are Yate mee ee ned Oo = A i yy Mt Aye il ai yf Iw a» Hist SX, peg Wei oi Note) wat *. WO, >. iy Hy eet tes SS ge of if 40 e o cee uy y | HU Fe we i 1 on rn te a " bw ae NU We Meee 7 a Pi cide ths i se a1, - 7 ” re Le rr. He 1 f . See Te t eo ) 7 i} 7 oJ Ls AA : , Yy 7 i] 5 J 7 6 14 oe Oat i) (ie O 7 oo 4 : : mr hte fi hh ir fe is ta eee 7 ae ) 7 y : y Oy ro ee ay 7 . if Vy i 4 ‘A Vie > ae 4h) A a e _ . 7 - 7 . ‘ ms en) | "ie | ah ’ fh "IS ibe idle loca | ” a0 re) 7 i an ‘nd 7 ; i U vy / ae) 4 7 ' : ' . yi, a ; 1s 7 Ta . i] 7 : : = (ug di any Wyo Hy Aad ei eh, Ay 7 ‘, P A) sj ra a ;, roiny 4 q an fore aan ae Pi me) fe : nn a a &, fis! ie - ; oun a a u grits oe Ay me : : it - si ‘ta ny ae ae, Ae 4 1 a \ (ihe “4 in I ; yt oa i m toe Peay My vo ay A i a oh eth wi aah 7 a ae a ‘ hae Coa Al J Mi Ad" Deen ir Sere ae ine oer a: i RY, ; Ts iu ay ‘ ae | ae ’ aT (jae £ a a a ce i - 7 a i 7 fj ry av on Pa {oat | i Md A 5 fp 7 " I Wy: _ Te j ro wali rf, oP an - y _e Bx . ease j _ : : ry i i tie my fh % 7. : it ( a ie , ny ; an’ - a a, en) ~6 7 ee 7) ar Uh cana ahs ore il Se a yt Ay ; ie Arey Pe: Se ae Tree fo ‘vaw - . ; : : 7 lei! ly eee ie ; MN, fe Cy iP): ; fi A “a y i. ay Mu 40 Pa mn 7 rr hy ke mi ee : le er ad 1 ; ; 7 : BAD a are 1! yg! ho we ot Se oad % a iene eo f fi a a ee ar oy rn n ! ; a Pe me Wied hae ve i os ia ) |i y oy A 1g » t ; at Ave 4 tes TV Oy as ae Tiel | Ore mie py yar i 5 ; ak a by a m 7 7 7 Vom. 40 Tt a suIT MA RSrs C. pWwiGh'l MA at 1b¢5 GEOLOGICAL AND NATURAL HISTORY SURVEY OF MINNESOTA fee a: | HENRY F. NACHTRIEB State Zoolog:ist invert. Lod . SECOND -REEOR | OF THE BTATE LOOLOGIS?# INCLUDING A SN EeSilks OF THE ENTOMOSTRACA MINNESOTA INVERTED fe ATE — \200L0GY Lrustacea ZOOLOGICAL SERIES II | NOVEMBER 1895 SAINT PAUL MINNESOTA Sie PAUL MINN.:: THE PJONEER PRESS COMPANY 1895 CONTENTS TPRID. . ochedagAcaweditos SURES CONACEE CELE SAEED Anes AEN A an am nme a ete eve 9 eee ARETE MEN ORO is OOMLEMUS terse cece ctl avve ih secele ce dees cieceed che uedeesesete ese eae eebeoe: peacetime ili SRNR rere tetas eee aM etnies sivoeenfentcteee .azics < ssiiuacalvehe+aseet sie tamecbces ons gedltraktettnase ct vi IATA MENA SIN Luba lente sectemaeccenaaes tees cessassaic bee sattencstn cd dixnatithlehone toes ca erences Vii ORD TCD CIVUS Petsei ce caer cove far see oeice nineas a qos antec seek co cdlee seme sae teens yt es secant viii Report of the State Zoologist for 1893 and 1894...............cssseccssscsscccsscocsccncrece 1x SV MOpsisOlebhe Emtomostraca OL MINMESOtAa..........ecsscecuccocesseraccascs esvocseesscuenedes 1 PLU HEAIMINO LO weet crc ce sais se tee inode oe ee ns cnc criicle o ociee’ sapics ce eaee habe aloe ca cen ee eee nee can. 3 PIRI nec edtecd maacISee CBGROBERE aCCaMHS badad ane MR ITINS slain Sins. c chain Ses eee ae SwER OS's oz eNO 2 Sa ET ene 5 Hae tACC ROBO ese NORIO SO At. sac deatlas lstes ec calorie cela’ cnldne anemelsaveuns seesenanaeaereceomeoseeaet 7 ESTILO OMA Mnyiane secrets este etace \ewaigtocesisslesciee cee: casa seaonicerescndele se tedsstenwseeee meteases 9 Orden OEP OMIA Part, Dex. si secs cde ce cscs cocssscectececcsdesssdaccdoccecd SR eon ore 39 Evacrird yal O12 1010 IG xaanere eee bodice onctijadis Was udeeb wens anaes ame 46 CEM Se lAMIN OC AMMAN See Aa caahaccceccmsteccatcnercccsce eee cddec ree eee cee te 48 Sema YU VGH O ROAR PASSE CoN. elt ose vena c.cideeivare teow tacet othe vhs Pave Some mean 49 Ae SET MO sD A TOMS acace nce tence sesncethoaccsr secnos eoebasec cc sanececess osueene 53 eee AMET IMU Sarteaseieee Set bice tices Sule sews bce te dose cok Gon coine eninge io haan ocak ahae 54 PAPEL ROA G Oren eae Rote te cae, card dunno. de ewusioes Mhinects siessceen vce antes te ses 80 eS IR OC OPH eee cement... Sok. ow vcosces ans cde coetbed scone ros MONE eeeae 80 ene BIS CH UR iAtr eee cee eas ve cnestchecte ie wioce, Peer ea aac ack oe eee satan ae Meet 81 ene OSH RA NERO UI Mirteisnacblsooceueotttencs ssc season comets se eeetoneeancetaamende de 85 sri a laysaMe Vie OPEC Rae. Sa. ale ecte as co ae's ocbion ole os a osecupoatiotln seditn Gobsd Dralsaccctuendes 87 CETUS On COPS Hermes restart er cereecsseclesereus cscs len reeele ete ced tao see cue im tlcaninn cord 88 ae R ANA PESEV ES UMMM OLS oon nas cess nnceccnobsscacse nemincs saseoeaal SetesateaSocinaces 124 SIND FATIAT ye C eWUNG ALO CHRIND OUI ES. occ sscer er corcectsodaneteas scsseceacdectendestonesans 3 OES CEMUSHO AN RHO GCANEPL US: vaielesccsesicnetvoesne vee tecncmueaes + 6 sdccesteeabder aie soe betes 125 same PACT TELE VGH TRIAGED tay US ct 2s BS ewhetnecices caren aS asec sabe bho eeaneemsaute 136 Somme VIRAGE? SELTe Attics Sarto we meciecjsinse asersiatisiticinceewh con caieae Vanden cies Seeee eeaearease cate 136 roger ADOC E TCA Part) ID). ....0.0..00...scesteseecesdssa voredesceecedersnebes seeeseeee IAT EAA UY MOR NGU >, Soe Seri cles oie esac «0 cae oe di chess ewlenclec Manca as soe eseeca soa dutist anieaccveneas 146 (ONT se IACMR CREE. acco clictenscasa ia cetee se pslcd cme buiccee te semaces em heneeteat ceeece ss 146 BELSISTE DI ORGID ACS sctate rae heMec wee tulotc gates coms oe eeee Soe oe Necoe eee toons bee 147 SERINE NO STIAG. oe. Sarcecccateoceceee ects aamace clas sweat ceca mnnes oc cltes o'eleie'ste oc 148 I FY AWETINU IU TAL ANIA wets eestor ewe c catea ra uiseeye Potato oie aale oats sav toes ole Ss deibio de octet oases 148 | SA MMIETACTA (NGA MN Ee cee Neato ac cacabt cclession slawaincaones Sune an oe noeeaas os Gants ceteneamted 150 MEMIDACLOUN CHESS ie se dha cteereee avasscos Aisoata aoec ccc ce nee etude cacwectur aries 150 Fant PEMUMURS PMN Rick tach otto c00 acer todas tnethaaedeuledeosccedasddeahatcstoss 151 Genus HOLOPEDIUM ..........065 peateshastascseneeeiny aeeereeecceeeeeeveeceeeneeaeneeeces 15] \ av CONTENTS. Family Daphmnidoe-.ti.:) acca. aosouetos tas seNetat igtetatuvauere ribatka caret teem Genus MOIN AL sei: cc. setisvetceen acces eats Wet cstcpn es saers neh Sa a Rea Heccceco Aiiot ff © SMOINADAPHNTA ici.ceotecces.cetcstics seetlnaane Tecee soe peeceiee sree: eesened ©» CPRIODAPHNTA ws .cn:trccnassecen sendonscassaadenata. leases wehRa ate nae cudistoese **), ISCAPHOUEBERIS .cocrececedense coe teces ia dea s'est nets. cannes Gene aeeet cotati Se oh | (OSIMOCEPHA TUS: catese ope donates tscustastecceaee ies sedlenate eseeeteecisvareetes S$ DA PHINTA Lis cs us'ndae te tone ssn gsouacecscene telecameare deere uae oceene eias someone Family Bosminidee ....... Bae ees bac\cbowelliieMtas «Soyeuse ooate ee Ly err ey Genus BOSMINAGS: c.cc.0cct coe sstcew ete encsansmeatameees aes soteeseac satete Seer ates Family Lyn cod aphnid[ee..% cccces et eee ee eee Breer Bs Genus, MACROTEHRIR bit feos teens oceintera tenes Basta tees Oe sagttas sade es cases ah Bric Sg TOATHONURA sot sscscicsce, eancecccch tates te teens dedmodae ante eetes sseceee eaten °S "+ STREBLOCEBRUStsoeetccsts cccep ete teen Sivdeowe Sele Suatens sucess MDERPANOTLEIR UX. s.. sccotncteaeecs teseeon Sas Then dete sh we same et snare ot * JACANTHOLEBERIS..<.scccchcathtas cesses seemeeeeesees Liemate dee ve vcs Mateos 1 PMOPRY OMUSS.cavcctes Secession ceesh ctor seq ctaseee pannatchectoareeetneaiisss rivdee oad I SV OCRVETUSsescretetsseS tisseestae isa'ea, ee neceennss Rete aemee sess sada tho te Bamily LiyMCerd 2.62. s0ccss on deunvecees sabots Saotocenaceebe euiaeres Pee cae its sacsaeeem : Sub-family Eurycercine............ above ar Seet tact deiie etacgeecnamertonteseute Sicaeaeea Genus EURYCERCUS....... sieidleccue edlsee anew enscwseniencadeceen Segeecek ei cas sees aae Sub-family Woy mCeim7e 15. sec: oan soon bees ecco eee We angen acc eee UR Genus CAMPTOCERCUS.........-- cheleieaeeeets oeeeee DE Ston apeencahbete pias tis sic SoD emeaeee ; Sub;genus ACROPERUS :.<..c0ee, ode sshossedan iw cdeemeeeadaeeaee eames PSE CRORES: FRE a CAMPTOCERCUS! 5. jiscunessach «densest ose sattacnedectee see ee oeetns Mane Genus [ALONOPSIS? si. ccs.eecereeo tas se wats eviee saeien ee daecs cosets ob tmeente ehueils cue da se e ). EEVADNGE: eens Jo cas ick ecevbup te, SMART Et onetsne habia Geseel ae ee ocr Family Leptod Ovid seni. z: ctor. vo.tsteeesaaeceteen cna Role pas stinces Sasa aaetee Reeceen} Genus LEPTODOR Aitn..cpscccenveceneneeeeers Mh aeielasteues egieenes os das wusestescetpeenans Appendix to Part IJ.—Notes on the Cladocera of the southeastern part of the United States ..........0.. PEON Lh yn PAT ore s Foes vaadealoncess ene esne deena CONTENTS. Orden OS LENCO ODA Parti lee ee oi acdeckh doshas chsotnshede seth ak voemiedeaees esses SNOT ACO Mp Nop Cee eee wc race hate tered baleialareiels Males sila piolhie rasa able ng Serbian bias are Reis Avsteealt are Men tulawacalelse EDU O STAD Myce escas esc stacoe nace aelehawectlor oh cn tte anes onto vot ds ppetsbeisyse sds ve Seseh se olnricievlsne TAL TOUT CLIO Mister nace cctecls sca We anaes code ences d aule/ee cts ostiaeaelie seo sasmesitetbleceete cease se ances Family Cypridide .......... SF ARES. Se CMe le te M cea ec eor aie eae tans eae (ETLUSENOTODROMAS bc 235 ose thawed neseu ewe enone sienme hacelane coemen obsess aeisclehiesase CO" “S(QHAGSABYOINT/: Wiran SER eo CS ESIC HE ME Serie Iara col eae f He essa co Sema UO) VaPTRTVAG Mae as cacti Mecdasice Sas sacmiec wer ae tet liewscastcatdmuancdeeas stuns sane sien CV. CUOONMER TS orc cme see he ce castes setnnce ox aendanetaseunisicar shasta acaneeenmulans EERE O NP RUD ORSIS: soshacaeoke tre ogoctescicsoaee cease henetie diac teniehetlietos Carietatcceb a eee IEP ETOG VIP BUS sdieckt ccs stole eda dese sscet’es qoaceelndcckis be saeas need amas ohacteees MeL MER RIG rates Sins ctchad coh Caster votin oss Gaels aa eee aiie UR Races sae gach See met ase Seman ONIP RDN OM US ss ovate oe etiitice othse sclacit ances as cloactiace te Memento Me coatmehnemenat ATL yc) A WV RIEU LN AG 22 FG. no saasenses teat en oseneaess sevaedeean. Sasi tay Ore ina GENUS DIATRAWALING Wi Al sec. colvec Gaateure secle's abo ciate otete Stasatetars oMlasinait dindotenice clearer a argilal eater eA NOME LAN AION Sespiecesei ec eleeeie cs seine = ove spi «=\lsisisinieMecelsses sain s sal nie sci se seinem amekt ETL Rae tM ae Ree ela crib cist ezrs diate Guetta cv tetletee n,clan tol duis ot ole ou lsiore tas eis'e Matas ae ato es CORRIGENDA. 56. In the ‘‘key,’’ thirteenth line from top, read tyrrelli for tyrelli. 73. Seventh line from top, read Herrick for He rick. 95. Second line from bottom, read americanus for Americanus. 101. Under Cyclops pulchellus, supply Plates X XVII, Figs. 4, 5; XXVIII, Figs. 5-8. 105. Middle of page, read m. q. fuscus for m. g. fuscus. 114. Twelfth line from top, read Cyclopina gracilis for Cyclopsina gracilis. 120. Fourteenth line from top, read lascivus for lascious. 124. Fourth line from bottom, read Copepoda for Copepode. 126. Second line from top, read Cladocera for Cladocere. 129. The last three page numbers of the ‘‘key,’’ and the last within the brackets, should read respectively 132, 134, 134, 135. 146. Third line from top, read Sidide for Sidide. 148. Third line from bottom, read Sida brachyura for Sida branchyura. 150. Transfer the plate reference under Latona to Latona setifera. 174. Under Ceriodaphnia cornuta, supply Plate LX VI, Figs. 4, 5. 175. Middle of page, read Rhypophilus for Ripophilus. 195. Eighth line from bottom, read D. kalbergensis for D. kahlbergensis. 203. Middle of page, read cedersticemii for ccederstroemii. 205. Thirteenth line from bottom, read D. schexfferi for D. sczehfferi. 210. Near middle of page, read Macrothrix (?) pauper for Macrothrix (?) pauper. 218. Read Acantholeberis curvirostris for Ancantholeberis curvi- rostris. 231. Eleventh line from bottom, read Alona elongata for Alono elongata. 255. Star Pleuroxus stramineus, Q 258. Under Pleuroxus procurvus, add LXV, Figs. 6, 7. 260. Under Leptorhynchus falcatus, supply Plate LXIT, Fig. 17. 266. Under Polyphemus pediculus, read LIX for LXIX. 272. Read Daphnia longiremis for Daphnia longiremus. 273. Read Ilyocryptus longiremis for Ilyocryptus longiremus. 274. Read Leydigia quadrangularis Leydig for Leydigia quadrangu- laris Leydig. 274. Read Dunhevidia setiger for Dunhevidia Setiger. 293. Fourth Jine from top, read adductor for abductor. 301. Read Candona peireei for Candona Peircei. 306. Read Cypria opthalmica (Jurine) for Cypria opthalmica Jurine. 321. Tenth line from top, read Cypris gibberula for Cypris qibberala. Unexplained remain, Plates XXV, Fig. 15; LVII, Fig. 9; LXI, Fig. 5a; LXV, Fig. 9, and a few unnumbered figures. A number of the plate references were supplied from the explanations of plates: A few species are noticed only in the index and the plates. e I am indebted to Professors Birge avd Marsh for deciding between the conflicting spellings of names in the manuscript that were not observed until the index was pre- pared in most cases from the final forms. I embrace this opportunity to acknowledge the courtesy and good nature of the officers connected with the manufacturing department of the Pioneer Press Company, particularly of Mr. George R. Morrissey. J a LETTER OF TRANSMITTAL. THE UNIVERSITY OF MINNESOTA, MINNEAPOLIS, MINN., November 30, 1894. To the President of the Board of Regents of the University of Minnesota. Str: I have the honor herewith to submit to the honorable Board of Regents my second report as zoologist of the Geological and Naturai History Survey of Minnesota, together with a report on the Entomostraca of Minnesota by Mr. C. L. Herrick, a graduate of the University and professor of Biology at Denison University. The report on one group of the Entomostraca, that of the Ostracoda, was written by C. H. Turner, professor of Natural Science at Clark Uni- versity, Atlanta, Ga. These gentlemén have given their services to the survey without charge, having asked for and received barely enough to cover their expenses. Very respectfully, your obedient servant, HENRY F. NACHTRIEB, State Zoologist. BOARD. OF REGENTS OF THE UNIVERSITY “OF MINNESOTS The HON .(JOHN SS. PICLSBURY, President sense n- ce ccicssoccse nese +e vouceteerisse Minneapolis. ihe HON? GREENLBARY CLARK. Ms Alcoa. tedesasscecddsecedees litecedtlecseredas-siaccere St. Paul. The Hon. CuSHMAN K. Davis, M. A....... vskauederiiabiasles Mes gaaehseceatsobmses «acess St. Paul. The HON: STEPHEN, MAHON By,» MEGAN. bcc tcceesces ew dlele salen tise sis seers cit eae Minneapolis. FPhesELON. (WILLIAM WIGGMWT I 5.250202 Gee da cleclolss\s ccetass tale enact den ges clean sioce setae Benson. MhevEHON. OZORA) P.) STWABNS Yor. .ccecceces actin cstecs oO natine Sen eave eae eeerenaveat aah Duluth. (ThevHON. JOEL (PE; HEATWOLE 2. .:..ccssesecce sete casei aer st tenements sidouaie seasons Northfield. The Hon. SIDNEY M.\OWEN2t.5...c.celaccseauesceeeeceestenss deeemeegresse deserters Minneapolis. The HON. WILLIAM EH: YALE .2....5.ctescessccsecceeccs sense ec puceeanens «pease tabineaaduan Winona. EX-OFFICIO. Cyrus NortHRop, LL. D., Corresponding Secretary............-.cscscsseeeees Minneapolis. The President of the University. Dhe Hon. KNULE NELSON..:.0s<...c.0es is sio'e diene dog Naming te alec ametele tans momaieasiens ant Alexandria, The Governor of the State. The Hon. W. W. PENDERGAST, M. Av... cescucces ccs sesectcensesse sce Nadesces saree er Hutchinson. The State Superintendent of Public Instruction. REPORT OF THE Sia. ZOOLOGIST BOR 1893 -A NID. WegA2 Shortly after the distribution of my first report a kindly criticism of the brief reference to the early history of the survey was received from a gentleman who formerly was a resident of Minnesota and took an active interest in the work of the survey. In accordance with the assurance given to the critic I take this opportunity of correcting, so far as possible, the feature which to him seems unjust. The statement taken exception to is the last sentence of the second paragraph of the ‘‘General Introduction,’”’ reading as follows: ‘‘For many years the Natural History Survey existed only in the wisely formulated law, for which excellent and comprehensive law we owe thanks to Dr. Wm. W. Folwell, who was president of the University at that time.’’ It is contended that the credit for the survey law is almost entirely due to the Honorable John §S. Pillsbury, and ‘‘that the truths of history require that those who know the facts should demand that credit be given where credit is due.’’ It is particularly stated that the Honorable A. J. Edgerton, now U.S. District Judge at Sioux Falls, South Dakota, while Railroad Commissioner of Minnesota, dis- covered there was a balance of a grant of land to the state, called the ‘*Salt Land Grant,’’ and suggested to the Honorable John 8. Pillsbury, then a senator from Hennepin county, that this so called salt land ought to be set aside for the survey fund. The suggestion was taken up and after considerable hard work the end was gained in ‘‘An act to aid the geological and natural history survey of the state,’’ approved March 10, 1873. To this reply: 1. There is no conflict between the bit of history given by the critic and my statement, which alluded only to the orig- inal draft of the law creating the survey. 2. My statement was based x , REPORT OF THE upon the published history* of the survey. To this I have never found nor heard of any recorded objection. Of those who have worked for the interests of the survey the Hon- orable John S. Pillsbury unquestionably has been the most persistent and unselfish. But with no thought of an historical review the refer- ence to even such bright lights did not occur to me. No one can desire to see honor given where honor is due more than myself, and I trust that, if the published history is wrong and unjust, those who know the facets will publish them. The disbursement of the funds available during the past two years I shall not tabulate here, as the accountant of the University will give full consideration of that in his report. During the past year the Survey lost by fire its boats and oars and a few minor pieces of apparatus that were stored in the ‘‘Coliseum.”’ The invoice of the Survey property will indicate more specifically the condition of the apparatus. The field work has been carried on as much as the meagre funds would allow. Special attention nas been given to the fishes, the birds and some of the invertebrates. During June, July and August of 1893, a party of four University students (August Bothe, George D. Head, Frank Manson and Clarence L. Whitman) collected material and data in the Gull lake region. The principal lakes investigated are the following: Gull, Round, Long, Mud, Hubert, Kilpatrick, Upper Gull, the Fishtrap series, Edna, the Cullen series, Mayo, Sibley, Lone, Twin, Pelican, Half Moon, Little and Big Gladstone, Sylvan, Edward, Bass and Mission. The principal streams in this region were also more or less thoroughly investigated. During the same time another party of four University students (John A. Crecelius, Francis B. Sumner, Clarke Barrows and Charles Topping) were carrying on field work in the region between Park Rapids and the headwaters of the Mississippi. The principal lakes here visited are: Fishhook, the Elbow series, five of the Crow Wing series, Itasca, Elk, Bemidji, Cass and Kitihi. The material collected by these parties is stored in Pillsbury Hall. Most of the material has been assorted, arranged and catalogued so as to make it readily accessible for study. The fishes of the several col- lections are being looked over by Mr. U. O. Cox of the Mankato normal school. Mr. Cox is also at work upon a preliminary report *The History of Geological Surveys of Minnesota, by N. H. Winchell. 