334 Messrs. Young on new Carboniferous Polyzoa. 
paper we sent to Professor Phillips specimens of Ph. gracile, 
and received in reply the following note, among the last which 
he wrote :-— 
“ April 3, 1874. 
“ My Dear Srr,—I agree with you in referring your beau- 
tiful specimens to the three species (MZ. gracilis, M. rhombifera, 
M. interporosa) named in my books (‘ Yorkshire,’ vol. ii., and 
‘ Paleozoic Fossils’). Your examples are better than mine 
were; but I have no doubt of the reference. The axis, which 
is jomted in your specimens, has probably been examined 
(small as it is) in transverse sections. The difference of oppo- 
site faces in C. or Rh. rhombifera is very interesting. .... 
“ Yours truly, 
“ JOHN PHILLIPS.” 
The appearance of jointing is fallacious, as Prof. Prestwich 
may ascertain, the specimens having been retained by Prof. 
Phillips for the Oxford Museum. 
RHABDOMESON, Young and Young, 1874. 
Rhabdomeson rhombiferum, Phillips’s species. 
Ceriopora rhombifera, Phillips. 
Stems slender, cylindrical, free ; branches of nearly equal 
diameter, given off at wide intervals, as in Rh. gracile, and 
at right angles to the stem. Cells in quincunx all round the 
stem; they open at the bottom of depressed areas which are 
rhomboidal or hexagonal in outline and are bounded by narrow 
tuberculated ridges, the tubercles on which are larger at the 
angles of junction ; average number of tubercles round each 
area, sixteen. Here and there depressed pits with quadran- 
gular boundaries intervene between adjacent cell-areas; but 
they are cecal, and do not show in transverse sections. Cell- 
areas more numerous on one face than on the other, in the pro- 
portion of 2 to 3, the size of the areas being inverse to their 
number. Central axis slender, slightly flexuous, and without 
transverse septa. Cells conical, tapering inferiorly ; their 
casts identical in form with those of 2h. gracile (Ann. & Mag. 
Nat. Hist. 1874, xiii. pl. xvi. B. figs. 3 & 4). 
Locality Hairmyres, East Kilbride, in limestone shales, 
and sparingly in every bed which yields Rh. gracile. 
This species is easily distinguished from Ph. gracile : 1, its 
stem is only half the thickness; 2, the cell-areas are larger 
and angular; 3, the prominent angular tubercle is wanting ; 
