April 1, 1867.] 



HARDWICKE'S SCIENCE-GOSSIP. 



83 



the support of a skeleton is that connected with 

 the movements of the teeth and jaws. 



This oral skeleton consists of the teeth, the 

 plates to which they are attached, and the pro- 

 cesses for the attachment of the muscles. From its 

 curious form it was compared by Aristotle to a 

 lantern, and hence is now often called the Lantern 

 of Aristotle ; it is a well-known seaside specimen. 

 The teeth resemble somewhat the front teeth of a 



Fig:. 64. Pedicellaria, x 60. Fig. 65. Section of Tooth. 



rodent ; they have the same chisel-shaped form, 

 but they have an addition in the shape of a keel 

 which runs along the back. If a longitudinal sec- 

 tion of one of these teeth be examined, it will be 

 seen to bear a striking resemblance in its structure 

 to the teeth of the higher animals. 



The keel is composed of rods of carbonate of 

 lime, lying obliquely to the axis of the tooth. The 

 chisel-shaped edge consists firstly of a series of 

 triangular calcareous plates, called the "primary 

 plates;" these constitute a framework with which 

 the other parts become connected. To these plates, 

 at some distance from the base, are attached a 



Fig-. 66. Longitudinal Section of Tooth. 



series of lappet-shaped lamina;, called by Mr. Salter 

 the " secondary plates" To these again are added a 

 third set of appendages named the "flabelliform 

 processes ; " these last consist of reticulations of 

 calcareous fibres, having a fan-shaped termination. 

 The flabelliform processes are succeeded nearer the 

 apex by an appearance closely resembling the 



tubuli of bone or dentine. This is caused by the 

 different portions of the tooth being more or less 

 closely cemented together by minute particles of 

 calcareous matter, which bear the name of the " sol- 

 dering' particles.'" Thus a longitudinal section of 

 the tooth presents somewhat the appearance of 

 bone with its lacunae, canaliculi, and laminae. The 

 edge of the chisel- shaped portion of this tooth is 

 coated with a layer of enamel. The tooth is shown 

 in longitudinal section in Figs. G5 and 66. 



The plates and processes of the " lantern " par- 

 take of the general network structure of the shell, 

 and therefore call for no particular remark. 



Thomas Graham Ponton. 



HARDY FOREIGN FERNS. 



rpHE question is sometimes asked — what hardy 

 ■*■ foreign ferns are there, which could be ob- 

 tained at a nursery, and which would succeed in an 

 open-air fernery ? It shall be our endeavour briefly 

 to enumerate those of which we have any know- 

 ledge, with a few of their characteristics inter- 

 spersed, so as to redeem our notes from condemna- 

 tion as a mere list. It may be premised that April 

 or May is a very good month in which to transplant 

 ferns, and therefore a few hints will be opportune. 

 Need we repeat the caution that if ferns are to 

 succeed they must not be planted in too dry a spot, 

 or much exposed to the sun. A shady sloping bank, 

 and good specimens will soon result in a good 

 fernery. 



Fig. 6". Ostrich Fern. 



The Royal Fern is a great favourite, and so would 

 be its foreign relatives if they were better known. 

 The Cinnamon Osmund [Osmunda cinnamomea) from 

 North America, is equally beautiful, and quite dis- 

 tinct in appearance. So also is Clayton's Osmund 

 {Osmunda Claytoniana), another hardy North Ame- 

 rican species. Either of these would flourish in the 

 open air, and prove a great acquisition to any one 

 with room to grow them. 



