calcahea. 



This classification is based primarily ou the arrangement of the spicules, as is 

 shown iu the following diagram, where the families are arranged in four columns to_ 

 show their dependence on the spiculation. The families on the same horizontal line 

 correspond more or less in their canal systems. 



No Sdbdermal Spicules. 



Spbdermal Trirawates. 



SCBDERMAL QUADRIEADIATES, 



Chiactines. 



Family. 



Genus. 



Family. 



Genus. 



Family. 



Genus. 



iSycetta . 

 Sycon. 

 Tenthrenodes 



'Grantia. 



Ute. 



Synute. 



Utella. 



.\namaxilla. 



Sycissa. 



Loucandra . 



Lelapia. 



Leucyssa. 



Dermatreton. 



2. Grautiida? 



3. Heteropidas 



^Grantessa. 

 Heteropia. 



j Voaraaji'opsis 



4. Araphoriscidiie 



/ Heteropegma 

 Amphoriseus. 

 Syculmis. 



I Leucilla 



iStreptoconus. 

 Hypodictyon. 



/Achramorpha. 

 Grantiopsis. 



Megapogou. 



New Families. — The two new families, Chiphoridee * and Staurorr}iapliidse,\ are 

 introduced to contain the 9 new species and 2 old ones which have chiaetine spicules. 

 The name chiaetine X is introduced to denote a sjiecial type of quadriradiate spic-ule 

 which diS"ers from the ordinary quadriradiates both in shape and in position in the 

 sponge. The chiaetine is a quadriradiate spicule lying with its basal ray directed 

 radially outwards (centrifugally) and its apical ray, which is lient at its base so as 

 to lie almost in line with the basal ray, directed radially inwards (centripetally) 

 and projecting into the gastral cavity. § This type of spicule has hitherto been 

 found in only 2 species of sponge, each represented by a single specimen, viz., 

 Leuconia crucifera, Pole'jaefl' (4) and Grant iojjsis cylindrica, Dendy (7). The 

 former is now included in the new genus Megapogon. The latter is transferred 

 to the new family Stanrori'haphtdse, the generic name being retained. In order to 

 make the present report a complete record of all S2:)ecies in the two new families, 

 l)rief descriptions of Megapogon crucifera and Grojitiopsis cglindrica, with drawing." 

 of the spicules, are included. 



In some of the new species this type of spicule occurs in conjunction with the 

 ordinary types, but in several it forms the whole gastral and body-wall skeleton, to 

 the exclusion of the ordinary quadiiradiates and triradiates ; its importance, therefore, 

 can hardly be over-rated, and fully justifies the formation of the new families. All 

 the species containing chiactines might have been included iu one family instead 

 of two, liut as they fall into two groups, which difier from each other in the same 

 way that the Sgcetfiilse do from the Grantiidse, it seemed better to divide them 

 under two corresponding new families. 



* X'-' "' cross ; tpo^xiv, to bear. 

 X \i, a cross ; (iktiV, a ray. 



t o-Touptis, a ci-oss ; /ja(^i's-, a needle or spicule. 

 § For a detailed description of the chiactines see Part III. 



