F. Børgesen: Rhodophyceæ of the Danish W. Indies. 



251 



Bay. St. Thomas in the Harbour of Charlotte Amalie; St. Jan: 

 Cruz Bay. 



Geogr. Distrib.: Warmer parts of the Atlantic Ocean, Mediterra- 

 nean Sea. 



4. Laurencia implicata J. Ag. 



Agardh, J., Spec. Alg., vol. II, p. Ill, p. 745; Epicrisis, p. 646. Harvey, 

 W. H., Nereis Bor.-Am., Part II, p. 72, tab. 18 D. 



It is not without hesitation that I have referred a few spe- 

 cimens gathered at St. Croix to this species. In doing so I partly 

 rely on a specimen in Maze and 

 Schramm's collection of algæ from 

 Guadeloupe named Laurencia implicata, 

 and partly on the description of J. 

 Agardh, which seems to me to agree 

 rather well with my specimens ; on the 

 other hand these differ somewhat from 

 Harvey's description and figure, 1. c, 

 branching somewhat more regularly 

 on all sides. 



The specimens reach a height of 

 about 16 cm, and have a fine rosy 

 colour. 



In a transverse section of the 

 young parts of the thallus (Fig. 242) the central axis is generally 

 rather clearly seen, having a small central cell and commonly 

 five large pericentral cells. The surrounding parenchymatic tissue 

 consists of rather large and thin-walled cells; the peripheric cells 

 are relatively large, about isodiametric in transverse section. 



The ramuli are nearly cylindrical or somewhat clavate; they 

 are generally alternate, in some of the specimens with some ten- 

 dency to be secund. The tetrasporangia are found in the summit 

 of the ramuli. 



The specimens were dredged in a depth of about 6 

 fathoms. 



This species is most probably described from specimens from 

 St. Croix, J. Agardh giving as locality for this species the above 

 named island. 



Fig. 242. Laurencia implicata 



J. Ag. Transverse section of 



the thalkis. (About 60:1). 



St. Croix: Off Frederikssted; near Buck Island. 

 Geogr. distrib.: West Indies. 



