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Stem branching, bearing at intervals groups of sub-verticillate zooecia, arranged on a 

 series of short internodes given off on each side of a nodal region in the stem. Each of the 

 lateral internodes bears a pair of elongated, sub-cylindrical zooecia, jointed at the base and 

 there provided with a series of muscles by vvhich they can no doubt be moved on their stalk-like 

 proximal end. Vestibule longer than in I\I. óigcwinata, the collar being stronger than in that 

 species. Tentacles 8, usually bent during retraction ; in which condition the oesophagus is folded 

 on the pharynx. Gizzard absent. 



The structure of the jointed base of the zooecia, with the existence of a cone of muscles, 

 obviously for moving the zooecium on its stalk, appears to justify the reference of this species 

 to Mimosella. But the disposition of the zooecia is very different from that found in M. gracilis 

 and M. bigeminata. The mode of formation of the zooecium-bearing internodes is, however, 

 not unlike that of the similar structures which, in M. bigeminata, give rise to rootlets; as vvill 

 be seen by the comparison of fig. 9 with fig. 6. In fig. 9, representing the present species, it 

 will be seen that the stem gives rise to a swelling (V) cut off distally from its prolongation by 

 a diaphragm, but not separated from the stem by a proximal diaphragm. On each side, the 

 swelling in question gives off a short internode vvhich forms the commencement of a series of 

 similar internodes arranged in such a way as to curve round towards the main stem (see also 

 fig. 10). Each internode of the lateral series bears a pair of bracket-like projections, similar to 

 those of M. öigeminata, each of which bears a zooecium. The internode is often prolonged 

 into an ordinary stem, which after a time may give rise to a new group of zooecia (fig. 10). 

 In addition to giving off these parts the internode may give off another internode, from one 

 side; and this in its turn produces another internode, on the corresponding side-, thus giving 

 rise to the curved series which are so characteristic of this species. A new internode may, 

 however, be formed medianly, between the two brackets which bear the zooecia. 



The zooecium commences with a short cylindrical portion, attached to the bracket by 

 a joint. It then dilates suddenly, a diaphragm being present in this position (fig. 8). From the 

 diaphragm originate the fibres of a pair of muscles which together form a cone, their fibres 

 being inserted into the inner side of the body-wall of the base of the dilated part of the 

 zooecium. It seems clear, from this arrangement, that there must be some flexibility in the 

 body-wall at the level of the diaphragm ; and that the two bundies of muscles must be used 

 for moving the zooecium, as in other species of Mimosella. 



The vestibule is of moderate length, and its orifice is square. The collar is sufficiently 

 strongly developed to be readily seen, in the retracted condition, inside the vestibule (fig. 8). The 

 tentacles are generally more or less bent during retraction. The oesophagus is of considerable 

 length and is bent distally on the pharynx when the polypide is retracted. The parietal 

 muscles form the usual doublé series, extending along most of the length of the zooecium. 

 They may occur singly, but they are usually in groups of two fibres, and sometimes of a 

 larger number. 



The zooecia are from 700 to 800 u. in length, and usually about 110 to 1 20 u. in breadth. 

 The zooecium shown in fig. 8 is rather broader than usual, its greatest breadth being 1 70 u.. 

 The main sterns are 30 — 40 n. broad. 



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