CALCAREA. 5 



of the flagellated chambers. The flagellated chambers touch each other only at the 

 corners and have no intercommunication canals. Serial tangential sections show that 

 each flagellated chamber opens independently into the gastral cavity. (See 

 Plate XXXVIII, Fig. 137.) This may also be inferred by comparing the distances 

 between the openings into the gastral cavity, shown in von Leudenfeld's Figs. 56 and 

 58, and the distances between the flagellated chambers shown in Fig. 57 (remembering 

 that the rectangles are alternately flagellated chambers and canals). The cross-sections 

 made by the author correspond exactly with the structure above described. It 

 is, therefore, evident that there is no similarity between Sycn tcni'llum, as it 

 should now be called, and the new genera with " linked " chambers. 



The new genus Streptoconus* in the family Staurorrhaphidse, corresponds with 

 Sycon in the Sycettidse, 



The new genera Achramorpha f and Megapogon J in the family Staurorrhaphidse 

 correspond with Grant/a and Leucandra in the Grantiidse. 



Dendy's sub-genus Grantiopsis is transferred from the Grant lid as to the St<nirtirrli<i- 

 pliiilve, because the only species (Grantiopais cylindrica) contains chiactines. 



TERMINOLOGY. The following terms arc used to describe the different pores 

 and passages by which the water passes through the sponge : 



Ostia. The pores in the dermal membrane through which the water first enters the spony . 



Prosopylf*. The openings in the flagellated chambers by which the water enters them. 



A/ni/ii/les. The openings in the flagellated chambers by which the water leaves them. 



Ports. This is a new term used to describe the openings in the gastral membrane by which the 

 water passes from the excurrent chambers into the gastral cavity. 



Pore.is, only used in a general sense for any of the above. 



Incurrent chambers. The large spaces sometimes found under the dermal cortex. The water 

 enters them by the ostia and leaves them by the incurrent canals. 



Innirrent, canals. The passages by which the water reaches the outside of the flagellated 

 chambers. They communicate with the outside water either through the ostia or directly. 



Excurrent canals. The passages by which the water, leaving the flagellated chambers through 

 the apopyles, reaches the gastral cavity or oscule. 



Exrurrent chambers. The spaces sometimes found outside the gastral membrane into which 

 several excurrent canals or several apopyles open. The water flows out of them through ports into 

 the gastral cavity. 



Oscule. The opening by which the water finally leaves the sponge. It may be at the end of one 

 or more excnrrent canals, or at the top of the gastral cavity. 



Oscular collar. A thin tubular extension of the body wall, without flagellated chambers, leading 

 to the oscule. 



The most interesting features of the collection are : 



(a) The large number of species (9) containing chiactinc spiculrs. 



(b) The five new species with " linked " flagellated chambers. 



(f) A remarkable sponge, Megapotjon rillosim, with larger spicules than any hitherto recorded for 

 a calcareous sponge. The oxea are upwards of 15 mm. long. 



* trrpciTTos, twisted ; K>VOS, a cone. t <<XP af ' a l lear > P"l"t> 



^ p.tyas, great ; nwyw, a beard, 



