on the Genus Paleacis. 217 
unanimity amongst them as to the systematic position of 
Paleacis amongst corals. There is, however, one fact we 
must not omit to refer to. It was pointed out by Meek and 
Worthen that increase took place by interstitial development ; 
we find that a kind of fission occurs in some of the cups of 
P. cyclostoma (Pl. XII. fig. 16); and we are inclined to 
regard this as one of the few characters present indicating any 
- alliance with the Actinozoa. 
We distinctly wish it to be understood, in closing this part 
of our remarks, that we by no means finally assert Palwacis 
to be a sponge, although we consider it has a much closer 
alliance with the latter than with the Actinozoa, so far as 
the researches we have at present undertaken enable us to 
judge. 
With regard to the name this organism should bear, Von 
Seebach, Kunth, and De Koninck have all adopted Paleacis 
in preference to Sphenopoterium, on account, as they state, of 
the previous publication of the former. The third volume of 
the ‘ Hist. Nat. des Coralliaires’ bears date of publication 
1860, whilst that portion of the ‘Proc. Acad. Nat. Sci. of 
Philad.’ containing the description of Sphenopotertum bears at 
the foot of certain of the pages the date “October, 1860.” If 
this represents the date of publication, as we believe it does, 
Meek and Worthen’s name may have as good a claim for 
recognition as Haime’s; and if the Protozoal character of the 
fossils known by these names come ultimately to be adopted, 
it will become a question if we should not rather make use of 
Sphenopoterium as the generic term. 
Addendum.—The genus Conoptertum, Winchell, is evidently 
very closely allied to Palwacis. We are, however, not suffi- 
ciently acquainted with it to enter into details on the subject. 
Conopterium was described by Prof. A. Winchell, in the Aca- 
demy of Natural Sciences of Philadelphia (‘ Proceedings,’ 1865, 
p- 110), as a coral, and its resemblance to Sphenopoterium, 
M. & W., pointed out. 
3. Description of the British Species. 
Paleacis cuneiformis (J. Haime), M.-Edw. 
Paleacis cuneiformis (J. Haime), M.-Edw. Hist. Nat. Corall. 1860, iii. 
3 
p- 171, Atlas, pl. E 1. f. 3. 
Sphenopoterium cuneatum, Meek and Worthen, Proc. Acad. Nat. Sci. 
Philad. for Oct. 1860, p. 448; id. Illinois Geol. Surv. Rep. 1866, ii. 
p. 262, pl. 19. f. 1, a-d. ; 
Paleacis cuneiformis, Von Seebach, Nachr. k, Gesellsch. Wissensch. zu 
Gott. for 1866, p. 241 ; id. Zeitschr. deutsch. geol.Gesellsch. 1866, xviii. 
Ann. & Mag. N. Hist. Ser. 5. Vol. i. 15 
