COLLECTING ZOOPHYTES 



871 



morphosed branches, developing in their interior certain bodies which 

 were formerly supposed to be ova, but which are now known to be 

 ' medusoids ' reduced to their most rudimentary condition. Within 

 these are developed in separate gonothecte, sometimes perhaps 011 

 distinct polyparies spermatozoa and ova ; and the latter are ferti- 

 lised by the entrance of the former whilst still contained within 

 their capsules. The fertilised ova, whether produced in free or in 

 attached medusoids, develop themselves in the first instance into 

 ciliated ' gemmules,' or planul;e. which soon evolve themselves into 

 true polypes, from every one of which a new composite polypary 

 may spring. 



There are few parts of our coast which Avill not supply some or 

 other of the beautiful and 

 interesting forms of zoo- 

 phytic life which have been 

 thus briefly noticed, with- 

 out any more trouble in 

 searching for them than 

 that of examining the sur- 

 faces of rocks, stones, sea- 

 weeds, and dead shells 

 between the tide-marks. 

 Many of them habitually 

 live in that situation ; and 

 others are frequently cast 

 up by the waves from the 

 deeper waters, especially 

 a ffcer a storm . Many kinds, 

 however, can only be obr 

 tained by means of the 

 dredge. Of the remarkable 

 forms dredged by the ' Chal- 

 lenger ' mention can only 

 be made here of the gigantic 

 Tubulariaii Monocaulus 

 the stem of which measured 

 seven feet four inches, 

 while there was a spread 

 of nine inches from tip to tip of the extended tentacles, and of the 

 elegant Streptocaidxs j>nlc/ier)-inms, in which by the twisting of 

 the stem the ultimate ramules are thrown into ' a graceful and 

 beautiful spiral.' For observing them during their living state, no 

 means is so convenient as the zoophyte -trough. In mounting com- 

 pound Hydrozoa, as well as Polyzoa, it will be found of great 

 advantage to place the specimens alive in the cells they are per- 

 manently to occupy, and to then add osmic acid drop by drop to 

 the sea-water ; this has the effect of causing the protrusion of the 

 animals, and of rendering their tentacles rigid. The liquid may be 

 withdrawn, and replaced by (Joadby's solution. Dearie's gelatine, 

 glycerin jelly, weak spirit, diluted glycerin, a mixture of spirit and 

 glycerin with sea-water, or any other menstruum, by means of 



FIG. 662. Sertularia cupressina : A, natural 

 size ; B, portion magnified. 



