1861.] MR. E. W. H. HOLDSWORTH ON A NEW ZOANTHUS. 99 



The breadth of the body is If inch. The most perfect arm iu 

 the specimen is 1 2 inches long ; but as this has been twice, perhaps 

 more frequently, broken and repaired, it is probable that its true 

 length would be at least 2 inches more. The relation of the body 

 to the arms is thus as 1 to 9. 



In the accompanying drawing (see woodcut, p. 98) the whole 

 animal is represented at about half the natural size, and the upper 

 surface of the disk at the size of life. Fig. 1 shows the under sur- 

 face of a ray about 2 inches from the disk ; fig. 2 the upper surface 

 of the same ray ; fig. 3 the under surface, towards the extremity of 

 the ray ; and fig. 4 one of the large inner spines magnified. 



5. On an UNDESCRIBED SPECIES OF BRITISH ZoANTHUS. 



By E. W. H. Holdsworth, F.L.S., etc. 



In August 1860 I received from Mr. T. H. Stewart, of the Royal 

 College of Surgeons, a Zoanthus which had been taken by him a few 

 days previously whilst dredging for Echinoderms iu Plymouth Sound. 

 After a careful examination of the specimen, I am induced to regard 

 it as specifically distinct from Z. couchii, to which species, of the 

 three found on our coasts, it is most nearly allied. As the polypes 

 were unfortunately dead, and beginning to decay when they came 

 into my possession, they were at once immersed in spirit ; and their 

 characters were noted whilst in that condition. 



The specimen consists of an unattached group of ten polypes, of 



various ages, ranging from a sim- 

 ple bud to individuals an inch in 

 length. They are all united at 

 the base, which is rounded below, 

 and encloses a small sandy nucleus, 

 particles of the same material 

 being also aggregated on the sur- 

 face from which the polypes spring, 

 and between their points of union. This radiating mode of deve- 

 lopment is the same as in some of the free varieties of Z. couchii, 

 and will doubtless bear a similar explanation. The largest polypes 

 are nearly a quarter of an inch in diameter at the head, and taper 

 slightly downwards. This form, however, is most apparent in half- 

 grown examples. The dermal coating consists of fine siliceous sand, 

 as in Z. couchii ; but the marginal serrations are not nearly so con- 

 spicuous as in that species, and indeed require a careful scrutiny, 

 under dissection, to distinguish them at all. The colour of the ten- 

 tacles, as observed by Mr. Stewart at the time of capture, was a 

 distinct red ; and after some days' immersion in spirit, the tint was 

 still perceptible through the integument surrounding the head, where 

 the sand is less densely impacted than in other parts of the surface. 

 The distinctions between these polypes and those of Z. couchii, so 

 far as I am now able to judge, consist in the colour of the tentacles, 

 the comparative absence of the serrated margin, and especially in 



