-9. 1896 Schaudinn, Das Tierreich, Heliozoa,Berlin, p. 11.Length of body, up to 30//., length of pedicle up to 100//,, diam-eter of pedicle 3-4//..Marine, Baltic Sea.2. A. pedatus, (Zach.) 1893 Actinosphceridium pedatum, Zacharias,Forschungber. Biol. Stat. Plon., v. 1 p. 15, f. 9a, 9b. 1896 ? Actinolophuspedatus, Schaudinn, Das Tierreich, Heliozoa, Berlin, p. 11. 1904 ?ActinosphcBridium pedatum, (? Nuclearia caulescens), (? Tokophrya), Pen-ard, Les Heliozoaires d'eau douce, p. 318.Length of body 23//., diameter 18//, length of pedicle 11-30//.,diameter 1.7//.. Body provided with a thick gelatinous envelopefrom which extends extremely fine and rather short pseudopodia.Nucleus oval, situated in the inferior part of the body. Con-tractile vesicle not known. Color pale yellow, individuals occa-sionally agglomerated by their bodies into colonies.Fresh water, Germany.Zacharias placed A. pedatus in a new genus Actinosphgeridiumon the basis that it differed from Actinolophus by possessing, inthe encysted condition, plates covering the body. Schaudinnenumerates it among the doubtful species of Actinolophus, whilePenard refers it back to Actinosphseridium, at the same time call-ing attention to its remarkable similarity to Nuclearia and toTokophrya.Jan., 1905.] Actinolophus minutus. 2633. A. minuuib, n. sp.Body spherical, diameter 12/x including gelatinous envelopeapproximately I/A thick. Length of pedicle 70/A, diameter 1/x.Extremely fine short pseudopodia of about 2/x in length extendbeyond the envelope on all sides. Nucleus suboval situated inthe inferior part of the body. Contractile vesicle (?). Base ofpedicle (in the form studied) imbedded in a gelatinous mass10-12/x in extent containing small algse, etc.Gambier, Ohio, U. S. A.A single specimen observed Oct. 29, 1904, in sediment froman aquarium jar containing Hydra fusca, the entire contents ofthe jar having been collected Sept. 13. 1904, in the KokosingRiver at Gambier and subsequently covered with a glass plate forthe purpose of preventing too rapid evaporation. The form wasunder observation at intervals during a period of four hours.4. A. capitatus, Penard. 1890 A. c. Penard, Jahrb. nassau. Ver. v.43 p. 16 t. If. 11. 1896 A. c. Schaudinn, Das Tierreich, Heliozoa, Berlin,p. 12. 1901 A. p. Sand. Etude monographique stir le groupe des Infu-sorres tentaculiferes, Ann. Soc. Beige de Microscopic 1904 A. c. Penard,Les Heliozoaires d'eau douce, Geneva, p. 316.Diameter 30/A, length of pedicle 90//.. Nucleus (?), Contractilevesicle, Pseudopodia few in number, knobbed.In fresh water, Germany.Penard described this species in 1890 from a single individualreferring it to the genus Actinolophus although noting its closerelationship with the tentaculiferous infusoria. Sand, 1901, inhis study of that group came to the conclusion that A. capitatuswas nearer related to the Heliozoa than to the Suctoria for thefollowing reasons, (a) the pedicle resembles that of Clathrulinaelegans, (b) the pedicle does not penetrate into the gelatinousenvelope as in Tokophrya limbata one of the Suctoria, (c) thenucleus is excentric, (d) the species closely resembles A. pedun-culatus. Penard, 1904, in his paper on the fresh water Heliozoa,after having examined several more specimens which he remarksare exceedingly rare, insisted on the suctorian nature of the form,maintaining that the points raised by Sand have little value.Penard at the same time suggests the desirability for a furtherstudy of the form. Consequently it seems advisable at presentto allow it to remain in the genus Actinolophus.BIBLIOGRAPHY.SCHULZE, F. E. 1874, Rhizopodienstudien, Arch. f. mikr. Anat., v. 10.PENARD, EUGENE, 1890, Ueber einige neue oder wenig bekannte Pro-tozoen, Jahrb. Nassau Ver. f. Naturk. Jahrg. 43.ZACHARIAS, O. 1893, Forschungsber. Biol. Stat. Plon, v. 1.SCHAUDINN, FRITZ, 1896, Das Tierreich, Heliozoa, Berlin.SAND, Rene. 1901, Etude monographique sur le groupe des Infusoirestentaculiferes. Ann. de la Soc. Beige de MicroscopicPENARD, EUGENE. 1904. Les Heliozoaires d'eau douce. Geneva.Kenyon College, Gambier, Ohio.

Actinolophus Minutus a New Heliozoan, with a Review of the Species Enumerated in the Genus

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Actinolophus Minutus a New Heliozoan, with a Review of the Species Enumerated in the Genus

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