ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
129 
One advantage of this view is, the author urges, that theories which 
at one time “ appeared to be logical necessities, will be quite ruled out 
of the field of possibilities.” 
The new group Archiplanoidea is for the reception of the families 
Ooeloplanidge and Ctenoplanidse. Off New Guinea the author found, at 
any rate, one new species of Ctenoplana , and as his specimens were 
active, he was able to see that the ctonophoral plates are the sole organs 
of locomotion. The circlet of sensory tentacles was found to consist 
of two distinct and separate halves, and this observation is crucial for 
deciding upon the homologies of the axes of Ctenoplana with those of 
other bilateral animals. Cilia do not appear to be as generally distri- 
buted as Korotneff thought. 
Dr. Willey was so fortunate as to discover the male genital organs 
of this creature. The author thinks he has proved that — 
(1) The tentacle axis of Ctenoplana = the longitudinal axis of 
Planarians. 
(2) „ stomachal „ „ = the transverse „ „ 
(3) „ main axis of Ctenoplana and Ctenophores = the dorsoventral 
axis of Bilateralia. 
Ctenoplana would, finally, appear to be an ancestral form, and not a 
highly modified creeping Ctenophore. 
Echinoderma. 
Embryology of Starfish.* — Mr. S. Goto has a preliminary note on 
the development of Asterias pallida , which he has studied at Newport, 
R.I. From a careful examination of the axes of the larva the author 
concludes that the oral side of the adult is the anterior, the aboral the 
posterior, the inadreporic (interradius) the dorsal, and the side opposite 
this the ventral, side of the larva. Both definite mouth and anus are 
new formations. With Mr. Bury the author distinguishes four portions 
in the body-cavity of the larva. The formation of the water-vascular 
ring is found to be not a mechanical result of the breaking through of 
the adult mouth, for this ring exists as such some time before the mouth is 
formed. 
In agreement with both Mr. Bury and Mr. M‘Bride, Mr. Goto 
distinguishes sharply the pore-canal and the stone-canal. There is a 
stage when the first of these alone is present; the two canals are, 
probably, distinct phylogenetically, and, in comparing Echinoderms 
with Enteropneustans it seems right that the pore-canal alone should 
primarily be taken into consideration. It seems likely that the openings 
of these canals into the body-cavity persist throughout life in all 
starfishes. 
Bury’s t{ dorsal organ ” arises as a tube from the left posterior 
enterocoel, and, as M‘Bride has taught, it forms the perioesophageal portion 
of the body-cavity of the adult. The perihaemal spaces (with the 
exception of the inner ring) as well as the peribranchial spaces are 
reported to be of true schizoccel origin. 
Echinocystis and Palseodiscus.-f — Dr. J. W. Gregory has some very 
interesting observations on these two enigmatical Echinoderms; he 
* Proc. Amer. Acad. Sci., xxiii. (1896) pp. 833-5. 
f Quart. Joum. Geol. Soc., liii. (1897) pp. 123-34 (2 figs.). 
1897 
K 
