I 
459 
jij brane is covering both furrows and “islands“, it is very thin and 
'I delicate; in the furrows it covers spacious dermal cavities and ca- 
rj nals, and only here are situated the oscula (and ostia?), which are 
up to 1 mm in diameter. The surface is all over 
[• 
i very finely hispid. Texture rather firm, somewhat 
crumbling. Colour dirty grey with a reddish tint 
in the bigger specimens (formaline), light grey in 
the smaller ones (spirit). 
The skeleton is a triangular reticulation of spi- 
cula-strands ; the sides of the meshes are ca. 450 /t, 
the strands are ca. 60 // thick; no distinction be- 
tween primary and secondary fibres can be drawn; 
many megascleres are scattered disorderly every- 
where in the soft tissues; in one of the examined 
ij specimens this condition is the prevailing one, so 
as to nearly extinguish the before mentioned re- 
rr gular reticulation. 
1 1 
Spicules. a. Megascleres. Oxea (fig. 16a) long, 
siender, straight or nearly so, often a little irre- 
, gularly undulated, the apices rather abruptly set 
I off; up to ca. 450 fi in length and ca. 9 thick; 
a few styli of about the same dimensions are seen- 
b. Microscleres. 1. Plachochelae (fig. 16b—c), 
the ordinary Guitarra-form, varying in length from 
40—100 /f. 2. Bipocilli (fig. 16 d—f); seen in 
> side-view they closely resemble sigmata, and, in 
I* 
faet, I first took them for sigmata, only two feeble 
; transverse lines, dividing the shaft in three parts, 
J show that we here have to deal with cheloid spi- 
j cules. The shaft is C-shaped, the distal third ex- 
* panding into a shallow cup with nearly circular 
I 
margin; the cups are obliquely placed towards 
the middle portion of the shaft; the bipocilli are 
10—14./( long. These spicules are exceedingly 
delicate, and their real nature easily overlooked. 
It is very interesting to meet these lophori'WkQ 
spicules in quite another genus. Perhaps the sigmata of some of 
the other described Guitarra-spQcies will prove to be of the same 
CO 
Fig. 16. Giiitarra 
bipocillifera nov. 
spec. a. Oxea. b. 
Side-view of pla- 
chochel. c. Front- 
view of plachochel. 
d. Side-view of bi¬ 
pocilli. e. Front- 
view of bipocillon. 
f. Half front, lialf 
side view of bipo¬ 
cillon. 
nature. 
