26 Nils Hj. Odhner. 
modified in view of this circumstance. In most of the characters 
there is, in fact, a complete concordance between the two forms, 
above all in the structure of the radula, the salivary glands, the 
gills and the hypodermis. The differences, on the other hand, 
exist in the size and shape of the spicula, which in K. minima 
are of many kinds, also hook-shaped; the needles, further, seem 
to be longer. The pharynx of K. borealis is furnished with a 
pair of small pre-radular pockets — whether these are present 
in K. minima is not known. No cloacal or copulatory spicula 
exist in K. borealis, though there may be homologa of the spicula 
sheaths in the form of deeply penetrating tubular invaginations 
(,,preanal glands“) from the lateral and ventral walls of the 
cloacal chamber. 
The genus Kruppomenia is evidently closely related to 
Pruvotina COCKERELL, in which, however, the salivary glands are 
lobated and hypodermis papillae may be present. The radula, 
further, has freely projecting pectinate teeth (cf. NIERSTRASZ 1905). 
Description of the morphology. 
From a transverse section it is evident that the cuticula is 
rather thick and contains both radiating and tangential spicula 
(fig. 39); along the margins of the ventral furrow, however, only 
radial ones occur. No regular hypodermis papillae exist; they 
are replaced by irregular projections formed by the cells in the 
lower part of the cuticula beneath the spicula (fig. 40). 
Inside the hypodermis there follows a thin layer of circular 
muscles and within the latter a longitudinal one, feebly developed 
throughout. On each side of the ventral furrow the latter forms 
a longitudinal fascicle of rather loose structure and of slight 
thickness, about the same as the cuticula. More stronger devel- 
oped than the said muscular layers are the septal cords which 
are as usual extended from the inside of the ventral furrow to- 
wards the lateral sides of the body, and form the support of the 
mighty dissepiments of the intestine. Between body wall and 
intestine a small space is occupied by lymphatic lacunae. 
The single ventral fold is composed, as usual, of cylindrical 
ciliated cells, intermingled with scattered excretory ones. A single 
layer of similar cells, but without the cilia, also lines the inside 
of the furrow. The ventral fold passes directly into the epithelium 
of the cloaca, and is not separated from it by any invagination 
