664 The American Naturalist. [July, 
ZOOLOGY. 
Motion in the Protozoa.—Ryder has some interesting remarks 
on the contraction of the Vorticellid stalk? which has not before been 
properly understood. The muscle in the stalk is composed of alter- 
nating discs of anisotropic and isotropic matter, the former being in 
contact with the sheath on the inside of the coils, a type unknown 
elsewhere. Notes are also given on the motion of Trypanosoma. 
Morphology of the Siphonophores.—Brooks and Conklin have 
recently studied ? the reproductive organs of a Siphonophore belonging 
to Haeckel’s order Auronectz. The specimens came from near the 
Galapagos Islands, and were subjected to sectioning. The authors 
found only female organs, and are inclined to think that Haeckel’s 
‘*androphores’’’ some long, spindle-shaped gynophores filled with 
yolk, but into which the egg nucleus had not yet passed, or from 
which it has been forced out by pressure. The development of the 
gynophores is described, and the authors conclude that the ‘‘ monovone 
gonophores’’ are true gonophores, while the ‘‘ polyovone gonophores ” 
are merely pouches containing ova, and are not, strictly speaking, 
gonophores. The attention is called to the fact that only male Physaliz 
have been found, and the suggestion is made that in these two cases 
the other sex may be so different in form as to have been classed as a 
wholly different genus. 
The Starfish Larva.—In a paper read before the National 
Academy of Sciences,’ Dr. Brooks says that in numerous starfish larve 
taken at Wood’s Holl, the water system is at first bilaterally symmetri- 
cal in every particular, although the right pore and pore canal early 
disappear. This is regarded as an additional argument for regarding 
the larva as ancestral, and attention is called to the similarity in 
ontogeny between the water pores of the starfish larva and the spira- 
cles of Appendicularia and the tunicate tadpole. 
Anatomy of the Synaptidz.—Among the results derived from 
a study of the six species of Synaptide belonging to the genera Syn- 
apta, Chirodota, and Myriotrochus, Drs. Ludwig and Barthels con- 
clude‘ that in the adult Synaptid there is no radial water canal; that 
1 Proc. Acad. Nat. Sci., Phila., 1891, p. ro. 
2 Johns Hopkins Univ. Circ., X., p. 87, 1891. 
3 Johns Hopkins Univ. Circ., X., p. 101, 1891. 
4 Zool. Anzeiger, Vol. XIV., p. 117, 1891. 


