66 



One specimen has been seen by the writer which he con- 

 sidered as the fossil remains of the second species ; it pos- 

 sessed the general external characters, and also had the 

 peculiar ochraceous appearance which is attributed to it 

 by Solander. 



Advancing on the scale of organization, we arrive at that 

 division of zoophytes in which our admiration is excited by 

 the minuteness and elegance of forms, observable in their 

 receptacles ; the habitations of the animals appearing like 

 minute plants of beautiful forms, whilst the animals who 

 formed and inhabit these dwellings require the aid of the 

 microscope to examine into their nature, and oftentimes 

 even to discover their existence. These little architects are 

 divided into those which form their domiciles of a soft and 

 yielding substance ; and those which have the property of 

 secreting and depositing for this purpose a substance rapidly 

 indurating and acquiring a hardness almost approaching to 

 that of stone : the latter alone require attention here. 



POLYPIFERS FORMED LIKE XET-WORK. 



Plustra. — A submembranous, flexible, lapidescent poly- 

 pifer ; frondescent, or expanded in a thin crust, formed by 

 numerous rows of cells, disposed as if woven together, on 

 one, or on the two opposite surfaces. The cells sessile, con- 

 tiguous, adherent, short and oblique ; the terminating mouth 

 rather gaping, and in some dentated or ciliated. 



The following are given by Lamarck as fossil species, but 

 of which the genera appear to be doubtful.* 



1. Fl.tesselata. — Incnisting ; with septa rounded forward ; cells de- 

 pressed upwards ; the mouth small and nearly round. — Des- 

 marets and Le Sueur, Bull, des Sc. 1814, p. 53, PL ii. fig. 2. 



* Histoire Naturelle des Animaux sans Vertebres, par M. le 

 Chev. de Lamarck. 



