252 



is 135 mm. in height and 65 mm. in breadth. The smaller colony bears 

 numerous cirripede galls ; these are completely overgrown by the coenenchyma, 

 and from the overgrowth numerous polyps arise. The /rnihocodiie are white. 



In the larger colony the spicules are not so regular as in the smaller 

 as to size, arrangement or distribution ; they stand out markedly from the 

 coenenchyma. 



Muricella ramosa, Thomson and Henderson. 

 = M. Geylonensis, Thomson and Henderson (1905). 



In the collection there are a great number of colonies which undoubtedly 

 belong to this species. Many of the characters are so variable that by means 

 of a comparative study we have been enabled to find transitions which taken 

 together connect this species with M. rei/h)U'/isis so that we cannot regard 

 the latter as a valid species. 



The branching as in most other species of this genus is in one plane ; the 

 branches arise generally at about right angles and seldom deviate from their 

 original direction. In the majority of the specimens anastomosis is very abun- 

 dant, in others it is scarce, while in several it is entirely absent, so that we 

 cannot regard this as a character of specific moment, in fact we find that it 

 depends largely on the closeness of the branching and no doubt also on the 

 habitat. The axis is black and very hard in the older parts, yellow and more 

 slender in the twigs, but on the whole the colony is very rigid. In the main 

 stem and larger branches the axis is very much flattened in a plane perpendicu- 

 lar to that of ramification, but in the younger twigs it is almost cylindrical. 

 The coenenchyma is very thin and uneven and allows the dark axis to appear 

 through ; it is composed of two layers, an outer discontinuous, consisting of 

 large warty spindles disposed for the most part longitudinally, and an inner 

 continuous layer of much smaller spicules arranged irregularly. As in M. 

 rubra we find great disparity in the size of the spicules according to the posi- 

 tion in the colony. In the younger twigs the spindles of the outer layer are 

 more numerous, larger, and more definitely arranged. The verrucae are more 

 ragged than in many of the other species and the structure is by no means 

 compact ; they arise betireen the large spicules of the outer layer but in no 

 regular manner. Sometimes they are encircled by a group of large spindles, at 

 other times they arise close to the interlocking ends of the spicules. The 

 disposition of the verrucee is also a feature of great variability ; in some places 

 there is a distinct hint of a spiral arrangement, but in others they occur alter- 

 nate, sub-opposite or irregular but markedly bilateral. The anthocoditii are not 

 completely retractile. There is a distinct dome-like operculum consisting of 

 eight triangular groups, each composed of about eight spindles arranged "en 

 chevron," at the base of which there is a collar of about five transverse rows. 



