mi Li B B. 137 



re however are nol sufficiently definite, and an i 

 to the microscope may be necessary. This at one 

 plays the admirable character by which the Bpeciee 

 be recognized, namely, the solitary) three-iointed spine, 

 arming the outer margin of every joint. The only other 

 : British Ceramium which has a spine at all similar, 

 Is C. jlabelligerum, but that is at once distinguished by its 



- being coloured, no1 hyaline; nol to speak of ite 

 different branching, and the Bmalln< - ine. 



238 ciliatum (The ciliated C \ frond slender, of nearly 



equal diameter throughout, rigid, repeatedly di 

 with <»r without lateral branchlets, the apices 



- ongly involute ; articulations pellucid, those of the mid- 

 dle of the stem from three to four times Longer than broad, 



dually shorter; dissepiments coloured, 

 nished with a whorl of robust, subulate, three-jo 

 prickles; tetraspores alternating with the prickles; 

 Bubtended by two or three ramuli, Duel . 01. 



(Atlas, PI. LIT. Fig. 241.) 



turn diaphanum, var., Duty. Echinoceras ciliatm 

 Boryna ciliata, Gratel. Conferva ciliata, Ellis. C. | . 

 Both. 

 Hah. On rocks and Btones in the sea, either in tide-pools or ex- 

 posed at low-water; also attached to Corallines and other 

 Alga?. Annual. Summer. 

 Under the common name ciliatum at least three distinct 

 varieties of Ceramium, now regarded as distinct species, 

 have hitherto been confounded by British botanists — C. 

 echionotum, C. acanthonotum, and the present Bpecies. To 

 the naked eye they have very much the same appearance, 

 and to the touch the same peculiarly harsh feel, and it is 

 not till we submit small portions to the test of the micro- 

 thai their differences are perceived. Obvious differ- 

 ences maj thefl be observed in the spines with which the 

 joints are armed, and these appear to he constant. 



I XIII. 8PYRIDIA. 



239. nlamentosa 



larly branched, sub-opaque; branches tapering at thi 



more or Less densely <-l>>t I 



of the stem jerj Bhort, of the ramuli once and a 



. / '"/.-. Br. /' -7. (Atlas 



LILT. I-:-. 244.) 

 Bpyridia crassiuscula, E S. t ... la, A".:. 



