178 Objects for the Microscope. 



but may be seen in long files within the horny tube of 

 Ptumatella repens (the most abundant species), both during 

 the life and long after the death of the parent polype. 

 Probably the shelter is a needful protection against the 

 hungry minnows or sticklebats ; but when the Polypidom 

 decays the Statoblasts float freely on the surface of the 

 water, attach themselves to Lemna and Anacharis, or even 

 to stones and sticks, until the warmth of a spring morning 

 quickens them into life. 



If kept in a room they develop sooner. As I write in 

 this month of February, there are several Statoblasts in my 

 aquarium with a young Plumatella fully formed, sheltered 

 beneath the open valves, and waving a circlet of white 

 tentacles, feeding almost incessantly, and with body so 

 transparent that every part of its internal economy is visible. 

 The lophophore, or membrane, which bears the tentacles, 

 can be seen drawn in like the retracted finger of a glove, 

 the open oesophagus and striated stomach, its muscular 

 bands across, and longitudinal, the pyloric cavity, the 

 cardial cavity, and the movement of the intestine, as it 

 ejects the rejectamenta. 



In a further state we should see the ovary and developing 

 Statoblasts. 



THE PLUMATELLA REPENS, 



so called from the Latin word signifying plumed and repens, 

 or creeping, because of its habit of lengthening the small 

 brown tubes along stones or leaves, or twining round 

 Lemna. ( It looks merely like a dead spray of horny sub- 

 stance when taken out of the water ; but replace it in a 

 tumbler of its own soft element, and from every spray will 

 peer forth a multitude ot ciliated polypes, like Membrani- 

 pora, except and observe this the tentacula, ranging from 

 twenty to fifty in number, are not in a starry ray, but in the 

 form of a double horseshoe, the outer one fan-shaped, and 

 the inner one likewise, but more compact, only it sometimes 

 arches over, and the plumed tentacles seem like a feathery 

 tent protecting the indweller; or, as was really the case, 

 enclosing hopelessly the caught infusoria whirled by the 

 outer current into the hungry mouth beneath. When, 



