The Morphology of a Solenogastre, 721 
The coelomoducts (LANKESTER, 1900) have the form of simple tubes 
extending from the pericardium to separate exits in the cloacal 
chamber (Figs. 6, 8). Their inner openings are located in the infero- 
lateral angles of the pericardial cavity and are guarded by high 
pyriform cells that show no signs of cilia. On the other hand the 
succeeding portion of the canal, of very small calibre, is composed 
of cubical elements covered with a heavy ciliated coat. This section 
makes its way forward to the outside of the dorsal gill retractor 
and unites abruptly with the glandular portion, which although a 
single tube is so sacculated that it becomes a relatively voluminous 
structure. Its walls are composed of more or less cubical cells in 
which the small spherical nucleus is usually basal and the cytoplasm 
scant in amount owing to the presence of one or two great vacuoles. 
The general structure bears a fairly close resemblance to certain 
chiton kidney tissue yet there is no positive proof that it possesses 
an excretory function. The outer openings are on each side of the 
anus a short distance anterior to it and though very minute in 
preserved material are nevertheless well defined. Their presence 
is further indicated by the surrounding cells which are high and 
slender and probably sensory judging by the small nerves in their 
vicinity. 
It is an interesting fact that the developing egg cells are 
surrounded by a follicular membrane, composed of very thin flat 
cells, with invisible boundaries and flattened disc-like nuclei. Whether 
these elements develop any cuticular processes such as SCHWEIKART 
(1904) so accurately describes for the chitons it is impossible to 
state for all the eggs are in an immature condition. 
General considerations. 
Since the publication of SPENGEL’s (1881) work on the nervous 
system of molluscs, in which von JHERING’s group of the Amphineura 
(chitons and solenogastres) was removed from the „Vermes“ and 
placed in the Mollusca, the solenogastres have enjoyed comparative 
quiet in this group. It is to be admitted however that certain 
features of their organization have not been fully understood and 
have appeared to be without a counterpart in other classes of 
molluses as a few zoologists have vigorously contended. Chief among 
these is THTELE (1902) whose knowledge of the comparative anatomy 
of the solenogastres and molluscs generally has led him to the belief 
that „die Solenogastren sind eine mit Gordiiden und Anneliden nächst 
