262 Rev. T. Hiucks on the 



entirely open in front, and scarcely sheltering the membra- 

 nous sac enclosing the embryo, placed at the top of the cell 

 and overhangino; the orifice. 



In most of the structural elements there is a complete re- 

 semblance between this form and the well-known B. plumosa. 

 It is less flexible and graceful in habit than the " soft-feathered 

 coralline," and the cells are perhaps flatter and less turned 

 inwards than in that species ; but these ai-e trifling differences, 

 and in the absence of the occcium no one probably would 

 hesitate to rank it under Pallas's name. The ovicells, how- 

 ever, of the two forms are essentially dissimilar : that of B. 

 plumosa is subglobular and of the usual type ; that of the 

 present form is a mere shield slightly hollowed out and per- 

 fectly open in front (PI. IX. figs. 6 a, 6 i). It resembles that 

 of B. purpurotincta, but seems to be even more rudimentary. 

 The difference is undoubtedly important, and in most cases 

 would be accounted distinctive ; but in view of tlie general 

 structural agreement it seems better to rank the present form 

 under B. plumosa. 



Bugula spicata, n. sp. (PI. IX. fig. 5.) 



Zoarium simple and rather stiff in habit, about | inch liigh. 

 Shoots originating from a stem composed of a number of 

 tubular fibres united together ; branches tall, much divided and 

 subdivided dichotomously, spreading. Zooecia in from two to 

 four series, elongate, straight above, of about the same width 

 throughout (rectangular) ; aperture occupying nearly the 

 whole front, narrowing downward, the lower extremity pointed', 

 a strong spike-like spine on the outer margin above, and two, 

 placed one in front of the other, on the inner. Avicularium 

 on the outer margin, almost close to the top, well rounded 

 behind, beak short, the extremity slightly bent. Ooicium 

 terminal, rounded, smooth. 



The zooecia are generally biserial, but are often quadri- 

 serial towards the upper part of the branches. I can only 

 speak doubtfully of the size and habit of growth, as I have 

 not seen more than one or tw^o specimens, which might be 

 immature, but the minute characters are sufficiently dis- 

 tinctive. 



Bugula simplex, n. sp. (PL IX. fig. 7.) 



Zooecia in from two to five or six series, alternate, elongate, 

 subrectangular, rather broad, very slightly contracted below, 

 top of the cell straight ; aperture extending almost to the 

 bottom, broad as the cell above, narrowing slightly below, 



