72 MARINE POLYZOA. 



Its nearest congener is Lepralia verrucosa ; it is, however, 

 much smaller, and distinguished by the lateral, alar avicularia. 

 In the older state the appearance of the polyzoary is very con- 

 fused, and the peculiar characters are only to be sought at the 

 growing edge, and in the younger or more recent cells. 



15. LEPRALIA MONOCEROS, n. s. PI. XCIII. figs. 5, 6. 



Cells immersed, outline more or less oval, broad above, pointed 

 below ; surface punctured ; mouth narrow, transverse, a strong 

 projecting rostrum on the lower margin ; a very strong and long- 

 articulated spine on one side only of the mouth. Ovicell pyra- 

 midal, hollowed inferiorly in front, and often crowned with a 

 small avicularium on the summit ; numerous scattered avicularia 

 of larger and smaller size on or between ? the cells, throughout 

 the polyzoary. 



Hab. Straits of Magellan, 10 to 20 fathoms ; Tierra del Fuego ; 

 Patagonia, 48 56' S. L., 19 fathoms; Falkland Islands, 4 to 

 10 fathoms; Cape Horn, 40 fathoms, Darwin. On stone and 

 fuci. 



A very peculiar and remarkable form, readily distinguishable 

 by the enormous azygos spine on one side of the mouth, which 

 appears to be articulated to a short basal joint by a constricted 

 portion composed of cartilaginous or horny substance. 



16. LEPRALIA BICRISTATA. PI. XCIV. figs. 3, 4, 5. 



Cells ovate, ventricose, punctured round the margin, with a 

 central umbo perforated above ; occasionally a small avicularium 

 with a pointed mandible on one side of the cell near the top ; 

 mouth straight below, with four to six oral spines. Ovicell 

 globose, with two raised keels running across it from side to side, 



Hab. Cape Horn, 40 fathoms, Darwin. 



17. LEPRALIA MARGARITIFERA. PI. CI. figs. 5, 6. 



Cells deeply immersed, outline marked by punctures ; front 

 of cell raised into an elevated umbo ; mouth very large, nearly 

 round, with a thickened margin ; numerous larger and smaller 

 oval avicularia dispersed all over the polyzoarium, usually one on 

 the side of the mouth of each cell. Ovicell immersed, umbonate 

 in front. 

 F. margaritifera, Quoy fy Gaimard, Voy. de I'Uranie, pi. 92. 



figs. 7, 8. 

 Hab. Tierra del Fuego, on shell, Darwin. 



