NO. 9 RESEARCHES OF JOSEPH JACKSON LISTER HERON-ALLEN 9 



2. In some ten cases (out of say 150 which I have now seen) the 

 spheres have separated after some hours, sending out long and abun- 

 dant pseudopodia, and moving rapidly away from one another. 



Within 24 hours a second chamber is added to the sphere/ and a 

 calcareous shell is developed.' In this condition they are readily recog- 

 nized as young megalospheric individuals.^ 



July 22. — After writing the above yesterday it occurred to me that 

 the first of the two processes described above was an abnormal one — 

 the result of the impurity of the water. I therefore changed the water 



^ This was first observed at 7 : 10 p. m. on July 2. Lister's note (note-book, vol. 

 ii, p. 91) reads "The empty shell is now surrounded by a host of small bodies. 

 These all possess a globular mass containing yellow protoplasm. In many cases a 

 second mass shaped like the second chamber of a megalospheric form, and more 

 transparent than the globular mass is present. In other cases two transparent 

 4-oval masses are present. Some of them have extended pseudopodia." On July 3, 

 at 9 a. m. these second chambers had highly accentuated themselves. (See draw- 

 ing note-book iii, p. 27.) All the stages were observed on this day in another 

 specimen between 9 a. m. and 9 : 40 p. m. (drawing in note-book, vol. ii, p. 92). 

 This had acquired its second chamber at 8 : 30 a. m. on July 4. 



"This was first observed at 12: 20 a. m. on July 5. At 9: 10 a. m. the former 

 specimen had its young " with a rough shell-hyaline material outside this." 

 (Note-book, vol. ii, p. 99.) 



' On July 7 (the day Lister began the account we are studying) at 10: 15 a. m. 

 he writes (note-book, vol. ii, p. loi) "The specimen which yesterday morning 

 at 10 : 30 a. m. was in stage 3, and whose spheres then separated, I have now 

 transferred to picric with several of the spheres attached. They are 'young 

 megalospheric forms with a second chamber formed." These observations were 

 continued and repeated day after day with the same patient observations and 

 accurate records. On July 11 Lister was able to construct a table, founded upon 

 23 specimens which had been observed, at the times passed in the stages, the 

 average being: Stage i, 3 hours. Stage 2, 2 hours. Stage 3, 7 hours. (On the 

 1 2th he observed the same phenomena in Rofalia hcccarii (Linn.) of which he 

 made a beautiful drawing (note-book, vol. ii, p. 106).) The average for 12 

 specimens watched on July 13 was : Stage i, 4 hours. Stage 2, 2 hours. Stage 3, 

 8 hours. (The young Rotalia (66 specimens) gave an average of stage i, 3 hours, 

 20 minutes. Stage 2, i hour, 30 minutes. Stage 3, 4 hours, 20 minutes. The 

 observations went on as before, thereby confirming the accuracy of his previous 

 records up to the 21st; on the 22nd he made the discovery as to the water which 

 has been recorded in his own words, which now follow. When making dredgings 

 at Plymouth, while this paper was awaiting publication (in April, 1929), we 

 had the good fortune to find, in a dredging from inside Drake Island (the 

 locality from which Lister obtained his material) a very large number of young 

 Polystomellae, in exactly the condition here discribed — ('. c, a megalospheric 

 chamber, followed by one or two succeeding chambers. See our paper, " The 

 Foraminifera of the Plymouth District," E. Heron-Allen and A. Earland, Journ. 

 Roy. Micro. Soc, 1930, vol. 50, p. 194. 



