ved Bindevey ere sammenbundne til en Hud, Fig. 4, d. 
Længdemusklerne ere bredere, ligge indenfor Ring- 
musklerne og danne ligeledes en sammenhængende Hud, 
Fig. 4, e. 
Indenfor Længdemusklerne, altsaa nærmest Kropshul- 
heden, kun skilt fra denne ved Peritonealovertrækket, findes 
Skraamuskellaget, Fig. 4, f, hvis Muskler ere ligesaa, stærke 
som Længdemusklerne, men ere fjernede noget længere fra 
hverandre, hvorved det sammenbindende Bindevæv bliver 
noget bredere. Ogsaa dette Lag danner en sammenhæn- 
gende Hud. 
Sammenlignes nu Huden hos Hamingia med Bonel- 
liens, saa vil der findes baade Overensstemmelser og Af- 
vigelser. 
Efter Schmarda! skal der i Bonelliens Hud være et 
udpræget Epithelallag, bestaaende af Cylinderceller, inden- 
for hvilket skal findes et maskedannende Hudlag, som dan- 
nes af stærke sammenvevede Cellevevsfibre og Kar. 
I dette Lag fandt Schmarda enkelte Pigmenteeller og 
større Hobe af samme, hvilke forenede sig til kjertelagtige 
Organer. Indenfor dette Lag angiver han Muskellaget be- 
staaende af Længde- og Ringfibre; paa den forreste Krops- 
del føier sig dertil skjæve Muskelfibre. 
Allerede Lacaze-Duthiers? har paavist, at der ikke, 
findes noget særegent Kjertelapparat i Huden hos Bonellia, 
hvilket ogsaa stemmer overens med Grabers* Undersøgelser. 
Denne Forsker betvivler stærkt Tilstedeværelsen af Oylin- 
derepithellaget; derimod tror han at have fundet en af 
talrige Porekanaler gjennemboret Cuticula, indenfor hvilken” 
han angiver et kornet Matrixlag, i hvilket findes kjerne- 
agtige Indleiringer, snart enkeltvis, snart i Grupper. Inden- 
for dette Matrixlag har han fundet det egentlige Binde- 
vævslag, der bestaar af hyalint Bindevæv, hvori findes spar- 
somt Bindevæyslegemer. Sammenvævede Cellevævsfibre og 
Kar har Graber ikke fundet. Det vil heraf sees, at Huden 
hos Hamingia nærmer sig i histologisk Henseende meget 
til Bonelliens Hud ifølge Grabers Iagttagelser; men afviger 
dog noget fra den. Saaledes er Cuticula langt fra saa 
bred og heller ikke gjennemboret af Porekanaler hos Ha- 
mingia, som Tilfældet er hos Bonellia; noget Matrixlag 
findes ikke, derimod et hyalint Bindevævslag med ind- 
leirede, tildels pigmenterede Celler, nogenlunde svarende 
til hvad der findes hos Bonellia. Endelig har Hamingia 
et tredie Muskellag, nemlig de skraa Muskler, som Graber 
aldeles ikke omtaler hos Bonellia, imedens Schmarda an- 
giver, at paa dennes forreste Kropsdel føier skraa Muskler 
1 Schmarda. Denkschrift. der k. k. Akad. dér Wissenschaft in 
Wren “Wore, IV, pes wilt, pl 7 
* Lacaze-Duthiers. Recherches sur la Bonellie. Annal. des Sciences 
nat. III Série. Tome X, pag. 53. 
3 Graber., Sitzb. der Akad. der Wissenschaften. Wien. 1te Abth. 
Jin. Heft. Jahrgang 1873. 
22 
sion. 
slender fibrils, which, being webbed together by connective 
tissue, constitute a continuous membrane, fig. 4, d. 
The longitudinal muscles are broader, lie underneath 
those of the annular layer, and constitute, like the latter, 
a continuous membrane, fig. 4, e. 
Underneath the longitudinal muscles — accordingly 
nearest the perivisceral cavity, with only the peritoneal 
tunic between — is seen the oblique layer, fig. 4, f, the 
muscles of which are as strong as those in the longitudinal 
layer, but somewhat farther apart, giving greater breadth 
to the contiective tissue that webs them together. This 
layer, too, constitutes a continuous membrane. 
On comparing the skin in Hamingia with that in 
Bonellia, it will be found to exhibit both agreement and 
difference. 
According to Schmarda,! the skin in Bonellia has a 
well developed epithelial layer, consisting of cylindrical 
cells, underneath which is said to extend a reticulated teg- 
umentary layer, composed of strong interwoven vessels and 
fibres of cellular tissue. 
In this layer, Schmarda found a few isolated pig- 
mentary, cells, and agglomerations of such, which, uniting, 
formed glandulous organs. Underneath this layer, extends, 
he states, the muscular layer, composed of longitudinal and 
annular fibres, to which are united, on the anterior portion 
of the body, oblique muscular fibres. 
Years ago, Lacaze-Duthiers? showed there was no 
special glandular apparatus in the skin of Bonellia; and 
since then, Graber* has been led to form a similar conclu- 
Indeed, that observer very much questions the exis- 
tence of a cylindric epithelial layer, whereas he believes 
to haye detected a cuticle perforated by canaliculated pores, 
extending underneath a granulated layer of matrix, through- 
out which were dispersed, both isolated and in groups, 
agglomerations of nucleal corpuscles. Underneath this layer 
of matrix, was the true layer of hyaline connective tissue, 
sparingly furnished with corpuscles of connective tissue. Inter- 
woven fibres of connective tissue, and vessels, Graber did not ob- 
serve. Hence it is obvious, according to Graber’s investigation, 
that the skin in Hamingia bears, histologically, considerable 
resemblance to that in Bonellia, though not strictly agree- 
ing. Thus, for instance, the cuticle is far less broad in 
Hamingia than in Bonellia, nor is it perforated by canal- 
iculated pores; moreover, it has no layer of matrix; but 
there is a layer of hyaline tissue, with cells, in part pig- 
mentary, much the same asin Bonellia. Finally, Hamingia 
is furnished with a third muscular assemblage, viz. the 
oblique layer, of which Graber makes no mention whatever 
as occurring in Bonellia, whereas Schmarda distinctly states, 
1 Schmarda. Denkschrift. der k. k. Akad. der Wissenschaft in 
Wien. Tom. IV, pag. 117, pl. 4—7. 
2 Lacaze-Duthiers. Recherches sur la Bonellie. Annal. des Sciences 
nat. III Série. Tome X, pag. 53. 
3 Graber. Sitzb. der Akad. der Wissenschaften. Wien. 
Jin. Heft. Jahrgang 1873. 
ite Abth. 
