THE SPONGES OF THE WEST-CENTRAL PACIFIC 149 



only two branchings occurred, one of them near the tip of one of the two 

 first branches. 



The color in life was dull dark red, and the interior was somewhat paler 

 than the exterior. The consistency was extremely spongy. 



The surface was more or less smooth and lipostomous, but it is here 

 considered probable that pores and oscules closed very quickly at the time of 

 collection. 



The ectosome and the endosome are separated chiefly by a color differ- 

 ence, but the ectosome is somewhat more dense in structure. The endosome 

 is characterized by a fibro-reticulation. 



The skeleton consists of fibers of yellow transparent spongin with scat- 

 tered spicules inside them. The fiber diameter is about 120 ll, and the meshes 

 are of very irregular size, often as much as 600 fi in diameter. The spicules 

 consist of smooth tylostyles, 2 ^ by 180 li to 4 ll by 320 fi in dimensions. The 

 microscleres comprise typical toxas, 50 ll to 65 il long, and palmate isochelas 

 12 ll long. 



No other species in the genus Axociella has such an extremely attenuate 

 shape, and most of them have very much larger spicules. Others have smaller 

 spicules and lack toxas, but there is probably just one species in the vicinity 

 of Australia thus characterized (but having several names already attributed 

 to it). 



The species name selected refers to the fact that the specimen from 

 Ponape looked exceedingly like injected arteries. 



The species first described as Axociella calla by de Laubenfels, 1934, 

 page 16, is here transferred to the genus Axocielita because of its incrusting 

 shape. The same action is also taken with that species first described as 

 Ophlitaspongia membranacea by Thiele, 1905, page 450, and erroneously 

 transferred to Axociella by de Laubenfels, 1936, page 113. The species calla 

 is from the West Indies, and the species membranacea is from the west coast 

 of South America. 



GENUS IOTROCHOSTYLA, new 



This genus is characterized by having a spiculation of smooth styles with 

 birotulate microscleres. It obviously belongs close to such genera as Iotro- 

 chota, which is in the Desmacidonidae, and Hiattrochota, which is in the 

 Myxillidae. Yet, it conforms nicely to the family diagnoses of Ophlita- 

 spongiidae. If sponges were reclassified in such a way that those having 

 similar microscleres were therefore in the same family, chaos would result, 

 because as a rule it is discovered that exceedingly different species may have 

 similar microscleres. Those having birotulate microscleres may constitute a 

 special case, inasmuch as they do seem related in other respects — not true in 



