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Genus 72.— FISTULANA.— Zawarc^. 



Generic Character. — With a tubular testaceous sheath, tumid, 

 and posteriorly closed, and attenuated at the anterior end ; open 

 at the summit, and containing an unattached bivalve shell ; 

 valves of the shell equal, and gaping when shut ; animal provid- 

 ed with two tubular appendages in front. 



Lamarck ascertained that the testaceous tubes were not the shells them- 

 selves, and that the attached bivalve was such. 



Fistulana gregata. — The Gregarious Fistulana. Plate 

 XVIII. fig. 24 to 26. Sheath doubly club-shaped, congregat- 

 ing ; the shells angularly arcuated, with double, angulated, ser- 

 rated wings. Minute. 



Genus 73.— CLAVAGELLA.— Za»iarc/;. 



Generic Character Sheath tubular, testaceous, attenuated, 



and open before ; terminating posteriorly in an oval, subcom- 

 pressed 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 the Clavagella as intermediate between Fistulana and 

 Aspergillum, differing from the latter in having but one external fixed valve, 

 the other being free and internal, and from the former having no perforation 

 at the larger extremity. 



Clavagella aperta.— The Open Clavagella. Plate XVIII. 

 fig. 27 and 28. An erect tube, adhering to another body ; with 

 a funnel-shaped, expanding, entire, and waved aperture ; provid- 

 ed with an ovate face-valve. 



Genus 74.— ASPERGILLUM — Lamarck. 



Generic Character. — Sheath tubul-ar, testaceous, attenuated 

 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, having a fissure in the 

 centre. 



Jspergillum Javanmv. — The Java Aspergillum. Plate 

 XVIII. fig. 29. Smooth, club-shaped, the apex surrounded by 

 fimbriated rays. Five inches long. Inhabits the sea at Java. 

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