C'ODIACEAE. 



615 



Peripheral utricles galeate-cuspidate. 1. H. scalra. 



Peripheral utricles truncate or rounded-obtuse. 



Fusion of nodal filaments complete (or sometimes in- 

 complete in H. dtecoidea) ; segments not ribbed 

 or nerved. 



Peripheral utricles in contact for one-eighth of their 

 length or less ; utricles of subcortical layer sub- 

 turbinate, obconic, cornucopiaeform, or clavate, 

 35-1 10 /j. in max. width; segments moderately 

 calcified, 5-15 mm. broad. 2. H. Tuna. 



Peripheral utricles in contact for one-fifth to two- 

 thirds of their length; utricles of the subcortical 

 layer bullate, mostly ventricose-obovoid, 110-215 /* 

 in max. width ; segments very lightly calcified, 



6-35 mm. broad. 3. H. discoidea. 



Fusion of nodal filaments incomplete (i.e., filaments re- 

 taining their identity) in pairs; segments more or 

 less ribbed or nerved. 4. H. Opuntia. 



Segments discoid or subterete, often 3-lobed or 3-dentate. 

 Nodal filaments of the central strand coherent, com- 

 municating by pits, pores, or very short tubular processes, 

 very rarely (especially in H. Monile) merely thick-walled 

 and separable. 

 Peripheral utricles less than 80 # in average maximum 



diameter, surface view. 



Pe/ipheral utricles 49-77 /j. in average maximum diam- 

 eter, surface view : segments usually flattened. 5. H. tridem. 

 Peripheral utricles 30-44 /j. in average maximum diam- 

 eter. 



Segments mostly subterete. 6. H. Monile. 



Segments discoid (suggesting H. Tuna). 7. H.simulans. 



Peripheral utricles 175-190 # in average maximum diameter, 



surface view. 8. H. favulosa. 



Segments obovoid, pyriform, or subglobose. Nodal filaments of 

 the central strand fusing in twos or threes or rarely lours, 

 the resulting filaments sometimes again incompletely fused. 9. H. lacrimosa. 



1. Halimeda scabra M. A. Howe, Bull. Torrey Club 32: 241. pi. 11, 12. 1905. 



Common on rocks, old corals, the bases of sponges, etc., from low-water mark 

 down to a depth of 3 meters or more. New Providence, Rose Island, Berry Islands, 

 Great Bahama, Bimini, North Cat Cay, South Cat Cay. Gun Cay, Eleuthera, Exuma 

 Chain, Watling's Island. Atwood Cay, Mariguana, Caicos Islands, Castle Island, 

 Great Ragged Island. Anguilla Isles, and Salt Cay : Florida. Type from Sands 

 Key, Florida. 



2. Halimeda Tuna (Ell. & iSoland.) Lamour. Hist. Polyp. 309. pi. 11. f. 8a. 



1816. 



Corallina Tuna Ell. & Soland. Nat. Hist. Zooph. 111. pi. 20. f. e. 1786. 

 Flabellaria Tuna Lamarck, Ann. Mus. Hist. Nat. 20: 302. 1813. 

 Halimeda platydisca Decaisne, Ann. Sci. Nat. Bot. II. 18: 102. 1842. 



On rocks, etc., from low-water mark down to 60 meters. Atwood Cay, 

 Mariguana, Caicos Islands, Great Ragged Island, and Anguilla Isles : Bermuda 

 and Florida to Jamaica and Barbados ; apparently of wide distribution in the 

 warmer seas. Type from the Mediterranean Sea. 



3. Halimeda discoidea Decaisne, Ann. Sci. Nat. Bot. II. 18: 102. 1842. 



Mostly in shallow, somewhat agitated water (down to 2040 meters, fide 

 Borgesen) Great Bahama : Florida, Cuba, Porto Rico, Lower California, Hawaii, 

 and the Philippines. Type locality unknown (" Kamtschatka "). 



4. Halimeda Opuntia (L.) Lamour. Hist. Polyp. 308. 1816. 



Corallina Opuntia L. Syst. Nat. 1: 805 p.p. 1758. Ell. & Sol. Nat. Hist. 

 Zooph. 110. pi. 20. f. ~b. 1786. 



Common from near low-water mark down to a depth of 20 meters or more, 

 often forming extensive beds. New Providence, Rose Island, Berry Islands, South 

 Cat Cay, Gun Cay, Exuma Chain, Watling's Island, Mariguana, and Anguilla Isles : 

 Florida to Barbados and Panama (Colon) ; widely distributed in the warmer seas 

 and important as a reef-builder and land-former. Type from Jamaica. 



