122 ^Ir. II. J. Carter on the Genus Rossella. 



General Observations. 



The essential ditrerenccs between the species of Rossella 

 above described are as follows : — 



IL antarctica differs from the other two In possessing an 

 erect fringe of stout spicules round the aperture and the 

 peculiar form of rosette liesh-spiculc above described. 



B. philippensis differs from B. antarctica and R. velata in 

 710/ possessing the raonticular 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. 



R. velata differs from R. antarctica in not having the form 

 of rosette peculiar to the latter, and from R. 2)hf(ipj)easis in 

 possessing the veil-like covering of crucially headed spicules. 



EXPLANATION OF PLATE X. 



Fi(/. 1. Hossclla philippejisis, Gray, old individual, natural size; cup- 

 like and much worn : a, body ; bbb, mammiform prolongations 

 of the body ; c ccc, hair-like locks of long anchoriug-spicidea 

 issuing fi-oni the prolongations ; d, cavity or cup-like excavation 

 of the body ; e e, pit-like depressions on the surf^ice of the 

 same ; /, hair-like lock of spicules on which a young individual 

 of the same species has become developed. 



Fiff. 2. The same, young specimen which has become developed on the 

 hair-like lock of fig. 1, /, natural size : a, body ; b, apertm-e ; 

 c c, mammiform prolongations of the body supporting the hair- 

 like locks of spicules respectively. 



Fiff. 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 74n° south latitude : 

 a, body ; b b, external or veil-like covering composed of crucially 

 headed spicules ; c, erect fi'inge of spicules round the aperture ; 

 d d, anchoring-spicules of the lower extremity ; e v, dotted line 

 indicating the shape of the cavity. 



Fig. 5. The same, apertural end : a, aperture. 



Fig. 6. Form of rosette or tiesh-spicule peculiar to R. antarctica : a, arms 

 subspined ; b, four-rayed head ; c, 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. l-12th to l-0(X)Otli of an inch, to show 

 their sizes relatively : a, arms of the rosette ; b, head of one arm 

 with rays. 



N.B. For convenience only one head of rays has here been 

 inserted. 



