Ill 



systems of three cycles, which are unequal according to the orders, a 

 little thick hut conspicuously swollen and rounded at the extra-mural 

 part. The costae are conspicuous on the edge of the young calices, but 

 the whole corallum is covered with a thick compact outer layer or 

 sheathing tissue, which is covered with fine anastomosing grooves. On 

 one branch these grooves form circles like tattooing ; underneath this 

 the costae seem to he very continuous, and each is covered with a linear 

 series of small granules. In most of the broken fragments the outer 

 sheath can be seen plainly. 



This species comes very near A. venusta, E. and EL, but the peculiar 

 striations on the outer sheath, and the costae distinguishes it sufficiently. 

 Some of the calices fill up from below by a kind of spongy tissue which 

 results apparently from a union of the septa ; others are quite empty to 

 the base to which the calice narrows in a curved line, the point being 

 only separated by a very thin wall from the curved upper portion of the 

 alternate calice below. This is a variation in the structure which affects 

 Prof. Duncan's reasons for transferring Amphihelia to the Turbinolidse. 

 It is not confined to the young branches, but is seen in the oldest 

 portions of the corallum and in calices adjoining one another. 



Amphihelia Ziczac, n.sp., pi. 2, fig. 2. 



In the species which I am about to describe there are peculiarities 

 which I think should place it almost in a genus apart. There is an axis 

 into which the calices are sunk, and then outside this, but separated by 

 hollow space3, there is an outer sheath of some thickness. These hollow 

 spaces seem to have no communication with the visceral cavities. It 

 seems like an outer covering of dermic tissue, which was secreted over 

 the basal structure while the lower cells were alive, leaving large 

 apertures for them. As far as can be seen also, the septa are represented 

 only by merely raised rounded lines on the upper part of the calice, and 

 though they are never conspicuous in the genus, yet here they can 

 scarcely be seen except at the bottom of the visceral chamber where thev 

 are confluent. The following is the diagnosis : — 



Corallum in zigzac branches of various thickness, the longer or pro- 

 bably basilar ones having an outer sheath with interstices, which do 

 not communicate with the visceral cavities. Calices at every angle, pro- 

 jecting, alternate, numerous, and at equal short distances. Septa only 

 salient at the bottom of the calices, and represented by rounded lines at 

 the upper part, and not visible at all at the margin, in three cycles ; 

 the two first equal, and confluent at the base, but no calice was preserved 



