Spengelomenia. 475 
the digestive and circulatory systems are of value and may be 
compared in the case of the solenogastres and chitons with consider- 
able profit. In another connection (HrArz, 1911) these have been 
discussed in considerable detail, and it is needless to rehearse the 
matter here. 
In conelusion there is a word to say concerning the most pri- 
mitive type of solenogastre, but here again there must, for the 
present, be differences of opinion. Not knowing the developmental 
history of any of these animals the difficulty is far greater than 
otherwise, since we cannot with even a fair degree of certainty 
differentiate primary and secondary features. It does seem however 
that in those species where the coelomoducts, in the adult condition, 
are comparativly plain and unmodified, and in this respect resemble 
the chitons, we are dealing with a primitive condition. In the 
young of several neomenians that I have examined, these structures 
likewise are relativly simple tubes, and I am strongly persuaded 
that when they appear in a fully developed condition provided with 
glandular appendages and penial spines and a relativly high degree 
of complexity they are not primitive species. Furthermore it fre- 
quently happens that this lack of simplieity in the posterior end of 
the body is correlated with a complex organisation in the anterior 
end. The basis for my belief is more or less intangible, but has 
resulted from the study of a comparativly large number of species, 
yet I cannot look upon Neomenia and Alexandromenia as primitive 
types. The genus Spengelomenia is accordingly one of the more 
specialized genera, and far removed from Proneomenia which to me 
appears to be one of the least modified genera. 
The following diagnosis will distinguish the genus: 
Spengelomenia n. 9. Body worm-like, measuring 23 by 1,5 mn. 
Spieules slightly curved, needle-like. Papillae large, multinucleate. 
Three ventral folds. Gill folds 10—12. Numerous pharyngeal glands 
and enormous lobulate glands opening on sides of pharynx. Radula 
monoserial. Four pairs of vesicular appendages on dorsal limb of the 
coelomoduct; ventral limb surrounded in part by lobulated glands. 
Type of genus S. bathybia n. sp. 
With character of the genus. Off the northeastern coast of 
Florida. 
