1382 



Nelson, Thurlow C. 1921. 



Aids to successful oyster culture. I. Procuring the seed. N. J. Agric. 

 Experim. Stas., Bull. 351: 1-59. 



Other than a reference in the foreword, to the effect that Dr. Julius 

 Nelson was brought to Tuckerton in 18 92 to investigate the "greening" of 

 clams, there is no other reference to clams in this bulletin. - J.L.M. 



1383 



Nelson, Thurlow C. 1925. 



Recent contributions to the knowledge of the crystalline style of 

 lamellibranchs. Biol. Bull. 49(2): 86-99. 



Venus is mentioned only by reference to work of other authors. Reformation 

 of the style can be very rapid. Approximately 15 min to a few hrs at summer 

 temp is sufficient in some bivalves. The style contains strong amylolytic 

 ferments. One function of the style is to separate food materials from sand 

 and other waste. The powerful cilia of the style sac spin the style on its 

 long axis and push it anteriorly into the stomach. The head of the style 

 gathers food strings coming from the oesophagus. As the mass is whirled 

 around in the stomach most sand and other non-digestible matter is sorted 

 out mechanically by the ciliary tracts of the stomach wall and passed on to 

 the intestine. Where the head of the style comes in contact with the stomach 

 wall is a tough resistant covering, the gastric shield. The sorting and 

 stirring mechanism is important in. animals in which ciliary activity is 

 substituted for muscular peristalsis. Food particles escaping from the 

 stomach may be passed across the faces of the typhlosoles from the intestine 

 and be incorporated in the style. This recovers part of the food materials 

 rejected from the stomach during separation of inert materials. Styles _ of _ 

 some bivalves, but not Venus, contain a large active spirochaete, Crist-ispira. 

 The conclusion of Berkeley that the style plays a part in anaerobic respiration 

 is not supported. Secretion of a crystalline style may be a direct response 

 to siphoning, whether the water contains food organisms or not. - J.L.M. 



1384 



Nelson, Thurlow C. 1928. 



On the distribution of critical temperatures for spawning and for ciliary 

 activity in bivalve molluscs: Science 67(1730): 220-221. 



Lamellibranch mollusks breed at a specific water temperature, constant for 

 species throughout their range. Spawning occurs during a period of rising 

 temperature and is started by a "trigger" temperature slightly below that of 

 the water in which spawning first occurs. Venus mereenaria spawns at 24-25 

 degrees Celsius. Lamellibranchs also have a critical temperature below which 

 ciliary activity is inhibited or abolished. Critical temperatures, especially 

 those for spawning, are of prime importance in determining distribution of 

 mollusks. Venus meroenaria is limited to a relatively few sheltered areas 

 where spawning temperatures of 25°C occur during summer. Mollusk species 

 with lower spawning temperatures, such as Mytilus edulis (10-12°C), are more 

 widely distributed. - W.J.B. 



1385 



Nelson, Thurlow. 1947. 



Some contributions from the land in determining conditions of life in the sea. 

 Ecol. Monogr. 17(3): 337-346. 



Natica, the predatory snail, penetrates into the bottom to destroy many Venus . 

 From Delaware Bay southward giant sting rays excavate deep pits with their 

 wings, washing out hard and soft clams and other mollusks for food. Ravs, 

 chimeras, and bottom-feeding sharks have teeth adapted to crushing hard- 

 shelled mollusks. In Great South Bay, Long Island, in 1924 and in Barnegat 

 Bay, N.J. in 1925 the entire oyster set was killed in a few hours on the 

 bottom where temporary low oxygen conditions prevailed. - J.L.M. 



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