1880.] Notice of some Aquatic Worms of the Family Naides. 421 
ones of Lithospermum canescéns Lehm., we may see how far L. 
longiflorum is from showing dimorphism: 
Flower} Length of Height of | Height of 
Ee Noi N os. | Corolla Tube. | Anthers. Stigma. Poen: 
Plant No. I| I 7.8mm. | 6.8 mm. | 2.8 mm. Pollen grains ovoidal, 
i 2 6r e yr n si w stigmy eo ep om in the 
“s 3 so S wo 25 iddl x 
Plant No. 2| 4 9.0% Haa 3.0." 
= 2 ie i as is es 7 Pollen grains oblong, 
“ 7 p ú ap u 7.3 « | { much constricted in the 
; : : ddle 
“cc 8 8.6 “ 29 cs 7.3 “ mi 
“ 9 8.6 c 2.7 i 7.3 í ol >< .019 mm. 
These measurements are entered upon the diagram (Plate) at 
the lower left hand corner, upon the same scale as those of L. 
longiflorum., 
The following facts are Der shown above in the case of L. 
longiflorum: 
Ist. The length of the corolla is exceedingly variable. 
2d. The distance from the anthers to the top of the corolla 
tube is approximately uniform, so that the position of the anthers 
is largely dependent upon the length of the corolla tube. 
3d. The length of the style is even more variable than that of 
the corolla tube. 
Have we here a case of incipient heterostyly; or has this 
species but recently (since falling into cleistogamy) abandoned its 
former heterostylous form and habits? Probably there is some 
connection between the cleistegamy of the later flowers and the 
irregularity of the earlier ones. 
-Q 
NOTICE OF SOME AQUATIC WORMS r THE 
FAMILY NAIDES. 
BY PROF. JOSEPH LEIDY. 
T little worms of the family of Naides, comprising the 
genera Nais, Pristina, Stylaria, Dero, Æolosoma, Aulophorus, 
Chætogaster, etc., are common in ponds, ditches and other quiet 
waters, ‘mostly living among various aquatic plants, or in the 
Superficial sediment. They have always been viewed with spe- 
cial interest from their conspicuously exhibiting the process of 
multiplication through division, often being seen in a string of 
