122 My. H. J. Carter on the Genus Rossella. 
General Observations. 
The essential differences between the species of Rossella 
above described are as follows :— 
R. antarctica differs from’ the other two in possessing an 
erect fringe of stout spicules round the aperture and the 
peculiar form of rosette tlesh-spicule above described. 
Rh. philippensis differs from Rk. antarctica and R. velata in 
not possessing the monticular or boss-like surface, together 
with the veil-like covering of crucially headed spicules, but 
in lieu thereof probably the mammiform prolongations of the 
body with the large hair-like locks of anchoring-spicules 
issuing from them respectively. 
ft. velata differs from &. antarctica in not having the form 
of rosette peculiar to the latter, and from R. philippensis in 
possessing the veil-like covering of crucially headed spicules. 
EXPLANATION OF PLATE X. 
Fig. 1. Rossella philippensis, Gray, old individual, natural size; cup- 
like and much worn: a, body; 66b, mammiform prolongations 
of the body; ecce, hair-like locks of long anchoring-spicules 
issuing from the prolongations ; d, cavity or cup-like excavation 
of the body; ee, pit-like depressions on the surface of the 
same ; 7, hair-like lock of spicules on which a young individual 
of the same species has become developed. 
Fig. 2. The same, young specimen which has become developed on the 
hair-like lock of fig. 1, f, natural size: a, body; 4, aperture ; 
ec, mammiform prolongations of the body supporting the hair- 
like locks of spicules respectively. 
Fig. 3. Form of free end of the anchoring-spicule characteristic of the 
genus Rossella. 
Fig. 4. Rossella antarctica, Carter, natural size, from the largest of two 
specimens dredged up by Sir J. Ross in 743° south latitude : 
a, body ; 66, external or veil-like covering composed of crucially 
headed spicules; e¢, erect fringe of spicules round the aperture ; 
dd, anchoring-spicules of the lower extremity; ee, dotted line 
indicating the shape of the cavity. 
Fig. 5. The same, apertural end: a, aperture. 
Fig. 6. Form of rosette or flesh-spicule peculiar to R. antarctica: a, arms 
subspined ; 0, four-rayed head; ¢, six-rayed head; d, end of a 
single ray, more magnified, to show that it is capitate and micro- 
spined over the shaft. 
Fig. 7. R. antarctica, “ pappiform rosette,” magnified to the same scale 
as the foregoing, viz. 1-12th to 1-6000th of an inch, to show 
their sizes relatively : a, arms of the rosette; 5, head of one arm 
with rays. 
N.B. For convenience only one head of rays has here been 
inserted. 
