Dr. J. E. Gray on the Development 0/ Aspergillum. 42S 



lines; while it forms semi-solid masses in the chlorophyll- cor- 

 puscles. These corpuscles contain imbedded starch-granules in 

 certain stages of development of the cell, being accumulated 

 when the cell is abundantly nourished, and is not in process of 

 division. 



The chief points to which I call attention in this note are— r- 

 1. the existence of diffused or formless chlorophyll constituting 

 the mass of the cell-contents, and containing also chlorophyll- 

 corpuscles of greater density ; 2. the description of the course 

 of the circulation as being a current running in one direction 

 over the cell-wall, and in the opposite direction over the green 

 endochrome; and 3. the assertion that the clear spots at the 

 ends are vacuoles. 



May 7th, 1858. 



XLTI. — On the Development of the Shetland Tube 0/ Aspergillum. 

 By Dr. J. E. Gray, F.R.S. &c. 



Inquiries are so frequently made of me, how the tube of the 

 Aspergillum and its fringe can be formed, that I am induced to 

 offer the following explanations of the probable process, in the 

 hope that some naturalist residing on the sEores which the mol- 

 lusk inhabits will verify the theory. As yet, I am not aware 

 that any but fully-developed specimens have been brought to 

 this country. I presume every one knows that the animal lives 

 buried in sand or soft mud, with the broad end and fringe 

 downwards, and the narrow end of the tube just exposed above 

 the surface ; and it does not live attached to rocks by the narrow 

 end of the tube, with the broad end, the fringe and cap above, 

 like a flower in the sea, as it is figured in one of the older authors, 

 — a mistake which seems somehow to have taken a firm hold on 

 the public mind, probably because it is anomalous, and against 

 all our previous knowledge of the habit and manner of a bivalve 

 mollusk*. 



The mollusk, like all other known Conchifers, in its very 

 young state is free, floating about in the sea, and covered with 

 a pair of regular-shaped, equal valves, united by a ligament. 

 These valves are formed of a thin, opake, white, external coat 

 (which is often eroded at the umbones in the older specimens), 

 and a thicker, pearly, internal layer. 



* Miss E. Warne, in a note just received from Alexandria, observes, 

 speaking of the Aspergillum of the Red Sea, " You are aware that the disk 

 is the lower end, and the ruffles the upper end ; the said ruffles give the 

 different stages of growth. The disk and tube are buried in the sand ; it 

 puts forth glutinous tentacula through the tubes. It lives in the little 

 Ijays of sand formed by the rocky recesses of the coast, where they are in 

 hundreds." 



