120 



It is generally encrusting, but sometimes it rises into 

 frond-like prolongations, with a layer of cells on either side, 

 separated from each other by a central cavity ; the sides 

 however are generally in contact, and afford each other 

 mutual support. 



M. UNICORNIS. Encrusting, calcareous; cells oval, with 

 a short stout spine on the lateral or distal rim. 



Flustra unicornis, Fleming's Brit. An., p. 536. 



Hab. On stones, not uncommon. Polperro. Goran, &c. 



This encrusting calcareous species occurs in patches of 

 about three-fourths of an inch in diameter. The cells are 

 oval, with stout calcareous rims, and are arranged in circular 

 rows. The margins of the oral apertures, are embossed and 

 marked with three or four circular orifices. The apertures 

 are circular and armed with a stout spine on the distal or 

 lateral margins. 



M. PEACHII. Encrusting; cells radiating; apertures 

 oval, unarmed, with two punctures at each extremity. 



Flustra Peachii, 9th Report of the Cornwall Polytechnic 

 Society, p, 81. 



Hab. On dead muscle and oyster shells in the Falmouth 

 and Fowey rivers; off the Deadinan point; common. 



Encrusting, membrano-calcareous ; cells ovoid, having 

 their longest diameter in the axis of growth, and at each 

 extremity two minute punctures; the apertures even and 

 unarmed. The cells which have a radiating distribution, 

 appear somewhat confused from their radiating from so many 

 points and intermingling with each other. 



This species was first found by Mr. Peach in the Fowey 

 river; since then in company with him I have found it 

 abundantly encrusting almost every shell dredged up, from 

 Mixtow to the mouth of the river. I have since found it in 

 deep water nine leagues south of the Deadman and in many 

 other parts of the British Channel. It is now acknowledged 

 to be a good species and I therefore give it the name of its 

 discoverer. 



ESCHARID^S. 

 Polypidoms calcareous, or membrano-calcareous, very 

 variable in form; composed of cells usually disposed in quin- 

 cunx; the cells oblong, pentagonal or hexagonal, conjunct, 

 immersed, horizontal to the plane of axis, with subterminal 

 or lateral apertures, which are usually covered with oper- 

 ©iila. Polypes ascidian. 



