878 DR. J. STUART THOMSON ON 



ivory-white internocles, as described by Hickson, appear to become 

 reddish in the upper part of" the colony, but this is appai-ently not 

 always the case. 



Locality, e^c— P.F. 13197. Cove Rock, N.W. | W. 13.| miles. 

 By dredge. Depth, 80-130 fathoms. Nature of bottom, coral 

 and rocks. Date, July 30, 1901. 



Family Muriceid^. 



MuRicEiDES FUSCA, sp. n. (Plate XLIY. figs. 4 a-e.) 



The colonies are about 102 mm. in height and 95 mm. in 

 breadth. The branches are all in one plane. The main trunk 

 has a strong horny axis and an expanded base measuring 14 mm. 

 in length and 1 2 mm. in breadth. The main trunk has a diameter 

 of 5 mm. and gives off its first branch 13 mm. from the base. 

 The branches of the first order are given oft' irregularly from the 

 trunk, and these, in their turn, give off branches of the second 

 order, which may also bear small terminal branches. The 

 branches of any order do not, as a rule, originate opposite one 

 another. The axis of all parts is thick, the coenenchyma thin. 

 The axis is brown near the base, and light yellow at the apices. 



The main trunk is fairly cylindrical, but the branches are 

 slightly flattened. This flattening of the branches appears to be 

 due to the manner in which the coenenchyma grows over the 

 axis, as the latter is fairly cylindrical in shape. The upper branches 

 are thin and flexible, but their apices are expanded. The polyps 

 are mainly confined to three sides of the axis. The general 

 surface of the coenenchyma is covered by small, protruding 

 spicules. These spicules do not overlap, but there are only 

 minute spaces between them. 



The polyps are also well protected by spicules. There is a 

 crown of spindles, in which the spicules are disposed en chevron, 

 in eight triangular areas which are very pointed towards the 

 apices. In each of these ti-iangular areas thei'e appear to be 

 about 8-12 spindles, which are placed more or less vertically to 

 the surface. At the base of those areas the spindles are arranged 

 in a continuous ring surrounding the polyp. The spindles 

 forming the ring also overlap one another, but not to such an 

 extent as those in the triangular areas. There appear to be about 

 ten spicules at any one place in this ring, enumerating in a 

 proximo-distal direction. Distally to this ring, spicules of 

 another form are situated on the polyp wall. These are very 

 protuberant, and stand more or less m a vertical direction. 

 These spicules are " Blattkeuleti" and pass over basally into small 

 spicules of the same general form as those of the general surface 

 of the coenenchyma, namely " Kalhkorper" The entire polyp is 

 thus well protected by spicules. 



The polyps are capable of being withdrawn within the verruc?e, 

 but the latter are small and do not rise any distance beyond the 

 surface of the coenenchyma. The polyps vary considerably as to 



