396 
Dr. 0. Burger on the 
of an outer longitudinal muscular layer, of the subepithelial 
muscle-layers, and the formation of a muscular tissue at the 
cephalic extremity, where, in the case of Garinella , we found 
a parenchyma, which persists in the Enopla also. Moreover, 
we find these forms provided with cephalic glands, not present 
in Garinella , and probably likewise absent in its allies. A 
cephalic gland is characteristic also of the Enopla ; and with 
regard to this group we may make the same observation as in 
the case of that to w T hich Eupolia , Gerebratulus , &c. belong, 
viz. that the cephalic gland remains small in forms which, 
judged by the development of their nervous system, sense- 
organs, and cephalic grooves, must be regarded as the 
higher, such as Drepanophorus and Amphiporus , as also 
Cerebratulus and Langia ; but that in Tetrastemma , Prosade - 
noporuSj and Geonemerfes , on the contrary, as in the more 
primitive Eupolia , it has undergone a colossal development. 
The musculature of the body-wall is precisely similar in 
structure in the case of the first group, in which I unhesi- 
tatingly include Garinella , Garinina ) and Garinoma — I would 
prefer not to come to any decision as to the position of Cepha - 
lotlirix , although I am inclined to assign it to the first group 
— and in that of the third, which embraces the Enopla, and 
consists of a circular, a diagonal, and a longitudinal layer. 
In the second group, which includes the remaining forms 
unprovided with a stylet in the proboscis ( Valencinia , Eupolia , 
Linens , Borlasia , Gerebratulus , and Langia) , we find that the 
musculature of the body-wall consists of a longitudinal, 
diagonal, circular, and longitudinal layer. The entirely 
different position of the diagonal muscular layer in Group II. 
as compared with Groups I. and III. is most remarkable. 
We have recognized the inner circular muscle-layer of 
Group I. as not belonging to the musculature of the body- 
wall, and have homologized it with the dorso-ventral system 
which appears in the metamerized forms of Groups II. and 
III., and which we have derived from the circular layer in 
question. 
None of the groups is without a system of radial muscles, 
the tracts of which split up the layers of the body-wall, 
dividing them into compartments. 
In its ciliated epithelium, the manifold gland-cells thereof, 
and the development of the deeper system of gland-cells lying 
beneath the basement-membrane, the integument of the 
Nemertines exhibits an unmistakable resemblance to that of 
the Turbellarians. 
The musculature of the body- wall of the Khabdocoela * 
* V. Graff, ‘Monographic der Turbellarien. — I. Rhabdoccelida,’ ]882. 
