NO. 17 NEW SPONGES— DE LAUBENFELS 7 



in which the dichotomously branched portion of each clad is longer 

 than the unbranched proximal portion. The chord diameter is about 

 800 /x, the rhabd 70 /x by 2,000 /x. There are also a few anatriaenes, 

 chord about 80 /x, rhalxls 10 /x by 1,000 /x. The microscleres are chiefly 

 abundant spiny microrhabds 2 ^u, by 9 /x, mainly in the ectosome. There 

 is a slight tendency for the spines to be nodally arranged. On a few of 

 these microscleres the spines are very thick and coarse, in which cases 

 not so many occur. Such spicules reach external dimensions of 3 ju by 



IS/"- 



In addition to Tcthyopsis and Monosyringa, a third closely related 

 genus is Trihrachion Weltner, of which the genotype, T. schmidtii 

 Weltner (1882, p. 50), is a West Indian species. The external shape 

 is similar, but the dichotriaenes seem lacking and the anatriaenes com- 

 mon. There are euasters in schmidtii^ but I could not find them in 

 fisheri, and the streptasters were only slightly bent spirasters with 

 rather long spines. This must nevertheless be regarded as the species 

 most closely related here. 



Named for Prof. Walter K. Fisher, of Stanford University. 



Family GEODIIDAE Gray 

 Considered here to include Erylidae Sollas. 



ERYLUS Gray 

 ERYLUS ALLENI, n. sp. 



Holotype. — U.S.N.M. no. 22268; from station 16, latitude i8°29' 

 40" N., longitude 66°o8'3o" to latitude i8°3i' N., longitude 66°io' 

 15" W., February 3, 1933, of 38 to 95 fathoms. 



This specimen is a cylindrical structure 1.5 cm in diameter, 2.5 cm 

 high, with one conspicuous cloaca or oscule apically located. The color 

 is pale gray. The consistency is astonishingly spongy. The surface 

 is skinlike, even. The pores are abundant, about 400 fi apart, 40 /x to 

 80 ju, in diameter. The internal structure is like " crumb-of-bread ", 

 minutely cavernous. The spicules are chiefly oxea, 12 fx by 660 /*, and 

 triaenes that are almost calthrops. The clads are 13 /x by 200 /x to 

 300 p., the rhabds 13 /x by 250 fx to 300 /x. The most conspicuous micro- 

 scleres are the ectosomal aspidasters, which are 35 ;W by 70 ju, in great- 

 est dimensions. Those that seem to be most fully developed have 

 conspicuously granular surfaces and reach a total thickness of about 

 5 IX. As is usual in this genus, they overlap to make a special armor. 

 There are two distinctive size ranges of euasters. The larger ones. 



