Skptkmber 23, 1898. ] 



SCIENCE. 



397 



more or less closely parallel to the onto- 

 genesis of the organism as a whole, re- 

 peating characters seen in similar parts in 

 the young individual and in adults of an- 

 cestral types. The repetition is usually of 

 poembryonic or nepionic characters. 



In asexual reproduction of Hydrozoa 

 and Actinozoa, buds are given off, which 

 during growth repeat characters seen in 

 later stages of embryos from the egg. 

 Young plates of the stem of certain crinoids 

 throughout life repeat the features of the 

 whole stem of ancestral forms. In am- 

 monites that portion of the complex septum 

 which lies close to the umbilicus is rela- 

 tively simple, in this localized area repeat- 

 ing youthful and ancestral characters. 



In plants, suckers from the roots, or base 

 of stem, or stump, often repeat characters 

 of the seedling, Pitch Pine, Areca, Oaks, 

 Ash, Aralia, Sassafras, Ailanthus. In Am- 

 pelopsis tricuspidata, at the base, throughout 

 life, the leaves are compound, as in seedlings. 

 On all the remaining old wood, leaves are 

 simple, trilobed (the species character); on 

 wood of the current season's growth, leaves 

 are simple, cordate, like a late stage in 

 growths of seedlings. Degradational local- 

 ized growth may be reversionary, as tuftlike 

 growths of the Eed Cedar, resembling the 

 young and fossil allies. The terminal por- 

 tion of leaves often repeats the chai-acter of 

 leaves of seedlings in a close degree, seen 

 in Tulip tree. Ashes, Ailanthus, Phoenix. 

 Reversionary individual leaves often occur. 

 These have failed to develop full specific 

 characters and bear more or less resem- 

 blance to the young and fossil allies, seen 

 in Tulip tree. Ashes, Negundo, Phoenix. 



On the Carboniferous Fauna of Rhode Island. 



By Pbofessoe A. S. Packard. 



The fauna comprises worms, Anthracomya 

 arenacea, crustacean trails, an Arachnid, and 

 14 species of insects, mostly cockroaches. 

 Comparing with South Joggins, the animal 



remains support Lesquereux's reference of 



the beds (based on the flora) to the upper 



Carboniferous. 



On the Present State of our Knowledge of the 



North American Tertiary Mollush Fauna. By 



De. Wm. H. Dall. 



Eeviewed fields covered by early workers 

 from Say and Leseuer, in 1822, down to 

 1860, forming the first period, which was 

 mostly on the coastal plain. A second 

 group, Sowerby, Guppy, Gabb, were occu- 

 pied with the Oligocene and Pliocene of the 

 Antillean region. 



A second period began about 1880. The 

 new workers revised faunal lists, discrim- 

 inated horizons, correlated continental and 

 Antillean horizons, and discovered new hori- 

 zons. The most important of these were 

 the Pliocene of Florida, Miocene of Galves- 

 ton, Texas, and Upper Oligocene of western 

 Florida, as made known by Willeox, Heil- 

 prin, Dall, G. D. Harris, Aldrich and others. 

 From recent discoveries, rich faunas have 

 added a multitude of new forms. 

 Leidy's Genus Our amoeba. By Wm. L. Po- 



TEAT. 



He showed that Leidy's view of the fila- 

 ments as extensions of protoplasm was in- 

 correct. They are mycelial filaments of a 

 fungus, partially parasitic on an Amoeba. 

 The filaments arise from the germination of 

 a spore, and issue at once into the water. 

 The structure of the filaments is that of un- 

 septate hyphse, not of pseudopodia. The 

 genus Ouramoeba is not valid. 



Moniloporidce, a Neiv Family of Palaeozoic 

 Corals. By A. W. Gbabau. 



Notes on JEolosoma tenerarum. By Miss 



Edith M. Beace. 



It is shown that the nervous system of 

 this worm, previously considered aberrant, 

 conforms to the annelid type. The nervous 

 system is connected throughout with the 

 epidermis. The distribution of nerves and 

 ganglia were described in detail. The sym- 



