356 ORDER CHOANO-FLAGELLATA. 



cule flask-shaped, flattened, occupying the greater portion of the cavity of 

 the lorica. Height of lorica, without the pedicle, 1-3250", diameter across 

 the centre equal to or exceeding this dimension. 

 Hab. — Salt water, gregarious. 



This species was obtained by the author at St. Heliers, Jersey, in June 1877, 

 clustered in profusion upon various filamentous marine algas under conditions closely 

 parallel with those already related of the more cosmopolitan fresh-water type, 

 Salpingoeca amphoridium. The depressed napiform contour of the lorica of this 

 species isolates it completely from any of the preceding forms. 



Salpingoeca infusionum, S. K. Pl, VI. Figs. 8-16. 



Lorica simply ovate, not everted anteriorly, about one and a half times 

 as long as broad, mounted on a short, straight pedicle, varying from a 

 similar length to twice the length of the lorica ; contained animalcule 

 evenly ovate, occupying from one-half to two-thirds of the cavity of the 

 lorica. Length of lorica, without pedicle, 1-3000" to 1-2500". 



Hab. — Salt water, more especially abundant in vegetable infusions 

 compounded with that medium ; solitary or scattered. 



This species has been obtained by the author in remarkable profusion in 

 connection with those experimental infusions of hay in salt water, productive of 

 Monas {Heteromitd) lens, Difiovionas vorax, Dinovionas tuber ciilata, and Sterro- 

 tnonas formicina, described elsewhere in this volume. Its earliest appearance, 

 and then in a larval and immature form, was first noticed on the fourth day 

 succeeding the setting aside of the hay to macerate, while after that date it con- 

 stituted for some weeks one of the most characteristic and abundant Flagellate 

 types. Through the artificial cultivation of this animalcule in the manner indi- 

 cated, an intimate acquaintance has been made with the more important and 

 highly interesting phases of its life-history. The earliest stage in this life-cycle, 

 in common with that of the majority, or in all probability of all its congeners, is a 

 simple, spherical, spore-like body measuring, in this case, the i-ro,oooth of an inch in 

 diameter ; from this spore there is developed a minute spherical monadiform body 

 bearing a single lash-like flagellum at its apical pole. This monadiform germ speedily 

 assumes a symmetrically ovate shape, and as it pursues its nomadic course through 

 the water might be readily regarded as a typical representative of the genus Monas. 

 Delineations of such earlier migratory developmental phases of this species are given 

 at PI. VI, Figs. 10 and 16, the germ in the former instance, while precisely similar in 

 character, being derived from the process of transverse fission. A little later this vagrant 

 monad, finding a site suited to the requirements of its adult sedentary existence, 

 anchors itself by its posterior extremity, and speedily develops from this region a 

 delicate hair-like pedicle, as shown at Fig. 11. There is as yet no appearance of 

 the characteristic collar, the stalked monad with its single terminal flagellum pre- 

 senting at this epoch of its ontogeny a striking likeness to the sedentary states of the 

 representatives of the genus Oikomonas. While under examination the missing 

 collar gradually makes its appearance as a film-like extension of the anterior 

 substance of the sarcode, while the pedicle, at first short, gradually lengthens and 

 acquires a rigid consistence. The animalcule, however, see Figs. 12 and 13, by no 

 means possesses as yet a sound claim for admission into the present generic group. 

 The external protective sheath or lorica remains to be developed, and pending the 

 production of that structure, the immature monad corresponds to all appearances 

 with the members of the illoricate collar-bearing genus Monosiga. A few brief 

 minutes suffice now, however, for the development of this last-named essential 

 element, and with it the assumption by the animalcule of its complete specific 

 features as described in the introductory diagnosis, and depicted at Fig. 8, 



