416 BULLETIN 100, UNITED STATES NATIONAL MUSEUM. 



This difference in morphogenetic behavior may be looked on as a 

 variable feature. In Dendy's type the main fibers are about 140 u, 

 thick, connectives about 84 [*; oxea 84 by 3.5 |x; color, deep blue. 

 . Dendy (1905, p. 155) proposes to regard S. crassifibra as a variety 

 of S. {Tuhulodigitus) communis (Carter), recorded by himself 

 (1889, p. 81) and Carter (1881, p. 367) from the Gulf of Manaar, 

 also by Ridley (1884, p. 401) from Port Jackson, Australia. For 

 this form Ridley gives the primary fibers as only 35-42 u, thick; 

 oxea 100 by 5 jx. Dendy more recently (19165, p. 114) has recorded 

 S. crassifibra from Okhamandal. In these (Okhamandal) sponges 

 it may be noted that the primary fibers are only about 50 u, thick, 

 a close approach to S communis. Dendy (1905) touches on the 

 vagueness of the characters which differentiate S. communis, crassi- 

 fibra and a number of other Siphonochalinas. Row (1911, p. 325) 

 has recorded S. communis from the Red Sea. 



Genus DACTYLOCHALINA Lendenfeld (1887). 



Dactylochalina Lendenfeld, 1887, p. 810 plus Chalinodendron Lendenfeld, 

 1887, p. 819. 



Sponges with solid digitate processes, the processes generally 

 cjdindrical and slender, often branching and anastomosing, some- 

 times very numerous. Fibers of skeletal reticulum polyspicular, 

 generally slender. Meshes of reticulum remarkably large. 



In Lendenf eld's classification (1887) of the Chalinine sponges, 

 Chalinodendron is distinguished from Dactylochalina chiefly by the 

 reticular appearance of the surface ("mit netzformiger Oberfliichen- 

 Structur"). This would seem to be a secondary feature dependent 

 on the large size of the skeletal meshes, and these in both genera are 

 large, varying from 200 to 300 [x in width in Chalinodendron, from 

 130 to 400 ;x in Dactylochalina. 



The fibers are polyspicular and generally slender in both genera, 

 but slenderer in Dactylochalina, in most species of which, but not 

 invariably, there is no noteworthy difference in thickness between 

 the main fibers and the connectives. In some of the Chalinodendron 

 species (C. exiguum and C. minimum), however, the fibers (50 u.) 

 are no thicker than in some of the Dactylochalinas, and in one spe- 

 cies (C. exiguum) there is no noteworthy difference in thickness 

 between main fibers and connectives. 



The spicules are somewhat, or considerably, larger in Chalin- 

 odendron than in Dactylochalina, but in C. ramosum they are only 

 110 by 5 u, and in the Albatross form, described below, and which is 

 obviously very close to C. exiguum, they are still smaller, 100 by 4 [x. 

 Among the Dactylochalina species, we find spicules 100 by 3 u., 90 

 by 2 [x, 67 by 4 [x, 60 by 2 [x. 



