BULLETIN 59, UNITED STATES NATIONAL MUSEUM. 35 



lioth less and jjfroattM' than i'.") fathoms, in fact the greater limit in (l(']>tii mii^ht lie 

 placed at itt or 17 fathoms, should he especially noted. The specimens from th(> lower 

 hatlnineti-ic limits arc smaller, more slender and fragile in ramose forms, appearing 

 to be stunted. The cause of the ditlerences is not ktiown at ])resent. It proljablj- 

 is not due to dift'erences in tem[)erature, as will be shown later; nor can it be attril)- 

 uted to ditlerences in the character of the bottom. Three possible causes suggest 

 themselves, but no data are a\ailable to aid in reaching a conclusion. They are, 

 differences in the strength of the light, in the pressure due to greater depth, oi' in 

 the food supply. These physiologic factors need investigation. 



Within this bathymetric zone the reef-building species cross boundaries with the 

 leel)(>r water forms: that is. the species of LcjdoserLs. 



(!(•( 



SPECIES LIVING BETVk'EEN 40 AND 100 FATHOMS. 



Madracis kanaiensifi Vaughan. 



Fiingia patella (Ellis and Solander). 



Fimgid fnKjiUs ( Alcock). 



LeptoseriK hawaiiennit< Vaughan. 



Leptoseris ^cabra Vaughan. 



Stephdti iiphylUa fonii oximitna M oseley . 



BithiiKiphi/llid di'i<iiiop}iijllioide>i Vaughan. 

 The fauna of this jjathymetric zone is poor. The two Fungim are confined to 

 it, while the two species of LtptotK rix are Itest represented here. The other forms 

 really belong to a deeper water fauna. 



SPECIES LIVING BETWEEN icx) AND 200 FATHOMS. 



Flabelluin pavmihiuiii Lesson, typical. 

 F. pavoninitin var. d'n<tinctmn Milne P^dwards and Ilaime. 

 F. pavoninuiit, var. paripavoninuin Alcock. 

 Placotroch xx fuscKn Vaughan . 

 Parart/idkux mnuie/isis Vaughan. 

 Paracydtlms iiiolokenHiH Vaughan. 

 Deltoeyathus andaiiuinlciiH Alcock. 

 CaryoplnjUia haimiiemtis Vaughan. 

 Oyatlioceraii dlomedex Vaughan. 

 Anthemiphyllid pacijica Vaughan. 

 Madrac/'s kauaiens/s A^aughan. 

 Jil. kauaiensis var. riMcrocaly.c Vaughan. 

 LeptoneiHH hawaiiensis Vaughan. 

 StephitnaphyHia formosisx! ina Moseley. 

 Endopiuliyx oalitnHC Vaughan. 

 BnlanopliyUia desmopfiyllioidcs Vaughan. 

 BidanophyUia htynaii'iisis Vaughan. 

 B. dioiiiede;e Vaughan. 



BalanophyUla diomcdeae, var. initu'u-nxiK Vaughan. 

 Drndraphyllia oaJuiiKix Vaughan. 

 J)i iidriijiliyllia st-r/mifina \ aughaiL 

 This zone is the richest in forms iie.xt to the reef /one. 



