112 



THE SPONGES OF THE WEST-CENTRAL PACIFIC 



Dendoricella, in the Desmacidonidae, which is almost the only other sponge 

 with similar megascleres. The microscleres which occur in the type species 

 of Dendoricella are very peculiar chelas with stegosaurian projections on 

 their convex side. The other species referred to Dendoricella has chelas 

 which are between palmate and arcuate. 



The type species of Ichnodonax is characterized by a peculiar shape in 

 which cylinders arise at intervals from a buried rhizome so that they look 

 almost like footprints as they reach the surface. The generic name selected 

 is derived from the Greek for "a series of tracks." 



Ichnodonax kapne, new 



Text Figure No. 71 

 Plate VI, Figure a 



This species is here represented by the following : 

 U.S.N.M. No. 23130, My No. M. 513, here designated as type, collected Sep- 

 tember 6, 1949, by using a fish spear in Iwayama Bay near Ulebsechel 

 Island. The depth was less than 2 meters, and the sponge was living 

 partially buried in coral sand. 



This species consists primarily of a rhizome, nearly 1 cm in diameter, 

 which was buried in sand. It extended laterally at least 10 cm. The portion 

 which was collected probably represents only a fragment of the whole. From 

 this buried portion chimneys arise at intervals. These hollow cylinders are 

 commonly 3 to 4 cm high and reach 14 mm in diameter. Only one has the 



CK> <C=^d3 ==c> 



Text Figure No. 71. Spicules of Ichnodonax kapne, X 781. A: Oxea; the entire spicule 



is shown, but in two parts. B and C: Two of the strongyles. D: Three of the palmate 



isochelas ; the central one of the three is drawn as seen in side view. 



