12 A, C. OUDEMANS. 
nella and Carinoma) short, and the same is the case with 
the proboscis. . 
We must now enumerate those characters which Carinoma 
does not share with Valencinia, and which are common to 
one, two, or three of the other above-mentioned genera. 
In all the four genera the mouth is situated behind the 
ganglia, there are no stylets in the proboscis, and the lateral 
longitudinal furrows are absent. Thus they are all Palzo- 
nemertea. 
In Valencinia well-developed posterior lobes occur, coa- 
lesced with the ganglia. Also well developed intestinal diver- 
ticula, and through the whole length of the body three well 
developed muscular coats. These characters at once are absent 
in the genera Cephalotrix, Carinella, and Carinoma. 
In Valencinia the cesophageal constrictor muscle is 
absent, but it occurs in the three other genera. In Cari- 
nella and Cephalotrix only a part of, in Carinoma all the 
fibres. of the proboscidian sheath are used to form it. In 
Carinella it extends much further backwards; there is thus 
formed an intestinal constrictor. 
The third muscular coat of Valencinia (the first from 
without inwards) which is situated exteriorly to the brain, 
occurs in Carinoma, but much less developed and only in 
the head and the cesophageal region. (This, and certain 
peculiarities of the vascular system in the head are the only 
characters which are common to Carinoma and Valen- 
cinia, and not common to Carinoma and the other two 
genera.) 
The ganglia (excluding the posterior lobes) are placed in 
Valencinia, Carinoma, and Carinella outside of the 
circular muscular coat, in Cephalotrix within this and the 
longitudinal one. The lateral nerves always remain to the 
exterior of the circular muscular layer in Valencinia and 
Carinella. In Carinoma they penetrate, in the hindmost 
half of the cesophageal region, the circular layer till they lie in 
the midst of the longitudinal layer, a little further backwards 
again moving outwards, and finally remaining between the 
