and then ü »n puts oul a tuit of branches above, which dicho 



nul th, I !i. propagation is repeated, and thus whole colonies of plants 



I with "ii- anoth< 

 lt m.i\ iii.it among other problems which awail investigation are the 



chromatophores, etc . and the meaning and mode of development 

 • 



distr ibu tion. Penicillus flourishes mainly in the West Indian region 



Atlantic, and indeed Penicillus and Rhipocephalus are both especially well 



Bahamas. I me species of Penicillus occurs in the Moluccas and in West 



th Australia ; a new species was collected in the Malay Archipelago by the Siboga 



and another occurs in the Mediterranean. The species are mosdy rather I< 

 nfined to their own respective regions. This at least is the case with the West Indian 

 and Mediterranean species lt is however not improbable that /'. nodulosus, tht- Indian < I 



may be found more widely distributed, and it should be sought on the coral reefs 

 and islands between Ceylon and the coast of Africa as well as in the Red Sea, and perhaps 

 in the Pacil 



Sj stemati c. 



The species of Penicillus have always been founded <>n external characters and in the 



ent monograph they are perforce, through scarcity of sufficiënt anatomical differences, treated 



on similar lines. The absence of sharp distinctions between some of the species is feit when 



collectioiis are examined ; and for this reason Harvey, who had collected specimens both 



in the Tropical Atlantic and the Pacific, considered that only three species can reasonablv be 



maintained, viz., P. dumetosus, P. capitatus, and /'. arbuscula (= P. nodulosus). All inter- 



mediate species would therefore have to be sunk into one or other of the two first mentioned, 



since P. nodulosus, recorded only from the Eastern hemisphere, has a distinct character of its 



own. This view of the species of Penicillus is too limited to be maintained at the present day. 



Having had the opportunity of examining the types of Penicillus in the herbaria of Dei visne 



and 1 oux, and the specimens collected in the West Indies by Dr. Marshall A. Howe 



and others, we have realised that at least two species stand between /'. dumetosus and /'. capi- 



tatit<. < )ne of these intermediates is represented by /'. Lamourouxii Decne. and the other by 



/'. / To /'. Lamourouxii we have added a variety, var. gracilis dep]), which we 



to represent Nesea pyramidalis Lamouroux, the type of which, as mentioned below, 



is non-existent. This new form is almost as nearly related to /'. capitatus as to P. Lamourouxii. 



As to /' - 'ongatus Decne., it approaches so near to /'. capitatus that we have made it a 



•ï of that spe, i 



1 or the material of P. pyriformis and /', Lamourouxii var. gracilis we are indebted 

 i • Dr Marshali A. Howe, whose algological researches and careful observations in the West 

 Indi oducing many interesting results 



The synopsis of species given on p. 76 is based on the diameter o\ the filaments of 

 ilum and on the character of the stipes-cortex. fhe habit of each species is charac 



