14 RHIZOPODA. 



which frequently assumes a fluted appearance, 

 caused by the presence of numerous longitudinal 

 striae. In addition to the outlet at the mouth of 

 the shell the entire surface of the latter is perfo- 

 rated by a number of exceedingly minute aper- 

 tures, through which the pseudopodia are protrii- 

 sible. Entosolenia may be compared to Lagena 

 with the tubular neck inserted into the hollow in- 

 terior of the shell, 



8. Polytha lamia. — Among the Polythala- 

 onia the modifications in external confiofuration 

 assumed by the shell would seem to be almost 

 without limit. In Nodosaria [Jig. 3, a') it pre- 

 sents the aspect of a cylindrical beaded rod, which 

 in Lingidina becomes compressed, and in Denta- 

 lina more or less curved, whilst in Frondicularia 

 the peculiar sagittate form of the chambers will 

 be found a distinctive test. 



The term 'nautiloid' has been applied to a 

 large group of multilocular Khizopods, the shells 

 of which present externally a remarkable resem- 

 blance to those of a well known group of Mollus- 

 cous animals, including the Pearly Nautilus and 

 its numerous extinct allies. It was this similarity 

 of outward form which led the earlier naturalists 

 to refer the Foraminifera to the class of Cephalo- 

 poda ; a view of their nature which received the 

 sanction of Cuvier and D'Orbigny, and continued 

 to be generally adopted until the year 1835, 

 when its incorrectness was fully demonstrated 

 by Dujardin, who was the first to point out the 

 simple nature of the animal body which occupied 

 the interior of these many-chambered shells. 

 These nautiloid forms constitute an extensive 



