PANAMA SPONGES — DE LAUBENFELS 449 



dermal tylostyles are as small as 1/x by lOO/i. Some of the endosomal 

 tylostyles reach the maximum size of 20^ by 670)u and are minutely 

 spined on their heads. The echinating acanthostyles are 9m by 90/x, 

 the toxas 120/i long, and the palmate isochelas 12^ to 15/x. 



This, the genotype of Microciona, was described by Bowerbank 

 (1862, p. 1109) from Great Britain, and his description of European 

 specimens might do well for this from Central America. There is 

 no significant point of difference, and the identification is made 

 confidently. 



Genus HALICHONDRIA Fleming 



HALICHONDRIA PANICEA (Pallas) 



This cosmopolitan sponge is represented in the collection by 

 U.S.N.M. no. 22202 from the Pacific coast and by no. 22232 from 

 the Caribbean, It was found encrusting rocks intertidally at both 

 ends of the Panama Canal, on the beach at Fort Randolph on the 

 Atlantic end, and on the Pacific side both on the mainland at Panama 

 City and also on Taboga Island, 10 kilometers offshore. It is a thin 

 crust, pale orange in life, friable in consistency, with a smooth sur- 

 face, readily detachable special dermal membrane containing tan- 

 gential spicules, which are, however, like those in the endosome, 

 namely, sharply pointed oxeas of great variation in size. They range 

 commonly from 3/x by ISO/x to ll/x by 270^ and sometimes even to 

 16m by 930m. 



It may conceivably be that there are different species of sponges 

 in various parts of the world all of which by convergent evolution 

 happen to share the same characteristics in common, and all identi- 

 fied as Halichondria panicea, but since it is impossible to separate 

 them sharply on any characteristics that may be recorded on paper, 

 it is customary to identify them all with the long-known European 

 form first described as Spongia panicea by Pallas (1766, p. 388). 



Genus PSEUDOSUBERITES Topsent 



PSEUDOSUBERITES SULCATUS (Thiele) 



This species, represented in the collection by U.S.N.M. no. 22214, 

 was found growing on submerged wood near the piers in Balboa 

 Harbor at the Pacific end of the Panama Canal. In life it was dull 

 drab and semitransparent. The consistency is very soft; the surface 

 is even, provided with a detachable special membrane over extensive 

 subdermal cavities. This ectosome contains spicules tangentially 

 placed. There are surface openings about 140m in diameter, but 

 these are not sharply differentiated into oscules and pores. In the 

 endosome the spicules are arranged in considerable confusion. They 

 are tylostyles ranging from 4m by 160m to 6m by 275m. 



56905—36 2 



