ANARTHROPORA MONODOX. 233 



by the thickening of the peristome, and is somewhat 

 irregular in adult cells ; but in its primary condition it is 

 arched above and straight below. The special pore is 

 absent ; the opening which usually exists on the front of 

 the elevated portion of the cell is merely avicularian, and 

 is in no sense the equivalent of the raised tubular pore 

 of the Porince. 



Anarthropora monodon, Busk. 



Plate XXXIII. figs. 10, 11. 



Lephai.ia monodon, Bu»k, Quart. Journ. Micr. Sc. vii. 213, ^\. xxix. figs. 3, 4 : 

 Norman, Shetland Pol., Rep. B. A. 1868, 308. 



An'.vrthropora monodon, forma majuscula, Smitf, CEfvers. &c., 1867, Bi- 

 hang, 7 and 64, pi. xxiv. figs. 23, 24 {not figs. 20-22) : 

 Hincks {A. monodon), Ann. N. H. Dec. 1877, 528. 



Anarthropora minuscula (part.), Smitt, Flor. Bryoz. pt. ii. pi. vi. fig. 141. 



Zooecia ovate below, somewhat depressed_, above suberect, 

 produced into a short neck ; surface (in the adult 

 state) reticulato-punctate, covered with stellate perfora- 

 tions ; occasionally radiating ridges round the border ; 

 orifice (primarily) arched above^ with the lower margin 

 almost straight, often much contracted in the older 

 cells j peristome much thickened, without spines ; a 

 circular hole in front, immediately below the inferior 

 margin, placed centrally or at one side, which is fre- 

 quently covered by an avicidarium, with an acute man- 

 dible, directed obliquely upwards ; on the upper margin 

 also an aviculariiim, or, in its absence, a small circular 

 pore. Ooecia unknown. 



Colonies w^ith a somewhat branching or dendritic habit of 

 growth. 



B/ANGE OF Variation. In young cells the surface is smooth 

 and polished, and wants the rather coarse reticulated 

 covering which characterizes the adult. In this condition 

 the punctures are very distinct, and show their beauti- 



