June 5, 1896.] 



SCIENCE. 



851 



barren plains were little pyramids from which 

 the sand was thrown up in jets by a hairless 

 mole, which was only observed 200 miles from 

 the coast. The hairlessness of this animal, 

 Seterocephalus glaber Eiipp, is a unique fea- 

 ture among the rodentia. The specimen pre- 

 sented by Dr. Smith to the Academy is the only 

 alcoholic preparation of the species known to 

 exist and the second one on record in any form, 

 the type being in the Senckenburg Museum. 



Another specimen of unusual interest and 

 variety is one of Trilophomys imhaitsi Milne 

 Edw. — a maned rat covered with long, stiff 

 hair, arranged in three longitudinal divisions. 

 Its nearest affinities in externals and habits are 

 to our marmots. 



A Colobus or horse-tailed monkey occurred 

 in troups of 500 or 600 and formed a very 

 peculiar feature of the landscape. The skins 

 are used by the natives to form bands for the 

 ankles and knees. The species is the guereza 

 of Eiippell. Guinea fowls were found plenti- 

 fully wherever there was water, a beautiful 

 vulturine form being of special interest. An 

 infinite number of bee eaters were observed, 

 especially about Lake Rudolf, where they were 

 active in catching the insects driven up by the 

 volcanic smoke. 



The entire collection of mammals, which was 

 commented on in detail by Mr. Samuel N. 

 Rhoads, includes fifty genera and about seventy 

 species represented by 200 specimens. Seven 

 genera and twelve species are new to Ameri- 

 can museums. This portion of Dr. Smith's 

 gift is of special interest and value, as the mam- 

 mals alone have not been examined and de- 

 scribed by specialists elsewhere. Mr. Rhoads 

 also spoke of the fishes and reptiles. The 

 batrachia embrace 40 species of 18 genera, 

 mostly new to the Academy. 



Mr. Witmer Stone spoke of the collection of 

 birds which had been determined by Mr. 

 Bowdler Sharp, of the British Museum. The 

 portion presented to the Academy consists 

 of 150 specimens of about 100 species, fully 

 one-half new to the museum. A new species 

 of Turacus was found in the darkest portion of 

 the inland forest and had been named in recog- 

 nition^of the discoverer's distinguished services 

 to science. 



Dr. Henry Skinner stated that the insects 

 included 871 specimens ; the distribution in the 

 several groups was noted. A report on the 

 diptera was made by Mr. Chas. W. Johnson, 

 and Mr. Wm. J. Fox spoke of the collection of 

 hymenoptera consisting of 160 specimens, all 

 of 'which were new to the Academy's cabinet, 

 eight being of undescribed species. 



There were but few mollusks, but on those 

 which were presented, Mr. Henry A. Pilsbry 

 based some remarks on the molluscan fauna of 

 Africa and its geographical distribution. 



The entire collection is probably the most 

 extensive and important yet brought from 

 Africa by an individual explorer, and the por- 

 tions so generously given to the Academy by 

 Dr. Smith form a valuable addition to its re- 

 sources. 



Mr. Henry A. Pilsbry spoke of the geology of 

 the deposit containing fossil Unionidse at Fish 

 House, New Jersey. The mussels, some twelve 

 species of Uiiio and Anodonta, occur in a thick 

 black clay stratum used for brick and tile mak- 

 ing. Below this is a stratum of red clay, gravel 

 and ' ironstone ' (bog iron), about two feet 

 thick, which rests on a bed of sand of unknown 

 depth. This sand shows the stratification and 

 oblique lamination characteristic of arenaceous 

 deposits in running water. The speaker con- 

 sidered that the hypothesis of an ancient ' ox- 

 bow ' of the Delaware river explained the 

 phenomena presented, the underlying sand 

 having been deposited in the bed of the river ; 

 the channel was then abandoned for a new one, 

 leaving a lagoon or 'slough,' in which the 

 layer of yellow material was deposited at sub- 

 sequent times of freshet, and after the up-stream 

 end of the lagoon was entirely filled up, the 

 black clay was formed in idle water, largely by 

 the decay of organic matter, molluscan and 

 other life flourshing in lagoons of this nature. 

 Mr. Pilsbry held that the black clay and under- 

 lying sand was a deposit wholly different in 

 genesis and earlier in time than the gravel 

 which overlies the clay bed, this last gravel be- 

 ing referred by Prof. Salisbury to the Pensauken 

 formation. Besides the mussels, fossil wood 

 occurs in the black clay, as well as remains of 

 the pleistocene horse, Equus major Leidy, deter- 

 mined by Prof Cope. 



