Morse.] 3 5 6 (March 19, 
owing to the difficulty at that time of keeping the water at the 
frigid temperature they were accustomed to, the embryos all died. 
I saw enough, however,.to lead me to believe that they eventually 
become attached by their caudal segment. 
Thus the three series of observations by Schmidt, Lacaze-Duthiers 
and myself, on entirely different forms of Brachiopods, show the 
most perfect vermian development. 
In regard to the early stages of Brachiopoda, Fritz Miiller + has 
published some interesting observations on the early stages of Discina, 
which he studied at Santa Catharina, Brazil. The larva is described 
as having a perfectly orbicular dorsal and ventral plate, the pallial 
membrane gaping all round, and the dorsal plate freely moving, or 
sliding back and forth. Five pair of very stiff sete project from 
the periphery, two pair forward and three pair backward, one pair 
much larger and stronger than the rest, and these were coarsely 
barbed. The posterior half is occupied by the alimentary canal, two 
auditory vescicles, and two eyes. The anterior half is occupied by 
four pair of cylindrical tentacles or cirri, strongly ciliated, between 
which a rounded knob is situated. (Possibly related to the rounded 
knob in Spirorbis and allied forms.) 
The arms or cirri are supported upon a long retractile neck or 
esophagus, at the forward extremity of which the mouth is situated. 
The larva not only swims by means of the cilia lining the cirri, but 
crawls by means of the ventral scale, and pushing itself along by the 
larger pair of bristles which have a vigorous motion, often crossing 
behind. 
These barbed bristles of Discina, Miiller finds, are deciduous, and 
it is interesting to remember in these comparisons that the larval 
worm has also coarsely barbed bristles which are likewise deciduous. 
What could be more annelidan than the description of this larva. It 
is true there are no larval worms possessing the dorsal and ventral 
plates, though in that degraded worm Sternaspis there is a pair of 
ventral plates or scuta, from the edges of which sete project, and by - 
means of which the worm shoves itself along. (The lines of growth 
are prominent on these scuta, as in Discina.) 
Since then I have received, through the kindness of Dr. Hagen, a 
letter from Herr Miller, accompanied with a sketch of another 
larval form of Discina, in which he describes features similar to those 
1 Reichert und Du Bois-Reymond’s Archiv., 1860, p. 72. Wiegmann’s Archiv. 
1861, p. 58. 