1889. Bulletin No.1 of the Geological and Natural History Survey of Minnesota, page 6. Final Report of the Geological and Natural History Survey of Minnesota, 1884. Vol. I, page 106. See also the footnote on page 29 of President Folwell’s Inaugural Address, delivered Dec. 22, 1869, and printed immediately after. STATE ZOOLOGIST. Xi on the fishes of the State. This report we hope to have ready for the printer before next spring. It will be issued as one of the bulletins of the Survey. The ornithologist, Dr. Thomas 8. Roberts of Minneapolis, made a trip of ten days into the southwestern part of the State during the latter part of May, 1893, and one of ten days into the Lake Vermillion region during June, 1894. Both trips were very profitable, and dem- onstrated conclusively that nothing but a visit of the ornithologist to the varions important sections of the State at the proper seasons can gain for the Survey the information and material required as a basis for a reliable and satisfactory final report. The wisdom of prosecuting the ornithological work with a view to a final illustrated report is fully vindicated by the great interest taken in the ‘‘Notes on the Birds of Minnesota,’’ published with my first report, and by the numerous inquiries as to when the final report on the Birds of Minnesota is to appear. The edition of Dr. Hatch’s ‘‘Notes’’ is already exhausted. The demand for this publication has been gratifyingly great, particularly in the State, where, I am glad to say, the great majority of the books have found interested owners. The distribution fund for this report was insufficient, and the last three hundred or more applicants were obliged to pay the transporta- tion charges. The willingness with which these charges were paid > has convinced me that all persons really interested in such reports will gladly pay the transportation charges on them. In view of the facts i would suggest that hereafter provision be made to pay trans- portation charges on only those copies of the reports and bulletins sent to our ‘‘exchanges”’ and to citizens of Minnesota. During the past summer Mr. C. L. Herrick, a graduate of the Uni- versity and Professor of Biology in Denison University, with the as- sistance of Professor C. H. Turner of South Atlanta, Georgia, com- pleted a report on the Copenoda, Cladocera and Ostracoda of the State and tendered it to the Survey for publication. The demand for Mr. Herrick’s report on the Crustacea of Minnesota, published in the Twelfth Annual Report of the State Geologist, and the many import- ant and interesting problems connected with this group of animals are a sufficient reason for publishing a revision of the report for 1884. The report will also be of special value to our teachers of zoology. A few purchases have been made for the museum during the past two years. Of these may be mentioned a young bull moose, two déer, one wolf, one black woodchuck, and several smaller mammals. During the same time the museum has been enriched by valuable donations, of which the following are worthy of special mention: xii REPORT OF THE From Dr. W. 8. Strode, Lewistown, IIl., a collection of land and freshwater shells representing about fifty species. From Nathan Butler, Barnesville, Minn., the bones of a large moose. From Mr. Benjamin LaMere, Hickory, Aitkin County, a few mammalian skulls and skins. From Mr. D. D. Stone, Lansing, N. Y., a collection of eleven sets of bird eggs containing forty-two eggs, of which five sets are accom- panied with the nests and three sets with the skins of the female birds. ; From Mr. Denis Gale, Gold Hill, Boulder county, Colorado, forty- three sets of bird eggs containing one hundred and ninety-seven eggs, of which twenty-two sets are accompanied with the nests. Also the skins of eight birds and three small mammals. From Mr. James Hobson, Ann Arbor, Michigan, thirty-four mounted skulls, nearly all of them the skulls of different species of ~ birds. From Mr. A. D. Brown, Pipestone, Minn., three bird skins of special value to us. From Dr. ©. J. Cooke, New Richland, Minn., about one hundred bird skins, the majority of which are from Minnesota. From Mr. Franklin Benner, Minneapolis, his entire collection of bird skins, eggs and nests. This collection contains about six hun- . dred and fifty skins and represents about two hundred and _ fifty species. From Dr. Thomas 8. Roberts, Minneapolis, his entire collection of bird skins, eggs and nests. This collection contains eight hundred and fifty skins and represents about three hundred species. In the Roberts and Benner collections the University has the most complete and perfect collection of Minnesota birds in existence, a col- lection that makes the ornithological room of the utmost importance to the student of the ornithology of the Northwest. For the excellence of our ornithological collection we are especially indebted to Dr. Roberts, who was not only the first to present to the University so valuable a collection as his own but was also instru- mental in inducing Messrs. Benner, Cooke, and Brown to give us their valuable collections. Dr. Roberts has also given much of his valuable time to the arrangement of the collection since it has become the property of the University. In the tedious work of relabeling aud arranging the collection Rev. H. W. Gleason is gratuitously ren- dering indispensable assistance. In the field work Mr. Thomas Miller of Herron lake has gratuit- ously rendered great service to the ornithologist. Several amateur STATE ZOOLOGIST. Xlil ornithologists residing in different parts of the State have very gen- erously offered me their assistance in the prosecution of the ornith- ological work, and it will be a pleasure to properly credit all such assistance in the final report. All acquisitions are properly recorded in the accession record of the museum, the record containing the accession number, the original number and all known data relating to each specimen, whether pur- chased, collected or donated. The ornithological material is recorded in a special record. A ecard catalogue of all this material is now being prepared, and when completed will make the material readily accessible. Other collec- tions, such as the collection of fishes and insects, will be similarly recorded and catalogued. It would be unpardonable not to call attention to the cramped con- dition of the zoological museum at this time. Some of the valuable collections noted above were presented rather reluctantly on account of the insecurity and insufficiency of the quarters. The insufficient protection against fire and the lack of room for proper display of speci- mens have diverted from us some most valuable material that is now the property of museums in the East. Collectors, and particularly specialists, will continue sending their best and rarest specimens to other museums just as long as we do not offer a safe and adequate de- pository. A zoological museum in good quarters and properly taken care of soon acquires material of great general interest and incalculable scientific value,—material that costs more in both time and money to collect and prepare than any other, and that often can not be dupli- cated at any price. It ought, therefore, be housed in the safest pos- sible building. The zoological museum in Pillsbury Hall has, without any special effort on the part of the curator, already acquired an amount of ma- terial that simply cannot be properly displayed or arranged in the present quarters. Hundreds of fine specimens are crowded into cup- boards, drawers and boxes. In this condition the zoological museum must be unsatisfactory to the visitors and discouraging to those in charge of it and desirous of building it up. Moreover, our opportun- ity to get representatives of those animals which are rapidly disap- pearing from the State is slipping by. If the museum is ever to offer a true survey of what the animal kingdom of the State is and was, adequate and safe quarters must be provided very soon. Very respectfully, your obedient servant, HENRY F. NACHTRIEB. >. * " i. ’ . 7 Ons a4 i % ; ‘a * ’ A : + * . q ca “ i Fe ; oS ee a +s ae H c \ z 6? “ff a. f a : a * bh. . 4 ms - i . ; ; * G * ma - - e “) 4 A A vn 7 j r; . et ee s a . a : L. i : ind a : tho ' \* . ‘' \ * Z a b of - 2 A i f we +t 7 ; ‘ * ; au > 5 é , ¥ raf . % : ._ i - _< -. GEOLOGICAL AND NATURAL HISTORY SURVEY OF MINNESOTA HENRY F. NACHTRIEB State Zoologist SU NOP StS OF THE + ENTOMOSTRACA MINNESOTA WITH DESCRIPTIONS OF RELATED SPECIES COMPRISING ALL KNOWN FORMS FROM THE UNITED STATES INCLUDED IN THE ORDERS COPEPODA CEADOCERA OSTRACODA By Gab snERRICK andi@. ft. TURNER NOVEMBER 1895 SAINT PAUL MINNESOTA HDITORIAL. NOTE. Early in the spring of 1894 the state geologist, N. H. Winchell, referred to me a letter from Professor C. L. Herrick containing two propositions, viz.: (1) That the Survey accept and publish the present revision of the report of 1884; (2) that the author be permitted to make such use of the old report as he saw fit and publish the revision independently of the Survey. After having been assured that the errors of the 1884 report had been corrected and the report had been bettered in other respects, it was decided, for reasons that seemed sufficient, to accept the first offer, though the revision had been begun and practically finished without the knowledge of any one connected with the Survey. The manuscript was received during the last week of October, 1894. The editorial work as well as the proofreading all fell to the zoolo- gist of the Survey. The author’s serious illness and his great distance from the University made it impracticable to put any of this work upon him, The work was at times very disheartening, but I did my best, and trust that at least most of the errors and shortcomings of the manuscript have been eliminated. In justice to the author the following matters deserve special men- tion: The author’s title, ‘‘Synopsis of the Microcrustacea,”’ ete., was changed for reasons found principally in the primary destination of the report and in the usage of some of our best and most generally used text-books of zoology. For making reference only by author and date the editor is wholly responsible. The date is always an important and often a very essen- tial part of a publication, and for that reason alone is far superior to a reference by a purely artificial number. The superiority of an abbreviated reference to a full or more or less mutilated citation is so obvious that it needs no vindication. In the bibliography the editor has supplied the number of pages, number of plates and similar data of detail from Taschenberg’s Bibliotheca Zoologica, Zoologischer Anzeiger, Zoologischer Jahresbericht, and the Catalogue of Scientific Papers compiled by the Royal Society of London. Where these data are wanting the citation could not be found in these publications or could not be identified beyond a doubt: In comparatively few cases could these data be obtained from original sources. More or less gross discrepancies between the manuscript and the publications noted above were very numerous as to date, title 4 : GEOL. AND NAT. HIST. SURVEY OF MINNESOTA. ete. As a rule, these could be satisfactorily cleared. Whenever there was any doubt as to which was correct in part or as a whole, both the author’s citation and that of the editor’s source were given, the latter parentketically. Several references made to Strauss have been referred to Straus-Durekheim, and Sars cited with four different sets of initials it seemed clear was intended for George Ossian Sars. A few citations have been added by the editor from original sources. Those interested will not fail to collect others from the Bibliotheca Zoologica and similar publications. Under the Cladocera the citations had to be given in the original form, because the data given in the manuscript did not make possible a more definite reference. In these cases all but the references to Synonyms were cut out. In accordance with the rules of nomenclature of the German Zoo- logical Society, the comma between the specific and author’s names has been eliminated and all specific names appear in lower case. So far as possible these rules have been followed in other respects. The absence of literature, however, made it unsafe for me to touch doubt- ful cases. The ‘‘sp. n.’’ of the old report has been replaced by the author’s name, Herrick. The various ‘‘keys’’ have been reduced to a uniform plan, and several of them have been compiled by bringing the sections together from various parts of the manuscript. To increase the value of these ‘‘keys,’”? the page upon which the description of the genus or species begins has been added and names of authors and other details have been dropped. The names of families, genera, etc., have been italicized in the gen- eral text. The order and arrangement of the plates is most unsatisfactory. None of the drawings had been called for by me before they were sent to the engraver, and besides the necessity of using so many of the old plates made an orderly and respectable arrangement impossible. The index is wholly the work of the editor. Professor Turner’s paper practically appears in its original shape. The key to the Cyprididw was changed from the bracket form to the paragraph form for practical reasons only. I take this opportunity to express my indebtedness to Professor ©. Judson Herrick of Granville, Ohio, for kindly looking after the engraving and printing of the plates, and to Mr, W. H. Kussmaul of Granville for the care he exercised in the printing of the plates. To the state printing expert, Mr. George C. Stevens, I am indebted for indulgent considerations and a lasting patience. HENRY F. NACHTRIEB. APRIL 29, 1895. die dy a AME The exhaustion of the edition of ‘‘A Final Report on the Crustacea of Minnesota included in the Orders Cladocera and Copepoda’’ has led to a demand for republication. It has seemed unfortunate that the imperfections of this work, many of them due to the unsatisfactory state of the European literature, while others were the result of im- perfect information and faulty observation or hasty judgment, should be perpetuated. The original paper grew out of studies made chiefly while the author was an undergraduate at The University of Minne- sota and was very fully occupied otherwise, and circumstances have prevented him from anything but the most casual pursuit of the sub- ject since 1884. It might have appeared that the work had served its purpose, but there were many indications of a need for a comprehen- Sive, Synoptical survey of this field, and the present paper seemed the only approximation to such a work. A _ serious illness, which has greatly impeded the progress of the revision at last decided on, has at the same time made it possible by forcibly relieving the author of more pressing duties. It would have been a great satisfaction to him to have given to the subject the thorough field work and comprehen- Sive bibliographic elaboration it deserves, but strength and opportu- nity forbid. In default of this it might seem wiser to enumerate only American species, but experience has shown that geographical limi- tations do not prevail to any great extent in most of the families here considered. In such instances, Calanidew for example, the attempt has been made to include all valid species and a full Synonomy. In the others as full a list is given as is now possible, and while this work may not be alone sufficient to enable the specialist to formulate new diagnoses and descriptions, it yet offers much fuller Synopsis than yet published and will give a bird’s-eye view of the taxonomy of the subject. The most important aspect of the subject, namely, the biological relations of these organisms, has been too generally neglected. {n no other group can the problems of parthenogenesis and heterogenesis be so easily and accurately studied. The transparency of the body 6 GEOL. AND NAT. HIST. SURVEY OF MINNESOTA. makes it possible to examine vital phenomena directly and watch the effects of stimuli upon the circulation, etc., in continuo. Many curious problems, among them bathymetric distribution and the effects of. environment, can be satisfactorily studied in these groups. Itisa matter of wonder that greater use is not made of these types in the laboratory courses of our universities. Probably the chief obstacle has been the lack of suitable means of determining species. This we evdeavor to offer in so far as may be necessary for this purpose, but purposely abstain from the theoretical questions everywhere pressing on the attention. This work claims to be a report on the Crustacea of Minnesota, but it was found impracticable to sufficiently describe our forms without a rapid survey of the whole territory. I am under obligations to Pro- fessor C.. Dwight Marsh and to Professor E. A. Birge for loan of litera- ture, and to Professor Charles Turner of Atlanta for many notes incor- porated in this work. My greatest obligation is to my wife, who has collated the bibliography accompanying. This tedious but most useful labor has been wholly performed by her. For many incidental aids during the progress of the work I am indebted to my brother, Professor C. Judson Herrick. The reader is requested to remember that this is a revision, follow- ing to a large extent the mould set in 1834, and therefore should not be held to the standard of a work wholly prepared in the light of our present knowledge. The third part of this paper, that dealing with the Ostracoda, is wholly prepared by Professor C. H. Turner, who has been assiduously studying the group for several years, and I feel sure that his contribu- tion will be highly appreciated at the present time, especially as no attempt to monograph the order in America has yet been made. ALBUQUERQUE. NEW MEXI©co, Nov. 1, 1894. PREFACE TO THE REPORT OF 1884 ON THE CLADO- CERA AND COPEPODA OF MINNESOTA. In presenting what may be denominated a final report of the work done in this state upon the group of Crustacea best represented and, all things considered, most important, the author must admit that the term ‘‘final’’ refers only to his own opportunities and the limitation of time imposed by circumstances. While a comparatively large proportion of all the species existing within our limits have been examined during the progress of these investigations, there undoubtedly remain many additional and curious forms to reward the search of the student. A great variation in the degree of completeness with which the different genera and species _ have been treated will be observed, due in part to the circumstances under which they were studied and frequently to the poverty of ma- terial. The entomostracean fauna is quite different at different sea- sons, and a complete knowledge of even our local fauna requires a long period of observation. Even the dead of winter is a favorable time to study some groups. The late autumn is, perhaps, the most favorable opportunity; for then, in one group, the sexual activities are just at their height and both sexes may be studied. A number of Cladocera are restricted to this season. There are a number (how large it is not yet possible to tell) of species in both groups which are to be sought by night, though no phosphorescent species are yet known, Our larger and, especially, deeper lakes have a quite different fauna from the shallow pools and rivers. In general, the flowing waters are poor in Entomostraca. The Cladocera or shelled Entomostraca have here received a large share of attention, and more particularly the Lyn- ceide, which are the most minute of Arthropods. This study has been rewarded with an unexpectedly large number of forms, and a particu- larly large number of species identical with those of Europe and else- “where. Professor Birge is the only American writer who has attempted this group, and his valuable work has made us familiar with the more striking new species. A few new species are included in our list and several varieties hidly yet known in Europe. ‘The 8 GEOL. AND NAT. HIST. SURVEY OF MINNESOTA. remarkable