ANTHOZOA OF THE WOODS HOLE REGION. 



237 



It may not be out of place to briefly glance at certain features of variation more or less common. 

 In color it varies from yellowish brown, which is the more common, to orange, pink, white, or various 

 combinations of these, in stripes, mottlings, etc. McMurrich has pointed out im apparent tendency in 

 the coloration to assume some three types, brown, orange or salmon, and white, and has suggested a 

 correlation as to age, modes of reproduction, etc. 



Parker (1897) has also proposed similar suggestions as to this and other aspects of variation. 



Duerden, whose work on Anthozoa is well known, has in a recent paper suggested the influence of 

 light as a factor affecting color varieties. 



In a still more recent paper Torrey (1902) has undertaken to ascertain more certainly the factors 

 concerned in tliis and other aspects of variation, especially as it relates to this species along the Pacific 

 coast. He concludes that as yet it is impossible to ascribe it to any definite known cause. 



Body cylindrical, smooth, capable of a high degree of contractility; disk well defined, with distinct 

 marginal lobes which are abundantly supplied with short, pointed tentacles. ^ In full expansion this 

 actinian is a most exquisite creature, beautiful and plant like, and meriting the title "the fringed 

 anemone, " often applied to it. The disk is smooth and more or less concave. Mouth rather prominent, 

 with corrugated, or tuberculate- 



lips, and with well-marked oesopha- A^Ji^\W!*V MIWP^^ 



geal grooves, often with but one, 

 and more rarely with three or 

 several. Parker has directed par- 

 ticular attention to this feature of 

 variation, as has also Torrey. 

 (Cf. op. cit., supra.) 



As an explanation of this fea- 

 tiu-e the suggestion has been made 

 that it may have its origin in the 

 process of fission, often involved 

 in asexual reproduction. Torrey 

 doubts the validity of this view. 

 In text figure i is shown a careful 

 drawing of one of these twin 

 anemones in process of fission. A 

 brief reference has been made in an earlier connection to this aspect of reproduction. In this connection 

 may also be noted the process known as fragmentation, the origination of small individuals by a sort of 

 budding processofportionsof the margin of the pedal disk. This is frequently observed in specimens in 

 tlie aquarium, but I have found it occurring also in specimens taken from piles about the docks, making 

 it quite certain that it is not due to any unusual or abnormal conditions. 



The pedal disk is strongly adhesive and capable of being used as an organ of locomotion, the creature 

 creeping with a slow, snail-like movement from place to place. The mesenteries are abundantly 

 supplied with acontia, which are protruded in profusion from both the mouth and through cinclides 

 when a specimen is irritated. The sphincter is mesogleal and strongly developed, enabling the creature 

 to contract in a most remarkable degree. Mesenteries very numerous in adult specimens and more or 

 less variable as to number and arrangement. 



Distribution and habitat: As has already been pointed out, the range of this species is very wide. 

 It may be doubted whether any other known species has quite so remarkable a distribution. It is 

 found abundantly throughout the region of Woods Hole and along the entire New England coast. Its 

 habitat is in keeping with the range of distribution. It abounds in tide pools, upon rocks, piles, shells, 

 alg£e, etc. 



Fig. I. — Melridiuni dianthits. Specimen in process of fission. 



a Tentacles of inner or oral series larger, attentuate in form, and often marked by transverse bars or rings of opaque whitish 

 color. 



17328°— 14 ^3 



