SERPULiE. 399 



animal because its tube has a decided keel ui ridge upon its 

 upper surface. The colour of the animal is blue, and the fan- 

 like tuft of gills is blue, banded with white. An allied species, 

 Placostegtis latiliffidatiis, is remarkable for the shape of its tube, 

 which is defended at the orifice by a kind of pent-house or hood, 

 which projects boldly from the upper edge, just like the peak of 

 a boy's cap. 



Another genus of Serpulae, called Cymospira, has the opercu- 

 lum horny, elliptical, and furnished with two or more large 

 toothed horns, which are generally placed near the hinder edge. 

 Some of the species are very large, one, which is in the British 

 Museum, being as thick as a man's finger, and being inhabited 

 by a Serpula three inches in length, and more than a quarter of 

 an inch in diameter. Sometimes the horns are long and boldly 

 projecting, and sometimes the tube has a pointed projection like 

 the hood which has already been mentioned. One of the short- 

 horned species which was procured from Swain's Keefs, on the 

 eastern coast of Australia, was always so embedded in corals and 

 madrepores, that the true shape of its tube cannot be ascertained. 



Perhaps the most extraordinary example of the operculum is 

 furnished by the genus Pomatostegus, in which the operculum 

 is made in three stories, each smaller than that below it, so that 

 it bears a distant resemblance to the fusee of a watch. In the 

 British Museum is a fine example of this genus (Pomatostegus 

 BaiverhanMi), in which the operculum rises like the conventional 

 tower of Babel, all the stories being devoid of horns, but covered 

 with short hairs of a fibrous nature. If the reader should happen 

 to be acquainted with conchology, he can form a very good idea 

 of this remarkable operculum by taking up the similar organ in 

 any species of solarium, or staircase shell, except that in the 

 Serpula the stories of the operculum are distinct, and not formed 

 by successive whorls. 



The operculum of the animal which is supposed to be under 

 examination does not present any of these singular appendages, 

 but is more or less conical, grooved above in a radiated form, and 

 horny in substance. It is, however, a very beautiful object, if 

 only for the elegant shape, which remains after the softer parts 

 have perished, and is in form so like a wine-glass with beauti- 

 fully fluted sides, that Dr. Johnston has remarked that it might 

 swerve as a pattern for that article. 