Monospilius 1s among these. This animal has but a single larval eye in the middle of its forehead, and wears its old covering over the newly-formed shell till the latter is a curious patchwork mass. The attempt has been made to incorporate a brief description of all American species with those found in Minnesota, and also to frame keys for the larger genera, so that the place of a species among its congeners may, at least approximately, be found. The difficulty of framing such keys is very great; for few authors have employed the Sathe distinctions in their descriptions, and it is necessary to select points sharply distinctive and conspicuous from the often meager remainder after striking off scattering particulars. In some eases this difficulty has been greatly enhanced by the possibility that some of the species should be considered synonyms or varietal forms. The tendency to combine questionable forms thus produced it was neces- sary to offset by what may seem a too great conservatism. Faulty, however, as these keys may be, it is hoped that they will serve a good purpose in the extent which they cover. While the limits of this work preclude much more than a systematic outline, opportunity is taken here and there to admit a word on the anatomy or development. Such allusions must be considered simply accidental, for a complete treatment of these subjects would require large volumes, and the ma- terial will be long in gathering. A larger proportion of the rare males of the Cladocera are here referred to than in any previous work of equal extent. The genus Cyclops, one of the bugbears to fresh- water carcinologists, is perhaps somewhat summarily treated. The excuse must be the condition of the synonomy. However, most of the combinations made were the result of careful study of large series from different localities. The sketches illustrating this paper are photo printed from the writer’s own drawings, and, without the ele- gance of lithographs, serve the purpose of explaining points of struc- ture which cannot be communicated verbally. J am indebted to Pro- fessor A.S. Forbes for very timely aid in bibliography, without which the paper could not have been completed. To Dr. Lindahl, through my friend Mr. Oestlund, I am indebted fora like service. But my obli- gation is deepest to Professor Rudolph Leuckart of Leipzig, who kindly afforded access to almost a complete set of works on European Ento_ mostraca. Professor C. W. Hall has collected, at much expenditure of time and labor, a set of specimens from different parts of the state, which he kindly placed in my hands, thus enabling me to observe the great similarity of widely-separated faune. Mr. Lieberg also sent specimens of Diaptomus stagnalis from saline pools in Dakota. BIBLIOGRAPHY. The present list, chiefly the work of Mrs. C. L. Herrick, cannot hope to prove complete, nor has it been possible to verify references in many cases. The imperfections arising from securing titles at secondhand, however much to be regretted, will not, it is hoped, pre- vent this catalogue (by far the most complete yet printed) from hav- ing a certain value to the working naturalist. [See editorial note. Dates later than 1800 are abbreviated. | Adams, George. 1746. Micrographia illustrata, or the knowledge of the microscope explained. (4 pl.) London. (Plates in 4°. London 1747. 4th edit.1771. 8°. 72 pl.) Allman, G. J. 47, Description of a new genus and species of Entomostraca. (Biological Con- tributions. No. III.) Ann. and Mag. Nat. Hist. Vol. 20, pp. 1-9 and 47-52. 48, On the Development of Notodelphys Allm., a new Genus of Entomostraca. Rep. 17th Meet. Brit. Assoc. Advance. Sc. in 1847. Notices and Abstracts, p. 74. Anderson, John. 762. On the Anatomy of Sacculina, with a Description of the Species. Ann. and Mag. Nat. Hist. Ser. 3, Vol. 9, pp. 12-19. (Proc. Roy. Phys. Soe. Edinb. Vol. 2, 1863, pp. 304-314.) Asper, G. 80. Beitrage zur Kenntniss der TiefSeefauna der Schweizerseen. Zool. Anzeiger. Jahrg. 3, No. 51, pp. 130-134 and No. 54, pp. 200-207. Aurivillius, 0. C. "79, Balzenophilus unisetus nov. Gen. et Sp. Ett Bidrag till Kannedomen om Harpacticidernas Utvecklingshistoria och Systematik. (4 pl., 26 pp.) Akad. Afhandl. Stockholm, Central-Tryck. 8°. "791, On a New Genusand Species of Harpacticida. (Baleenophilus unisetus. 4 pl., 16 pp.) Bihang till K. Svenska Vet. Akad. Handl. Vol. 5, No. 18. Baird, W. 934. List of Entomostraca found in Berwickshire. Trans. Berwick. Nat. Field Club. Vol. 1. 37. The Natural History of British Entomostraca. Mag. Zool. and Bot. Vol. 1, pp. 35-41, 309-333 (3 pl.), 514-526. 38. Id. Ibid. Vol. 2, pp. 132-144, 400-412. 7381, Id. Ann. Nat. Hist. Vol. 1, pp. 245-257. 43. Id. Ann. and Mag. Nat. Hist. Vol. 11, pp. 81-95 (2 pl.) 10 GEOL. AND NAT. HIST. SURVEY OF MINNESOTA. 46, Description of some new genera and species of British Entomostraca. (1 pl.) Ibid. Vol. 17, pp. 410-416. ‘ 49, Arrangement of British Entomostraca, with a list of species, Trans. Berwick. Nat. Field Club. Vol. 2. ‘50. The Natural History of the British Entomostraca. (36 pl. VIII., 364 pp.) Ray Society, London. 59, Description of several species of Entomostracous Crustacea from Jerusalem. (2 pl.) Ann. and Mag. Nat. Hist. Ser. 3, Vol. 4, pp. 280-283. Balbiani, G. ’69, Observations relatives 1 une Note récente de M. Gerbe, sur la Constitution et le Développement de |’ceuf ovarien des Sacculines. Compt. Rend. de 1’ Acad. des Sc. Paris. T. 68, pp. 615-618. 69.1 Sur la Constitution et le Mode de Formation de l’ceuf des Sacculines. Ibid. T. 69, pp. 1320-1324. °69.2. Sur la Constitution et le Mode de Formation de l’ceuf des Sacculines. Re- marques concernant une Note récente de M. Ed. van Beneden. Ibid. T. 69, pp. 1376-1379. Barrois, Th., et R. Moniez. ’88. Materiaux pour servir al’ étude de la I'aune des eaux douces des Acores. IV. Crustacés. [Copepodes par Barrois; Ostracodes, Cladoceres, Branchiopodes par Moniez.] Lille, 1888. 8°. 20 pp. Beck, Cour. ’—. On some new Cladocera of the English lakes. Journ. Roy. Mic. Soc. London. Vol. 3. Beneden, Edouard van. 69. Sur le Mode de Formation de l’ceuf et le Développement embryonnaire des. Sacculines. Compt. Rend. de l’Acad. des Se. Paris. T. 69, pp. 1146-1151. ‘70, Recherches sur l’Embryogénie des Crustacés. III. Développement de l’ceuf et de l’Embryon des Sacculines (Sacculina carcini Thomps.). (1 pl.) Bull. de l’Acad. Roy. de Belgique. Ser. 2, T. 29, pp. 99-112. 70.1 Reponse A quelques-unes des Observations de M. Balbiani sur l’ceuf des Sac- culines. Compt. Rend. de 1’ Acad. des Se. Paris. T, 70, pp. 197-200. Beneden, Eduard van, et Emile Bessels. 0. Mémoire sur la Formation du Blastoderme chez les Amphipodes, les Ler- néens et les Copépodes. (5 pl.) Mém. cour. et Mém. d. sav. étrang. de Belgique. T. 34, p. 59. Beneden, P. J. van. ‘51, Recherches sur quelques Crustacés inférieurs. (5 pl.) Ann. Science. Nat.-Zool. Ser. 3, T. 16, pp. 71-131. 61, Recherches sur les Crustacés du littoralde Belgique. (21 pl.) Mém. de l’Acad. roy. de Belgique. T. 33, p. 174. [Title given by Herrick is: Recherches sur la faune littorale de Belgique, Crustacés. Mem. d. l’Acad. de Bruxelles. Tome 33. | ENTOMOSTRACA OF MINNESOTA. il Birge, Edward A. "78. Notes on Cladocera. (2 pl.) Trans. Wisconsin Acad. Sciences, Arts and Letters. Vol. 4, pp. 77-112. 91, List of Crustacea Cladocera from Madison, Wisconsin. (1 pl.) Ibid. Vol. 8, pp. 379-398. ’ . Notes on Crustacea in Chicago water supply, with remarks on the forma- tion of the Carapace. Chicago Med. Journ. and Ex. Vol. 5. Boeck, Axel. 59, Tvende nye parasitiske Krebsdyr. Forhandlinger. 65, Oversigt over de ved Norges Kyster iagttagne Copepoder henhorende til Cal- anidernes, Cyclopidernes og Harpactidernes Familier. Forhandl. Vidensk. Selsk. Christiania. (Aar 1864.) VII, pp. 226-281. 68, Om Sildeaat. Tidskrift for Fiskeri I. 1876, and Archiv f. Naturgesch. XXXIV. 1868. "73, Nye Slaegter og Arter af Saltvands-Copepoder. Forhand]. Vidensk. Selsk. Christiania. (Aar 1872.) XIV, pp. 35-60. Bourne, G. C. 89. Report on the Pelagic Copepoda collected at Plymouth in 1888-89. (2 pl.) Journ. of the Marine Bio]. Assoc. of the United Kingdom. New Series, Vol. 1, No. 2, pp. 144-152. Brady, George Stewardson. 64, On the Zoology of the Hylton Dene. Trans. Tyneside Nat. Hist. Club. Vol. 6. 67, Reports of Deep sea Dredging on the Coasts of Northumberland and Dur- ham, 1862-64. Pelagic Entomostraca. Nat. Hist. Trans. Northumb. and Durham (1865). Vol. 1, pp. 29-40. 68. On the Crustacean Fauna of the Salt Marshes of Northumberland and Dur- ham. (2 pl.) Ibid. Vol. 3, pt. 1 (1869), pp. 120-136. 69. Description of an Entomostracan inhabiting a Coal Mine. (Canthocamptus cryptorum. (1 pl.) Quart. Journ. Microsc. Sec. New Ser. Vol. 9, pp. 23-24. 70. Id. Nat. Hist. Trans. Northumb. and Durham. Vol. 3, pt. 1 (1869), pp. 203-205. "72, Poggenpol ’74 (clausii); Uljanin ’75; Hoek ’78 (coronatus, and signatus) Brady ’78 (tenuicornis, and signatus); Cragin ’83 (tenuicornis, and C, signatus fasciacornis) 5 Herrick ’82 and ’84 (tenuicornis); Daday ’85 (tenuicornis, and signatus); Vosseler ’86 (tenuicornis, and signatus); Forbes ’87 (gyrinus); Sostaric ’88 (fuscus); Thall- witz ’90; Lande ’90; Schmeil ’91 (albidus); Brady ’91; Richard ’91 (fuscus, annul- icornis, and tenuicornis); Schmeil ’92 (fuscus, and albidus); Marsh '92; Turner ’92 (tenuicornis). Of the identity of the two varieties which have so long been recog- nized as distinct species (C. tenuwicornis and O. corvnatus) the writer has little doubt. The development history has been traced sufficiently to settle this point. This combination was first made by the writer, and not by Brady, as Marsh implies. Cephalothorax large and broad, considerably longer than the abdomen. First thoracic segment large, more than half as long as the whole thorax, Abdomen rather short, cylindrical. Stylets short and not tapering, shorter than the preced- ing abdominal segment. Sete very plumose, three of them long, the longest being about as long as the abdomen, the innermost being nearly half as long and the outermost apical seta short. In the male the first thoracic is much longer and the abdomen relatively shorter. Antenne long and the terminal joints attenuated, the last three being armed by hyaline plates. Fourth foot with the following armature: 106 GEOL. AND NAT. HIST. SURVEY OF MINNESOTA. ex. 2 spines. ex. 1 seta. Outer ramus {0 1 spine, 1 seta. Inner ramus | 2 spines. in. 4 spines. in. 2 sete: The spines are serrulate and the sete very plumose. Fifth foot two-jointed, basal joint longer than wide, with a series of small teeth and a long seta, apical joint with three plumose sete. Color bluish or banded, the antenne especially banded on the fifth to sixth and twelfth to fourteenth joints. * Cyclops signatus var. coronatus. O11 PLATE XV, Fias. 1-4. First segment of thorax long, its length to that of the entire thorax about as 1: 1.50. Last segment of antennz with the proximal portion of its hyaline plate coarsely serrate. Caudal stylets short, ciliated internally, length to width as 1.25: 1. Second segment of antennules short. Inner apical seta.of stylets one-third longer. Color marked. * Cyclops signatus var. tenuicornis. PLATES XV, Fias. 5-7; XX, Fias. 1-7; XX XIII, Fies. 1, 2. First segment of thorax shorter, its length to that of the entire thorax as 1:1.9. Last segment of antenne with unserrated lamella. Caudal stylets longer, length to width as 2.1:1, inner aspect not ciliated. Outer apical seta half as long as inner. Second segment of antennules longer. Color variable but always banded or splotched. It is also generally true that the ovisaecs in the present variety are more strongly divaricate than in the variety coronatus. Schmeil also finds differences in the form of the receptaculum and sexual elements. Over against the above differences must be set the close agreement in the armature of the feet and the fact that the late stages of coronatus remain to be described while it is always associated with C. tenuicornis, generally in greater numbers. The greater hairiness and stronger serrations of C. coronatus are characters suggestive of advanced age, as has been observed in other species. C. tenwicornis is frequently found without C. coronatus, but the reverse has not been found true in our experience. Finally attempts at experimental rearing of coronatus from tenuicornis have been made, and, while some possible sources of error unfortunately crept in, yet I am morally convinced that the ap- parent transformation was genuine. Dr. Schmeil discusses this question at length without adding any- thing to the evidence. He adduces the differences in structure, though he fails to find anything but such as consist in altered pro- portions of structures common to both. He claims that embryos of ENTOMOSTRACA OF MINNESOTA. 107 C. coronatus are ‘‘allgemein bekannt,”’ though adding that Rehberg ad- mits that the young of the two species cannot be distinguished until the last moult, which seems to show that the late larvie of C. coronatus are hardly ‘‘allgemein bekannt’’ even in Europe. Finally Schmeil denies the possibility of sexual precosity with the general statement that ‘‘Auch mir ist trotz der grossten Aufmerksamkeit unter den vielen Tausenden der von mir beobachteten Copepoden noch nicht ein einziges Mal eine solche Larve mit Eiballen zu Gesicht gekommen.”’ To this we can only say that such larvie have been frequently seen during the last ten years, though only under certain conditions of time and place. It is hoped.to furnish conclusive evidence on this head soon if it is really needed. We had supposed that such precosity was now a well-recognized fact. It is to be hoped that careful embryolog- ical and biological studies may be instituted upon the Copepoda. Cyleops languidus Sars. PLATE XVII, Fiaes. 19, 11. Sars ’63; Herrick ’84; Schmeil ’91 and ’92; Richard ’91. This species has not yet been encountered in America, and from the extended discussion of Schmeil we still think there is considerable probability that this form is an illustration of retarded development of some 17-jointed species, perhaps C. bicuspidatus. Cephalothorax attenuated anteriorly and posteriorly, narrow. Abdomen slender. Stylets exceeding in length the two preceding segments. Lateral seta at two-thirds the length from the base, two median sete long, two lateral apical setze very short, the outer a ser- rate spine. Antenne slightly longer than the first segment, with short sete, 16-jointed by the more or less complete fusion of the third and fourth segments. First feet with both rami two-jointed, formula: ex. 3 spines, ex. 1 seta. Outer ramus jap. 2 sete. Inner ramus ; ap. 1 spine, 1 seta. in. 3 sete. in. 3 sete. Second foot with a three-jointed outer and two-jointed inner ramus. Formula as follows: ex. 2 spines. ex. 1 seta. Outer ramus { ap. 1 spine, 1 seta. Inner ramus 4; ap. 1 spine, 1 seta. In, 3 sete. in. 4 sete. Notr.— The following measurements will serve to illustrate the usual proportions of variety tenuicornis: Total length, including stylets,1.4 mm., first segment of thorax 0.5 mm., whole thorax 0,85 mm., abdomen 0.52 mm., stylets 0.10 mm., antenn 0.85 mm., last joint of antennz 0.05 mm., longest caudal seta 0.55 mm., inner seta 0.30 mm. The corresponding measurements of C. coronatus are the following: Total length 1.66 mm,, first seg- ment 0.67 mm., entire thorax 1.12 mm., abdomen 0.54 mm., stylets 0.07 mm., longest seta 0.6 mm., inner seta 0.3 mm., antenne 0.95 mm. 108 GEOL. AND NAT. HIST. SURVEY OF MINNESOTA. As very strong evidence of our observation of the occurrence of sexual adults with larval characters may be noted a statement of Schmeil himself, who nevertheless seems to be so given to his theory as to be quite unable to see its bearing. Hesays: ‘‘ Nicht unerwahnt soll bleiben, dass zwischen den exemplaren dieser art, welche den Tumpeln des Brockengipfels entstammten, sich eine Anzah] Mannchen vorfanden, bei welchen samtliche Aeste der Schwimmfiisse aus je drei Segmenten bestanden. Dieser Fall ist desshalb besonders interessant, weil hier ein Fortschreiten nach Vervollkommnung im Korperbau eines Tieres direct zu konstantiren ist.’’ The writer is obliged to confess that he cannot understand why it is not more natural to regard the two-jointed condition (which is common to all larvie) as a retarded or atavistic state, from which the species tends to escape toward the norm under favorable condition, than to postulate an exceptional specific norm (which in this case is confessedly unstable), and assume that from some cause, utterly unknown to us, the form tends to ‘‘ pro- ceed to a greater completeness in structure.’? The ‘‘greater comple- tion” or realizing of its ideal—‘‘Vervollkommnung’’—imples that it is incomplete or has failed to attain its specific possibilities, unless, indeed, the generic characters have for Schmeil a sort of metaphysical cogency or power over its members apart from its heredity. The same considerations apply to the antenne. The fifth feet are as in C. bicus- pidatus, The form of the receptaculum is much relied on to differen- tiate this form, but is admitted to vary within wide limits. Length 0.86 to 1.1 mm. Motions slow. * Cyclops modestus Herrick. PLATE XXI, Fias. 1-5. Herrick ’83 and 784; Marsh ’92. This small species, 1.0 mm. long, was first recognized in Cullman county, Ala., but occurs also in our lakes. The color varies, but very characteristic is the peculiar shining or glaucous surface of the strongly arched thoracic shield and the evenly curved segments of the abdomen. The antenne reach but little beyond the very long first segment; they are usually 16 jointed, but I have notes of a similar form in which the antenne are 17-jointed. The feet are all three-jointed and armed as follows: First Foor. ( ex. 3 spines. ex. 1 seta. Outer ramus + ap. 1 spine, 1 seta. Inner ramus {i 2 spines, 1 seta. in. 3 sete. in. 2 sete. SECOND Foor. (ex. 3 spines. ex. 1 seta. Outer ramus + ap. 1 spine, 1 seta. Inner ramus {i 2 spines. in. 4 sete. in. 1 spine, 2 sete. ENTOMOSTRACA OF MINNESOTA. 