24 



SCIENCE. 



[Vol. IV., No. 74. 



veneering of yellow soil enclosed the silken case, but 

 otherwise no mud was used. On comparing these 

 specimens with those from Illinois, it was believed 

 that they were the work of closely related or perhaps 

 the same species. It is very common for spiders 

 of various and widely separated families to give their 

 cocoons a protective upholstering of scraped bark, 

 old wood, etc., and not unusual to find species that 

 cover their egg-nests wholly or in part with mud; 

 but the speaker was not aware that any species 

 had yet been published as making cocoons like 

 either of the above described forms. He believed, 

 therefore, that the facts were wholly new to science : 

 certainly they were new to the field of American 

 araneology. 



June 17. — Referring to the Lycosa, whose weaving 

 of a round cocoon had been the subject of study in 

 the early part of May (see Science, iii. 685), Rev. H. 

 C. McCook stated that on June 4 the spider was 

 found with the young hatched, and covering the upper 

 surface of her body. The empty egg-sac still clung 

 to the spinnerets, and the young were grouped over 

 the upper part of the same. The entire brood was 

 tightly packed upon and around each other, the lower 

 layers apparently holding on to the mother's body, 

 and the upper to those beneath. Twenty-four 

 hours afterward the cocoon-case was dropped, and 

 the spiderlings clung to the mother alone. An ex- 

 amination of the cocoon showed that the young had 

 escaped through the thin seam or joint formed by the 

 union of the egg-cover with the circular cushion when 

 the latter was pulled up at the circumference into 

 globular shape. There was no flossy wadding within, 

 as is common with orb-weaving spiders — nothing 

 but the pinkish shells of the escaped young. One 

 week later about one hundred of the spiderlings had 

 abandoned the maternal perch, and were dispersed 

 over the inner surface of the jar, and upon a series 

 of lines stretched from side to side. About half as 

 many more remained upon the mother's back, but by 

 the 13th all had dismounted. Meantime they had 

 increased in size at least one-half, apparently with- 

 out food. Professor Angelo Heilprin exhibited 



a number of microscopic slides, received from Mr. 

 K. M. Cunningham of Mobile, containing foraminifer- 

 ous dredging from the Red Snapper Bank, off Mobile 

 harbor, Gulf of Mexico, and preparations of organ- 

 isms from the rotten limestone of the north-eastern 

 portion of Mississippi, — a rock which represents the 

 inner border of the Gulf during the cretaceous period. 

 The recent forms of foraminifera are interesting as 

 affording material for comparison with those of the 

 ancient sea. There is a remarkable difference in the 

 forms. From the present waters, about eight genera 

 are indicated by the slides in question; Discorbina, 

 Rotalia, Textularia, Crist ellaria, and Nodosaria being 

 included among the Perforata. Although Globige- 

 rina forms such an important feature of the ooze of 

 the open seas, not a single specimen which could 

 with certainty be referred to this genus was found 

 in the material from the Gulf of Mexico. Tex- 

 tularia was the most abundant form. Among the 

 Imperforata, we have, of the family Miliolidae, a 



very considerable abundance of Quinqueloculina and 

 Biloculina. In the foraminifera of the limestone 

 the family represented by these genera seems to be 

 entirely absent, and but few of the others are left. 

 Discorbina and Textularia almost make up the entire 

 fauna represented by the specimens received. Even 

 these are of much smaller size than corresponding 

 forms from the Gulf ooze. It is not a little surpris- 

 ing that there should be such a distinction between 

 the organisms of the two periods, in view of the con- 

 tinuous existence of the body of water in which they 

 lived, and of the persistent types which they repre- 

 sent. About twenty-five distinct forms of forami- 

 nifera had been determined from the greensand of 

 New Jersey, which is the approximate geological 



equivalent of the rotten limestone of Mississippi. 



Professor Heilprin also exhibited a specimen of a 

 beautiful little trilobite, Calymene Niagarensis, from 

 the bank of the Yazoo River, above Vicksburg. The 

 formation at the locality indicated is eocene; but, as 

 Silurian beds exist farther up the stream, the presence 

 of the specimens at the point from which they were 

 collected undoubtedly represents a downwash from 

 above. 



Botanical section, June 5. — Mr. Thomas Meehan 

 remarked that few botanists would expect to find op- 

 posite leaves in Salix; but in S. nigra Marshall they 

 appear at a certain stage of growth, — a fact which 

 has much significance. This species is of that section 

 which has the flowers co-aetaneous with the leaves; 

 that is to say, instead of the aments being sessile, 

 they terminate short branches. They are, however, 

 not absolutely terminal, but appear so by the sup- 

 pression for a time of the terminal bud. In the case 

 of the female ament, this terminal bud usually starts 

 to grow very soon after the flowers mature, and forms 

 a second growth, when the fertile catkin or raceme of 

 fruit becomes lateral. It is the first pair of leaves on 

 this second growth that is opposite : all the rest are 

 alternate, as in the normal character of the genus. 

 The leaves are so uniformly opposite, under these 

 circumstances, that there must be some general law 

 determining the condition, which has not yet been 

 developed. 



Engineers' club, Philadelphia. 



June 7. — Mr. William H. Ridgway described a 

 simple crane, consisting of a cylinder hung from the 

 jibs of an ordinary foundry crane, and using the steam 



directly to' hoist the load. Mr. C. Henry Roney 



exhibited specimens of American sectional electric 



underground conduits as laid in Philadelphia. 



Prof. L. M. Haupt supplemented his paper of May 

 17, upon rapid transit, by an interesting collection 

 of statistics of the growth of the city from the time 

 of the ' pack-horse ' to the present, and showed by 

 maps that his previous statements were verified by 



these statistics. Mr. A. E. Lehman exhibited to 



the club a model of a new protractor, and described 

 the invention and the improvements he has made in it. 

 It consists of a combination of protractor, T-square, 

 scales, etc., which may be worked separately or to- 

 gether. As a protractor only, it is complete, being 



