AET. 12 HEXACTINELLID SPONGES — OKADA 11 



times forming a large bundle. These macrouncinates (fig. 1, n) 

 are covered with spines, which protrude very obliquely and extend 

 nearly parallel close to the surface of the shaft of spicules. 



Pinnies are found on the dermal and gastral membranes, much 

 more sparsely on the latter. They usually stand close together, 

 their basal rays extending parallel for considerable distances and 

 forming a very irregular network. The dermal pinnies (fig. 1, c, d) 

 are 60/* to 80/a high, usually 65^. The four basal rays are nearly 

 always quite straight and form a regular cross with beams inter- 

 secting vertically. They vary from lOO/t to 200/x long, averaging 

 140/i, and are 4/* thick, proximally smooth for a very short distance, 

 and distally covered sparsely or thickly with either vertical or oblique 

 spines, which are sharply pointed. The distal ray is vertical to 

 the plane of the basal rays and consists of a smooth proximal part, 

 6/Li thick and lOju, or more long, and a bushy, distal, nearly conical 

 part covered with curved stout spines. This distal part is usually 

 50/A or more long and covered with stout, lateral spines, terminally 

 only slightly curved and extended obliquely upward, proximally 

 projecting almost transversely. 



Tiie gastral pinnies (fig. 1, /, g) are somewhat different from those 

 on the dermalia. The basal rays, measuring ISOj^ on an average, are 

 a little longer than the distal ray, which measures 120/i to 160jLt in 

 length. Most of the pinnies have a prominent, stout, terminal spine 

 and lateral spines obliquely extended upward on both sides, so that 

 the distal yrj makes a distally expanded bushy tuft. 



Besides these pentactinic pinnies, there are infrequently hexactinic 

 pinnies on the dermalia. They have a sparsely spined and some- 

 what shorter distal pinular ray, which, as a whole, is narrow and 

 feather-shaped, measuring 56^ on an average. The proximal ray is 

 slightly shorter than the paratangential rays of the same pinule, 

 measuring 68/* long and 4)U. thick at the base, with sharply pointed 

 end. It is beset with small, generally erect prickles, sparingly 

 present or entirely absent at the base but more numerous at the end. 



Among these pinnies there are found much more delicate pinnies, 

 which may be younger or abnormal forms. These spicules may occur 

 in ectosome and endosome as well as in choanosome ; in the hexactinic 

 pinnies, the six rays are unequal, beset with several sharply pointed, 

 echinated spines near the distal ends. The paratangentials are the 

 longest of all, 100/a to 140ju in length, and 4/x thick at tlie base, grad- 

 ually attenuating toward the sharply or conically pointed and some- 

 what curved end. The distal ray is the shortest and is covered with 

 weak lateral spines on the distal part. The pentactinic pinnies (fig. 

 1, e), which may occur together with the hexactinic ones, are nearly 

 the same size. The distal unpaired ra}^ usually measures d^ix long 