109 THIRD Foor. ex. 2 spines. ex. 1 seta. Outer ramus ap. 1 spine, 1 seta. Inner ramus 4 ap. 2 spines. in. 4 sete. in. 1 spine, 2 sete. FourTH Foot. ex. 2 spines. ex. 1 seta. Outer ramus jap. 1 spine, 1 seta. Inner ramus jap. 2 spines. in. 4 sete. in, ~ 2 setz. The fifth foot is obscurely three-jointed, the second joint bearing a. short spine and the terminal joint two spines of varying length. The caudal stylets are once and a half as long as the last segment, and are peculiarly excavated for more than the caudal one-third, beginning at the point where the lateral spine is situated. The outer apical seta is short, the median sete are rather short while the inner seta is nearly as long as the outer median. AI] these setie are pectinate. The recep- taculum seminis is elongate oval. The antenna of the male is divisi- ble into five regions, the third being formed by the thickening and union of four or more segments. Color violet or purplish red. * Cyclops capilliferus Forbes. PLatss VI, Fra. 13; XXVIII, Fras. 1-4. Forbes 793. This is a symmetrical, compact Cyclops, with the cephalothorax closely articulated, widest in the middle, and the sides regularly con- vex, with the abdomen narrow and slender, with three well developed caudal sets, and 16 jointed antennze bearing several very long sete. The abdomen, with caudal furca, is contained a little less than twice in the cephalothorax, and the breadth of the latter is just half its length. First segment very long, five times the length of the sec- ond; second and third equal; the fourth very short, on the median line semicircularly excavate behind. The abdominal segments in the female diminish regularly in length from first to last. The caudal rami are twice the length of the last segment and one fourth as broad as long. The lateral seta is placed a trifle beyond the middle of the ramus; the outer terminal seta is a short, naked spine; the other three well developed and plumose. The inner and outer of these are of nearly equal length, the latter a little longer, the middle one much the longest one of the group. Antenna moderate, reaching about to the middle of the second segment of the cephalothorax. Sixteen- jointed in all adult females, and further especially distinguished by the presence of very long flexible sete upon the first, third, tenth and fourteenth segments. Terminal sete likewise very long. The seta borne by the first segment extends to the twelfth; that of the third reaches to the fourteenth; that upon the tenth segment extends to the 110 GEOL. AND NAT. HIST. SURVEY OF MINNESOTA. tip of the antenna, and that upon the fourteenth far beyond it. The first segment is as long as the two following, and very nearly twice as long as wide. The second is very short, its length one-fourth its width, and the length and width of the third are equal. Of the three terminal segments the penultimate is longest, being twice as long as broad; the antepenult two thirds the length of the following; the last is about as wide as long. The armature of the legs is as follows: FIRST FEET. ex. 2 spines. ex. 2 sete. Outer ramus + ap. 1 spine, 2 sete. Inner ramus 4 ap. 2 sete. in. 3 sete. in. 1 seta. SECOND FEET. ex. 2 spines. ex. 3 sete. Outer ramus jap. 1 spine, 2 sete. Inner ramus jap. 2 sete. in, 4 sete. in. 1 seta. THIRD FEET. ex. 2 spines. ex. 1 seta. Outer ramus jap. 2 sete. Inner ramus ; ap. 2 sete. in. 4 sete. in. 3 sete. FouRTH FEET. ( ex. 2 spines. ex. 1 seta. Outer ramus 4 ap. 2 sete. Inner ramus jap. 2 sete. lin. 4 sete. in. 2 sete: The fifth feet are two-jointed, the terminal joint with one long and one short seta at tip; the basal joint with one long seta without. Length without set 1.2mm. Grebe lake, Yellowstone Park. *Cyclops insignis Claus. PLATES XXII, Fies. 11-14; XXIII, Fies. 6, 7. Claus ’57 and ’63; Sars ’63; Fric ’72; Brady ’68 (lubbockii) and ’78 and ’91; Rehberg : 780; Herrick ’84; Richard ’91; Schmeil ’91 and ’92. Schmeil has doubtfully identified C. lubbockii Brady with the brack- ish varieties of C. bicuspidatus = C. helgolandicus Rehberg. Though the names are given in the synonomy above, it is with the under- Standing that they at least constitute a distinct variety. The typical form has an elliptical cephalothorax, the first segment being more than half as long as the remainder. The abdomen is rela- tively short and its first segment greatly expanded, ‘The stylets are very long, fully half as long as the rest of the abdomen, and are longi- tudinally ridged as in CO. strenuus. The lateral apical set are short, while the median ones are long and more nearly equal than usual. Antenne 14-jointed, not much longer than the first segment of thorax, similar to C. strenuus. Fifth foot exactly as in C. strenuus. Length 2.5 to 5.0 mm, Cie eT ENTOMOSTRACA OF MINNESOTA. 111 In the previous edition it was suggested that this is but an atavistic form of ©. pulchellus = C. strenuus, and although Schmeil does not accept this suggestion, he adds strong probability to it by noticing that the eighth joint of the antenne show indications of subdivision and have the armature requisite to correspond with C. strenuus aftersuch division. Against the suggestion he urges, (1) that this form is notsimply found in scattered individuals but in large groups; (2) that there seems no sufficient reason for such suppression; (3) that the animal is often very large, and we should therefore expect it to attain its full development. ‘To these it must be replied (1) that it is very common for Copepods of a given stage to be associated almost to the exclusion of others, thus the net will sometimes bring in from a given locality almost solely half grown Diaptomi where on a previous visit adults preponderated; (2) that we know too little of the biology of these ani- mals to plead our ignorance as a reason for rejecting what is anatom- ically probable; (3) rapid increase in size (unusually rank nutrition) may be just a condition for retardation of development, as it often is in other groups of crustacea. Questions of this nature demand careful and continuous observation and experiment, and should not be arbi- trarily closed by a prior arguments. Respecting C. lubbockii Brady, whether it should be considered an atavistic form of C. strenuus or of C. bicuspidatus is difficult to say. Its brackish habitat speaks strongly in favor of its not being a distinct or permanent species. The short first thoracic segment and antennie incline me to ally it to the latter species. Specimens sent me by Mr. E. A. Congdon of Columbia College, from Long IJsland, seemed iden- tical with C. lubbockii Brady, and if this form cannot be brought into relation to a 17-jointed species, Brady’s earlier name should be revived. It must be observed, however, that the American specimens were within direct influence of the sea. * Cyclops serrulatus Fischer. PGAmHS) XeVe HrGs, 8-115 XIX, 2-5; XOXVl, Pies 10; X XIX, Fries, 17-19) Fischer 751; Lilljeborg ’53; Claus ’57 and ’63; Sars ’63; Lubbock ’63; Heller ’70; Fric 72; Hoek ’78; Brady ’78 (serrulatus var. montanus, and serrulatus); Uljanin "75; Herrick ’82, and ’84 (serrulatus var. elegans, and serrulatus); Rehberg ’80 (agilis); Cragin ’83 (pectinifer); Daday ’85° (agilis); Sostaric ’88 (agilis); Thall- witz ’90 (agilis); Lande ’90 (agilis); Richard ’91; Schmeil ’91 and 792; Marsh 192° ‘Turner 792. The commonest and most abundant species of the Eastern States. Cephalothorax oval, compact. Abdomen slender and about three- fourths as long as the thorax, cylindrical, suddenly enlarged before its union with the thorax. Antenne slender, reaching nearly to the £12 GEOL. AND NAT. HIST. SURVEY OF MINNESOTA. cephalic margin of the last thoracic segment, tending to assume dur- ing life the form of arude Z, the proximal four joints forming the base; the last three joints are slender and elongate and are each armed with a hyaline plate. Antennules small, reaching about the sixth joint of the antenne. Jaws small, with large teeth. Caudal stylets over four times as long as wide, nearly as long as the last two abdom- inal segments, serrate down the outer margin. Outer apical seta changed to a very strong and serrate spine, inner seta weak, outer median seta over two-thirds as long as the inner. Formula for the armature of the feet as follows: First FEET. ex. 3 spines. ‘ex. 1 seta. Outer ramus {3 2 sete. Inner ramus ae 1 spine, 1 seta. in. 3 sete. in. 3 sete. SECOND AND THIRD FEET. ex. 3 spines. ex. 1 spine. Outer ramus {se 1 spine, 1 seta. Inner ramus {se 1 spine, 1 seta. in. 4 sete. in. 3 sete. FouRTH Foor. ex. 2 spines. ex. 1 seta. Outer ramus ; ap. 1 spine, 1 seta. Inner ramus jap. 2 spines. in. 4 sete. in. 2 sete. The spines of the feet are strongly serrate and the sete fully pec- tinate. The fifth foot is one-jointed, having one very strong serrated spine, an apical seta and a longer inner seta. The adjacent margins of the fifth segment are serrate. Egg sacs oval, as long as the abdo- men, divaricate. Eggs few, dark. Length inclusive of stylets 1.5 mm., thorax 0.62 mm., first segment 0.32 mm., abdomen 0.42 mm., stylets 0.11 mm., longest seta 5.0 mm., antenne 0.5 mm, Color rather opaque. A pelagic form or variety has been distinguished, but it must not be confused with var. montanus of Brady. * Cyclops serrulatus var. elegans Herrick. Distingnished from the type by the greater size, and the elongation of antenne and caudal stylets. We will first of all give the measure- ments which afford a criterion for judging of the form and proportions. Total length 1.34 mm., thorax 0.76 mm., abdomen 0.40 mm., stylets 0.18 mm., greatest width 0.42 mm., inner median caudal seta 0.60 mm., outer median seta 0.36 mm., inner seta 0.08 mm. ‘The first seg- ment of the thorax is long proportionally (0.40 mm.). The antennz are very long, reaching beyond the base of the third segment (0.68 mm. ). The egg-saes are elongate-oval, being more slender even than in typi- cal C. serrulatus; in the animal measured they were 0.50 mm. long by 0.19 mm. wide. The caudal stylets are slightly longer than the last two segments of the abdomen. The antennules are very short, and ENTOMOSTRACA OF MINNESOTA. 113 each joint has its series of fine teeth. The free lower margins of the thorax are ornamented with series of prominences, while the last seg- ment is extended into a blunt angle bearing long teeth. The last seg- ment of the abdomen is spiny-margined and is ornamented with a double row of spines at the anus. The armature of the stylets as well as that of the feet is identical with that in typical ©. serrulatus. The last two joints of the antenne measure 0.1 mm. each, while the two previous measure unitedly 0.12 mm. The color is not opaque as in the smaller form usually. Brady’s var. montanus has shorter stylets than the type, but seems nearest the small dark form found in peaty waters in America. Cyclops pectinifer Cragin has no distinctive points, it being typical C. serrulatus. Marsh also finds this variety rarely elsewhere than in pelagic local ties, and only in occasional association with the type. Schmeil notes discrepancies in the original measurements of the two forms, and is led to doubt their distinctness. It can only be replied that the distine- tions insisted on do actually exist, and are very apparent when the forms are before one, and are sufficiently obvious from the measure- ments given above. Cyclops macrurus Sars. Sars ’63; Uljanin ’74 (alajensis); Brady ’78; Rehberg ’80; Sostaric ’80; Herrick ’84; Vosseler ’89; Lande ’90; Richard ’91; Schmeil ’91 and ’92. This form is so close to C. serrulatus as to suggest the question whether it is more than a well-marked variety. From that species it differs in the shorter antenne which are hardly longer than the first seg- ment, the slender, smooth abdomen, and the greatly elongated stylets, which lack the lateral line of teeth. The feet and the proportional length of the joints of the antenne are as in serrulatus. The species occurs in Scandinavia and Germany, but rarely. Cyclops prasinus Fischer. Jurine ’20; Fischer ’60; Vernet ’71 (longicornis); Vosseler ’86 (pentagonus); Richard ’87 (pentagonus var. vichyensis) and ’91 (pentagonus); Schmeil ’91 (pentagonus) and ’92. Cephalothorax broad, attenutated behind. Abdomen slender, nearly cylindrical. Stylets one and one-half as long as last abdominal segment. Lateral seta a little distad of the middle. Outer apical seta forming a strong spine and about as long as the inner slender seta. Longest seta four times the length of the stylet, shorter median seta three-fourths as long. Antenna reaching the end of third thoracic Segment, proportions and armature as in C. serrulatus. Fifth foot one-jointed, closely resembling that of C. serrulatus, but the external seta is delicate and not a strong, heavy spine. Ova few, appressed. Length 0.8 to 0.9 mm. Color green. 114 GEOL. AND NAT. HIST. SURVEY OF MINNESOTA. * Cyclops fluviatilis Herrick. PLATES X XVI, Fias. 1-8; XXX, Fre. 1. Herrick ’82, ’84 and ’87; Cragin ’83 (magnoctavus); Brady ’91 (magnoctavus); Turner 792; Marsh 793. This small species, first described in America, has been encoun- tered by Brady in Great Britain, though he chooses to make the com- parison to Calanide of the original description a reason for adopting a subsequent name. It is one of the most abundant forms in many of our lakes and their outlets. In its smaller age form it is barely visi- ble to the eye, while the Jarger and particularly the highly colored condition is conspicuous especially by reason of its rapid motions. In appearance it reminds one of Cyclopsina gracilis. The body is slender, the cephalothorax being elongate, oval, with its first segment very long. In a specimen measuring 0.57 mm. to the end of the stylets, the following proportions were noted: First seg- ment of thorax 0.22 mm., second and third segments each 0.056, fourth 0.032, total length of abdomen 0.17, stylets 0.032, longest seta 0.128, outer median 0.10 mm. The antenne are nearly as long as the whole thorax, and are remarkable for the elongation of the seventh to ninth segments. There are elongated sete upon the first and fourth segments. The last joint of the antennz is slightly curved and carried at an angle to its predecessor during life, giving it the appearance of being hinged. It has also the rudiment of a knife ridge. The antennules are slender and elongate. The labrum has about twelve small teeth. The maxille have the usual form. The feet are peculiar in the exceedingly long sete. The armature of the apical segments is as follows: First Foor. ex. 3 spines. ex. 1 seta. Outer ramus + ap. 2 sete. Inner ramus 4 ap. 2 sete. in. 3 sete. in. 3 sets. SECOND AND THIRD FEET. ex. 3 spines. ex. 1 seta. Outer ramus ; ap. 1 spine, 1 seta. Inner ramus < ap. 2 seta. in. 4 sete. les 3 sete. FourTH Foor. (ex. 2 spines. ex. 1 seta. Outer ramus < ap. 1 spine, 1 seta. Inner ramus 4 ap. 1 spine, 1 seta. (in. 4 sete. in. 2 sete. The fifth foot is small, one-jointed, and bears three small setae. The abdomen is slender, though rather short. The stylets are three times as long as broad. The outer of the terminal sete is a short spine, shorter than the stylet. The egg-saes are appressed and contain four or five ova in the first state and a few more in the adult. The two ENTOMOSTRACA OF MINNESOTA. 115 dimorphic states are very distinct and seem, in part at least, to be governed by habitat. The colors are frequently brilliant, varying from deep indigo to greenish brown. The coloring matter is some. what irregularly distributed but is most persistent between the bases of the feet, in the last segment of the abdomen and in the last joints of the antenne. The full-grown female measures about 0.70 mm., the males being more slender. Oviferous females often have the fourth pair of feet with two-jointed rami. American authors find the species pelagie, and Brady, though he found it in ditches immediately connected with large sheets of water. Marsh notes that there is a resemblance between this species and C. pentugonus Vosseler. Cyclops capillatus Sars. ‘*Cephalothorax sub-ovate; anteriorly uniformly rounded; seg- ments projecting somewhat laterally, the last being scarcely wider than the first abdominal segment. Abdomen attenuated posteriorly; caudal rami almost as long as the last three abdominal segments, hardly divergent; the external and internal apical setze short and nearly equal, the interior of the median setze as long as the abdomen, lateral seta about in the middle of the stylet. Antenne of the first pair robust, slightly exceeding the first segment of the body when re- flexed, with the twelve joints densely covered with long and divergent hairs. The last joint of the outer rami of swimming feet are elongated and armed externally with three spines, internally with four setie; the interior apical spine of the interior rami of the fourth pair of feet longer than the exterior. Feet of the fifth pair large, with a large and thick basal segment and a small oval second joint bearing one long seta and a short spine. Ovisaecs small, narrow and divergent. Eye very small. Length nearly 2.0 mm.” Very close to (. viridis in many points. Found only in Sean- dinavia. Cyclops crassicaudis Sars. Cephalothorax elongate-ovate; segments produced laterally, espe- cially the last, which extends into a somewhat procurved process. Abdomen short and thick, first segment somewhat excavated; caudal rami equaling the last two segments of the abdomen. HExternay apical seta longer than the internal, both short; median setie long. Antenne of the first pair 12-jointed, scarcely longer than the first Segment. Swimming feet short and thick, spines and sete short; the interior apical spine of the last joint of the inner ramus of the fourth 8 116 GEOL. AND NAT. HIST. SURVEY OF MINNESOTA. foot almost twice as long as the exterior spine. Terminal joint of the fifth foot small, armed with a spine and a seta; seta of the basal seg- ment short. Ovisacs oval, somewhat divergent. Length 0.75 mm. Found only in Seandinavia. * Cyclops varicans Sars. PLATES XIX, Fies. 12 AND 13; XXX, Fias. 2-8. Sars 63; Uljanin ’75 (orientalis); Lande ’90; Schmeil ’91 and 92. The American form which approaches nearest to this species dif- fers from it apparently in proportions. Unhappily we have only gathered the species once and our information depends on the camera drawings taken at that time. Rather slender, especially the abdomen which is nearly as long as the cephalothorax. First abdominal seg- ment very long, as long as the rest of the abdomen. Stylets over twice as long as wide, lateral spine one-third from the apex, outer lateral spine shorter than inner seta, median sete rather long, outer two-thirds as long as inner, inner three-fourths as long as abdomen. Antenne shorter than the first thoracic segment, 12-jointed, formula ~~ ~~ ——-——-xX-—-—=X=-, sete of moderate length. Feet with the fol- lowing formula: FIRST FEET. ex. 3 spines. ex.) i 1\seta: Outer ramus ap. 2 sete. Inner ramus 4 ap. 1 spine, 1 seta. in. 3 sete. in. 3 sete. FourtTH Foor. ex. 3 spines. ° : ex, | ljseta- Outer ramus 4 ap. 1 spine, 1 seta. Inner ramus ; ap. 1 spine, 1 seta. in. 4 sete. sas 4 set. Respecting the fourth foot it is plain that the last joint is homol- ogous to two fused segments, and that the separation might take place at the next moult. Fifth foot as in C. bicolor, but the basal segment more distinct, apical segment long, cylindrical and bearing a long seta. In the form of the stylets and antennz this species corresponds to Schmeil’s figures, but the first segment of the thorax is shorter and the abdomen is more slender. The specimen from which our outline was taken was extended by pressure, while that figured by Schmeil may be a little fore-shortened. We must leave to later study the settlement of the question, as also that of the relation between this and the next. Length 0.8 mm.; abdomen 0.35 mm., stylet 0.05 mm., longest seta 0.28 mm., antenne 0.25. ENTOMOSTRACA OF MINNESOTA. 117 Cyclops gracilis Lilljeborg. PLATE XIX, Fies. 10, 11. Lilljeborg 753; Schmeil ’91 (diaphanus), and ’92. Apparently this is a distinct species, characterized by the slender form, especially of the abdomen, which is to the thorax as 5: 7, di- vergent cylindrical stylets, short setze and form of the fifth foot and receptaculum. The antenne are slender, reaching the caudal border of the fourth segment, and are of the form of the 12-jointed species; POTD, 23, =__=<==. Fifth foot with a broad basal segment and a cylindrical terminal one, which bears a short spine and a long seta. Eggs few. Feet all two-jointed. Schmeil speaks of the fifth foot as one-jointed, but the fact that the basal segment is immovably soldered to the body should not prevent us from recognizing its existence. This species has been found only in Sweden, Poland and Germany. Cyclops diaphanus Fischer. PLATE XIX, Fiaes. 