\< TIM.fi. 7 



HUH CltlBRINA. 



Cribrinidir with sin mi: 'n.l.xli'rnial sphincter; frequently with pseudoacroragi; 

 ecUxlermal musculature . .t discs and tentacles not iml>C(l(le<l in the mesogloea ; column 

 wall provided with verruca} arranged more or leas distinctly in vertical rows ; 



:,' ' .:..;.;. 



CKIRRINA OCTORADIATA. 



Bwttdtt trtoradiaiu* (Vtrlgren, Huntraiy. Maplhaeoi Sammolrciw, K<>anlh. (!'.), p. 20, Fipi. 11 mid 12. 

 1898. 



This special was formed by Carlgrcn (1, p. 20) for a numlx-r of specimens taken 

 from the Straits of Magellan and other localities in the South Sous. In one of the 

 ' Discovery* bottles, labelled " Falkland Islands, Port Harris," were fourteen specimens 

 of very similar-looking Actinians. Upon dissection and microscopical examination, 

 however, I find two distinct species Bunodr* octoradititux, Carlgren, and Pttrmtktoptu 

 crutntata, Couthouy. Both Carlgren (1, pp. 12 and 21) and McMurrich (10, p. 2:13) 

 c-omment on the similarity of appearance of this Crihrinid and this Actiniid, and it is 

 interesting to note in this instance that they were apparently found in association in 

 the same habitat. If this is commonly the case it is not surprising that confusion has 

 occurred in previous descriptions of the Actiuiid. Unfortunately I have no record as 

 to the colours of the ' Discovery ' specimens, but McMurrich (10, p. 234) descriltes tho 

 colour of the Actiniid as being very variable ; it is possible that when in association 

 the two species may also approximate in appearance when living, and if this be so it 

 at once suggests mimetic resemblance. 



In size the ' Discovery ' specimens of Criltritui ttctoradiata agree with I'arlgren's 

 specimens (1, p. 20). The sixteen rows of verruca; on the distal portion of the column 

 and the sixteen pseudoacroragi are well seen in all the specimens. Usually gravel 

 and broken shell are attached to the verruca?. The number of the tentacles 

 (8 + 8 4- 16 = 32) appears quite constant. The two siphonoglyphs are well marked 

 and quite regular. The sphincter muscle is strongly circumscribed, and may l>e 

 described in McMurrich's terms (9, p. 20) as of the pedunculate palmate variety 

 (PI. 3, Fig. 16). The section figured is through the space between the pseudoacroragi, 

 I nit sections passing through the latter show the sphincter projecting from the inner 

 wall, near its base, so that the cavities of the pseudoacroragi project beyond and 

 the sphincter. The mesenteries number sixteen pairs (8 + 8 = 16), all 

 to ami fertile, including the directives (PL 3, fig. 18). The longitudinal 

 "I" the tentacles arc ectodermal and transverse sections (PI. 3, Fig. 17) show 

 strong mesogloeal lamella}. The longitudinal muscles of the mesenteries and the 

 parieto-ba&Uar muscles are exceedingly large and strong, and in the contracted 

 specimens are closely packed into a solid mass, so that the various organs are quite 

 dovetailed together (PI. 3, Fig. 18). The mesogloeal lamellae of the muscles arc long 

 and branched. The circular muscles of the body-wall too are very strong. . The 

 strength of the musculature generally is quite a feature of the sjiecies. 



