418 SPH BROMIDE. 
moderately produced at the inner angle. The maxillx 
are very delicate and thin membranous plates, setose at 
the tip. (In our figures of the second maxille in 
D. rubra and Montagui, only one of the lobes was ob- 
served on dissection.) ~ The legs are moderately robust, 
terminated by a strong hook, having a small tooth on its 
inner edge. The tail is terminated by a simple slit, not 
enclosing a central tooth, and the lateral appendages have 
the outer lobe exposed. 
The species are of small size, and agree in their habits 
with the Sphzrome. They frequent rocky coasts, 
preferring them on account of the small rock-pools 
which abound in such situations, in which they reside. 
They are also found among Thalassiophyte at low water. 
They swim with much quickness and elegance, turning 
themselves over on their backs and executing various 
evolutions with great agility. They are probably com- 
mon all round our coasts. 
