APPENDIX. 649 



Vol. ii. p. 337. Genus CLAVAGELLA. 



The genus Glavagella should be restricted to those species, 

 only known in a fossil state, having the lower end of the tube 

 surrounded by hollow spinous processes. The recent species, 

 where the lower end of the tube is simple, form the genus 

 Bryopa, Gray; and Dr. Gray further distinguishes the species 

 with the siphonal end of the tube simple, under the name of 

 Dacosta, of which sub-genus B. australis is an example. 



Vol. ii. p. 338. Genus BRECHITES. 



In a recent revision of the family Gastrochamidce, by Dr. 

 Gray, he has formed several genera of the species of Brechites, 

 which may be arranged as follows. 



Genus BRECHITES, 



Shell with the embedded portion of the valves considerably 

 exposed. Tube with the siphonal end simple. 

 Ex. B. Javanus, Lamarck. 



Sub-gen. warnea, Gray. 



Tube with the siphonal end fringed. B. vaglniferus is an 

 example. 



Genus PENICILLUS, Gray, not Bruguiere. 



Shell with the umboes only of the valves exposed externally. 

 Disk surrounded by a fringe composed of a single series of 

 tubes. 



Ex. P. aquarius, Burrow (sparsus, Sow.). 



Sub-gen. clepsydra, Gray, not Meuschen. 

 Disk surrounded by a fringe composed of two or three series 

 of tubes. P. strangulatus is an example. 



Genus PCEGIA. 

 Shell with the umboes only of the valves exposed externally 



