GENUS STYL OBR YON. 279 



a conspicuous position, and might with ease be identified with the looked-for 

 "collar." A reference to the plate illustrative of this type, in which at Figs. 27 

 and 28 are reproduced out of Stein's work two colony-stocks with their reputed 

 collars, and at Figs. 17-23 delineations of aggregated colonies and isolated zooids 

 in various aspects and conditions, as observed by the author, will at once make 

 clear the ground of such identification. In Figs. 19 and 20 especially, where a 

 front and profile view is given of an animalcule under the high magnifying power 

 of 1500 diameters, it will be at once seen that the more attenuated sarcode sub- 

 stance entering into the composition of the anterior lip-like prominence necessarily 

 presents in juxtaposition to the denser mass of the body proper the appearance of 

 an independent hyaline organ. Such an aspect and correlated type of structure is 

 by no means, however, restricted to the type now being considered, but is more or 

 less prominent throughout all the members of both the present family and that of 

 the preceding one of the Dendromonadidce. The presence of the shorter of the two 

 flagella, overlooked by Stein, is not easy to detect in living examples, but is shown 

 distinctly in specimens killed with osmic acid. 



As indicated in the figures given by the authority just quoted, the compound 

 polythecium, built up of the more or less numerous separate and independent loricae, 

 exhibit a very considerable range of variation. Thus sometimes, as in Figs. 18 and 

 27, the loricae may be so closely approximated that the pedicles as independent 

 elements are almost completely subordinated, while in other cases, as at Figs. 17 

 and 28, these structures may equal or considerably exceed the length of the loricae. 

 The exceptionally long-stalked variety illustrated in the first of these two figures, 

 was obtained by the author from a pond in the neighbourhood of Prestwich, Man- 

 chester, in November 1875 ; more ordinary examples of this species have been 

 collected both in the vicinity of London and at St. Heliers, Jersey. An excep- 

 tionally fine specimen preserved with osmic acid, and obtained from one of the 

 water-fowl ponds in the Zoological Gardens, Regent's Park, has been recently placed 

 at the author's disposal by Mr. L. Dreyfus. The zoothecium embraces over one 

 hundred loricae, united by short pedicles as in the example figured at PI. XXIII. 

 Fig. 27. Among this group furthermore were included several loricae in which the 

 bodies of the animalcules had become divided up into sporular elements, these in 

 some instances being entirely enclosed within and in others partly discharged from 

 the apertures of the loricae. Examples of such spore-bearing loricae are represented 

 at Figs. 24 and 25, as also isolated spores more highly magnified at Fig. 26. 



Stylobryon (Poteriodendrori) petiolatum, considered with the aid of the hitherto 

 unrecorded structural details here submitted, must undoubtedly be regarded as a 

 compound modification only of the form Bicosceca lacustris, previously described. 

 It is a noteworthy circumstance, in this connection, that Stein himself, while 

 advocating so distinct an interpretation of its structural features, admits it in his 

 classification scheme to the same- family group as Bicosceca, while Biitschli * figures 

 and describes it without indicating the presence of a second flagellum as a 

 probable compound example only of the last-named species. 



While going to press, October 1880, the author has received luxuriant colony- 

 stocks of this species from the neighbourhood of Dundee, through Mr. John Hood, 

 in company with an interesting Melicertan, apparently new to science. 



Stylobryon epistyloides, S. K. PL. XVIII. FIG. 32. 



Loricae evenly ovate, about twice as long as broad, attached by short 

 secondary peduncles, in social clusters of from two or three to six or 

 eight zooids, to the summit of a simple, straight, rigid pedicle ; anterior 

 extremity of animalcules prolonged into a lip-like prominence, projecting 

 slightly beyond the orifice of the loricae. Length of loricae 1-2000", of 

 contained animalcules 1-3250". HAB. Fresh water. 



* " Beitrage zur Kenntniss der Flagellaten," ' Zeit. Wiss. Zool.,' Bd. xxx., 1878. 



