MARINE POLYZOA. 11 



13. CATENICELLA CORNUTA. PI. X. figs. 1, 2, 3. 



Cells oval. Avicularia in most cells wholly transformed into 

 long pointed retrocedent spines, on one or both sides ; in others 

 into shorter spines, or unaltered. Vittse linear, extremely nar- 

 row, lateral, and extending the whole length of the cell from the 

 base of the avicularium. Surface in front smooth. 



Catenicella cornuta, Busk, Voy. of Rattlesn. i. 361. 

 Rob. Bass' Strait, 45 fathoms. 



Colour yellowish white; growth small; parasitic upon C. am- 

 phora. As some difficulty might be experienced in the discrimi- 

 nation of this species from C. elegans and another South African 

 species (C. taurina), it is requisite to remark that the long re- 

 trocedent spines, when present, are not placed upon or super- 

 added to the avicularia, but that they seem to represent an 

 aborted or transformed state of those organs. They vary much 

 in length and size in different cells, and even in those of the 

 same branch, as it frequently happens that there is a spine, 

 usually of diminutive size, on one side, and a very large avicu- 

 larium on the other; sometimes (but rarely) an avicularium 

 of more moderate size on both sides. But the character of the 

 species by wiiich it is more particularly distinguished, consists in 

 the presence on a great many cells, in one part or other of the 

 polyzoary, of the two long and strong spines projecting back- 

 wards. 



14. CATENICELLA UMBONATA. PI. X. figs. 4, 5. 



Cells more or less pyriform, narrow below, bulging or ventri- 

 cose above. Avicularia large and strong. Vittae strap-shaped, 

 anterior, extending from the level of the mouth to the bottom of 

 the cell, with acuminate papillae. A broad compressed project- 

 ing process on the middle of the back. Surface in front papil- 

 lose. 



Catenicella umbonata, Busk, Voy. of Rattlesn. i. 362. 

 Hab. Bass' Strait, 45 fathoms. 



The cells in this species are small, inflated or ventricose, and, 

 as it were, subglobular above, becoming much attenuated below ; 

 but the cavity of the cell does not appear to extend into this 

 contracted portion, in which is contained the connecting tube, 

 strengthened by calcareous matter, the inferior continuation of 

 the lateral alee, which descend from the base of the avicularium. 

 Owing to the large size of the avicularia the upper part of the 

 cell is much widened, and the whole acquires somewhat of a tri- 

 angular form, and has a peculiar rugose aspect ; derived in part 

 also from the large size and elevation of the acuminated papilla?. 



