BRYOZOA. 297 



morphologically the same. In a strict sense the "monticules" 

 are circumscribed areas on the surface of the zoarium which are 

 elevated to a variable degree above the general level and con- 

 stitute a more or less regularly distributed series of conical 

 rounded or elongated eminences. Usually the "monticules" 

 are occupied by zooecia more or less decidedly larger than those 

 of the average size in the intervening spaces, though in some 

 cases the difference in this respect is quite inappreciable. Ap- 

 parently always, however, the cells on the monticules are dis- 

 tinguished by some peculiarity, so that if they are not larger 

 they may be recognized by their thicker walls, or by the greater 

 width of the spaces between them. Monticules having the struc- 

 ture here described are present in Afonticulipora mammulata 

 D'Orb., M. cincinnatiensis Nicholson, Callopora ramosa D'Orb., 

 Monotrypa? filiosa D'Orb., Discotrypa elegans, Spatiopora 

 montifera and Homotrypa dawsoni Nicholson. 



The "maculae" like the "monticules" are circumscribed spaces 

 on the surface of the zoarium, but differ from them in being 

 composed of aggregations of mesopores or vesicular tissue, in- 

 stead of groups of large zooecia. It is a fact, however, that 

 the zooecia which surround the "maculae" are almost invaria- 

 bly appreciably larger than those farther removed from the 

 centre of a "macula." The surface of the maculae may 

 be finely porous (e. g. Heterotrypa subpulchella NicholsoD, 

 Crepipora impressa), with the mesopores visible but closed 

 (e. g. Dekayella obscura and Peronopora decipiens Rom- 

 inger). apparently solid and elevated above the general 

 level of the surface (e. g. Atactopora maculata, Crepipora 

 solida), or smooth and depressed. The last condition is the 

 most typical and common, and is represented in a more or less 

 marked manner by all of the FISTULIPORIDJ;, and many of the 

 CYSTODICTYONID.E. In these families the interspaces between the 

 zooecia are occupied by lenticular vescicles which, at any rate 

 in the perfect adult state, are not visible at the surface. The 

 'maculae" are depressed, often stellate and quite regularly 

 arranged, when they impart a very characteristic and orna- 

 mental appearance to the zoarium. Though of rare occurrence, 

 "maculae" are also occasionally present among the STICTOPO- 

 (e. g. Pachvdictya and Phyllodictya) , but the non-porifer- 

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