September 17, in09] 



SCIENCE 



S69 



ter of the moon whieli comes in the period 

 between June 29 and July 28. 



Four papers are more or less embryological. 

 The late Professor Brooks and Mr. Kellner 

 have a few notes on the embryology of Olko- 

 pleura, which are of especial interest because 

 of our slight knowledge of the development 

 of the appendicularians. Both eggs and em- 

 bryos were found attached to the tails of the 

 adults. Brooks and McGlone studied the de- 

 velopment of the lung of the snail, Ampul- 

 laria, and find that giU, lung and osphradium 

 are developed from a ridge in the mantle 

 cavity, forming a series of homologous organs, 

 differentiated for different functions. The 

 lung becomes functional some time before the 

 gill, as young individuals are easily drowned. 



Professor E. G. Conklin traces the develop- 

 ment of the medusa, Linerges, up to the gas- 

 trula stage and the free-swimming planula. 

 The sudden appearance of large swarms of the 

 medusse seems to be connected with reproduc- 

 tion. The medusse as rapidly disappear, sink- 

 ing to the bottom and degenerating after de- 

 positing the eggs. Dr. Conklin also describes 

 two peculiar actinian larvse which are assigned 

 to Van Beneden's provisional genera Zoan- 

 thella (Semper's larva) and Zoanthina. The 

 description covers the morphology and histol- 

 ogy. All attempts to rear the larva to adult 

 conditions were in vain, so that exact relation- 

 ships are unknown. 



Dr. H. E. Jordan has three cytological 

 papers in the first volume. The studies on 

 the spermatogenesis of Aplopus seem in the 

 main to be confirmative of the results of 

 Wilson on other forms. Both of the other 

 papers are based upon echinoderms and ap- 

 parently are part of an attack upon the prob- 

 lem of the continuity of the chromosomes. In 

 Echinaster the chromosomes are derived ex- 

 clusively from the nucleolus, in Asterias 

 partly from the nucleolus, and in Ophiocoma 

 exclusively from the nuclear reticulum. 

 These results are reconciled by a study of the 

 nuclear constituents which leads to the con- 

 clusion that the chromosomes arise from any 

 part that contains chromatin. At least in 

 some forms his studies show little to confirm 

 the idea of chromosome continuity. 



The systematic papers are all in the first 

 volume. A paper on the tunicates of the 

 Gulf Stream is divided into sections. In the- 

 first Dr. Brooks redescribes both solitary and 

 chain forms of Salpa floridana. In the second 

 he presents renewed studies on the muscles of 

 Cyclosalpa, reiterating his opinion that the- 

 ordinary distinctions in the text-books be- 

 tween the Cyclomyaria and the Hemimyaria 

 are based on erroneous observations. The- 

 third section, by Brooks and Kellner, describes. 

 a new appendieularian, Oihopleura tortu- 

 genesis. A parasitic protozoan is described 

 as Gromia appendicularice, which occurred 

 attached to the tails of the tunicates, but it 

 clearly does not belong to the genus to which 

 it is assigned. 



Dr. H. F. Perkins has a paper on the- 

 medusae, describing several new species, with 

 notes on others. It is interesting that not a 

 single male Cassiopea was found. Dr. E. S. 

 Linton notes the presence of 29 species of 

 cestode parasites of fishes, several of which, 

 including a genus Pedioiothrium, are sup- 

 posed to be new. C. H. Edmondson describes; 

 a new variety of Flagellata from the salt 

 water of the moat around Ft. Jefferson. 



J. S. KiNGSLEY 



The Green Algoe of North America. By 

 Frank Shipley Collins. Pp. 480, 18' 

 plates containing 160 figures. Tufts Col- 

 lege Studies, Vol. II., No. 3, July, 1909. 

 This synopsis is certain to find a ready 

 welcome among all botanists who deal with 

 the green algse either in class work or with 

 more special interests. Among the algae there- 

 has been no group in greater need of compre- 

 hensive systematic treatment than that of the- 

 Chlorophycese. A descriptive work on the- 

 fresh-water forms has been especially desired 

 since these are more numerous and more ex- 

 tensively studied as plant types than are the- 

 marine species. Moreover, such general ac- 

 counts of the fresh-water green algae as have 

 heretofore been published have not treated the- 

 taxonomic side with the fulness and accuracy 

 demanded by the difiiculties of the subject. 

 Mr. Collins must feel great satisfaction in 

 bringing to such a fruition the results of" 



