98 THE SPONGES OF THE WEST-CENTRAL PACIFIC 



The ectosome, as noted above, is a confused jumble. The interior is a 

 fibro-reticulation but also is so confused that it is not practical to give mesh 

 sizes. 



The skeleton contains spongin, to judge from its flexibility, but this is 

 not conspicuous in sections. The principal skeletal structures are the spicules, 

 which are diactinal and 5 /x by 175 /x to 5 fi by 180 fx in dimensions. The 

 ends appear hastate but, on the other hand, show a progressively graded series 

 of steps so that they may be malformed strongyles. A number of thinner 

 spicules may be juvenile forms. 



The species aga is more like the two species which hitherto have been 

 placed in this genus than was ada, The type of the genus was first described 

 as Siphonochalina bispiculata by Dendy, 1895, page 246. Burton, 1934, 

 page 562, established it as type of Protophlitaspongia and, at the same time, 

 added a new second species, oxeata. Both of these are from Australia. The 

 first, that is to say bispiculata, has megascleres about the same diameter as 

 those in aga but some very much shorter, and its structure, being lamellate, 

 is very different. The second, or oxeata, is closer to aga but is described as 

 brown in color and as having a very different appearing surface. 



The species name is selected for brevity, because the genus name is long. 

 It has no especial translation or significance. 



ORDER POECILOSCLERINA, Topsent (or POECILOSCLERIDA*) 



FAMILY ADOCIIDAE de Laubenfels 



GENUS PELLINA Schmidt 



Pellina eusiphonia Ridley 



Text Figure No. 60 



This species is here represented by the following : 

 U.S.N.M. No. 22983, My No. M. 360, collected July 5, 1949, by diver in 

 the Pearl Pool at the western portion of the lagoon at Ebon Atoll. The 

 depth was 5 meters, and the substrate was dead coral. 



The sponge has the shape of hollow cylinders with walls less than 1 mm 

 thick and often only 250 (x thick. The diameter of the tube is about 3 mm, 

 more or less, and the length is often 10 cm. 



The color in life was pale grayish purple to pink, and the consistency 

 was weakly spongy. 



To the naked eye, the surface is even, but microscopically a few spicules 

 project at right angles here and there. The pores are 80 /x in diameter and 

 are crowded very closely together. The oscules cannot be seen, or they may 

 be represented by the distal terminations of the tubes. 



See footnote on page 4. 



