412 Mr. A. H. Hassall on the genus Lepralia, 



with two slender divergent teeth, the length of which rather 

 more than equals the diameter of the mouth of the cell. 



This zoophyte resembles somewhat my Lepra/ m linearis*, 

 from which it differs principally in the number of the teeth, 

 rarely more than two, and in the absence of the short rounded 

 processes placed just below the aperture met with in it. It 

 likewise approaches, I should think, near to the Lepralia va- 

 riolosa of Dr. Johnston, a species with the characters of which 

 I must confess myself but ill acquainted at present. Most 

 probably a deep-water species, being found principally on the 

 same description of shell as the preceding, than which it is 

 less rare, as I have met with eight specimens trawled up off 

 Bray ; teeth but seldom present, and as they are very straight 

 and somewhat divergent, they present the appearance of ears, 

 whence the name of the species is derived. A cream-coloured 

 variety is occasionally met with. 



This species is also English, and is found on oyster-shells 

 from Burnham, Norfolk. 



Lepralia ventricosa. 



Spec. Char. Crust when dry brownish and glistening ; 

 cells denned and ventricose ; apertures circular, the lower lip 

 rising up so as to form a pointed process ; armed with four 

 short, tubular, erect teeth. 



The above is a very striking species ; it is evidently one of 

 the rarest of the genus, as I have but two Irish specimens, 

 collected in the bay of Dublin. It is likewise found on the 

 English coast at Burnham, Norfolk. 



Lepralia tenuis. 



Spec. Char. Crust translucent ; cells but little elevated ; 

 walls distantly perforated ; apertures semicircular and mostly 

 provided with circular opercula, which are also perforated ; a 

 small tooth arises from the anterior wall of the cell just be- 

 neath the aperture. 



This species can only be distinguished from L. hyalina by 

 the aid of the microscope ; it is generally found upon the 

 frond of Laminaria digitata, upon which it forms circular 

 patches of about one-third of an inch in diameter. 



Dublin Bay, rare. 



Lepralia assimilis. 

 Spec. Char. Crust transparent ; cells rounded superiorly ; 

 apertures triangular and mostly furnished with an acuminate 

 operculum. A large and very blunt process is placed beneath 

 each aperture. 



It is no easy matter at first to distinguish this species from 



* See Annals, vol. vii. p. 368. 



