332 ORDER CHOANO-FLAGELLATA. 



growing on similar organisms taken direct from the sea at Bognor, Sussex, in Sep- 

 tember 1872. In the examples derived from the last-named locality, the bodies of 

 the animalcules presented a somewhat more rounded outline than those obtained at 

 Manchester, both, however, agreeing in that essential plastic character of the distal 

 region of the pedicle referred to in the foregoing diagnosis. The elegant wineglass- 

 shaped collar in this type attains a greater comparative altitude than has been observed 

 of any other member of this group, its total height not unfrequently equalling twice 

 that of the body. It is at the same time of such extreme tenuity as to be scarcely 

 visible throughout its entire length without recourse to the artificial feeding 

 process described in the introductory remarks upon the group (see p. 326). Such 

 feeding process at once shows up the outline of the hyaline organ with marvellous 

 distinctness, and may be advantageously adopted in all cases where the contour of 

 this structure is difficult to determine. An example of this species has been selected 

 for the illustration given, in the frontispiece, of the ingestive phenomena exhibited 

 by the animalcules of this order, the characteristic collar being somewhat fore- 

 shortened for want of space. 



Monosiga ovata, S. K. PL. II. FIGS. 33-35. 



Body subject to considerable variation in its proportions, normally 

 inversely egg-shaped or obovate, broadest posteriorly, seated upon a rigid 

 pedicle of a length equal or subequal to that of the body. Length of body 

 1-5000" to 1-3500". HAB. Salt water. 



The normal contour of the body of this species closely resembles that of 

 Monosiga gracilis with the proportions reversed, e. g. the broader region being the 

 end next to the pedicle instead of the one forming the free or distal extremity. 

 The pedicle is also proportionally much shorter and rigid throughout its entire 

 length. Representatives of this species frequently occur in which the form of the 

 body differs considerably from the above and typical state, the outline then 

 assumed being considerably more elongate and almost subcylindrical. These 

 elongate zooids, as shown at PI. II. Fig. 35, are sometimes slightly constricted 

 towards the centre, and point probably to a phase preparatory to multiplication by 

 transverse fission. The examples supplying this description were found, in company 

 with Monosiga gracilis, attached to filamentous marine algae collected at Bognor, 

 Sussex, in September 1872. 



Monosiga globosa, S. K. PL. II. FIGS. 4-6. 



Body subspheroidal, attached to a very long, straight, and slender 

 pedicle, whose total length equals four or five times that of the diameter of 

 the body. Dimensions of body 1-4000". HAB. Fresh water. 



The globular contour of the body and, in fully developed zooids, the great 

 proportional length of the supporting pedicle, distinguish this type from any of 

 the various species here described. Propagation by transverse fission, or by the 

 separating off from the anterior extremity of monoflagellate free-swimming gemmules, 

 has been frequently observed ; the zooid so liberated, after passing a short nomadic 

 existence, attaches itself by its posterior extremity, and developing a pedicle and 

 collar, grows to the parent form. Such a separated monadiform zooid, with its 

 primitively attached state, is represented at PI. II. Figs. 5 and 6. 



Monosiga brevipes, S. K. PL. II. FIGS. 7-9. 



Body in its more normal state symmetrically ovate or elliptical, the 

 posterior and anterior extremities being equally and obtusely pointed ; 



