100 BIOLOGICAL SUBVEY OF 



Geographical distribution. Davis Strait (Liindbeck) ; Gulf 

 of St. Lawrence (Lambe) ; Mount Desert Region. 



Myxilla fimbriata (Bowerbank) 



Lundbeck (1905, p. 141, pi. 4, figs. 9, 10; pi. 14, fig. 5a-i). 



This species was taken at Stations D 40, 96, 117. On hard 

 bottoms, depth 62 to 81 feet. Has a somewhat lumpy, some- 

 times lobed form and is frequently found attached to shells, 

 stones, etc. The specimens taken in this region are rosy-red 

 in the living condition, but soon become dark brown in alcohol. 



Skeleton. This is a polyspicular, most frequently irregular 

 network of triangular or rectangular meshes. 



Spicules. Megascleres are spined styli, usually smooth, 

 with a slight curve nearer the blunt end, although straight 

 styli are found. These styli are not so heavily spined as the 

 corresponding ones in Myxilla incrustans. Bowerbank de- 

 scribed them as being 'incipiently spined.' The styli vary in 

 length from .259 mm. to .364 mm., with a mode at .284 mm. 

 Smooth tornota, usually straight, are present, but not so 

 abundantly as the styli. The two ends of the tornota are 

 usually dissimilar with one end finely and gradually pointed 

 whereas the other end is more broadly pointed, ending in a 

 little mucro. These tornota usually have a distinct constric- 

 tion at the broadly pointed end and vary in length from .243 

 mm. to .284 mm., with the mode at .267 mm. 



Microscleres are tridentate isochelae of two sizes. The 

 isochelae are present in profusion; the small isochelae are 

 much more abundant than the large ones. The large isochelae 

 vary in length from .072 mm. to .089 mm., with a modal length 

 of .081 mm. The small isochelae are identical in form with 

 the large ones and range in size from .028 mm. to .043 mm., 

 with the mode at .033 mm. 



Remarks. This species is most conspicuously distinguished 

 from Myxilla incrnsfans by the absence of sigmata. 



Geographical distribution. Davis Strait (Lundbeck; Mount 

 Desert Region. 



