ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
81 
Hew Turbellaria.* — Mr. W. McM. Woodworth, in the second part 
of his 4 Contributions to the Morphology of the Turbellaria,’ describes 
and figures two new species of Planaria , P. unionicola and P. doroto- 
•cephala, found at Havana, Illinois, and gives some notes upon the 
morphology of some other fresh-water forms from the same region. 
The notes are illustrated by figures, some of living forms. 
Incertae Sedis. 
Notochord of Cephalodiscus.f — Mr. S. F. Harmer has a note upon 
Mr. Masterman’s researches on the above subject. Mr. Harmer appears 
to accept generally Masterman’s results, but strongly opposes his 
homology of the “ notochord,” which he formerly described, with the 
proboscis-gland of Balanoglossus , and with the structure called by Mas- 
terman the sub-neural gland in Actinotrocha. Harmer is not prepared 
apparently to offer suggestions as to the meaning of Masterman’s 
“ paired notochords,” so that his criticism is in large part a reassertion 
of his own previous position. This he does chiefly on account of the 
relation of his notochord to surrounding structures. He believes that 
the structure called by Masterman the sub-neural sinus is homologous 
with the proboscis-vesicle of Balanoglossus, and opens neither into the 
blood-system nor into the anterior body-cavity. The position of this 
structure in regard to the “ notochord ” confirms, in his opinion, the view 
that the latter is homologous with the Eicheldarm of Balanoglossus. 
Mr. Masterman’s reply ^ is, like his opponent’s paper, confused by 
the use of terms which involve in themselves the assumptions to be 
proved. He believes that his “sub-neural gland” is throughout of 
glandular structure ; it certainly has not the structure of a notochord. 
His sections show clearly that the sub-neural sinus is merely the swollen 
end of the dorsal blood-vessel, and is continuous with it. Further, the 
Eicheldarm of Balanoglossus lies between the ventral body-wall and 
the anterior body-cavity, while the “ sub-neural gland ” of Cephalodiscus 
lies between the dorsal body-wall and the anterior body-cavity ; and 
finally, the similarity of the “ sub-neural gland ” of Cephalodiscus to 
an epiblastic structure in Actinotrocha is against the view that it has 
notochordal significance. Masterman therefore denies that Harmer’s 
“ notochord ” can legitimately be described as such, especially on histo- 
logical grounds, and reiterates his homology of the pharyngeal dorso- 
lateral grooves of Cephalodiscus with “ double notochords.” Apart from 
the question of chordate affinities, the paper is interesting as affording 
additional evidence of the relations between Phoronis, Cephalodiscus , and 
Balanoglossus. 
Development of Mesoderm in Phoronis.§— Herr E. Schultz finds 
that in the blastula-stage some mesoderm (mesenchyme ?) cells migrate 
into the blastocoel. In the first stages of gastrulation many others ori- 
ginate from the endoderm. They become massed together in the region 
of the future head-lobe and towards the anus. Those lying freely in the 
blastoccel become disposed on the ectoderm and the endoderm, forming a 
* Bull. Mus. Comp. Zool. Harvard, xxxi. (1897) pp. 1-16 (1 pi.). 
t Zool. Anzeig., xx. (1897) pp. 312-6. % Tom- cit., pp. 113-50 (5 figs.). 
§ Zool. Centralbl., iv. (1897) pp. 781-2. 
1808 
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