254" DESCBiPTiON OF {Polygostrica. 



CosMAEnnir conspersmn. — Rougli with depressed granules ; segments 

 quadrilateral ; end view elliptical, larger than C. margaritiferum : 

 notch on each side linear deep. Is peculiar in its quadrilateral 

 figure, and linear disposition of its granules. (1 -260th.) 



C. amcenum. — Twice as long as broad, with parallel sides and 

 rounded ends ; rough, with pearly granules ; smaller than C. marga- 

 ritiferum ; notch linear and deep. In form, it resembles the cylin- 

 drical rather than the compressed species. (l-560th.) 



2. Constriction, in the front view, forming a linear notch on each 

 side ; end view with a lohe or protuherance wt each side. 

 f Frond rough, xvitli pearly granules. 



C. hiretum. — Segments compressed, quadiilateral, broadest at the 

 end; end margin convex. Frond larger than that of any other 

 species in this section. The empty frond punctate rather than gra- 

 nulate. End view slightly inflated at the middle. From all except 

 C. Broomeii, this species is known by its quadrangular segments, the 

 lateral margins of which are sloped and straight, not rounded. 

 (l-330th.) 



C. Broomeii. — Segments compressed, minutely granxilate, quadri- 

 lateral ; end view slightly inflated at the middle ; end margin 

 straight. The inflation does not project at the margin in the front 

 view as in C. ornatum ; the lateral margins are also less rounded, 

 and the pearly granules smaller (l-500th.) 



C. ccelatwm. — Suborbicular ; segments crenate, rough with pearly 

 granules; end view slightly inflated at the middle. (P. 13, f, 26 — 

 shewing the process of self-division.) 



C. ornatum. — Segments twice as long as broad, rough with pearly 

 granules, giving a dentate appearance to the margin ; inflation form- 

 ing a truncate projection at the end ; end view cruciform. The frond 

 is generally smaller than that of C. margaritiferum; notch linear. 

 Sporangia spinous; spines elongated, slightly divided at the ex- 

 tremity, and dilated at the base. 



C. commissurale. — Segments narrow, reniform, three times broader 

 tlian long ; rough with pearly granules ; end view with a constriction 

 between the central inflation and the extremities. Smaller than 

 that of any other species in this section. Sporangia orbicular; 

 spinous. 



