I 
187 
is most suitable to hold apart the larval genera from the genera 
enclosing the ripe Ceriantharia. Therefore, I have proposed the 
name Isarachnanthus for the two species, described below. Besides, 
obconica is no true Åpiatis, and pilula no true Peponactis. In an- 
other Work I have regarded obconica as the type of a new larval 
genus Isapiactis, and pilula as the type of a new larval genus 
Paranactinia. 
5. Isarachnanthus handanensis n. sp. 
Diagnosis: An ordinary large species. Marginal and labial 
tentacles of ordinary length. Number of marginal tentacles to about 
140. Arrangement of the marginal tentacles probably typical in 3 
or 4 cycles. Labial tentacles arranged 3 (dt) 413 | 4242 I 4312 I 
■ 2 
. Directive labial tentacle present. Actinopharynx of or¬ 
dinary length, hyposulcus somewhat more than half as long as 
actinopharynx with cnidoglandular tract distinctly limited and with 
one ciliated streak on each side. 16—18 mesenteries attached to 
the very broad siphonoglyph. Directive mesenteries of the length 
pf the hyposulcus. P 2 long, somewhat shorter than the oldest M 
iand m. P 3 and most of the B- and b-mesenteries of about the 
^same length as the directives, with short ciliated tract and long 
midoglandular tract. The oldest M and m reaching almost to the 
iboral body-end. No distinet difference between M- and m-mesent- 
jjnes. P 2 -, M- and m-mesenteries with long ciliated tract and long 
praspedion region. Without distinet limit between the ciliated streaks 
ind the craspedion region (interrupted ciliated streaks). Craspedion 
egion broad, somewhat invaginated in the middle line. Well devel- 
'•ped acontoids on p 2 on the 3—4 oldest M and m with compar- 
tively few gland-cells, but with numerous very large curved nema- 
ocysts in their endodermal part. Mesenteries not distinctly arranged 
|i quartettes. 
^ Colour in formol: Column in both specimens red-brown, in 
He uppermost part a small uncoloured area. Marginal tentacles on 
'le inside with transverse broad bands of brownish colour, between 
'hich narrower uncoloured parts. Labial tentacles on the inside 
bre or less distinctly olive-brown coloured, on the outside paler, 
►ral disc almost uncoloured in the one specimen, at the base of 
