458 DR A. MILNES MARSHALL AND MR U. H. FOWLER ON 



that of the ordinary P. pkosphorea. The spicules are numerous everywhere 

 except at the very bottom of the stalk. 



Specimen A. (PI. XXXII. figs. 4, 5). — The terminal autozooid is entirely 

 normal in respect of tentacles, marginal teeth, &c: it is 2*2 mm. long, and "4 mm. 

 wide at the middle of its length. The leaves are in pairs, the left member 

 being a little in advance of the right. 



The first pair of leaves consists, on the left, of a single autozooid 3 5 mm. 

 long, the top of which is almost on a level with that of the terminal one ; on 

 the right the leaf is formed of two autozooids, the main one of which is rather 

 larger than that last mentioned, and bears on its dorsal surface a second, 

 which is *3 mm. wide, and free for a length of - 58 mm. At the base of this 

 leaf, as in many others in these specimens, is a slight swelling, probably the 

 commencement of a third autozooid. 



Of the second pair of leaves, that on the left, in length 4*8 mm., is formed 

 of three autozooids ; that on the right, also of three autozooids, is the largest of 

 all on the colony, measuring 5 mm. in length. 



Below these are three pairs of leaves, diminishing in size and in the number 

 of the autozooids of which they are composed, the outermost, i.e., most ventral, 

 autozooid being always the largest on the leaf. Below these are two pairs of 

 papillae, the rudiments of future leaves. 



The terminal siphonozooid is placed ventrally to the base of the terminal 

 autozooid, and is in all the specimens much larger than any other. The rest 

 are arranged in a series of about twenty pairs down the ventral surface of the 

 rachis, extending as far as the fifth pair of leaves. Externally they appear as 

 simple fan-shaped spicular sheaths. 



Specimen B. — The terminal autozooid is much shorter than either of the 

 two which compose the first pair of leaves, and is placed much more dorsally 

 than is the case in the other three specimens. The right side has suffered 

 considerable damage. There are in all five pairs of leaves. 



Specimen C. — The leaves are placed rather opposite than alternately to each 

 other, and the general appearance distinctly suggests deformity. There is a 

 terminal autozooid bent sharply to the left. There are four pairs of leaves, the 

 largest consisting of four autozooids ; below these four pairs are slight papillae. 



Specimen D. (PI. XXXII. figs. 6, 7). — The terminal autozooid is one of the 

 largest on the colony, measuring 33 mm. in length, and 75 mm. in diameter. 



Of the first pair of leaves, each of which consists of two autozooids, that on 

 the left is 39 mm. in length, and projects *66 mm. beyond the terminal auto- 

 zooid, the smaller autozooid being 1*9 mm. in length, and fused for the greater 

 part with the main one ; that on the right is closely similar. The leaves are in 

 close contact at their bases, and are slightly displaced in the figure, as in the; 

 natural condition they almost concealed the terminal autozooid. 



