GENUS SPONGOMONAS. 287 



This genus is founded by Stein * upon the Phalansterium intestinuvi of Cien- 

 kowski, two new and highly characteristic species being added. The desirabihty 

 of separating this type from the monotlagellate Phalansteriuin consociatuin of the 

 last-named writer, had been recognized by the author previous to the publication of 

 Stein's volume, and he had allotted to it in the manuscript of this work, then in the 

 printer's hands, the new generic title of Glcoinouas. The animalcules of Spongomonas 

 correspond essentially in general form and structure with those of Rhipidodemh-on 

 and C/adoinonas, differing only in the character of the common supporting and 

 protective element they collectively excrete, which here takes the form of a gelatinous 

 and more or less granular zoocytium, closely analogous to the common slime-sheath 

 produced by Ophrydimn in the section of the Ciliata. 



Spongomonas intestinalis, Cienk. sp. Pl. XL Figs. 11-14. 



Gelatinous zoocytium or common investing matrix presenting a slender, 

 attenuate, more or less irregularly convolute, thread-like contour ; contained 

 animalcules ovate or subglobose ; flagella similar in size and character, 

 twice the length of the body, protruding for almost their entire length 

 beyond the periphery of the zoocytium ; contractile vesicle single, lateral ; 

 endoplast spherical, subcentral. Length of zooids 1-3000", diameter of 

 thread-like matrix 1-250" to 1-125". 



Hab. — Pond water with AntJiopJiysa and Dinobryon. 



As already stated, this species was primarily included by Cienkowski in his 

 newly established genus, Phalansteriuin.\ The more luxuriant colony-stocks may 

 attain, according to this same authority, a length of as much as three centimetres, 

 forming, under such circumstances, conspicuous objects to the unaided vision. 

 These extensive colonies are produced by continuous fission and sporular subdivision 

 from a single primary individual, accompanied by the secretion or exudation by 

 each monad so produced, of mucus and rejectamenta, towards the building-up of the 

 common gelatinous slime-sheath. The free ingestion of particles of indigo, at 

 apparently no distinct oral aperture, is recorded by Cienkowski. The more explicit 

 details of the form, structure, and mode of subdivision of the monads, supplied by 

 Stein's recent illustrations, are reproduced in the accompanying plate. As there 

 shown, a single zooid, by encystment and segmentation, becomes divided into two, 

 four, or eight sporular elements. 



Spongomonas discus, Stein. Pl. XL Fig. 10. 



Zoocytium discoidal, flattened, gelatinous, and highly granular ; ani- 

 malcules subspheroidal ; flagella two or three times the length of the body. 

 Dimensions 1-3200". Hab. — Fresh water. 



The zoothecium of this species corresponds closely in general form with that of 

 Phalansterium consociatuin^ but does not exhibit the radiating or chambered sub- 

 division of its structure characteristic of that type. Stein is somewhat uncertain 

 which of these two represents the originally described Monas consociata of Fresenius, 

 but the possession by each animalcule of a single flagellum only, is so clearly indicated 

 in the figures given by that authority, as to leave but little doubt as to the correct- 

 ness of Cienkowski's interpretation. Many individuals in the group figured by 

 Stein, here reproduced, have withdrawn their flagella and become separated into 



* 'Infusionsthiere,' Abth. iii., 1878. 



t L. Cienkowski, " Ueber Palmellaceenund einige Flagellaten," ' Archiv f. Mik. Anat.,' Bd. vi. 

 II eft 4, 1870. 



