844 ORDER TENTACULIFERA-SUCTORIA. 



subsequently with picrocarmine the component protoplasm of the stolon was dis- 

 tinctly coloured, and the limits of its extension upon the surface of the plant to 

 which it was attached distinctly denned. By the same process it was also shown 

 that the nucleus or endoplast was largely developed in this region, assuming a more 

 or less convoluted or ramifying contour, the same modification of this element being 

 noticeable in the larger of the erect trunks. Of such erect branches there were in the 

 example under special notice no less than nine, all of them giving off a greater or 

 less number of secondary branchlets, the central one being specially conspicuous for 

 its thickness, and yet more extensive subdivision. The terminations of all the ultimate 

 ramifications were, for the most part, alike, in so far as they bore a sheaf or coronet 

 of capitate, highly extensile tentacles. This uniformity did not, however, extend to the 

 composition of the axial regions of the main trunks or branches. Certain of these, 

 more especially towards the left-hand region of the colony-stock delineated in the 

 accompanying illustration, exhibited an altogether abnormal zigzag contour, the 

 knee-shaped joints produced by this form of growth being much swollen or cyst- 

 like, and enclosing a distinctly differentiated ovate or subspheroidal body. It was 

 at first supposed that these structures represented either a diseased condition or some 

 parasitic growth. After prolonged examination, the enclosed bodies were, however, 

 observed to make their escape, through rupture of the parent, as single large hypo- 

 trichously ciliated embryos, whose reattachment and development to the parent 

 form was subsequently followed. That these ciliated embryos were produced, as in 

 many other Acinetidse, by a separating off of a fragment of the parental endoplast 

 accompanied by a circumferential portion of its body-substance, was clearly traced 

 in the less developed examples. 



In addition to the nodular excrescences which gave birth to the ciliated embryos, 

 developed mostly towards the basal region of the main trunks, the distal extremities 

 of the ultimate branchlets of the same colony-stock bore in many instances one or 

 two, or it might be a considerable number of laterally attached subspherical or pyri- 

 form capsular bodies, having clearly also a reproductive function. These, as com- 

 pared with the bodies previously described, were relatively of small size, and coin- 

 cide apparently with the structures to which Mr. Levick has assigned properties 

 identical with those of a testis and ovarium. As examined independently, without 

 being cognizant at the time of Mr. Levick's interpretation, as also subsequently, in 

 connection with preserved examples, the author has not been able to arrive at a like 

 result. On the contrary, it would seem to him that these bodies agree as nearly as 

 possible with the exogenously produced germs described by Stein of Arineta 

 mystacina. In the majority of instances these in a like manner possessed a distinct 

 membranous or capsular investment, derived from the pushing outwards and subse- 

 quent hardening of the parent cuticle. Within this capsule the protoplasmic matter 

 separated from the parent had usually contracted into subspheroidal form, showing 

 distinctly a large central nucleus, and in some instances a pulsating contractile 

 vesicle. The front walls of the capsule were evidently of greater tenuity than the 

 remaining area, being often lacerated and broken, leaving the germ freely exposed 

 to the surrounding water, and forming the point of least resistance at which it was 

 normally set free, as evidenced by the fact that many of these capsules remained 

 in an empty state attached to the parent stock, a ragged perforation at their distal 

 end indicating the point of exit of the previously contained body. Although in no 

 instance so far has the author been able to detect the presence of cilia in any form 

 upon these encapsuled germs, it was in several instances observed that short capitate 

 tentacles were developed at various parts of the periphery, as shown at PI. XLVII. 

 Fig. 1 8, so that on being liberated from the parent stock they would be scarcely 

 distinguishable from minute Sphcerophryce. Similar short capitate tentacles, it was 

 likewise noticed, were frequently developed from the bud-like processes of the 

 parent stem previous to their isolation from it by constriction and the formation of 

 a distinct capsule. 



While the further development of the more minute, encapsuled, subterminally 

 developed embryos has not so far been traced, the numerous phases of the larger 