6-9. Fischer 753; Claus ’63 (minutus); Heller ’63 (minutus); Daday ’85° (frivaldszkyi); Sostaric 788; Schmeil ’92. The above synonomy is derived from Schmeil’s monograph, which can hardly be considered very authoritative since its author never saw the species and offers only comparative data to discriminate this species from the last. Abdomen broader than C. bicolor, stylets as long as the two preceding segments, lateral seta nearer the base than the end. The lateral apical sets short, equal, median set as 2 : 3. Antenne 11-jointed, short, only reaching the second segment. Swim- ming feet with two-jointed rami. Fifth foot with a short spine and long seta at the end of the cylindrical apical joint. * Cyclops affinis Sars PLATE XXX, Fias. 9-11. Sars 63; Uljanin ’75; Brady ’78; Rehberg ’80 (pygmzeus); Daday ’85° (pygmeeus, and affinis); Herrick ’84; Vosseler ’86; Lande ’90; Richard ’91; Brady 791; Schmeil ’91 and ’92. Schmeil makes the statement that ‘‘ Herrick regards C. affinis as ‘var. b.’ of C. phaleratus Koch, and identifies it with his C, adolescens,”’ overlooking the plain statement that ‘‘it is impossible to sufficiently identify it [the American form] with any of the above,” and the fact that Sars’ description was appended in a separate rubric. Schmeil devotes considerable time to the relations of C. adolescens and is not unnaturally provoked by the inconsistencies in the two references, which are explained, however, by two provoking typographical errors 118 GEOL. AND NAT, HIST. SURVEY OF MINNESOTA. which were both beyond the writer’s control. The first was the dis- placement of a line in the tabulated list of species in the Alabama crustacea, by means of which the figure of C. phaleratus was referred to C. fimbriatus and the error then repeated in the making up of the description of plates; second, in the Final Report, Plate 24, in Fig. 15 the printer has set C. adolescens one line too soon, making the figure of the receptaculum of C. parcus refer to the former species. Upon this point Schmeil remarks, ‘‘Schon hieraus ergiebt sich * * * mit welcher sorgfalt Herrick die Zeichnung angefertigt hat!’? We beg that author to transfer his irritation to the typo, and believe that the drawing in question is substantially correct!} As to the position of C. adolescens, more beyond. The original description of Cyclops affinis Sars is here repeated, and it justifies the doubt which, in the absence of authentic specimens or figures, was felt respecting its position. ““Antecedenti [C. phalerato] simillimus. Corpus autem minus robustum colore cceruleo vel potius glauco sat saturato insigne. Segmentum ultimum thoracicum ad marginem posteriorem extrosum pilis vel spinulis subtilissimis pectenatim exornatum. Rami caudales quam in C. phalerato aliquanto longiores, setarum apicalium interna quam externa multo breviore, intermediarum interiore altera fere triplo longiore longitudinemque abdominis superante, in medio aculeata dein vero subtile ciliata. Antenne 1-mi paris segmento 1-mo corporis multo breviores, tenues, articulis 11 com- posite. Pedes 5-ti paris distincti, uniarticulati, setis 3, quarum interior ceteris multo major et ciliata, instructi. Sacci oviferi parvi abdomini appressi. Longit. circit. 3 mm.”’ From (C. phaleratus, which it closely resembles, it differs, according to Schmeil, in its more slender form, short stylets with single oblique series of spines, peculiar shape of the fifth foot and the method of motion and also especially in the number and relative length of the antennal joints and the form of this organ in the male. The formula for the length of the antennal joints in C. affinis is Se SUL = while that of C. phalerahisis =2 oe The fifth foot is one-jointed, and this joint is quadrate with three spines apically. The stylets are twice as long as broad and are orna- mented by an oblique line of small spines. The receptaculum is smilar in form to that cf C. phaleratus. The motion is a creeping or slow swimming near the surface. Length 0.85 mm. * Cyclops bicolor Sars. PLATES XVIII, Figs. 3-3e; XXI, Fia. 12. Sars ’63; Rehberg ’80 (diaphanus); Herrick ’84 and ’87 (diaphanus); Daday ’85° (diaphanus); Lande ’88 (diapbanus); Richard ’91 (diaphanus); Schmeil ’91; Marsh ’92. DESCRIPTION OF THE FEMALE: The body, not including the cau- dal setze, measures from 0.65 to 0.80 mm. The following are measure- {Very curiously in Schmeil’s reference to figures, p. 157, C. jimbriatus is referred to as C. affinis, Fig. 8, Plate VII. “as eee {ee “The - hk Fo tm » / NY \ hV A F #r ENTOMOSTRACA OF MINNESOTA. 119 ments of a rather small specimen: First segment of cephalothorax 0.24, second segment 0.068, third segment 0.06, fourth segment 0.036 mm.; the remainder of the body to the stylets measures 0.24 mm., while the stylets themselves are 0.024 mm. long and bear a lateral Spine about one-third their length from the apex. The longest seta is 0.24 mm. long, the outer median seta being about 0.19 mm. The body is comparatively rather slender and tapering, with an unusually long first thoracic segment. (Measurements of a large specimen of this Species may serve to indicate the observed fluctuation in size: Length 0.81 mm., thorax 0.50, abdomen 0.31, stylets 0.06, longest seta 0.40, outer median seta 0.36 mm.) The antennz are considerably shorter than the first thoracic segment, being about 0.19 mm. long, the sev- enth and eighth joints about equal and the longest of the eleven seg- ments. The first joint is very large. The antennce in a state of rest assume a curved position. The antennules are small, the terminal segment measuring (in the animal first above referred to) 0.032 mm. The labrum has six similar teeth, which are bordered on either side by a larger one. The longest joint of the outer maxilliped measures 0.06 mm. All the feet are usually two-jointed in both rami. The outer ramus of the first pair of feet has the terminal joint armed exter- nally with three stout spines, terminally with two setie, and internally with three sete. The second and third pairs of feet are alike in their spinous armature, the outer side of the terminal segment bearing three spines, the end a very large toothed spine and a seta, and the inside four sete. The fourth foot has two spines on the outside of the terminal joint, a heavy spine and a seta terminally, and four sete within, while the terminal joint of the inner ramus bears externally one spine, apically two spines, and internally three sets. The fifth foot consists of a fleshy basal segment, more or less coalescent with the last thoracic segment and bearing a curved spine externally, and a terete terminal segment 0.012 mm. long, which has an apical seta four times its own length. The abdomen is slender and its last seg- ment bears a series of spines dorsally on the caudal margin. The egg- sacs are appressed and contain eight to twenty rather large ova. The color is bronzy and opaque. Although Marsh says his ‘‘specimens agree very well with the descriptions of Sars and Schmeil, the only marked difference being in the length of the caudal sete,’ we find several points of divergence which may make it necessary to create a new variety or species. The Stylets are much shorter in the American form and the sete are longer. The external apical seta is a well-formed spine. The form of the basal segment of the fifth foot is more as in C, varicans, there being a decided protuberance to receive the second joint. The receptacu 120 GEOL. AND NAT. HIST. SURVEY OF MINNESOTA. lum is also more elongate, but this is subject to considerable varia- tion. The armature of the feet, structure of antenne and most diagnostic points agree so fully that I hesitate to separate the two forms. In the description of C. diaphanus given in the first edition some of the state- ments apply to C. varicans or an allied form. The form of the recep- taculum figured on Plate R, Fig. 12, of that report may be compared with that of Plate VII, Fig. 3°, Crustacea of Alabama, to illustrate the range of variation. * Cyclops phaleratus Koch. PiatTes XVII, Fies. 1-7; XVIII, Fias. 2-24; XIX Fie. 1; XXI, Fires. 6-10. Koch ’35; Fischer ’51 (canthocarpoides); Lilljeborg ’53 (canthocarpoides); Claus ’57 and ’63 (canthocarpoides); Lubbock ’63 (canthocarpoides); Sars 63; Fric ’72 (can- thocarpoides); Poggenpol ’74 (lascious); Uljanin ’75; Brady ’78 and ’91; Herrick 782 (adolescens), and ’84 and ’87; Cragin ’83 (perarmatus); Daday ’85°; Richard 791; Schmeil ’91 and ’92; Turner ’92; Marsh ’93. Body sub-eylindrical, thorax little enlarged for the genus, abdomen large and cylindrical. The transition from thorax to abdomen is less sharply marked than usual. Cephalothorax oval, first segment longer than the remainder. Abdomen shorter than thorax, stylets short and profusely spinous. An oblique row of spines passes across the stylet some distance behind the lateral spine, which is very short, and other rows of spines or teeth may ornament the inner aspect.or may be absent. The whole inner aspect is also ciliate. The outer apical seta is a ciliate or toothed spine and the inner is shorter and weaker. The outer median seta is nearly as long as the abdomen and is sparsely clothed with sharp teeth. The inner median seta is about half as long and similarly ornamented. The antenna is usually 10 jointed but fre- quently is 11-jointed, (?) and is much shorter than the first thoracic segment. The swimming feet all have three-jointed rami and are strongly armed with closely set short teeth. The armature of the ter- minal joints of the fourth foot is as follows: ; (ex. 2 spines. ex. 1 seta. Outer ramus jap. 1 spine, 1 seta. Inner ramus + ap. 2 spines. (in. 4 sete. fp 2 sete. Hgg-sacs appressed, closely filled with many ova. I here append the original description of Cyclops adolescens Herrick (—C. perarmatus Cragin) for comparison with the description of C. affinis as transcribed below, as it contains other data: ‘‘Thorax oval, broad, acute ante- riorly; last segment large and separated by a constriction from the anterior ones. The head is beaked below; first thoracic segment large and long (0.36 mm.); last thoracic segment wide, united closely with the first abdominal segment, armed with series of teeth. Abdomen ENTOMOSTRACA OF MINNESOTA. 121 short, especially the last segment, with is toothed behind; stylets very short. The antenne are much shorter than the first segment, 11- jointed. The maxillipeds are very small. All the feet are armed with a row of very large teeth or lanceolate spines down one side; fifth foot one-jointed, with three spines, the outer being smooth, the others spiny; egg-sacs variable, narrow, appressed; eggs large, color usually dark. The animal moves like Canthocamptus, and is able to progress out of water better than other species. The following measurements will give an idea of the proportions: Length 1.26 mm., thorax 0.76 mm., abdomen 0.44 mm., stylets 0.06 mm., longest seta 0.34 mm., an- tenn 0.28 mm., width of thorax 0.44 mm.”’ Measurements of another specimen are as follows: Length 1.1 mm., thorax 0.65, first segment 0.33, abdomen 0.45, longest seta 0.6. The male is more slender (0.93 mm. long) and the longest caudal seta greatly exceeds in length the whole abdomen. The antenne are strongly modified. * Cyclops fimbriatus Fischer. PLATES XVII, Fies. 8, 9; XXI, Fie. 11; XXV,-Fies. 9-14. Herrick ’82 (crassicornis), and ’84 and ’87{; Turner ’92; Marsh ’93. [The manuscript gave not the slightest hint as to date or reference in the following, given in the order of the manuscript:] Mueller (crassicornis); Fischer; Sars (crassicornis); Hel- ler (gredleri); Frie (pauper); Uljanin (crassicornis); Brady (crassicornis, and fimbriatus); Rehberg (poppei, and fimbriatus); Daday (fimbriatus, and margoi); Vosseler; Schmeil; Richard. A small species (0.8 to 0.9 mm.). Thorax oval, not greatly ex- panded, angles of segments rather prominent. First thoracie seg- ment forming about half the length of the cephalothorax. Abdomen rather long and thick, terete, about as long as the thorax. Last two abdominal segments armed with a row of spines at the caudal margin. Caudal stylets twice as long as the last abdominal segment. A series of small teeth in a longitudinal series generally ornaments the stylet. Lateral spine small. The outer apical spine strong, the two median sete long, spinously armed, inner two-thirds as long as the outer. Inner apical seta weak and short, pectinate. Antenne shorter than the first segment, 8-jointed; formula: -—~—--~<~, the basal joint with a small semicircular series of fine bristles. Antennules short, apical segment short with but two strong sete and several smaller ones. Feet armed with spines and bristles. Formule for fourth foot as follows: ex. 2 spines. ex. 1 seta. Outer ramus {0 1 spine, 1 seta. Inner ramus + ap. 2 spines. in. 4 sete. in. 2 sete. { By a curious mistake in this paper on p. 14, the reference to Plate VII, Fig. 2, is placed opposite C. fimbriatus and not, as it should be. opposite C. phaleratus, This mistake was then reproduced in the description of plates, p. 56. 122 GEOL. AND NAT. HIST. SURVEY OF MINNESOTA. Fifth foot small, one-jointed, with three spines, of which the inner is large and serrate. Total length 0.8 mm., thorax 0.42 mm., abdomen 0.38 mm., stylet 0.09 mm., antenna 0.18 mm. Egg-sacs appressed, with few ova. Cyclops aequoreus Fischer. PLATE XXIII, Fie. 5. Lilljeborg 753 (magniceps); Fischer ’60; Brady ’68, ’78 and ’91. Body compressed, attenuated caudad. Antenne shorter than first segment, stout, six-jointed, fourth and sixth segments longest. Fifth feet with a small basal joint and a triangular lamina bearing on the distal margin three spines and a seta, lateral margins ciliate. Abdo- men slender, first segment very long, last very short. Stylets less than twice as long as wide. Longest seta as long as the abdomen. First foot with the formula ex. 3 spines. ex. 1 spine. Outer ramus + ap. 1 spine, 1 seta. Inner ramus {0 2 spines. in. 4 sete. in. 3 sete. Length 0.85 mi. This species lives in salt marshes and brackish pools, and is inter- esting for its departure from the generic type in several particulars. Three species of Cyclops were found by E. Pratz in 1866 in the hydrant water of Munich and described as new. : The first of these, C. cwcus, is blind and colorless and has 11-jointed antenne. The second species, C. subterraneus, is doubtfully identified by Schmeil with C. bicuspidatus. The third, Cyclops serratus, is probably a form of C. viridis Jurine. Two blind species of Cyclops have been described by G. Joseph (82): OC. hyalinus and C. anophthalmus, but the descriptions are not accessible to me. | HETEROGENESIS AND PREIMAGO FERTILITY IN CYCLOPS, The present writer’s views and statements in respect to the relation of sexual and anatomical maturity and the influence of the environ- ment have given rise to a running criticism occupying many passages throughout the recent monograph of Schmeil, ’92. These criticisms are so inconsistent, and at times so contradictory of the author’s own observations and statements, that it is hopeless to attempt to answer them, especially as his notions respecting varietal and specific relations seem strangely obscure. Ifa plain statement of the position of the present writer will remove any obscurity he feels bound to offer it. ENTOMOSTRACA OF MINNESOTA. 123. First— As a matter of frequent observation and beyond all doubt, it frequently happens that a young female Cyclops becomes oviparous before the moult, when it acquires its full adult complement of seg- ments in the antenne and feet. Such animals are obviously larval and exhibit this fact in their small size, pale color, small number of eggs; imperfect development of serrations, spines, etc. Schmeil himself has observed males in this stage with spermatophores and had before him a figure in my Final Report (Plate Q, 5), reprinted from the tenth annual report, in which this matter is plainly stated, of young gravid females of C. serrulatus—a species not likely to be mistaken—with less than twelve joints in the antennze and two-jointed rami of the Swimming feet. After admitting that ‘‘kein Grund vorliegt, an der Richtigkeit der Herrick’schen Angabe zu zweifeln,”’ he says ‘‘ Herrick figures, as a matter of fact, not a young form but a completely devel- oped animal, in which, to be sure, in certain segments of the antenns: the normal subdivision has not taken place.’’ He adds (entirely mis- conceiving my position as to heterogeny’: ‘‘ Dass hier nicht an einem Fall von Padogonie oder gar Heterogenie zu denken ist, ist selbstvers- tandlich.’”’ Had he consulted the original paper Schmeil would have seen that the failure to develop a full complement of antennal joints is but one of the symptoms of the larval state manifested by this speci- men. Moreover, such forms are found among vast numbers of adults and larve in the midst of the most prolific seasons and in suitable situations. We claim that the next moult would have brought to this very animal its normal adult structure. Nor is this an isolated case. Yet Schmeil could in all consistency be forced to erect a variety for such forms. In glaring inconsequence, we find, on p. 101, Schmeil Says of C. clausii Heller: ‘‘Obgleich ich der Ansicht bin, dass wir es hier wohl kaum mit einer selbstandigen Art, sondern nur mit einer Jugendform einer anderen (des (. viridis) zu thun haben,”’ ete. Second— As a second and entirely distinct point, though confused with the former by Schmeil, it is believed that many of our species, especially such as live in pools which undergo great changes with the season by reason of evaporation, intrusion of water plants or animal forms serving as food, ete., may, after reaching full maturity and bear- ing more than one generation of eggs, undergo considerable changes, or that, under these changed conditions, what is usually the uitimate condition becomes a transitory one. This change may show itself not only in increased size but in enormous enlargement of the sete. For ' example, I have seen ©. ingens with the pectinating hairs on the set: elongated till they became long hairs. All the spines and plates and serrations are exaggerated, while the relative proportions are altered. In the case of C. viridis this is especially liable to occur, because of its stagnant stations. The color changes with the rest and the change 124 GEOL. AND NAT. HIST. SURVEY OF MINNESOTA. may be noticed in the same pool during the progress of the seasons. In these cases, according to our nomenclature, the modified form is a post-imago, and if young born from the ordinary female enter this state and produce young in turn which never reach that state, we have a case of what was termed ‘‘heterogenesis’”’ in the old general sense; i. e., two cycles of development occur in the same species... Now, as these cycles are dependent on environment, the process may be termed pedogony if the term is taken in the sense indicated. What to do with such cases is puzzling to taxonomy. It is obvious that they are quite different from the sporadic appearance of sexually functional larvee, for here we have a stage which does not necessarily belong in the history of the species, and is, as it were, Superinduced. The objec- tion raised by Schmeil against making varieties of them—i. e., that you cannot fix an arbitrary size limit— would militate against almost all geographical varieties equally. In fact, however, the changes fol- lowing the last moult are usually evident enough to produce no trouble, In the case of Cyclops signatus we are confronted by a question of fact. This is undoubtedly the most conspicuous instance, if an instance at all, of the change referred to. If the actual rearing of C. signatus var. coronatus should prove that C. signatus var. tenuicornis does not belong in its cycle then the two forms must be separated and this particular instance of pedogony disappears. We think it possible, however, to prove the contrary. Most remarkable of the many curious statements made by Schmeil on this point is the following: ‘‘ Herrick even in his later work is not in position to demonstrate among the known species a Single sexually mature larva. He is not in the position to bring a proof of a single one of his assertions. Also none of the other investi- gators has observed this, according to Herrick, common phenomenon.”’ Having overlooked my earlier paper he is surprised at the failure to again revert to it. But, after his own admissions, how he can deny the evidence of sexually mature larve is unintelligible. FAMILY HARPACTICIDE. Numerically the largest of the families of the Copepoda, this group contains predominatingly marine and mostly minute animals, fre- quently of strange and grotesque form. ete Pee) ee 2 ¥ @ eT Oe ope : oe ie eee 136 GEOL. AND NAT. HIST. SURVEY OF MINNESOTA. The swimming feet are all armed with very strong spines, aside from the usual quota of spines at the end of each joint. Length 0.65 mm. GENUS ATTHEYELLA Brady. This genus, the diagnostic characters of which have been above indicated, contains three nominal species. It is quite difficult to say what differences exist between Sars’ Canthocamptus pygmeus and Attheyella spinosa. Brady did not-seem to recognize the fact that his diagnosis included that species. The third species is the blind A. cryptorum of Brady, which it is interesting to compare with the blind Bradya limicola of the coast of the Gulf of Mexico. GENUS MARSHIA Gen. nov. ze Allied with Attheyella. Inner branch of first foot three-jointed, scarcely elongated, barely subprehensile. Second and third feet with etter ramus two-jointed, short. Fourth foot with minute one-jointed outer ramus and three-jointed #*¢r ramus. Fifth feet one-jointed. Antenne six-jointed, the fourth joint with a slender hyaline process longer than the end of the antenna. Second antennz without obvious — palpus, prehensile. Mandiblar palp simple? First foot-jaw with an uniciliate papillose palpus. Second foot-jaw with a long uncinate Special joint. Antenne ofthe male-strongly modified. Habit, fresh or brackish waters. *Marshia albuquerquensis sp. n. PLATES XX XI; XXXII, Fies. 1-5. Body with ten obvious segments, with the aspect of Canthocamptus. Antenne short, six-jointed. The proximal joints enlarged and spinous; second also tumid, with three or more cilia; third joint longer; fourth with a long seta and still longer flagellum; fifth joint very short; apical joint elongate bearing about ten sete. Antennules short, pre- hensile, with four geniculate setee apically and several short spines, especially a transverse series of sharp teeth on the dorsal aspect. Jaws with six sharp teeth. Anterior maxillipeds with a minute uni- Setose palp and three processes bearing curved spines. Posterior Nore.—C. frontinalis Rehberg. This author seems to have parted with his usual acumen in the remarks upon this species. After describing a Canthocamptus with the inner ramus of the first foot “reichlich doppelt so lang wie die beiden Grundglieder des Aussenasts,” he draws a moral on the muta- bility of genera from the fact that Brady founded the genus A/‘heyella“auf grund der Eingliede des innenastes am fierten Fusspaare und einer derartigen Bildung des ersten Fusses, wie er bei C. frontinalis beschrieben ist.” Brady says (brit. Copepoda, p. 58): “Inner branch of first pair of feet scarcely at all elongated, and either two- or three-jointed,” ete. The distinctive characters being the one- or two- ointed second and third feet and the one-jointed inner ramus of the fourth foot, it is doubtful if C. rontinalis is really new. > ENTOMOSTRACA OF MINNESOTA. 137 maxillipeds with a long claw longer than the preceding joint. First foot with the outer ramus nearly as long as the inner, two-jointed, bearing at the apex three pectinate sets. The basal joint bears a peec- tinate seta externally and a spine internally. The inner aspects of all the joints of both rami are spinous, the outer setose. The outer ramus of the second foot is two-jointed and has one pectinate seta apically, one spine internally and one spine externally, while the corresponding segment of the third foot has two pectinate sets apically and one internal seta and two external spines. The fourth foot has a minute one-jointed outer ramus bearing one long pectinate seta and a short external spine. The fifth foot seems to consist of one piece, armed as follows: Externally a conical projection near the base with a long simple seta, outer apical lobe (= the homologue of second joint) with five sets, the second and fourth of which are longer and pectinate; the inner apical lobe bears six (or five) setze, all but the innermost being pectinate. The two lobes are separated by a simple incision, and repeated examination showed no indication of any segmentation in either sex. The abdomen is very slender, and, like the thorax, its segments are all ornamented caudad with a series of spines or teeth. Stylet two and a half times as long as wide, with one or two small spines externally one third the length from the base and one longer spine near the middle of the inner margin, which is ciliate. The two median apical sete are fused at the base and the inner is three times as long as the outer, which is twice as long as the stylet. The inner apical seta is short, the outer obsolescent. In the male the antenna is reduced to a thick tumid member with the third and fourth segments greatly enlarged. The apical segment is furnished with three hook-like claws. Flagellum slender, of uni- formdiameter. Fifth foot has on the outer apical lobe four sets and a small spinule, and on the inner three non-pectinate sete. Caudal stylet greatly elongate, over four times as long as wide and nearly twice as long as the preceding segment. Marshia brevicaudata sp. n. PLATE XXXII, Fies. 6-13. The second speciesof this genus at present known may be described comparatively. Similar to M. albuquerquensis in most respects, but differing in a few points so far as known. The caudal stylets are short, about twice as long as broad, the longest seta being seven times the length of the stylet, while the outer median Seta is twice and a half as long as the stylet. These sete are not fused at the base. In the male the difference between the species is greater. The proportions of the stylet being the same as in the female, but the longest seta is perl 5 , 138 GEOL. AND NAT. HIST. SURVEY OF MINNESOTA. nine times as long as the stylet. The fifth foot of the female nearly as in the previous species, but the proportions of the sete differ. The fifth feet of the male are like those of MW. albuquerquensis. The antennee of the male seem to be different. In M. albuquerquensis the apical seg- ment is larger and the flagellum is long and of uniform width, while in the present species the flagellum is short and clavate. The swim- ming feet seem similar. Length of male 0.56 mm., length of first seg- ment 0.15 mm., length of stylet 0.04 mm., length of longest seta 0.28 mm. to 0.354 mm. The stylets in the female of MW. albuquerquensis measure 0.072 mm. in the female and over 0.08 in the male, the longest seta being 0.37 and 0.42 respectively. : It must remain for larger experience to determine the value of these distinctions, which rest on comparatively few individuals in the case of M. brevicaudata. g 3 Tee Sahat Ie 3 E -CLADOCERA OF MINNESOTA | E BY Cue? HERRICK a 3 oo s ae ‘ ‘i > - ata :* in 4 oe Par. ORDER CLADOCERA. This very extensive group contains a variety of types, but there are sufficiently evident connectlng links uniting the extremes of structure. The Gymnomera which, following the usual custom, we include here, stand distinct from the other groups, yet have suffic- iently evident cladoceran affinities. It is very unfortunate for e«tio- logical speculation that this the only truly marine group should stand thus isolated from its fellows. According to the notions at present prevailing, the Phyllopods stand nearest the primitive type of crusta- cea. There are unmistakable hints at an early origin for that group, and not less evident are certain analogies with both Cladocera and Copepoda. : There has, however, recently been made an attempt to derive the Phyllopods fiom an original cladoceran stem with, as we think, some- what unsatisfactory results. Do we not rather see in both groups two like phases which may be looked upon as incidental and comparatively trivial? The shelled and the shell-less phases appear in both. The most closely shelled Phyl/opod is unmistakably nearer Branchipus even than any of the Cladocera. It would seem that the brief and imper- fect embryonic nauplius condition of the latter sufficiently indicated their later origin. Again, no fanciful analogy can unite the Ostracoda with the Lynceide. We know of no recent discoveries casting dis- credit on the remark of Balfour: ‘‘The independent origin of the Ostracoda from the main crustacean stem seems probable.’’ Professor Packard says:* ‘‘We imagine that when a permanent body of fresh water became established, as, for example, in perhaps early Silurian times, the marine forms carried into it in the egg-condition, possibly by birds [sie?] or by high winds, hatched young, which, under favorable con- ditions, changed into Sida, Moina and Daphnia-like forms. The Clad- _ ocera are, then, probably the more generalized forms, from which the _ Phyllopods, at this time, and probably ever since Devonian times, par excellence a fresh-water assemblage of forms, took their origin. What- ever affinity there may be between the shelled Phyllopods and the 4 *“A Monograph of the Phyllopod Crustacea,” etc., AJ/ih Annual Rep. U.S. Geol. and Geog. Surv. err. 142 GEOL. AND NAT. HIST. SURVEY OF MINNESOTA. Cladocera, it would seem that the evidence is conclusive that the latter group is not the direct continuation of the line of development inau- gurated by an ostracode ancestor. As shown beyond, the present centre of the group seems near Moina, with indications of a divergence from this rather generalized type, especially of degradation and het- eronomy on the side of the Lynceids. It seems at the present time that more might be accomplished for wtiology by a careful study of such groups as the present, in which are a variety of closely allied forms, than by the attempt to join widely separated groups. When we shall have seized upon the latest eddies and mapped their direction, it may become possible to combine the indications in such a way that lines of divergence thus traced accurately through some small part of their course may be produced backward to their intersection. This, then, is our present duty—the accurate mapping of minute districts and the careful noting of any moving straws competent to indicate movements in the vast complex of vitalized nature. We conceive the Cladocera to have had a com- paratively recent origin, and to express the culmination and retrogade development of a plan of structure first differentiated after the appear- ance of clear bodies of fresh water. All the species save a very few are confined to inland waters. Accepting the above mentioned theory, the Sidide will occupy the first place as departing least from the type from which the whole group sprang, while it is connected by the genus Daphnella with the Daphnide. The Daphnide, beginning with Moina, find their ultimate development in some monstrous forms of the genus Daphnia, but pass into the Lyncodaphnide by way of Macrothrix. The links uniting all these minor groups are very obvious. Our ownideas of the relationships among the Calyptomerous Cladocera are expressed in the accompanying table. This table is to be consid- ered a projection of a portion of a genealogical tree, seen from below, in which the genus Moina forms the arbitrarily chosen fixed point. The heavy dotted line is imagined as directed downward vertically. That branch rising toward the top of the page is growing obliquely upward. The Daphnidw are represented as expanding upon the same plane as Moina, and the Lyncodaphnide extend diagonally downward, producing the Lynceid branch. The Bosminide spring from the stem at a lower point.* The Cladocera or Daphnoidea are characterized by the more or less leaf-like feet and the lamina of thin chitine which incloses the greater * Nore.—To adapt the diagram to the theory that the Lynceide are the progenitors of Cladocera, it is only necessary to revolve the imaginary line to the right, till it coincides with the axis of that family, The question mark may be understood to indicate that the source of the pivotal group, Moina, is uncer- tain. The author must confess that his inclination is toward a belief that the line culminating in the Daphnide diverged from a group of organisms resembling Phyllopoda, more definitely, resembling Limnetes. There is avery remarkable resemblance between the larva of Limnetes and Bosmina, The lateral spines of the former are, as will be shown, true homologues of the antennules of Bosmina. The later origin-of the P/y/lopoda io their present form may be well admitted. ENTOMOSTRACA OF MINNESOTA. 143 Limnosida Sig Pseudosid. __-Latona Holopedidz ve ee ape San She: ‘\ Daphnella a 2 ‘F Sal (SIDIDZ) Simocephalus I on mee (?) -~-~---- oa n--- MOINA----Ceriodaphnia ‘Daphnia 7 I vN / Hi \S . ‘ a . we ‘ Scapholeheris oa | “N SS va y MN PR ae Streblocercus Macr othrix ~ Lyncodaphnia osmina y Se ' / | ESS : Lathonura = Orepanothrik ~~ e =e Soe -< /Hocryptus ! ' Acantholeberis 4 LY NC EIDA » 1 | Leydidia Furycercus: © ~ 7° Camptocercus______7 zk Sid 7 ~o Alonopsis-~~ Wee artes ‘\ (Alona) +7 a Lynceus Graptolebris ff Pletroxus), s ‘\ Chydorts ae XN ‘Monospilus part of the body, or at least forms a sac for the protection of the eggs. This so called shell springs as a fold from the maxillary segment, and is the most conspicuous and variously formed, while really least im- portant, of the structural peculiarities. All Cladocera begin life with a single median eye, but some lose it during later life. In one case it remains the only visual organ. The outer covering is in most cases changed by frequent moults. The period of the moult is one of the most precarious in the life his- tory of the animal. Although figures and brief descriptions of animals belonging to this group are to be found in the works of Swammerdam, Leuwen- hoek, Trembley and others of the older authors, Mueller* was the first to produce a systematic work upon these in common with other minute fresh-water crustacea. He may be called the father of the study of micro-crustacea. Jurine,f an eminent Swiss naturalist, was the next to contribute important discoveries relating to these inter- esting animals, though Ramdohr had given anatomical details of sev- * Entomostraca, seu Insecta testacea, quie in aquis Danice et Norvegice repcrit descripsit, etc. Otto Friedrich Miiller, 1785. + Monoce. qui se trouvent aux Envir. de Geneve. 144 GEOL. AND NAT. HIST. SURVEY OF MINNESOTA. eral species. Gruithuisen, a little later, gives further details of g Daphnia sima (Simocephalus). The work of Milne Edwards gives a resume of what was known regarding these animals in that period. Soon afterwards the work of Baird became the beginning of a new era, and the study of the minute crustacea sprang into importance at once. The Scandivanian peninsula being the birthplace of the science, it is proper that the most exhaustive work on the group should be performed there. The most important of the later writers are Leydig, Schoedler, Fischer, Lilljeborg, P. E. Mueller, Sars, Weismann, Claus and Kurz. The complete bibliography of the subject up to Mueller’s time is found in Baird’s British Entomostraca; the greater part of the later bibliography is to be found in P. E. Mueller’s Danmark’s Cladocera. A few only of the more important works are here mentioned, the. com- plete list elsewhere given making repetition unnecessary. Lilljeborg, W., De Crustaceis ex ordinibus tribus, (or) Om de inom Skane forekom- mande Crustaceer af ordningarna Cladocere, Ostracoda och Copepoda. This valuable work is particularly good on the Cladocera, but is unfor- tunately without Latin descriptions; so that the Swedish text is a hindrance to its usefulness. It is chiefly of historic value now. Large 8vo. Lund, 1855. Leydig, Fr., Naturgeschichte der Daphniden. The most magnificent work published on this group. Surs, G@. O., Om Crustacea Cladocera, iagttagne i Omegnen af Christiania, 1862. This valuable work is difficult of access, printed on thin paper and without illustrations. A second paper by the same author in 1863 is mentioned, but I have never seen it. Schoedler, J. E., Neue Beitrage zur Naturgeschicte der Cladoceren, 1863. One of the most important works on the Lynceide. Sars, G. O., Norges Ferskvands ee et y sj ‘ ~ 5 . ray P xe ee awe my ' an, « 166 GEOL. AND NAT. HIST. SURVEY OF MINNESOTA. l’article terminal, mesure a partir de l’extremite de Ja branchie; chez la femelle cette meme patte est charaterisee par l’une des soies, qui s’est transformee en un batonnet court et gros, cilie d’une facon particuliere. La conformation des autres pattes, dans les deux sexes, presente egalement des characteres speciaux, difficiles a exposer sans le secours du dessin on sans une longue description. La carapace est marquee de tubercules termines par des poils; les crochets dorsaux sont simples et limitent un large espece qui prend la configuration d’un cceur quand la coquille est etalee. Les crochets terminaux du post-abdomen portent au cote interne et vers leur base une plaque dentee, et ils sont surmontes d’une dent unique; ils n’ont pas de peigne. La femelle porte deux ceufs dans son ephippium.’’ Daday mentions the fol lowing species, which are added provisionally: Moina salina Stephanow. Capite supra oculum impressione insigni, fornice indistincts; testa corporis fere quadrangulari, margine anteriore ac inferiore setis perpaucis; antennis in mare apice unguibus curvatis, majusculis 5; abdomine sine processu; cauda aculeis magnis 10 setosis armata, margine superiore tuberculis perparvis lateribusque setis minutis, in series transversales bositis; unguibus caudalibus sine spenarum serie pectiniformi margine anteriore processu dentiformi longe, usque ad medium setosis. Longit fem., 0.75 to 0.9 mm.; altit, 0.45 to 0.5 mm, Moina banftyi Daday. Testa capitis setis tecta; testa corporis fere quadrangulari, obtuse angulata, parte postica supra duos processus curvatos formanti; antennis primi peris abique ciliatis, laminis quadrangularibus obtectis; cauda apicem versus attenuata; unguibus caudali- bus curvatis, setosis. Longit. fem., 0.9 to 15 mm. GENUS MOINADAPHNIA Herrick. 1887. Head strongly arched above, angled in front of the eye, somewhat beaked at the caudal end of the lower margin, near which are affixed the slender antennules. Body quadrate, as in Daphnia, but merely angled at the dorso-caudal angle. Post-abdomen elongate, armed as in Moina. Brood sae occluded by strong abdominal processes. An- tenn with a long unjointed spine from the apex of the last joint of the four-jointed ramus, otherwise as in Moina. The first member of this genus was found by L. R. King (’52 to 754) in New South Wales and named Moina macleayii. The figure and description were repeated by Schoedler (77), but he does not suggest generic autonomy. *Moinadaphnia alabamensis Herrick. PLATE XXXVI, Fias. 7-10. Herrick ’87. As suggested in the original paper, this species not only affords a needed transition between Moina and Daphnia but also forms a link ENTOMOSTRACA OF MINNESOTA. 