SERTULAEIA. 207 



As this insignificant branch bore fifteen vesicles, wherein from 15 to 

 20 planulse belonging to each could be enumerated, its fruits amounted to 

 between 200 and 800 in whole. 



None of the animals escaped from fig. 13, during observation, though 

 all relaxed into ovoids and prisms, and altered their reciprocal position. 



The perfect transparence of the vesicle, exposes whatever succeeds 

 within as the contents are gradually discharged. — Fig. 14. 



Specimens of what might be denominated the Nemertesia ramosa, oc- 

 cur, with a short stem, boughs, and branches, set at a large angle, together 

 with the prolonged, slender, and very delicate twigs above described, as 

 issuing from parts of the latter. Two such specimens had a ruddy tinge 

 towards the root, while of a dull yellow colour above, where the pith had 

 decayed. The articulations were distinctly seen. Living hydrae occupied 

 the portions entire. 



A profusion of ovoidal vesicles, with a heart-shaped orifice, were set 

 in the axillae formed by the parts of these specimens, each containing a 

 corpusculum, which came forth as a pale yellowish planula, quite the 

 sixteenth of aia inch long. It swam supine as the Planaria, and it might 

 have been identified with the planula, coming from the ovate vesicle of 

 the former species, the Serttdaria antennina, rising by a single red stalk. 

 Similar facts have recurred at different times, when many planulse were 

 produced. 



Besides such ovoidal vesicles, the delicate, slender, plumose twigs 

 bore transparent empty flasks. 



Thus the same specimens bore ovoidal and ampuUate vesicles. 

 But greater perplexities have occurred from other specimens, bearing 

 three distinct vesicles on their different parts, stem, boughs, and branches. 

 Such specimens, green and branched, which I concluded the Ramosa, were 

 obtained in October. The vesicles consisted oi first, the owid with a late- 

 ral orifice as described, which never contains above a single planula, and 

 remains empty and transparent on its departure. Second, a cornide vesicle, 

 or one like an inverted horn, the larger diameter outwards, with the ex- 

 tremity a circular mouth : the vesicle set round the stem, after the arrange- 

 ment of the ovoidal vesicles, being also of about the same capacity. — 



