278 PROF. MARSHALL AND MR. Or. H. FOWLER ON THE 



length is very thin, forming little more than a membranous sheath 

 to the axis, from which the leaves arise. At the lower end of the 

 rachis there is on either side a longitudinal row of single small 

 zooids, about 50 millim. in length {cf. fig. 16), above which the 

 leaves commence. These are, for some distance, very small and 

 very close together, bat as they pass upwards become gradually 

 larger and further apart. Even in the lowest leaves the com- 

 ponent polypes are indicated by slight notchings of the margins. 

 The largest leaves occur about the junction of the middle and 

 upper thirds of the rachis, above which point they diminish 

 slightly in size. At the upper end the leaves are small, shrivelled, 

 and closely approximated to one another, appearing as mere 

 wrinklings of the surface. 



The leaves, even the largest ones, are of small size, and along 

 the lower half of the rachis are little more than transverse ridges. 

 Each leaf consists of 40 to 42 polypes arranged in a single row, 

 but slightly alternating in the largest leaves, owing to dis- 

 placement from mutual pressure. The ventral border of the leaf 

 is concave, and is continued as a ridge on to the ventral surface 

 of the rachis ; in this ridge and the adjacent part of the rachis 

 there is a very obvious network of branching canals, as described 

 and figured by Kolliker *. The siphonozooids are arranged in 

 transverse rows at the bases of the leaves, the number of zooids 

 in each row being about the same as that of the polypes in the 

 corresponding leaf. 



As in other species of Virgularia, the genital products are 

 contained in the lower immature leaves. Of the three specimens, 

 two are female and one male. 



Considerable quantities of sand occur between the leaves 

 closely adherent to the rachis, especially in its lower half. This 

 derives some interest in consequence of the statement made by 

 Rumphiusf, that the allied species, V. juncea, which lives in 

 very shallow water, has the habit of retracting almost completely 

 into the sand at low water or when disturbed. 



The principal measurements of the three specimens are as 

 follow s, 1 ho corresponding dimensions as given by Kolliker} of the 

 specimen in the Berlin Museum being added for comparison : — 



* Kolliker, op. ext. pi. xiii. fig. 123 



t Rumphim, D'Amboinsche Kariteitkamer (Amsterdam, 1705), pp. 43-44. 

 | Kolliker, op. oil. p. 205. 



