GENUS PYXICOLA. 725 



Cothurnia arenata, Mereschk. 



Lorica transparent, subcylindrical, slightly curved, about twice as high 

 as broad, its walls irregularly undulate ; the anterior aperture even, neither 

 constricted nor everted, obliquely set ; supporting pedicle stout, one-third 

 the height of the lorica, dilated at its base or point of attachment ; enclosed 

 animalcule elongate, pyriform, contracted and attenuate posteriorly, attached 

 to the bottom of the lorica without any intermediate prolongation of the 

 pedicle. Height of lorica 1-200". 



HAB. Salt water : White Sea (Mereschkowsky). 



Cothurnia pontica, Mereschk. PL. XL. FIG. n. 



Lorica urceolate or pitcher-shaped, about twice as long as broad, the 

 two sides of the anterior margin elevated and expanded in a lip-like 

 manner, terminating posteriorly in an exceedingly short boss-like pedicle, 

 which is supplemented by a somewhat longer interiorly produced hollow 

 conical peduncle, to which the body of the animalcule is attached ; the 

 posterior half of the lorica ornamented by four or five strongly developed 

 transverse annulations. Animalcule not observed in the living state. 

 Length of lorica 0*0171 millim. HAB. Salt water: Black Sea (Meresch.). 



This species is figured and described by M. C. Mereschkowsky in the ' Annals 

 and Magazine of Natural History' for March 1881. . 



GENUS XV. PYXICOLA, S. K. 



(La.t., yxis, box; colo > to inhabit.) 



Animalcules attached posteriorly within a corneous lorica, the lorica 

 erect and usually mounted on a pedicle ; a discoidal corneous operculum, 

 similar in consistence to the lorica, developed beneath the border of the 

 peristome, and which, when the zooid is retracted, effectually closes the 

 orifice of the lorica. 



Excepting for the presence of the corneous operculum, which closes down and 

 protects the animalcule from interference from without, the representatives of this 

 genus agree entirely with those of Cothurnia. So long, indeed, as a single represen- 

 tative only of this type was known, it seemed desirable to retain it in that genus ; 

 recent investigation has, however, elicited the existence of so many additional oper- 

 culiferous forms, that it has become desirable to institute a new generic group for 

 their reception. 



Pyxicola operculigera, S. K. PL. XL. FIG. 39. 



Lorica transparent when young, dark chestnut brown when old, ovate, 

 slightly gibbous, about twice as long as broad, posteriorly attenuate, the 

 anterior margin slightly oblique ; pedicle transparent, slender, straight, often 

 twice the length of the lorica; enclosed animalcule subcylindrical, pro- 

 truding to a considerable length beyond the aperture of the lorica, bear- 

 ing beneath the peristome a circular opercular-like disc similar in colour 



