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ordinary zocecia, from which they differ in form and size. In the majority of 

 species the kenozocecia are provided with scattered pores, while in a smaller 

 number of species and as it seems in all the species that may be referred to 

 Hippothoa Hincks, they are entirely without pores but possess a median, projec- 

 ting portion. In most species as in Chorizopora Brongniarti the zocecia are separ- 

 ated by a number of small openings, which however are wanting in a series of 

 species, e. g. in H. annularis and H. cornuta. 



H. annularis Moll. 

 Lepralia annularis Busk, Catalogue of Marine Polyzoa, Cheilostomata, pag. 85, 



PI. XCV, figs. 1, 2. 

 (Pis. XXI, figs. 7 a— 7 f). 



The zocecia are elongated, triangular, trapeziform or rectangular, from the 

 proximal end strongly ascending and terminating in a portion, which is strongly 

 arched from side to side as well as distally proximally and almost hunched or 

 expanded. The maximum height of this portion is attained approximately in the 

 distal third of the body. On either side of the aperture and bent a little towards 

 it there is a short, stout, wide expansion or acropetal spine, which is rounded at 

 the end and looks like a horn. The anter of the oblong aperture (fig. 7 b) is 

 provided with two lateral margins, which only converge slightly distally and 

 meet in a curve. Its poster has in the centre a very small, transversely oval 

 sinus bounded on each side by a trapeziform process, which is again separated 

 from a small hinge-tooth by a very small indentation. The well-chitinized oper- 

 culum (fig. 7 e), which has an accessory part corresponding to the sinus, is within 

 each lateral margin provided with a long, almost cucumber-shaped groove, which 

 is sm-rounded by a chitinized margin and probably serves as attachment for the 

 opercular muscles. The distal wall (fig. 7 d) is angularly bent from side to side, 

 and besides the two large distal pore-chambers, through which each zocecium 

 communicates with one or two others, we find in each lateral wall either 3 — 4 

 small pore-chambers or 3 openings, which correspond to as many pore-chambers in 

 the neighbouring zocecium. 1—4 small, superficial pore-chambers (fig. 7 c) are 

 found on most zocecia, most often on one side, but sometimes also on the other. 

 They appear near the suture towards the neigbouring zocecium and decrease in 

 size distally. Of these pore-chambers the proximal one is situated near the dis- 

 tal wall. 



The ooecia, which occur in shorter or longer, continuous, curved transverse 

 rows (fig. 1 a), are borne by short, broad, conically cup-shaped gonozocecia, which 

 are situated on the frontal surface of the zocecia and communicate with the latter 