167 with the fauna of the southern hemisphere. The species is large compared with Monia, being 1.68 mm. long. The head is shaped much as in Simocephalus, being acutely rounded in front of the eye and pro- vided with a distinet beak, near which the antenne are attached. The eye is large and the fornix evident, asin Daphnia. The antennules are long and slender, little narrowed apically, armed with a flagellum at the basal third. Antenne slender, segments narrow; apical segment of four-jointed ramus has in addition to the three geniculate set a very long spine representing the short thorn occupying that place in Moina, otherwise as in that genus. Body quadrangular, somewhat produced above at the posterior angle. Lower margin armed with short spines asin Daphnia. Abdomen slender, claw slightly curved and armed with a continuous series of small sete. A short spine in front of the claw. Lateral spines as in Moina, twelve or more in num- ber, the first being bifid. Dorsal part of abdomen with a long process for occluding the brood sac, also a blunt tuberosity caudad of it. The general habitus is like Moina, but in the form of the shell and many details it approaches Daphnia. The description of King’s species is not full enough to make specific comparison possible, but of the generic relationship there can be no question. The most important diagnostic difference —that in the formula of the antennary spines— not funda- mental but a mere matter of proportions. GENUS CERIODAPHNIA Dana. The genus Ceriodaphnia is the successor to Moina, which some species greatly resemble; the post-abdomen, however, is shorter and has a habitus resembling Daphnia; the antenne are smaller and the shell is thick and coarsely reticulated. Ceriodaphnia has the same general mode of life as Moina, living in muddy pools in late summer and bearing numerous broods which often greatly extend the brood cavity. The antennules are shorter but have a similar form; the male antennze show a transition in the various species from forms adapted for prehension to such as are found in Daphnia. The brood cavity is closed by two ridges on the abdomen instead of one, as in Moina, or three, as in Daphnia. The ephippium contains but a single ovum. In general, the form is oval or quadrate, angled but not spined posteriorly; head separated from the body by a deep depression; pigment fleck present; beak absent; antennules movable, rather short; antennz with the three- jointed ramus with five sete; first foot of the male with a hook or flagellum. 168 GEOL. AND NAT. HIST. SURVEY OF MINNESOTA. The members of this genus are danger signals from a hygienic point of view, for they frequent water containing decaying matter; as many as 1,400 were counted in a single quart of such water. The genus is particularly preplexing, as the varieties named seem to be hardly entitled to specific rank and are so similar as to require great care to properly distinguish. The following artificial key, it is believed, will assist in placing the specimens which may be obtained in America. There seems no reason to doubt that our fauna is very similar to that of north Europe. Of the twelve species here enumerated at least one-third may be synonyms and others of the remainder are with difficulty distinguished. KEY TO THE GENUS CERIODAPHNTA. I. Head without a ‘‘horn.”’ a. shell irregularly striate... 2. | sc ee ee eo EO LODSs tne b. Shell with hexagonal meshes. * Shell with doubly contoured markings. + Head broad, short. oes eth tie lee) het ee Ce eee +{ Head narrowed, depressed. ft Antennules‘normal. ; . | 9..5:. +... # = + wotundagica tt Antennuleselongate.. . . . . . . alabamensis, 170 ** Shell simply marked. + Claws with teeth. . . . . Yvreticulata, 170; dentata, 170 +t Claws without teeth. {.Antenns very long. . 9: «=< s & ». . punetata, t/t tf Antennze normal or short. Z Post-abdomen broad. . laticaudata. 171; consors, 171 274 Post-abdomen narrow. || Head not angled behind theeye. . quadrangula, 172 |||| Head abruptly angled behind the eye. . . Scitula, 172 *** Shell opening pointed. viet ae i) tine 5 eS CUOSal oles e. Shell recticulate with rectangular nfeehen ct logge te ig REO Awl II. Head with a curved ‘‘horn.”’ tibet won) otis hog) oo) ee eet CO LUD lret [ Not noticed in the key: asperata, 173; minuta, 173; textilis, 173; rotundata, 173; echinata, 173. | * Ceriodaphnia megops Sars. PLATE XLI, Fi4. 20. Birge ’78 (cristata). This species is one of the largest and most readily distinguished as well as rarest of the genus. Very characteristic is the fine anasto- mosing striation which breaks up into reticulation only near the shell margins. ‘This species seems to form the transition toward Simoceph- alus with Scapholeberis, which, however, diverges along its own pecu- ge tat Re AS eae ENTOMOSTRACA OF MINNESOTA. 169 liar track. The length is sometimes 1.0 mm. The head is obscurely angulated in front of the antennules, which are large. The antennules of the male are long and have hooked seta at the end. The description of Ceriodaphnia cristata given by Birge would apply in almost every particular to C. megops, though he seemed to overlook the close conformity. The size is much less (0.7 mm.), and the post- abdomen seems more abruptly truncate; moreover the number of anal spines is less. The crest upon the dorsal margin may be the effect of prominences such as are described by P. E. Mueller; at any rate, in view of the fact that but few specimens were discovered, the sugges- tion lies near that C. cristata is the young or, at least, a reduced form of C. megops. Professor Birge writes that he now unites cristata with C. megops. Found at Southampton, Mass. Ceriodaphnia pulchella Sars. PLATE XLI, Frias. 14, 19. Very much like C. reticulata, but smaller. Head large, turgid, and angled in front of the antennules, forming almost aright angle; for- nices moderate; antennules rather large; shell oval, reticulated with double contour lines; post-abdomen of medium size, narrowed toward the end, slightly truncate. with about nine spines; terminal claws short, smooth. The flagellum of the male antenne is but slightly hooked, 0.5 to 0.6 mm. long. This species is not certainly identified from America, though a form with smooth claws and small fornices occurs with C. dentat« in some places. Ceriodaphnia rotunda Straus. PLATES: XLI, FIGs. 12; 23; XLII, Fre. 1. Daphnia rotunda—Straus, Baird. As said by Kurz, this species is not easily mistaken; the small head (only paralleled by the following), the very evident reticulations and the broad abdomen give it a peculiar habitus which is unmistakable. Head depressed, small, spiny below, not angulated; fornices promi- nent, thorned; body rotund, almost spined above; shell doubly retic- ulate; post-abdomen broad, with seven or eight anal spines; claws large, smooth. The male antennules are little larger than those of the female. I have not yet seen this species in America. 170 - GEOL. AND NAT. HIST. SURVEY OF MINNESOTA. * Ceriodaphnia alabamensis Herrick. PLATE XLII, Fie, 2. (American Naturalist, May, 1883. Puiate V, Figs. 11, 12.) This species was seen but once and is insufficiently known. The body is elongate, quadrate, the shell reticulated with double contour lines, the head very small and produced downward below the eye, which is very small, the antennules are longer than in any other spe- cies, obviously two-jointed, with a lateral seta; the antenne are very long; post-abdomen long and rather narrow, with the margins nearly parallel, truncate at the end, with over nine anal spines; claws smooth, abruptly truncate. My drawing represents a daphnia-like set of processes for closing the brood cavity. Length 1.0 mm. Tuscaloosa, Ala. * Ceriodaphnia reticulata Jurine. PLATES XLI, Fias. 15, 21; XLII, Fie. 3; XLIII, Fie. 3; XLIV, Fias. 3, 4. Monoculus reticulatus—Jurine. Daphnia reticulata—Baird, Leydig. Ceriodaphnia quadrangula—Schoedler. Ceriodaphnia fischeri—Ley dig, Schoedler, etc. Head long, obscurely angled in front of the antennules; fornices very prominent; antennules small; post-abdomen of moderate size, rounded at the end, slightly tapering; about eight long anal teeth; terminal claws with a series of sharp spines at the base. The reticu- lations are sharp but simple. The flagellum of the male antennule is either straight or moderately curved. Kurz says that some varieties have the fornices blunt while others are sharp. I have seen only the blunt form, which is then much like the next. [* Ceriodaphnia dentata Birge. ] This form differs from the above only in having the inside of the claws fringed with minute bristles (sometimes absent), the angle of the head being more marked and the fornices less prominent. It is difficult to say whether our Minnesota specimens most resemble this or the typical C. reticulata of Europe. They seem intermediate, some having fornices with an abrupt angle. It may be instructive to quote Kurz on the European (©. reticulata: ‘‘ Examples occur 0.8 to 0.9 mm. long, others on the contrary only 0.5 to 0.6 mm. long and combining with the smaller size some differential characters. In the larger va- riety I found the fornix obtuse, while in the smaller it extends ina sharp thorn directed upward and outward. In this small sub-species isis ENTOMOSTRACA OF MINNESOTA. 171 the secondary teeth of the claws of the post-abdomen seemed to be absent, though in (@. reticulata three to five are constantly present.’ Professor Birge now identifies this species with C. reticulata. Ceriodaphnia punctata P. E. Mueller. PLATE XLI, Fia. 13. Head depressed, rounded at the end, not angulated, ornamented with minute spines within the hexagonal areas. Fornices slightly prominent, either smooth or spiny; antennules very long; shell rotund, reticulated; post-abdomen of medium size, width nearly uniform, truncate below at an obtuse angle; anal spines large, increasing toward the end; claws smooth. Length 0.7 to 0.9 mm. Found as yet only in Scandinavia. * Ceriodaphnia laticaudata P. E. Mueller. Prath Xi) Big. 22) Ceriodaphnia quadrangula—Sars (fide Mueller). Ceriodaphnia consors—Birge. Head small, depressed, rounded at the end, not angulated; fornices prominent; shell roundish, or sub-quadrangular, moderately reticu- lated, antennules rather large; post-abdomen broad, narrowed from the middle to the end; the nine or ten small anal spines nearly equal; claws large and smooth. In P. E. Mueller’s time males unknown. Length 1.0mm. Specimens 0.6 mm. long from Minnesota agree in most respects, but the reticulation is very marked and irregular and the terminal claws are pectinate. This form constitutes a transition to the next. ; A species related to C. laticaudata, but only half the size, was found in Clarke’s lake, a small but very deep pool, containing a fauna like that of the Great Lakes. The appearance is like the small form alluded to under that species, but the claws are smooth, the head is slender and strongly angled behind the eyes, and the antennules are of rather large size. The fornices are not very prominent. The shell is large-reticulate and the abdomen is large and obliquely truncate, the anal teeth being very large and strongly curved. The only indi- viduals seen were ephippial females measuring 0.55mm. This may be * Ceriodaphnia consors Birge. PLATES XLII, Fic. 4; XLIV, Fias. 5, 6. This differs from C. laticaudata in one or two points, being about one-half the size and having fewer caudal teeth. Birge says the abdo- 1 ee 172 GEOL. AND NAT. HIST. SURVEY OF MINNESOTA. men is broad and obliquely truncate. The difference between being obliquely truncate and narrowed at the end in some circumstances disappears, so that really this species seems quite close to laticaudata. Found in Madison, Wis. Ceriodaphnia quadrangula Mueller. PLATE XLI, Fias. 16-18. Daphnia quadrangula—O. F. Mueller. Daphnia reticulata—Baird. Head depressed, rounded at the end, only slightly angled; fornices prominent, antennules large; post-abdomen narrow, of equal width for the lower half, rounded at the end, with about eight small spines; claws smooth, length about 0.6 mm. This species resembles a smooth- clawed D. reticulata. *Ceriodaphnia scitula Herrick. PLATES XLII, Fias. 5-8; XLIV, Fias. 1, 2; XLV, Fia. 1. One of the most abundant species of Ceriodaphnia in Minnesota is a large form much resembling C. quadrangula. The post-abdomen is exactly as in ©. reticulata or C. dentata, which latter it resembles in having a sharp angulation in front of the antennules. The shell is oblong and heavily marked with minute, regular hexagonal lining; the upper angle is rather sharp. The head is closely appressed, the fornices are prominent and abruptly truncate at the tip, the eye is small, the pigment fleck also small; antennules short. The post- abdomen is of moderate size, narrowed toward the end and armed with about ten powerful curved spines; the terminal claw itself is large and curved, armed only with fine spines extending down the en- tire inner side. The size is 0.8 to 1.0 mm.; color pinkish, opaque; antenne, especially, often bright pink. Male 0.6 mm.; flagellum of the male antenne long; sensory filaments lateral, also one anterior, lateral flagellum. Distinguished from C. quadrangula by the prominent fornices, large anal spines, small reticulations, form of head and larger size. A small variety resembling the above very closely is the common- est form in our larger lakes; the reticulation is commonly larger but less distinct, the head is depressed and narrowed, with a sinuous upper outline. The fornices are prominent and the form of the post- abdomen is exactly as in the last. The spines of the post-abdomen are very long and seated on small eminences. The length hardly ex- ceeds 0.55 mm. The claw is densely ciliated, but not spined; these bas ee ENTOMOSTRACA OF MINNESOTA. Vite smaller forms have but few eggs (two). The young have a thorn on the angle of the fornices. Plate XLV, fig. 1, represents the ephippial female of this species. There seems no reason to doubt that this is only a variety of CO. scitula. The small form of C. reticulata mentioned by Kurz might be referred here, while the larger form with less promi- nent fornices is not so different from the American (. dentata, Ceriodaphnia nitida Schoedler. Ceriodaphnia quadrangula—Ley dig. This species seems to be characterized by the quadrangular form of the meshes of the shell-markings and the presence of teeth upon the claws. Probably invalid. Ceriodaphnia asperata aud CO. minuta of Moniez have remained un- known to me. Cf. Note sur des Ostracodes, Cladoceres, et Hy- drachnides observes en Normandie. Bul. @ etudes scientifiques de Paris, 1887. Ceriodaphnia textilis Dana is not sufficiently fully figured to allow of a suggestion as to its affinities. Daphnia rotundata Say is very probably a member of this genus, though the description is hardly intelligible. ‘‘ Body rounded behind; upper antenne three-branched, a small spine above at the joints; lower five-banched; color white. Length 0.5mm.’’ It is probable that we should read ‘‘upper branch of antennz with three sete,’’ ete., in which case we may identify the above with Chydorus or the like. Ceriodaphnia setosa Matile. Matile ’90. Body spherical, resembling C. rotunda and ©. laticaudata, brownish red. Head small, depressed. Front uniformly rounded. A deep depression between head and body. Fornix moderate, spiny. Head and body ornamented with polygonal meshes from every angle of which springs a spine perpendicular to the surface. Antennz very short. Antennules rather long, lateral seta nearer the base than the tip. Post-abdomen large, gradually narrowed toward the end. Anal teeth seven or eight and nearly equal. Claw armed with a series of fine cilia. Eye large. Macula small. Length 0.42 to 0.57 mm.; heighth 0.27 to 0.36 mm. It is probable that this is identical with Ceriodaphnia echinata Moniez (’87, p. 512), but there are minor differences and the problem must be left open. 174 GEOL. AND NAT. HIST. SURVEY OF MINNESOTA. Ceriodaphnia cornuta Sars. Sars ’85. This interesting species furnishes further evidence of the close re- lation between Ceriodaphnia and Scapholeberis by the possession of a frontal spine or ‘“‘horn.’?’ Head much depressed, with frontal part slightly dilated. A process arises directly cephalad of the eye, an- other forming a beak. Carapace broadly oval, tumid, with a bifid caudal projection from the upper angle. Whole shell distinetly retic- ulate with polygonal markings. Antennules short, fusiform, lateral seta near the middle. Two distinct abdominal processes. Anal spines about eight. Claw without basal teeth. Length 0.6mm. The form resembles OC. quadrangula. The fornices are acute. GENUS SCAPHOLEBERIS. The genus Scapholeberis stands rather closely related to Ceriodaph- nia, from which it is at once distinguished by the angled or spined lower posterior angle of the shell, The head is rather clumsy, and the continuation of the fornices runs toward the apex of the incurved beak, which commonly lies within the valves of the shell. The lower ante- rior angle has a prominence and there is a basin-shaped area inclosing the base of the antennie, part of which lies on the shell and part on the head. This area is more strongly lined or reticulated than the rest of the shell. The lower margin is straight and terminates, in most forms, in a long scythe-shaped spine which is directed backward. The shell itself is usually indistinctly reticulate or unmarked, and commonly is deep colored. The post-abdomen is very like Ceriodaph- nia or more as in Simocephalus; the anal spines are few and the older Specimens have more than the young; the place at which additional spines are to appear is marked by prominences. The eye is of mod- erate size, the pigment fleck rather small and the antennules short and hidden by the beak. The antennz are of small size and generally dark colored. The ephippium contains but one egg; the males do not have altered antennze or feet. The sexual periods fall in early sum- mer and in autumn, according to Weismann; the males appear but sparingly. The species S. mucronata is very abundant everywhere, while the others are less frequently seen. * Scapholeberis mucronata Mueller. PLATES XLIII, Fias. 4-7; XLV, Fia. 5. Dophnia mucronata—Mueller, Lievin, Lil)jeborg, Fischer, Leydig, Baird, Herrick. This well-known species with rather short spines below is found - ‘i s be / ENTOMOSTRACA OF MINNESOTA. 175 abundantly everywhere. In this country at least it is characterized by a dark color. The head is large, rounded in front of the large eye, serrate below and extending posteriorly into a roundish beak, back of which are the short antennules. The fornices are very short and rounded; a line connects the fornices with the beak by a sudden de- flection downward; it sets off the area which forms a part of the basin of the antenne. A second line springing from just above the termin- ation of the fornices passes over the eye by a broad curve. The post- abdomen is truncate and bears beside the terminal claws four or more spines which rapidly decrease in size. The claws are minutely spined; the spines on the shell are of variable length, but do not exceed one- fourth the length of the remainder of the lower margin. This species ranges over all Europe and eastern United States. Length 0.6 to 0.8 mm. Scapholeberis cornuta Schoedler. PLATE XLV, Fic. 6. Monoculus bispinosus—De Geer. Daphnia mucronata var. acute rostrata—Baird. Scapholeberis mucronata var. fronte cornuta—P. E. Mueller. This species differs from the above only in having a sharp curved horn on the head in front of the eye. The use of this appendage can only be conjectured; but it may be that, like the curved beak of Rip- ophilus, it serves to clear away rubbish in the filth in which these ani- mals frequently live. This form, be it variety or species, is not known in America. * Scapholeberis armata Herrick. PLATE XLII, Fies. 10, 11. Scapholeberis mucronata var. armata—Herrick. A very beautiful and unique species, which possesses the extreme development of the peculiarities of the genus, The head is shaped very much as in the previous species, the fornix is squarish, the basin for the antenne is small. The upper lines from the fornix meet be- hind the eye; the form of the shell is as in the above, but the spines upon the lower margin are longer. The scythe-likespine on the lower angles of the valves is extremely long, falling little short, in extreme cases, of being as long as the entire lower margin, in others about one- half as large. There are the usual lines parallel to the lower edge of the shell. The specimens having the longest spines were found in fresh water about Mobile, Ala., but the species occurs in Minnesota and intermediate points, though sparingly. Probably the earlier plan of regarding this as a variety of S. mucronata is nearer correct. 