188 
THE VOYAGE OF H.M.S. CHALLENGER. 
Fig. 56. 
decurrent or aclnate). Zooecia of one kind only (?) elongated, oval. Oral end 
prominent, subtubular, and bending forwards, especially in the lateral cells. Orifice 
arcuate with straight entire lower border. Immediately below the mouth is a median 
avicularium with an acute mandible pointing upwards and 
projecting usually beyond the lower border of the mouth. 
Below, the zooecium is immersed, convex on the sides with an 
oval perforated areola in front, pierced by about seven fimbriate 
pores. 
Habitat . — Station 75, lat. 38° 38' N., long. 28° 28' W., 450 
fathoms, volcanic mud. 
[Madeira, J.Y.J. ; Atlantic 268 to 322 fathoms, Yoy. of 
“Porcupine” (dead); Fossil, miocene, Reuss, &c.] 
The striking resemblance between the zooecia in this form 
and those figured by Dr. A. E. Reuss in his later papers, is so 
close as to leave little room for doubt that the latter are very 
closely allied to if not identical with my Lepralia distoma. But 
if Dr. Reuss’ earlier figure of Escliara coscinophora, in his Memoir 
on the Vienna tertiary fossils, is to be taken as the type, very 
considerable doubt might be thrown on the identification. But 
considering that the same original observer has regarded all 
those he figured subsequently as belonging to the same species, 
it would probably be right to yield the priority to him ; otherwise 
the forms described in the later memoirs would clearly come 
under my designation. 
The single small specimen in the Challenger Collection that 
I have noticed is in beautiful condition, and is shown in w T oodcut 57. Those I 
have from the “ Porcupine ” collection, on the other hand, are dead, and apparently 
much older and thicker, and they consequently demonstrate the similarity of the existing 
form with those of the Miocene period much more clearly than the younger living 
specimens. 
Fig. 57. 
Figs. 56, 57 . — Adeonella distoma. 
(7) Adeonella distoma, var. imperforata, nov. (PI. XX. fig. 4). 
In the gathering from Station 122, lat. 9° 5' to 10' S., long. 34° 49' to 53' W., are 
one or two fragments of a small form, in which the characters of the zooecia are 
precisely like those in Adeonella distoma, except that there is no perforated areola on 
the front. 
