264 VINE : POLYZOA OF THE LOWER AND UPPER GREENSAND. 
which two very simple branches dilate on either side, but unlike 
P. dilatata, these do not diverge at any great angle. From the 
centre of these two branches a larger flabellate, alternately diverging, 
branch is developed. The whole colony is about 15 mm. in length, 
and between 4 and 5 mm. in breadth at the widest part. Zooecia 
elongate, contiguous, slender, two of which measure about 1 mm. in 
length ; series of cells in the branches varying from 1 to 3 in the 
originating, to 8 or 10 in the wider portions. With the hand-glass 
I was unable to detect any puncture in the cells, and the fossils to 
which the species is adherent, is too large to place under the micro- 
scope. 
Habitat : On the inner side of Radiolites Mortoni Mant. 
Horizon : Cambridge Greensand. 
Prohoscina dilatata, D'Orb., is from Mans. Cenomanien., Etage 
20e, and is found in company with P. ramosa, D'Orb. Terr. 
Cret., t. v., p. 851, pi. 632 and 633. 
This species or variety certainly differs from D'Orbigny's 
P. dilatata in its general habit, so far as it is figured by the author, 
but the description in the text, p. 852, agTees to some extent with 
that of the British form. Still there is a difference, and I prefer to 
give the above a varietal name. I have only seen three examples of 
this beautiful Polyzoon, and these are close together on one fossil. 
Figs. 3 and 4 of the plate are first rubbed with damp paper, and 
the impression etched as figured. A similar varietal form to this 
is found on an Inoceramus from the Red Chalk, Hunstanton, but 
unless I had seen the forms now described I should not have been 
able to identify the Red Chalk one, as only a mere impression of the 
once existing colony is left on the shell. 
13. Proboscina ramosa? D'Orb., pi. xii., figs. 5 to 8. 
= Diastopora ramosa, Michelin (?), Icon. Zooph., p. 203. 
1850. Diastopora ramosa, Lonsd., Dixon's Geol. Sus., p. 295, 
tab. xviiis. figs. 1-lb. 
1847. Idmonea ramosa, D'Orb., Prod. 2, p. 175. 
1850. Idmonea cenomana, D'Orb., Voy., pi. 633, fig. 1-3. 
1852. Proboscina ramosa, D'Orb., Terr. Cret., t. v., pi. 632, figs. 1-3, 
pi. 633, figs. 1-3. 
