Miscellaneous. 69 



and habits of Limulus throw much light on the probable anatomy 

 and habits of Trilobites. The author infers that the eyes had a 

 similar structure, that the circulation and the nervous system were 

 alike, and that probably the genital organs were very similar in the 

 two groiips. He thence suggests that the eggs of the Trilobite were 

 probably laid in the sand or mud and impregnated by the sperm- 

 cells of the male floating freely in the water. The Trilobites probably 

 lived by burrowing in the mud and sand, digging in the shallow 

 palaeozoic waters after worms and stationary soft-bodied Inverte- 

 brates. — The American Chemist, Nov. 1870. 



On the Stijmles of Magnolia and Liriodendron. 

 By TnoMAS Meehan. 



An examination of the stipules of Maf/nolia affords some highly 

 interesting facts, most or perhaps all of which are known to leading 

 botanists, but which do not appear to be as generally known as they 

 deserve to be ; and these facts may have a more intimate bearing 

 on many of the questions connected with the laws of development 

 than is suspected. 



In most species of Magnolia a scar peculiar to the genus exists on 

 the petiole. This scar is elevated somewhat above the surrounding 

 tissue, as if the matter forming it had been laid on the surface after 

 the rest of the petiole had been formed. The green is not of the 

 same tint as in the rest of the petiole, but it is always of the same tint 

 as that of the leaf-blade. In Magnolia macroplujlla the petiole and 

 under surface of the leaf are grey ; the leaf-blade is pale green on the 

 upper surface. The surface of the scar is pale green, corresponding 

 to the surface of the leaf-blade. The whole appearance of the scar 

 is such as if a portion of a leaf-blade had been grafted by its under 

 surface on the petiole. 



On the upper part of the scar next the leaf-blade are two small 

 articulation points, where the membranaceous stipules finally parted 

 from the leaf. Examining a leaf before these stipules have fallen, 

 the main veins forming the skeleton of the stipules are found con- 

 necting with these articuli, and, spreading out, divei'ge downward 

 toward the base of the leaf. In separating at maturity from the 

 petiole, they part first from the base, and last from their place of 

 articulation. Their weakest hold is the point furthest away from 

 what thus appears to be their source at the apex of the scar. 



Magnolia Frazeri elongates its petiole beyond the stipule several 

 inches generally. The leaf-blade then exhibits the auricle so well 

 known in this species. The structure of this auricle is similar to 

 the stipules in M. macrophglla or M. tripetcda. The veins start out 

 in nearly as close a fascicle as in these stipules, and they diverge 

 and curve downwards just as these stipules do. Above these strong 

 veins of the auricle are very weak veins, necessitating a very 

 narrow blade })ortion there, until another set of strong veins push 

 out and make the main part of the lamina. 



If we press these auricles back against the petiole, and imagine a 



