SPONGES COLLECTED IN PORTO RICO. 
379 
DEFINITIONS OF SYSTEMATIC TERMS USED IN THIS REPORT. 
Actine. The ray of a uniaxial ( diactinal or monactinal ) spicule or of an aster. 
Anatrixne. A tritene in which the cladi are directed backward. Fig. 1. 
Aster. A microsclere in which several rays (actines) proceed from a center or from a longer or shorter 
axis. 
Chela. A microsclere consisting of a 
more or less curved axial part, 
the shaft bearing at each end 
several recurved processes, 
the teeth. The chela is said 
to be palmate when the teeth 
(three at each end ) are broad 
and palm-like, the lateral 
teeth united with the shaft 
throughout their length, the 
median tooth separated from 
the shaft. Figs. 3, 4. 
Chiasler. A minute aster with very 
slender cylindrical rays, 
knobbed or not, sometimes 
truncate, at the ends. Fig. 2. 
Choanosoinal. Said of inicroscleres restricted to the clioanosome. 
Choanosome. Vide ectosome. 
Chord. Vide trixnc. 
Cladome. Vide trixne. 
Cladostrongyle. A rod-like megaselere rounded off at one end and divided into branches at other. 
Cladus. Vide trixne. 
Collenchyma. A tissue consisting of more or less 
stellatebranching cells, irregularly dis- 
tributed through a transparent, jelly- 
like ground substance. 
Connective. Vide secondary fiber. 
Conidus. A more or less conical projection on 
the surface. 
Cortex. An especially differentiated, dense, and 
more or less fibrous ectosome. 
Dermal membrane. A thin membranous ecto- 
some, or the membranous outer layer 
of the ectosome. 
Desma. An irregular, gnarled spicule. Fig. 5. 
Deuterocladus. Vide dichotrixne. 
Diactinal. Term applied to a uniaxial spicule in 
which growth proceeds in opposite directions from the point of origin. Thus, two equivalent 
and usually similar rays (halves) are produced, the point of origin remaining at or near the 
middle of the spicule. 
Di<-hotrisene. A truene in which the cladi are dichotomously divided. The undivided part of the 
cladus is th q protocladus. The distal divisions are the deuterocladi. Fig. 6. 
Ecacline. The centrifugal part of a radially arranged rliabdus. 
Ectosome. The outer layer of the sponge, not containing flagellated chambers. The rest of the sponge 
body, containing flagellated chambers, is known as the choanosome or parenchyma. 
Esactine. The centripetal part of. a radially arranged rhabdus. 
Euaster. Comprehensive term applied to asters in which the rays proceed from a center and not from 
an axis. 
Filament. Term applied to the elongated thread-like bodies, of problematical nature, found in species 
of Hircinia. These bodies are 4 to 8 mm. long, very slender, and dilated at the ends. 
6. Dichotriajne, view of the cladome, from above. 
7. Orthodisene. 
1. Anatriaene. For lettering, see triaene. 
2. Chiaster. 
3. Chela, face view. 
1. Chela, side view. 
5. Desma. 
