ON THE GENUS EAMTJLINA. 



349 



to which it is attached, and gives off a stolon-tube of some 

 length, which was probably connected with other inflated 

 segments. The surface of the test is studded with strong, 

 sharp prickles. Grault ; Folkestone. — Fig. 36. 



17. O — Chapman Coll. — A subglobular segment, having three 



stolon-tubes radiating from it. The surface of the test is 

 sparsely studded with prickles. Grault ; Folkestone. 



18. Q — Chapman Coll. — A fragment of one of the stolon-tubes 

 of JRamulina aculeata, showing the coarse blunt spines 

 and the perforations of the test. Grault; Folkestone. — 

 Fig. 37. 



19. E — Chapman Coll. — A fragment of a stolon-tube of Hamu- 



lina aculeata. Gault ; Folkestone. — Fig. 38. 



20. Specimen M ; 21. S ; 22. T— Chapman Coll.— Three examples 

 of Hamulina aculeata (figs. 39, 40, 41) which have been sliced 

 horizontally and medially to demonstrate the presence of 

 septa within the segments. In fig. 39 (M) we have a well- 

 inflated segment, of sub triangular shape ; and from two of 

 the corners there proceed stolon-tubes. The interior of the 

 segment is divided by partial and complete septa, somewhat 

 after the manner of Polymorphina, although not so regularly 

 arranged. At the junction of the stolon-tube with the 

 segment there exists a partial partition of the shell-cavity, 

 the septum being interrupted either in the middle or at one 

 side near the outer shell-wall. 



Fig. 40 (S) is similar in shape to the foregoing, but there 

 are no apparent septa within the cavity of the segment. The 

 junctions of the stolon-tubes with the segment are partially 

 divided by imperfect, valve-like septa ; one being thin, and 

 with its free edges pointing up the tube ; the other almost 

 completely closing the tube, except a fine median canal, left 

 for intercommunication. 



The common triangular arrangement of the stolon-tubes 



