M. FOSLIE. [190O 



walls partly not. The conceptacles at length grow down into the 

 frond in great numbers. 



This species rather reminds one partly of Goniolithon elato- 

 carpum partly Lithothamnion Sonderi in habit. Otherwise it seems- 

 to stand nearest to L. funafutiense. As regards the conceptacles 

 it shows some relation partly to L. obtedulum partly L. Engelliartii. 

 Young specimens much approach certain forms of L. Lenormandi 

 both in habit and structure. 



Only known from the southern coast of Australia, gathered 

 in Half-moon Bay, Port Phillip Bay, Victoria by Mr. J. Gabriel. 



L. Lenormandi (Aresch.) Fosl. 



Norw. Lith. p. 150; Melobesia Lenormandi Aresch. in J. Ag. Spee. Alg. Z 

 p. 514. 



f. australis Fosl. mscr. 



The crust as in f. sublævis, but frequently thicker, the con- 

 ceptacles of sporangia less prominent, and the hypothailic cells a 

 little larger. 



A number of crustlike calcareous Algæ which I got from the- 

 southern coast of Australia shows that the above species is more 

 widely dispersed than hitherto known, but on the other hand even 

 more varying than hitherto considered, partly approaching one 

 partly another crustlike species, in southern waters especially L. 

 tenuissimum, L. siamense and L. fumigatwm. i\lthough each of 

 them in their typical development is easily recognisable and in fact 

 much differing, partly one partly the other assumes forms which 

 approach each other. This is especially due in localities where 

 the said species grow gregarious. Here two or three species often 

 grow together on the same substratum and anastomose with each 

 other, or the one species more or less covers the other, and in 

 connection with disturbing influence of animals attached to the 

 same substratum, or to the Algæ, or penetrating the latter, the 

 limits between the species may be extremely difficult to draw. 



With reference to the hitherto established forms of L. Lenor- 

 mandi there is a considerable difference between typical specimens 

 of f. sublævis and f. squamulosa, the latter when first met with 



