DIMYARIA. 167 



the shells angularly arcuated, with double, aiigulated, ser- 

 rated wings. Minute. 



Genus 73.— CLAV AG ELLA— ZamarcA. 



Generic Character. — Sheath tubular, testaceous, attenu- 

 ated and open before ; terminating posteriorly in an oval, 

 subcompressed club, roughened by spiniform tubes ; club 

 showing on one side a valve of the shell, attached to its 

 walls ; the other valve unattached, in the sheath. 



Lamarck considers Clavagella as intermediate between Fistulana 

 and Aspex'gillum, differing from the latter in having but one external 

 fixed valve, the other being free and internal, and from the fomier in 

 having no perforation at the larger extremity. 



Clavagella aperta The Open Clavagella. Plate 



XVIIL figs. 27 and 28. An erect tube, adhering to another 

 body ; with a funnel-shaped, expanding, entire, and waved 

 aperture; provided with an ovate face- valve. 



GenMs 74.— ASPERGILLUM Lamarck. 



Generic Character Sheath tubular, testaceous, attenu- 

 ated towards the anterior termination, where it is open, and 

 thickened posteriorly into a club, with the valve of the 

 shell incrusted on its walls; club convex, with a terminal 

 disk, perforated with scattered, somewhat tubular poles, 

 and having a fissure in the centre. 



Aspergillum Javanum The Java Aspergillubi. Plate 



XVIIL fig. 29. Smooth, club-shaped, the terminal disk 

 surrounded by fimbriated rays. Five inches long. Inhabits 

 the Indian seas. 



CLASS in.-CIEEIPEDA. 



The animals are soft, destitute of head or eyes, covered 

 with a shell, which is fixed to other substances, and in- 

 capable of locomotion. The body is reversed, inarticulated. 



