Videnskabelige meddelelser

booksnow2.scholarsportal.info

Videnskabelige meddelelser

176

in the named species and resembles more the analoguous part of

the buccal cavity of the genus Halichoanolaimus ; it is shaped as

a broad cup tapering posteriorly. The walls are thick and chitin-

ized but they lack the crenelated surface known in .S. hirsuius.

The hindmost part of the buccal cavity is deep and funnel-shaped ;

it lacks the thick chitinous rods which are found in Halichoanolai-

mus and resembles more 5. birsntns. It is strengthened by thin

longitudinal lists which meet in the bottom of the funnel and ap-

pear to continue into the chitinous intima of the æsophagus. The

edge of the funnel is provided with three, rather short prominences

terminating with an acute tip ; these three prominences appear to

be bent over the mouth of the funnel.

As to the shape of this fourth buccal division de Man states

for the species S. hirsiitus an asymmetry — the dorsal part being

flat and more thick-walled than is the case laterally and ventrally

I have not been able to ascertain the like in the species in question.

As in S. hirsiitus the lateral organ is circular. It is consider-

ably larger in the male than in the female. In the female the dia-

meter of the named organ measures 5 //, in the male 15 /i.

The æsophagus is of equal width during its whole length ex-

cepting the front part which is somewhat extended and encloses

the two posterior parts of the buccal cavity. The stout chitinous

tube known in the æsophagus of S', hirsiitus is not found in this

species.

The intestine lacks the brown pigment characteristic for the

^S. hirsutus. The nerve-ring is very indistinct.

A ventral gland is present; it is rather small; the excretory

pore is situated at the beginning of the second third of the æso-

phagus.

The spicules are much like those of Å\ hirsiitus; they are

rather strongly curved and of about the same width in their whole

length. An accessory piece, on which the distal part of the spicules

slides, is present.

The female organ is, as rernarked, asymmetricai. The vulva is

situated in the posterior part of the body, at the end of the second

third. The ovary, which is not reflexed, reaches far into the anterior

part of the body and passes the limit between the intestine and

the æsophagus (PI. VII, fig. 6). Behind the vulva is seen a rather

large vaginal gland, consisting of a single cell (PI. VII, fig. 3).

;

More magazines by this user
Similar magazines