416 THE AMERICAN NATURALIST. (VoL: XXXIX. 
One additional objection should be made. Pfeffer repeatedly talks 
of a pre-Tertiary South America, and of the separation of South 
America from the rest of the world at the end of the Cretaceous 
time (p. 411, p. 427, p. 430; “prapanamensisches Pan-America "). 
This tends to show that his ideas about the geological history of 
South America are entirely at variance with certain geological facts. 
We know that there was no South America at all as a continuous 
mass before the beginning of the Tertiary, and that the first connec- 
tion of what is now South America with North America falls into the 
Miocene. For this we do not possess a mere theory, but positive 
geological facts; it is impossible to deny the existence of Jurassic and 
Cretaceous marine deposits over large parts of South America, or to 
neglect the fact of their existence. But if we pay due attention to 
this, then it is inadmissible to speak of a pre-Tertiary South America, 
and to talk of a severing-off of South America from the rest of the 
world at the end of the Cretaceous. 
A. E. ORTMANN. 
A detailed account of the anatomy of the chiton, Cryptoplax larve- 
formis, has been published by E. Wettstein (Jena. Zeitschr., Bd. 38, 
P- 473). 
N. Maclaren (Jena. Zeitschr., Bd. 38, p. 573) discusses the struc- 
ture and systematic relations of two trematodes, Diplectanum equans 
Wagener and Nemathobothrium mole n. sp. 
Anatomy and Histology of Dentalium. — The following facts are 
recorded by M. Boissevain (Jena. Zeitschr., Bd. 38, p. 553) on the 
anatomy and histology of Dentalium. The whole foot is ciliated and 
glandular. The intestinal musculature consists of a thin layer of cir- 
cular fibers with occasional muscle bridges. The subradular organ 
carries an organ of taste. The communication between the genital 
glands and the kidney is renewed with each period of sexual activity. 
F. A. Bather, in the Geological Magazine (dec. 5, vol. 2, p. 161) 
characterizes Sympterura minveri,n. g. et sp., a Devonian Ophi- 
urid from Cornwall. The genus is thus diagnosed: a Lapworth- 
urid with spinulose disc extending to second arm-segment, with 
oral skeleton of teeth, long jaws, and short mouth-frames (torus 
not seen), with free arm-segments containing a vertebral ossicle, 
possibly compound, grooved ventrally and provided on each side 
with two wings, to the distal of which is attached an adambulacral 
spiniferous element, The structure of the arm-segments suggests 
