Mr Warden on a New Safety Gas Burner. 1 25 



maturity ; and when the ova separate successively from the 

 general mass by the action of the waves, the young in each 

 ovum is so large as nearly to fill the whole of the vesicle which 

 contains it. The cilice in these species are so long, and move 

 with such rapidity, while the young gasteropod is incessantly 

 revolving round its own centre, that probably the continued 

 pulsations of the cilice against the sides of the containing ve- 

 sicle tend to abrade or weaken it, and thus aid the escape of 

 the young animal. After their escape from the vesicles, the 

 rapid vibrations of these long cilicB cause the young animals 

 to swim with great velocity to and fro in the water, which will 

 greatly accelerate their means of procuring food during their 

 infant state ; and as they have neither a hyssus to fix them- 

 selves to rocks, nor a calcareous shell to protect them from 

 the violence of the sea, the power of rapid locomotion which 

 they possess by means of the cilice will add much to their 

 safety in an element in constant agitation. 



There is a remarkable similarity in the structure of the 

 ciliated parts in the embryos of all the gasteropodous mollusca 

 I have yet examined, and even in the general form of these 

 animals, whether naked or testaceous, in their infant state. 

 The existence of those singular minute vibrating organs term- 

 ed cilice, appears not to have been hitherto noticed in animals 

 so high in the scale ; but from their general occurrence in this 

 extensive class, it is highly probable that they are much more 

 frequent and important organs in the economy of the lower 

 animals than observation has hitherto shown. 



Art. XXVI. — Description of a New Safety Gas Burner. * 

 By Mr William Warden, Engineer to the Edinburgh 

 Portable Gas Company. In a Letter to the Editor. 

 Sir, 



I TAKE the liberty of sending you a plan of a safety burner 



* In Number iv. p. 345 of this Journal, we have given a drawing and 

 description of an improved patent gas burner invented by Mr Jennings, 

 in which the cock shuts itself when the flame is extinguished. Ingenious 

 as this contrivance was, we have no doubt that the following is more simple 

 and efficacious, and more applicable in practice. The Society of Arts has 

 adjudged to Mr Warden a silver medal for this invention. — Ed. 



