stokes.] ^50 [Sept. 16, 



with two or more posterior annulations, and always exhibiting at the an- 

 terior border a short, but conspicuous snout-like prolongation ; pedicle 

 profusely and dichotomously branching, longitudinally striate, annulate 

 irregularly and at wide intervals, the ultimate divisions very short. Length 

 of body, ^lo inch ; height of entire colony, -^^ inch. Sab. — Pond water ; 

 attached to Algae and various aquatic plants. 



At first glance this closely resembles 0. nutans (Ehr.) Stein, great dif- 

 ferences being discernible, however, on slight examination. In 0. nutans 

 the pedicle is strongly and conspicuously annulate ; here the annulations 

 are absent or few in number and irregularly placed. The zooids are here 

 transversely striate, while in 0. nutans they are presumably smooth. In 

 size the two forms are also widely and distinctly different, the bodies of 

 0. nutans measuring only ^^^ inch in length, while in 0. allensi they are 

 almost twice as large ; the height of the entire colony of the former is 

 from 2T to i inch, an enormous altitude in comparison with the -^^ inch of 

 0. allensi. In their contracted state their resemblance is very close. 



Opercularia vestiia, sp. nov. Fig. 15. 



Bodies elongate-conical, soft, flexible and somewhat changeable in 

 shape, less than three times as long as broad, tapering from the region 

 ■ beneath the peristome to the pedicle ; cuticular surface, with the excep- 

 tion of the peristome border and ciliary disc, entirely clothed with a 

 coarsely granular, mucilaginous investment ; peristome exceeding the 

 body-centre in width, the border slightly revolute ; ciliary disc conspicu- 

 ously exerted, and obliquely elevated ; ciliary circles three ; vestibular 

 seta conspicuous ; contractile vesicle single, spherical, anteriorly placed, 

 apparently within the base of the ciliary disc ; nucleus band-like, broad, 

 short and curved ; endoplasm granular ; contracted body obovate, with 

 several posteriorly developed annulations, and an anterior, snout-like pro- 

 jection; pedicle tree-like, profusely and dichotomously branching, longi- 

 tudinally striate, becoming chestnut-brown with age ; primary pedicle 

 seldom exceeding in height twice the length of a single body, the ultimate 

 branches about one-fifth as long as the zooids, often curved, a single 

 animalcule being stationed on the extremity of each ultimate division. 

 Length of body, -gig inch ; height of the entire foot-stalk, exclusive of the 

 zooids, ^0 inch. Hab. — Pond water ; attached to aquatic plants. 



T/iuricolopsis {Thuricola ; ofiq), gen. nov. 



Animalcules loricate, the loricse as in Thuricola, with the addition of an 

 internal, narrow, flexible valve-rest, adherent to the lorica wall by one 

 extremity, and projecting arcuately across the cavity to receive and sup- 

 port the descended valve ; zooid posteriorly attached to the lorica by a 

 distinctly developed pedicle ; otherwise essentially as in Thuricola, 



