670 _ General Notes. [July : 
considerably in their later development from those described by 
Bateson (vide Am. Nat.). The earliest stage had but a single 
transverse groove, but the later stages seem readily homologous — 
with Bateson’s form up to the time of the appearance of a pair — 
of rudimentary gills. From this point the majority of the speci- 
mens undergo a gradual process of degeneration, accompanied 
by considerable increase in size. The proboscis itself becomes — 
grooved on either side, each groove being provided with short, 
broad tentacles, while the circular post-proboscidean groove — 
nearly disappears. Internal changes also occur, involving the 
disappearance of both notched and gill cavities, and an extensive — 
degeneration occurs in the nervous system. The conclusions 
drawn are, “that there is fair ground for the belief that the or- _ 
ganisms described are Balanoglossus larvæ, which for some cause 
` or other have been unable to develop adult characters, and have — 
therefore varied,” a probable cause being the drifting of the | 
` larvæ into deep water by the action of currents and winds. If 
this be true, it follows: 1, that in some cases at least heredity 
can work only on the application of stimuli’ afforded by particu- — 
lar surroundings ; 2, that some larvz without stimuli are highly 
variable; 3, that variations produced by a given change may be 
uniform and definite in character; and, 4, these changes may — 
produce not the modification of ancestral characters, but & 
hypertrophy of those which are purely larval. 
__ The Glands in the Foot of Nudibranch Molluscs.—Dr. Jus 
H. List gives the result of his studies of the foot of Tethys fim- — 
briata (Zeit, wiss. Zool.,xlv.). After a few remarks upon the his- — 
tological structure of connective tissue, muscles, and epidermis, — 
he gives a detailed account of the glands. He recognizes in the © 
upper surface, I, unicellular mucous glands; 2, unicellular glands 3 
with fat-like contents (phosphorescent in function ?); 3, Uni 
cellular glands with peculiar, frequently laminated contents; — 
and, 4, unicellular glands with coarsely granular contents. On 
the under surface occur, besides beaker-cells and Nos. 1, 2,and 4 
of the upper surface, polynuclear glands, resembling those de-, 
scribed by Leydig as pigment and calcareous glands in the feet 
of terrestrial gasteropods, As in those cases, these latter glands — 
‘Fresh-Water Crustacea.—Mention should have been made 
before of Professor L. M. Underwood’s “List of the Descri 
Species of Fresh-Water Crustacea from America, north of Mex- 
ico,” which appears in the second volume of the Bulletin of te 
Illinois State Laboratory of Natural History. It is more than 18 
“name implies, for it includes the Oniscidz, which are terrestrial, 
‘as well. The total number of species enumerated is nominally 
