DUBLIN UNIVEESITT ZOOLOGICAL AND BOTANICAL ASSOCIATION. 135 
ditional terms I have adopted from Dr. Allman’s excellent “ Memoir on 
the EreSh-water Polyzoa.” As any accurate information with regard to 
the geographical distribution of these forms is of importance, I have iu - 
corporated with those collected by Dr. Harvey one or two smaller col¬ 
lections, sent to him with Algae from various parts of the world. A 
series, lately procured by Dr. Joliffe in Hew Zealand, is very interesting. 
I began an examination of foreign Polyzoa and Zoophytes in the hope 
of falling in with some clue to the affinities of some Palaeozoic forms, and 
especially of the Graptolites. In this I have hitherto been disappointed. 
Although the Graptolites appear in some respects to approach the Po¬ 
lyzoa ctenostomata, they have still peculiarities which are apparently 
inconsistent with the structure and mode of growth of any living order. 
In Dr. Harvey’s collection the Cyclostomata and Ctenostomata are 
few in number. The Hydroid Zoophytes are very numerous, and most 
interesting. They are in progress of illustration. 
The second part of this communication will conclude the Cheilosto- 
mata. 
Class.—POLYZOA. 
Order 1.—P. infundibulata. 
Sub-Order 1.— Cheilostomata. 
Sect. 1.—Articulata. 
Subsect. 1.—ITniserialaria. 
Family 1.—Catenicellidee {Busk), 
Genus 1.— Catenicella {Blainville). 
As usual in collections from the other side of the Equator, the Cate- 
nicellse are prominent and abundant. Most of the species in the “ Rat¬ 
tlesnake” collection are repeated, and seven undescribed forms occur. 
One new species belongs to the fenestrate division; the second differs so 
completely from every described form as scarcely to be referable to any 
of the formerly characterized groups, though occupying a position to a 
certain extent intermediate between the two first: four are vittate; and 
the seventh, though distinctly a Catenicella, and closely allied to C. aurita 
{Busk), simulates to a certain extent the structure of the remarkable 
genus Calpidium. 
Some of the new forms throw some little additional light upon the 
structure and development of the ccenoecium. In C. Harveyi and in 
C. alata , the two membranes of which the cell wall is composed are re¬ 
markably distinct. In the former species particularly the outer layer 
seems scarcely to be in contact at any point with the inner, investing it 
like a loose horny sac. The large 11 avicularian processes” are open and 
cup-like, with ragged edges. In C. alata the two layers are also very 
distinct; but they are in contact over the greater part of the surface of 
the cell. In both species the upper spine or cup and the lower division 
of the lateral processes are formed of the outer membrane alone; while 
the true avicularian chambers, with the avicularia, are processes of the 
