TIIK SKKTCLAHID^E. 39 



The tendency lo multiply 'jvnera reached it- iii;i.\iiiiiiin in a work published in Is'.m by 

 Marktanner-Turneretscher ' in which he adopt- all of Allinan'- yem-i-a. restores >'.//!//<//< //<-/. and 

 ])i-oposes two new <r,Miera. A- I hi- write]-'.- -c-hemc of elas-iticntion is more comprehensive than 

 any other, it i- o'iven |n<i-e in somewhat condensed t'oi'in and translated into Knu-li-h: 



1. I '.nun -lies formiiiL' a reticulate network .................................................................. 2 



2. Hydrothecse in more than two rows. Margins even .......................................... DKTYOC i. A m CM. 



llydrothcc.-c arranged otherwise ........................................................................ 3 



X. II yd n ill i, -r. i paired. ad jam it pairs at right aiiL-les to each cither ................................. ST.VI i:omi.< \. 



Ilyilrotlicc-.-i- alternate, margins dentate. O]>iTcnlnni present .............................. SvMi'i.KcTosc YI-III s. 



r.ninchcs in it normally forming a net work ............................................................... 4 



4. 1'. nine-lies arising from cavities of the hycln.thcca- ............................................. THKC-OCI.AI>II:M. 



Branches arising' as usual I'm in the stem ........ ......................................................... 5 



.">. SI en i polysiphonic, the central tube bearing hydrothec.-e ......................................... ( JUAMMAHIA. 



Stem monosi phonic. or tul.es differently arranged ........................................................ l> 



li. Minute i-ii]i-sha|ic-cl hodie- at the hyclrothecal bases ............................................... Ilvi'oi-y \|. 



No siic-h appendages ...................................... . ............................................. 7 



7. Ilyclroihec-.-i- arranged in a sinirle row ........................................................ HYDKAI.LMAMA. 



Ilyclro'.hc-c-.-e arranged in more- than a single row ......................................................... S 



5. ilydrotheca- in two rows, a<l Mate to each other in pairs ........................................ DE8MOBCYPHU8. 



I lydrothec-a- in two ci]i|iosite rows, or in several rows ..................................................... 9 



!l. Hydro! lu-c-ie in several longitudinal rows ...................................................... SKI.AC;INCU>M>. 



Hydrothecse in two longitudinal rows ................................................................... 10 



1(1. ( >perc-ulum present, composed of one or more- parts ..................................................... . 11 



Hydro! hec;e without open-ill mil ........................................................................ lo 



11. Open-ill mn with more than two parts .................................................................... 12 



( (pen ilium with tuo parts ................................ . ............................................. 13 



11'. Hydrotheca- usually alternate-, anil one to an internode .............................. . ......... SEKTI-LARKI.I.A. 



Hydrotheca_' opposite or alternate, several to cadi internode ................................. CALYITOTIH-I A HIA. 



1.".. Hydrothecse opposite ........ . ......................................................................... 14 



Hydrothc-c-ie alternate, often several to an internode. an opereiilum present ........................ MONOI-OMA. 



14. Hyilrotlieca- usually paired. Opc-n-ulnm hiiified at a single point ................................... I)II-IIASIA. 



1"). Hydrothecse opposite, several pairs ill the middle of each iuteniode ................................ P \SVTIIK A. 



One, two, or more hydrothec-a- to each internodc, the latter not much produced beyond the hydrotheca- 

 licarintr part ....................................................................................... Hi 



Iti. Hydrollie. :r strictly opposite, generally partly immersed, often without evident relation between hydrothec:. 



of oppo-ite rows ............................................................................. TnriAijiA. 



Ilydrotliec-.-e single-, or in more' or less distinct pairs on each internode ..................................... 17 



17. IIydrotliec-;e paired, sometimes in>| strictly opposite. Distal part of branches usually with a pair to cadi 



i nt erne M le. ( ionaii'_'ia on branches ..................................................... . ............ IS 



I lydrotheca- single or paired, (ionan^ia springing from lumen of hydrothec -a- .................... SVXTIIKC n vi. 



18. Ilydnithec-al niarL'in toothed. Ilydrothec-a- not conspicuously broader at base' ..................... SKKII I.UJIA. 



Ilydrothec-al niarL'in even or slightly sinuous. I [ydrotheca- swollen at base ....................... \UIETIXAKIA. '' 



It will be notcil that this scheme denies the prcsenee of theoperculum in the .Ljviiera r 

 S, rtiiliirin. Tliiiiiiri'i. and . \1>!< timiriii. iii all of which it is actually present. 



In iS'.'o there appeared a scholarly work by Prof. (i. M. K. Levinsen. :! in which a serioii- 

 attempt is made to ari'an^e the o'eneia of the- Sertularida' on the basis of the characters of the 

 operculum in connection with the condition of the hydrothecal margin.' This writer asserts that 

 the oporcuhim is found in all Sertularida', without exception, and carries his belief to the extent 

 of casting out all ovnera that do not posse-- that structure. He states that the oviirra <;,-"/ii- 

 i/Ktriii, Si/nt/it '/'i/in. and /////"^'//./-/A- should all lind their- places outside of the Sertularida-. an 

 opinion in which I concur, except in the ca-e of the u'emis Si/nfli'i-inin. lie maintain- that -uch 

 features as the relation of the hvdrothec,-e to the hydrocaillus and to one another are of little sys- 



1 Die Ilyilroiden des k. k. natnrhistorischen Ilofiniisenms, V. Vienna, Is; HI. 



-See Kirchenjiaiier, Nordisc-ln- ( lattunL'en mid Arten von Scrtularid, n, llamburir. 1SS4. p. l".i. Dr. Kirchenpaner 

 recognizes the following genera: Selaginopsis, 'rimim-iii. Ai'iiinmrin, and >,,//,<,,//,;. 



"Meclnser. Ctenophorc-r OL' I lyilroidc-r fra ( iriinlands Vestkyst tilli^emecl Bemserkninger om llydroidi-rnes Sys- 

 tematik. S:ertryk at Vidc'iHkal'eli^'c Meddclelser I'm den naturhiBtoriske KoreniiiL' i Kjiibcnhavn, 1S1IL', ls;i;',. 



The writer is under great obligation tu Mr. J. 11. raarmann for translating the systematic portion of Levinsen's 

 work. 



