398 HOMES WITHOUT HAUDS. 



to be a development of one of the antennae, the other antenna 

 being small, slender, and without any such appendage. To 

 systematic naturalists, the operculum is one of the most valuable 

 parts of the animal, as it is often found in the tube in good 

 preservation, long after all the softer parts of the animal have 

 disappeared. We can learn but little from the tube, as it is very 

 similar in animals belonging to different genera. The value of 

 the operculum was detected by Dr. Philippi, and has been cor- 

 roborated by Dr. Baird, who has made great use of it in some 

 valuable papers on specimens of Serpulaj which are now in the 

 British Museum. 



In one genus, Eupomatus, for instance, the operculum is 

 furnished with a number of moveable spikes. In one species, 

 Eupomatus Boltoni, these spikes are about twenty in number, 

 and are hard, flat, and calcareous. Their form is very much like 

 that of a hedger's bill-hook, except that they are furnished in the 

 inner edge with several bold tooth-like projections. These spikes 

 are called by Philippi, horns or cornua, and are always deeply 

 toothed, whatever may be the species. The very appropriate 

 name, Eupomatus, is formed from two Greek words, and signifies 

 " beautiful lid," in allusion to the elegant structure of the oper- 

 culum and its complement of horns. 



In another genus, which has been called Placostegus, the oper- 

 cvilum is calcareous, flat and rounded, looking so like the opercu- 

 lum of some aquatic mollusc, that it might easily be mistaken 

 for that object. The genus is so named on account of the shape 

 of the operculum, and the word is of Greek derivation, signifying 

 Plate-roofed. 



One species of this genus, Placostegus carinatits, is remarkable 

 for a peculiarity which has been brought forward by Dr. Baird, 

 in a paper read before the linnsean Society, in April, 1864. "I 

 wish particularly to bring before the notice of the Society the 

 fact that the animal gives out a beautiful dye or colour. The 

 specimens which were the subjects of my examination had been 

 for a number of years in the British Museum, some having been 

 placed there in 1845, and others in 1847. Notwithstanding their 

 having been so long dry, when softened in water, taken out of 

 the tubes and placed in spirits of wine, they imparted to the 

 liquid a beautiful and delicate red tint." 



The specific title of curinatus, or keeled, is given to the 



