762 



SCIENCE. 



[N. S. Vol. XX. No. 518. 



grass presents a bristling array to all comers. 

 Wings of insects alighting or flying within 

 reach are pierced and entangled by the mi- 

 nutely barbed spines and become inextricably 

 matted. Sometimes an insect is caught by 

 the leg. It is not the weak insects only which 

 are caught. Numbers were caught of Pyro- 

 phorus noctilucus Linn., a luminous snapping 

 beetle, so large and strong that it can be held 

 in the hand with difficulty. While most in- 

 sects can not free themselves once they alight 

 on this grass, two large ones do so with im- 

 punity, an earwig, Apterygida linearis Esch., 

 and a bug, QHbalus. Minute insects are not 

 caught, and no Orthoptera or Lepidoptera. 

 There seems to be no possible advantage to 

 the grass in its capture of insects. 



The grass is Cenchrus echinatus Linn., a 

 great pest in the rich soils along the edges of 

 sugar cane fields. It is found in the West 

 Indies and in southern Florida. 



A Very Curious Plant from Mexico. J. N. 



EosE. 



The plant in question is a large pumpkin- 

 shaped object, or giant puff ball, somewhat 

 flattened, with the bark of an oak. A few 

 weak roots from the under side form a con- 

 nection with the ground. The upper surface 

 has a few groups of crowded stems which bear 

 a few linear leaves. A broken specimen 

 shows the interior to consist of a very pithy 

 tissue, with a few roots traversing it from 

 the clusters of stems above to the point of 

 exit below. 



Portions of the corky layer were submitted 

 to various experts who could not agree as to 

 whether it was of fungus origin, or caused or 

 made by the insects inhabiting it. It is, 

 however, probably not of pathological origin. 



The plant is evidently of the lily family, 

 genus Nolina, possibly species humilis. It is 

 commonly called by the Mexicans ' palma.' 



The Segregation of Fresh-Water Fishes. 



Theo. Gill. 



One of the most remarkable facts in paleon- 

 tology is the abruptness of the appearance of 

 many families of fishes and especially of the 

 fresh-water families of the great group of 

 ostariophysans. This group or superorder 



contains the orders of Plectospondyles and 

 Nematognaths. It is only within a little 

 more than a decade that the relations of their 

 families have been recognized, the plectospon- 

 dyle families having been previously widely 

 dispersed, the cyprinids and three related 

 families having been placed in one section, 

 the charocinids and erythrinids next to the 

 salmonids, and the electrical eel and gymno- 

 tids next to the eels. Now, all these forms as 

 well as the nematognaths or catfishes have 

 practically no paleontological history, the 

 earliest known, Buchlandium of the Eocene, 

 being evidently a true silurid in a restricted 

 sense. There are no intermediate forms, no 

 generalized types known. When and how 

 did they originate? 



Both the Plectospondyles and Nematog- 

 naths are more diversely represented in South 

 America than elsewhere and it appears to be 

 most probable that the ancestral forms were 

 developed in what is now South America or 

 in regions of the southern hemisphere lost in 

 the waters of the Pacific or Atlantic. The 

 origin may have commenced as far back even 

 as the Devonian period. It may be recalled 

 that ceratodontids are so closely related to re- 

 cent forms that for a long time they were com- 

 bined in the same genus and that no remains 

 of species have been found in beds between 

 the Jurassic and Pliocene Tertiary. What is 

 true of ceratodontids may be true of other 

 fishes. 



The salt-water catfishes must be regarded as 

 estrays from the fresh-water types that have 

 accommodated themselves to new conditions. 

 The Exhibit of Living Animals at the 8t. 



Louis Exposition. A. B. Baker. 



More effort was made to exhibit living ani- 

 mals at the St. Louis Exposition than at pre- 

 vious expositions. The National Zoological 

 Park of Washington made a particularly good 

 display of birds in a large cage divided into 

 two compartments, one for land birds and the 

 smaller water birds, and the other for the 

 large water birds. 



The exhibit was largely an experiment, as 

 it was not known whether so many birds could 

 be displayed on so large a scale. It was a 

 success, however, the mortality, even among 



