1878. ] Recent Literature. 619 
masses, which place themselves in relation with the skin at three 
different points to form the three tactile organs. The larve of 
the Cyclostomes are formed 
by an extension of the crown 
in the form of a mouth on 
the aboral face, and finally 
the larvæ of the Chilostomes 
aboral face into two parts, 
the cupping glass-like part 
(ventouse) and. lower part, 
resulting from the with- F 
drawal of this same face. larva. 
Our author then compares the larval form of Polyzoa hie 
those of the Rotifera, and compares their ciliary crown with t 
rotary organ of Rotifers, the thoracic segment of Backo 
larvæ and the cil- 
.4.— Third derived form of Chilostome 
— 
sphere of mol- 
luscs andworms, 
and find a strong 
similarity be- 
tween them. He 
accepts the Tro- 
chosphere-forms 
of Rotifers, Poly- 
ZOa. radhio 
podes, Molluscs 
and Annelids, and thinks that there are 
Fic. 5—A Rotifer. essentially two forms, the first giving rise to 
the Polyzoa, the second to the Brachiopods, Molluscs and An- 
nelids; the first group having the ciliary crown placed below 
the mouth, and the second and last having the crown of cilia 
placed above the 
mouth. He is of 
the opinion that 
Fic. 6.—Annelid larva 
lic. 7.—Polyzoan larva. the 
semblance of the Fic. 8.—Branchiopod larva. 
larve of the entoproctous Polyzoa to the Rotifers he concludes 
