148 REPORT OF COMMISSIONER OF FISH AND FISHERIES. 



Ill tide-pools and just below low- water mark. 

 Very common from New York northward ; Europe. 



With the exception of Ceramium riibrum, the present is prohahly the most common 

 species of F lor idem found on our coast. It not unfrequently attains a length of a 

 foot and a half, and when washed from its attachment and exposed to the sunlight 

 assumes a bright orange color, which is attractive to many collectors. The Solieria 

 cliordalis, said by Mr. Samuel Ashinead* to have been collected in Greenland by the 

 Hayes Arctic expedition, was probably a sterile plant of Cystodonium purpurascens. 



GIGARTINA, Lam.x. 



(From yiyuprov, a grape-stone.) 



Fronds fleshy, cartilaginous, compressed, composed of an internal 

 layer of longitudinal, slender, anastomosing filaments, which pass hori- 

 zontally outwards and divide dichotomously iuto short moniliform fila- 

 ments, the whole set in a gelatinous substance; antheridia in super- 

 ficial spots ; tetraspores cruciate, densely aggregated, forming spots 

 just below the surface ; conceptacles external. 



A genus of which nearly fifty species have been described, but some of which are 

 of doubtful value. They abound in the Pacific Ocean, several species being found in 

 California, but we have only one species. 



G. mamillosa, Ag. ; Phyc. Brit., PI. 199. 



Fronds dark purple, three to six inches high, half an inch to two 

 inches broad, flatfish, channelled, linear, decompound, dichotomous, 

 fastigiate, upper segments wedge-shaped, bifid; cystocarps borne in 

 short papillae given off from the surface and margin of the frond. 



On rocks at low- water mark, in company with Ghondrus crisjnis. 



Common from Boston northward ; Europe. 



Bearing some resemblance to the common Irish moss, with which it usually grows, 

 but distinguished by the numerous papillae which cover the surface of the fronds and 

 bear the fruit. The present species may occur iu California, but most of the speci- 

 mens of G. mamillosa from the west coast belong rather to G. papillate, Ag. 



CHOKDPvUS, Stack. 



(From xovdpog, cartilage.) 



Fronds and tetraspores as in Gigartina ; cystocarps immersed in the 

 frond. 



A small genus as limited by modern writers, but formerly made to include a large 

 number of forms. The three genera Gigartina, Ch&ndrus, and Iridcea are very nearly 

 related. In the first-named genus the cystocarps are borne in external conceptacles, 

 and in the last two they are immersed. 



0. crispus (Linn.), Stack. ; Phyc. Brit., PI. 63. — Irish moss. 



Fronds purple, three to six inches high, stipitate, flabelliform, dichoto- 

 mous, fastigiate, flat, the segments linear-cuneate ; cystocarps immersed 

 in the frond and usually projecting on one side. 



* Proceed. Acad. Nat. Sci. Philadelphia, Vol. XV, p. 93. 



