ii8 



THE POPULAR SCIENCE MONTHLY, 



if skin stimuli be cut off ; 5. The direct 

 action on the respiratory centers of the 

 hotter blood of the heated animal is prob- 

 ably not, or not only, due to its temperature 

 but to its greater venosity. 



Dr. W. K. Brooks has an exhaustive 

 paper entitled " Observations upon the Early 

 Siagcs in the Development of the Fresh- 

 Water Pulmonates," in which he discusses 

 the works of Lankester, Fol, Rabl, Jhering, 

 and others. The plates accompanying his 

 paper are models of clearness. 



S. F. Clarke follows with an interesting 

 illustrated paper on " The Development of 

 Amblystoma," which closes the number. 



Part III, devoted to the work of the 

 Chesapeake Zoological Laboratory during 

 the session of ISVS, begins with an account 

 by Professor W. K. Brooks of the organi- 

 zation of the school, its location at Fort 

 "Wool, and the methods of study adopted. 

 This is followed by lists of the plants and 

 animals observed at Fort Wool the former 

 by Mr. N. B. Webster and the latter by Mr. 

 P. R. Uhler. The next paper, by Dr. Brooks, 

 is on the development of Lingula and the 

 systematic position of the Brachiopoda. He 

 succeeded in getting the free-swimming larva 

 of Lingula at a stage similar to the one de- 

 scribed by Professor McCready many years 

 ago, and carried it through to the early 

 staure of the adult form. It is useless to 

 attempt to do justice to this valuable con- 

 tribution without the plates which accom- 

 pany it. 



The other papers in this part are " On 

 the Larval Stage of iSquilla," by Dr. Brooks, 

 and the " Description of Lucifer Typus," by 

 Walter Faxon. 



Part IV contains a paper of great sci- 

 entific and economic value, on the devel- 

 opment of the oyster, by Dr. Brooks. Ger- 

 man and French authorities had stated that 

 eggs of the oyster were fertilized within 

 the body of the parent, and were carried 

 by them until they had reached an advanced 

 stage of development, when, provided with 

 shells of their own, they were discharged, 

 and swam freely in the water until they be- 

 came attached. Misled by these statements, 

 Dr. Brooks had failed the season before in 

 securing any results. On the 15th of May 

 he commenced operations by opening oys- 

 ters every day throughout the breeding-sea- 



son. Ilis success in artificially fecundating 

 the egg was remarkable. Millions of eggs 

 were fecundated with but little trouble. He 

 traced their developmental history from the 

 segmentation of the egg to those stages al- 

 ready described by European naturalists. 

 He found the female oyster in various con- 

 ditions : some in which the ovaries were 

 largely distended, and the eggs fairly oozing 

 from the oviducts ; others in which the 

 ovaries were half filled, and others still 

 wherein the ovaries were quite empty, and 

 in no case did he find a single fertilized egg 

 in the ovary. Dr. Brooks emphatically says 

 that, so far as the oyster of Chesapeake 

 Bay is concerned, " the eggs are fertilized 

 outside the body of the parent, and that, 

 during the period which the young Euro- 

 pean oyster passes inside the mantle cavity 

 of its parent, the young of our oyster swims 

 at large in the open ocean." A very clear 

 description is given of the anatomy of the 

 oyster, as well as some practical points in 

 regard to their artificial fecundation. A 

 careful estimate shows that an average- 

 sized female oyster contains about nine mill- 

 ion eggs; an unusually large oyster may 

 contain as many as sixty million eggs. 



Dr. Brooks's investigations have a very 

 practical bearing on the question as to the 

 final exhaustion of the natural oyster-beds 

 on our coast by unlimited dredging. 



One would naturally think that with 

 such remarkable fecundity the question of 

 extermination need be hardly entertained, 

 but the eggs after fertilization, if left un- 

 protected, meet at every moment of their 

 existence enemies who devour them, and, 

 when at a later stage they rise on the water 

 and form a film on the surface, fishes de- 

 vour them by millions. Dr. Brooks has 

 shown that if the egg is not immediately 

 fertilized it soon perishes, and of course in 

 its natural home the chances of its fertili- J 

 zation are infinitely less than in the artifi- 

 cial method actually tried. 



In a recent paper by Dr. Mobius a long 

 table is given showing the number of oys- 

 ters taken yearly from the Bay of Cancale, 

 on the coast of Norway, during the last 

 hundred years. Dr. Brooks reproduces this 

 table, to show that unlimited dredging has 

 greatly reduced the production. 



Without detailing the process here, Dr. 



