184 



SOIENCE. 



[N. S. Vol. IX. No. 214. 



or so are present the larvae have become almost 

 perfectly transparent. By this time the mouth 

 and anus have appeared and the three divisions 

 of the intestine are established, the mid-gut, or 

 stomach, which is very early distinguishable, 

 being sharply marked off from the fore- and 

 hind-guts, the latter of which is ciliated. The 

 anterior part of the fore -gut is eversible and 

 forms a proboscis, which appears at an early 

 stage, and by its activity the neighboring par- 

 ticles of debris are taken into the intestine, and 

 as they pass through the latter the food mate- 

 rial is extracted, just as in the adult. 



The essential habits of the adult are thus as- 

 sumed at a very early stage. As the larva 

 grows older the uniform segmentation of the 

 body undergoes an alteration, and by the time 

 thirty segments or so are attained there is per- 

 ceptible a division of the body into two quite 

 distinct regions, which correspond to a similar 

 division in the adult, where the anterior part 

 of the body, including the first eighteen seg- 

 ments, is of considerably greater diameter than 

 the remaining posterior part, which consists of a 

 large and inconstant number of very short seg- 

 ments of similar structure. This division grad- 

 ually becomes more definitely established, and 

 at the same time the gills make their appear- 

 ance a simple thin-walled outgrowth of the 

 body-wall, which gradually become branched in 

 a more and more complex manner. There are 

 thus formed eleven pairs of these structures, 

 situated in segments 8 to 18 inclusive and con- 

 taining looped blood-vessels derived from the 

 main vascular trunks. The nephridea are al- 

 ready visible through the transparent body- 

 wall, as six pairs of somewhat elongated sac- 

 like structures situated in segments 5 to 10. 

 The otocysts are now clearly visible ; the circu- 

 lation of the blood, with the contractions of the 

 dorsal vessel and of the two 'hearts,' can be 

 readily seen, as can also the secondary external 

 division of each of the anterior segments into 

 five by suiserficial circular grooves. At this stage, 

 in fact, apart from this small size (12 to 18 mm.) 

 and complete transparency, the larvas are in 

 both habits and structure practically identical 

 with the adult. E. S. Lillie. 



The following papers were also presented 

 during the quarter : ' Caspar Friedrich Wolff 



and the Theoria Generationis,' Dr. W. M. 

 Wheeler ; ' Field Work at Turkey Lake and a 

 Series of Turtle Embryos from that Locality,' 

 Miss E. E. Gregory ; ' Recent Literature on 

 Spermatogenesis,' M. F. Guyer ; ' Eisig on the 

 Development of the Capitellids,' Dr. C. M. 

 Child ; ' Early History of the Optic Vesicles 

 and Accessory, Eye-like Vesicles in Verte- 

 brates,' Dr. W. A. Locy, of Northwestern Uni- 

 versity; ' Characteristic Features of Mitosis and 

 Amitosis,' Dr. S. Watase ; 'The Field Colum- 

 bian Museum Expedition to Africa in 1896,' 

 Dr. D. G. Elliott, Director of the Expedition ; 

 ' Protective Coloration,' Dr. W. H. Dudley. 



DISCUSSION AND COBBESPONDENCE. 



THE STORING OF PAMPHLETS. 



A CHEAPER grade of pamphlet box than 

 those described by Dr. Minot can be obtained, 

 made of pasteboard instead of light wood. 

 They are strong enough for ordinary service. 

 Those which I use were obtained at a local 

 bindery, not made to order, but kept in stock, 

 and measures 11x7x3 inches. They are open 

 at the back ; the front face, 11 x 3, is covered 

 with black cloth, to which a label is easily at- 

 tached. 



For pamphlets of quarto size, too large to get 

 in these boxes, and not taking kindly to a ver- 

 tical position, I have procured covers with 

 pasteboard sides and a partly flexible back. 

 The two sides measure each 12 x 10 inches, and 

 the back, attached to 12-inch edges, is 3 inches 

 wide. The outside is of black cloth, two thick- 

 nesses of which make the flexible part of the 

 back. A strip of pasteboard one-inch wide 

 gives stiffness to the middle of the back and a 

 place for the label. When first put into ser- 

 vice a sufficient number of pamphlets must be 

 put in each cover to fill one inch in depth. The 

 flexible part of the back, one inch on either side 

 of the pasteboard strip, will allow an expan- 

 sion of two inches before the contents require 

 reassorting. The covers may be placed one 

 upon another on the shelves, arranged in 

 groujjs of subjects. These I find very service- 

 able for the larger pamphlets. 



WiNSLOW Upton. 



Beown University, 



January 28, 1899. 



