Note oil, Shidiria mirabilis. Bi/ I'm/. J. A. Tlwmxon. 11!) 



thesumiiiit there is a terminal polyp whicliis larger than the others. 

 In many cases a branch has a Icn^tli of 1") mm. and a maximum 

 diameter of 3 mm., but in re^fard tu tliese and other measurements 

 of soft parts it must be remembered that the whole colony hiis 

 been much contracted liy preservation in strong sjiirit (])late X^'I. 

 fig. 2.). 



The jiolyp-s liavc alniii.sl globular calyces or verruau, with 

 a (liaincler of about 1 mm. 'J'he tentacles are in most cases com- 

 pletely retracted, and the summit of the calyx shows a sharply 

 defined circular aperture. The polyps with their calyces and pre- 

 cise circular aperture recall those of some of the Pennatulids, such 

 as A'ii'gularids. On the wall of the calyx there are eight triangular 

 point.s, each con.sisting of two to three pairs of spicules arranged 

 111 rhcrron, .surmounting a c'oUaret of .several horizontal rows. In 

 most cases, however, the projecting spindles of the cortical camen- 

 chyma hide the base of the calyx and may even intrude upon 

 it. The anthocodia is very minute and is completely retractile 

 within the globular calyx. The tentacles are short and thick, 

 apparently without spicules, and with about half a dozen pairs of 

 pinnules. 



Spicules. — Apart I'rom a few irregular minute forms found on 

 the canal walls (and possibly extraneous) all the spicules are 

 spindles. Many are huge, most are densely warted. The warts 

 are often in close-set transverse rows, .so that the spindle has a 

 striated appearance. Many of the spindles are cuived in a sinuous 

 fashion ; not a few are irregularly forked (])late XVI. fig. 3). 



The following measurements were taken of the spicules, length 

 and breadth in millimetres : — 



Krom the stalk: 9-5 X -534; 7 X -51 ; o-?.". X --ITe. 



From the cortex : o 

 From the inner wall) 

 of the cup : I 



From the canal walls : 

 From the polyps : 1 



Position of Stiiilcria. — If this type is to be referred to any of 

 the recogni.sed families ol' the Alcyonacea it must In; to the Alcyo- 

 niidic. In the retractility of the whole polypariiim, as well as 

 in the mode of brand ling, the disposition of the polyps and 

 theii- armature, it is removed from the Nephthyids and Siphono- 

 gorgids. 



In certain respects, e.g. the distinct calyces into which the 

 delicate upper parts of the poly] is are retracted and the large 

 longitudinal canals continued in part to the base of the colony, 