176 GEOL. AND NAT. HIST. SURVEY OF MINNESOTA. *Scapholeberis aurita Fischer. Daphnia aurita—Fischer. Seapholeberis nasuta— Birge. Form much as in the last, head shorter, ‘‘prolonged into a rather sharp beak, at whose apex the continuations of the fornices unite. The beak does not project downward as in S. mucronata, but backward, and in its natural position lies between the valves.’’ The usual reticu- lated and lined areas are present and the balance of the shell is covered with ‘‘small pointed projections.”’ ‘‘The antennules are much larger than in S. mucronata, though they do not project beyond the rostrum.”’ The pigment fleck is long and large; the post-abdomen is much as in the preceding species; the terminal claws have several fine teeth. The males have the opening of the vas deferens close behind the terminal claws; mucro short and blunt, length 1.0 mm. This species is very near the next, but differs in several particulars. It forms the transition to the next, which is the extreme of the genus in a direction converse to that pursued by the S, armata. *Seapholeberis angulata Herrick. PLATES XLII, Fias. 9, 9a; XLV, FIas. 7, 7a. Herrick ’83. Form as in the above, but comparatively larger; valves quadran- gular, anterior margin strongly arched; head short, only slightly con- cave below the eyes; the beak is as in S. nasuta, but seems to be directed more nearly directly downward than in that species. The antennules are long and resemble those of Simocephalus. The pigment fleck is square and rather large; the antenne are of the usual size. The re- ticulated areas are as in the other species. The post-abdomen is more as in Daphnia, not so squarely truncate and with five to seven large teeth; the first foot has one elongated jointed seta; the posterior angle of the shell has no spine, at most there is a somewhat prominent acute angle, the inner shell layer is armed at this point with some elongated teeth as in the corresponding situation in Simocephalus. On the whole, there is a similarity to that genus in this as well as in the previous species. SS. nasuta has a short spine and elongated pigment fleck, the present species has a squarish but rather large fleck and no spine; the post-abdomen has a greater number of spines than any other species. South of Tennessee river, in Alabama and Mississippi. The species of this genus are predominatingly American, four out five being found in the United States; the fifth, moreover, is more often regarded a variety of one of the others; in fact, the absence of 5 abate ears 2 Sa pe ENTOMOSTRACA OF MINNESOTA. J beh S. cornuta from America is one of the most important supports of the specific independence of the two forms. All the species delight in disporting themselves near the surface in sunny weather. GENUS SIMOCEPHALUS. Although a very well circumscribed group, this genus passes into the next rather directly by means of S. macrothroides. The connection on the other hand seems to be by the way of Scapholeberis, though there is a rather broad separation between even Scapholeberis angulata and any known Simocephalus. The enlarged spines near the angle of the shell and the form of the antennules as well as some other points, show a transition through that species toward the present genus. The general form is quadrate with the lower posterior margin sinuate; in young specimens the shell is nearly a perfect rect- angle. The upper margin is produced more or less at the point of union with the free posterior margin, and the shell is either arched or very abruptly angled above the prominence in old females. The head is produced into a projection at the eye, while the beak proper is between the anterior margins of the valves; the pigment fleck is rather large and variously shaped. The fornices are larger than in Scapholeberis and extend to the front of the head over the eyes; the an- tennules have a lateral flagellum which is large and lance-shaped. The post-abdomen varies very little in shape; it is truncate and exca- vated below and very broad. The anal teeth are few, large, curved, pectinate; the claws are straightish and pectinate or spined; the labrum is shaped as in Daphnia; the anterior part of the stomach has the usual ceca. The members of this genus are among the most abundant and con- Spicuous of the family and are more persistent during the changing seasons than any other form. S. vetulus, the commonest species, stands in the centre of the genus, while two extremes are expressed by the other members of the group. The-winter or sexually produced eggs are lodged in an ephippium or saddle-like modification of the shell, which is finely reticulate; while the shell is usually marked by fine anastamosing lines which, in some species, show clearly their derivation from a rather fine hexagonal marking. The sexual periods, when males are produced, occur in autumn and spring. The males have few distinguishing characteristics, the form being that of the young female. Theopening of the vasa deferentia is back of the anus, hence these _ ducts cross the course of the intestine. They have ejaculatory muscles J & a Ta vee = i a is Ee ae 2 hg ORR ah Raby ee BM LT Uh eR) ka 8 A nae 178 GEOL. AND NAT. HIST. SURVEY OF MINNESOTA. about the lower part. The smaller species are frequently deeply col- ored with pink, purple and brown fatty deposits and the markings are more conspicuous than in the American Hurycereus, which is itself often brightly spotted with blue or purple. The aspect in the water is between that of Hurycercus and Daphnia. The first mention made of any member of this genus in America is Say’s description, repeated in Dekay’s Crustacea of New York, of Daphnia angulata. This description which follows is quite sufficient to identify the genus, and indeed to indicate that either S. americanus or a related form is intended, but it is hardly competent to alter names the significance of which is quite clear. ‘Sides striate with numerous parallel minute oblique lines; hind edge of the body with a prominent angle in the middle. Antenne with four filaments on the upper and five on the lower branch. Color white or red. Length 0.1mm. Stagnant water in the forests of the Southern states.”’ *Simocephalus vetulus Mueller. PLATES XLIV, Fic. 7; LII, Fias. 6-9. Daphnia vetula—Baird, Herrick. Daphnia sima—Mueller, Latreille, Bosc, Ramdohr,Gruithuisen, Desmarest, Lamarck, M. Edwards, Koch, Gmelin, Manuel, Jurine, Lilljeborg, Leydig. This commonest and one of the largest species is apparently dis- tributed over the northern hemisphere and abounds in all the more shallow lakes. Phe head is rounded in front and is not angled between the prominence of the eye and the beak. The body is very large and not abruptly angled above, the spine of the shell being inconspicuous and high, so that the free posterior edges of the shell lack little of equaling the greatest height of the shell. The shell is covered with minute dense striations which spring from the free edges. The pig- ment fleck is elongated in old specimens and the upper angle follows up beside the suture separating the antennary basin from the rest of the shell of the head. The antennules are ornamented with minute spines. At the lower angle of the shell are three curved spines which differ from the preceding filaments. ‘The number of eggs which are produced at once is truly immense. Under favorable circumstances this species reaches a large size, falling little if any short of 3.0 mm. S. vetulus lives, by preference, among the leaves of aquatic vegetation. With us this species seems to live in the smaller pools as well as in lakes of some size. I am not able to see any difference in this respect between the various species. ENTOMOSTRACA OF MINNESOTA. 179 *Simocephalus serrulatus Koch. Daphnia serrulata—Koch, Lievin, Fischer, Lilljeborg. Head narrow, extending anteriorly into a sharp spiny angle in front of the eye. Dorsal line of the shell abruptly angled or curved pos- teriorly, projecting to form a broad obtuse spine behind; this spine is serrate with sharp teeth and lies somewhat above the middle of the height of the animal, so that the free posterior margins of the shell fall much short of reaching the greatest height of the shell. Post- abmomen of the usual form, with the claws armed with two series of spines or bristles, the outer being much the larger; anal teeth curved or angled, dentate; pigment fleck triangular or rhomboidal. Length 2.0 to 2.5 mm. I am not sure that the three following species are more than varie- ties; the first in particular is very close to the Huropean type. [* Simocephalus americanus Birge. ] PLATE XLV, Fie. 9: My own observations of this form made throughout the Mississippi Valley are not in complete accord with the description of Birge, but it seems improbable that there is any mistake in the identification. The very generally distributed form on which this species rests is subject to marked variations within certain limits. This species dif- fers from S. serrulatus in the following points. The head, although prominent and spiny near the eye, is not angled between this promi- nence and the beak; in fact, it is either straight or simply curved. The pigment fleck is usually rhomboidal and only oceasionally oval, triangular or irregular. In other respects the agreement is rather close; the terminal claws have two series of spines, one of which is larger (not, as said by Birge, equal); the outer series is not so much larger as in S. rostratus, but not nearly as inconspicuous as in S. vetulus. The terminal claws are rather evenly curved. This species is frequently colored with pink or brown markings. In old females the back is squarely angled above, forming a pocket for the eggs. The size falls short of that of the last speeies. I have found this species from the Gulf of Mexico to Minnesota. Professor Birge now recognizes this as S. serrulatus. *Simocephalus rostratus Herrick. Herrick 784. This form is of the size and color of S. americanus, and approaches nearest to Schoedler’s S. exspinosus in general characters. The back is arched above but not abruptly angled; the spine is as in S. americanus but not solow. The free posterior shell margins are somewhat shorter 12 180 GEOL. AND NAT. HIST. SURVEY OF MINNESOTA. than the greatest height of the shell. The head is produced below the eyes in an angle like a right angle, which is not spiny. The lower margin of the head is excavated to form a right angle, and in front of the smooth antennules forms a very prominent beak, beyond which the antennules reach but a short distance. The terminal claws of the post-abdomen are straightish and are more heavily spined than in the preceding; the anal spines are doubly curved or geniculate. The pigment fleck is rhomboid or pentagonal; the antennules are smooth. The abdominal processes differ somewhat from the previous Species, in which the second one is rounded above, for in this it is squarely truncate. This species was found only in shallow pools at Ocean Springs, Miss., and was very carefully compared with S. ameri- canus, Which is also found there. Simocephalus exspinosus Koch. Head extending into an obtuse angle at the eye, pigment fleck rhomboidal. Shell without a spine; maximum height of the shell greater than that of the free posterior margin. Caudal claws with an unequal series of spines; anal spines evenly curved. There is little to distinguish the above from this species save the geniculate anal Spines and the presence of a blunt spine on the shell. Var. congener Schoedler has the lower outline of the head sinuate instead of angled. *Simocephalus daphnoides Herrick. PLATE XLVI, Fias. 5,6. Herrick ’83. A curious transition form, found only south of the Tennessee river, was described in the American Naturalist for May, 1885, under this name. By an oversight a comparison made with S. americanus ap- peared as though made with S. vetulus. The general shape is oval; the greatest height of the valves lies near the middle and not posterior to it as in all the other species. The head is short, depressed, rounded in front; the beak is wanting; the lower margin of the head is straight. The pigment fleck is small, oval or irregular; the fornices are small and short. The antennules are smooth. The post-abdomen is narrow, shaped more as in Daphnia; the ter- minal claws are straightish and fringed part way with spines; the anal spines are slightly curved. The processes of the abdomen are long, as in Daphnia. The shell is covered by the characteristic striations and extend into a blunt spine. In every detail, almost, there is an ap- proach toward the genus Daphnia, while the general result is suffi- » ENTOMOSTRACA OF MINNESOTA. 181 ciently llke Simocephalus. The lower angle of the shell is not armed with the peculiar curved spines as in all the other species. This species becomes over one-tenth inch long. In such old individuals the spine is nearly midway of the height. One could wish a trifle closer link to Scapholeberis than that furnished by S. angulata; but, on the whole, the position of this genus can not well be called in question. America has four species out of the six known and but one of these certainly identical with the European, though others are probably closely related. GENUS DAPHNIA. Long considered the type of the family, this genus is most frequently seen, or, at least, is more conspicuous than any other group. It has already been pointed out that the forms here united are the extreme development of a diverging line. Simocephalus is the link connecting it with the typical forms of the family. As might be expected, this genus presents more puzzling problems than any of the others. It con- tains more peculiarities of structure and diversities of habit and de- velopment than any other of the genera. Here the sexual differences are most interesting. The young are hatched with a pendant appendage attached to the upper posterior angle of the shell, which soon becomes the rigid spine characteristic of the younger stages and males of the genus. The females almost immediately after birth commence the production of eggs by an asexual process. Groups of epithelial cells containing four each are formed and one of the cells of each group develops at the expense of the others, forming the egg. Many such eggs are laid simultaneously and deposited in the cavity between the shell and the dorsal part of the animal. The eggs are prevented from escaping by means of three long processes, of which the first is much the larger and curves forward. At stated periods in spring and autumn the males appear; the females of the generation in which occur the males have a tendency to produce eggs of a different sort charged with a different mission. At the same time the upper portion of the shell (that surrounding the brood cavity) becomes finely reticulated and pigment is deposited between its layers. This ephippium, as it is called, in allusion to its saddle-like form, is the case in which the winter egg is to pass the period of cold or drought which is to follow. The method of the formation of the ephippium is obscure and, in spite of the investigations of Lubbock and Smitt, considerable remains to be learned with reference to this interesting modification of the shell. Some rather careful study has been devoted to this subject by the writer, but it was unfortunately interrupted before completion. The - 182 GEOL. AND NAT. HIST. SURVEY OF MINNESOTA. most promising method of pursuing the investigation is that of sectioning ephippial females in various stages with the microtome. A preparation of soap was employed with partial success as a medium for embedding. Development of Daphnia. Although the careful researches of Claus and Grobben have added much to our otherwise rather meager knowledge of the development of the Cladocera, there still remain many interesting points, particu- larly with reference to the individual species, which merit careful study. The following observations relate to the single species D. scheffert which was available during a short stay in Leipzig. The winter eggs of D. schefferi are two in number and are lodged jin the well known manner in an ephippium. The shape of these eggs is sharply ovoid, there being no distin- guishable difference between the two ends. The position in the ephippium is not, as might be expected, with the longer diameter parallel to the axis of the body, but the posterior end is slightly ele- vated. This is undoubtedly due to frequent elevation of the abdomen between the valves during the extrusion of the eggs. The color is dark green and the only protection as the egg leaves the ovary is a thick, tough shell which is at first so soft as to be sus- ceptible to pressure. It is thus reticulated, apparently through the simple pressure of the walls of the ephippium. The length is 0.43 mm.; width 0.33 mm. in the average, though eggs were occasionally found of an elongated form, measuring 0.48, 0.31 mm. The contents of the egg consist of spheres of greenish plasma of various sizes and fat or oil drops. These oil globules are not very numerous as compared with those of the summer eggs, and likewise never attain the dominant size seen in the latter. The various forms assumed by the plasma balls are perplexing but frequently result from the action of external agents. The cleavage stage was not seen, and if actual segmentation takes place, it must be inconspicuous as would be expected from the large quantity of yolk present. The differentiation of the blastoderm occurs very early, perhaps in the ovary itself, and the result is a tolerably uniform layer of prismatic cells. The egg now comes to a period of repose after the blastoderm has produced a second external envelope apparently by simple secretion. This envelope consists of a fine structureless membrane. The egg, under ordinary circumstances, remains dormant during the winter in this most favorable stage. The reason for which is evidently the fact ENTOMOSTRACA OF MINNESOTA. 183 that the differentiation has proceeded to the extent of producing the greatest number of protective layers without materially increasing the complexity, and thus the sensitiveness, of the organism. Under favor- able circumstances the development proceeds farther and near one pole appears a slight indenture of the surface which grows deeper and seems to form a true invagination. This blastopore, if such it really be, remains for some time, generally till the two ‘‘Scheitel’’ plates appear. These ‘‘Scheitelplatte’’ are formed by a simultaneous thick- ening and lengthening of the cells of limited areas on opposite sides of the egg, near the opposite pole from that occupied by the blastopore. The ‘‘Scheitelplatte’”’ are situated at right angles to a plane perpen- dicular to the blastopore. The nuclei of the cells of the ‘‘Scheitel- platte’’ are nearly 0.0208 mm. in diameter, while those of the other blastoderm cells are about half that size. : The egg remains a long time in this stage, while the following stages are passed through quite rapidly till the embryo assumes its nauplius form. The remainder of the development agrees, so far as seen, quite fully with that of the summer eggs, to which we will now return. The summer eggs vary greatly in size and number, but are nearly as large as the winter eggs. The number is sometimes reduced to two or three or rises to as many as fifteen or even more. In color the eggs vary from green to brown. The fresh egg consists, as the winter egg, of two sorts of yolk spheres. The plasma or formative yolk con- tains colored globules of rather small size, distributed throughout the whole of the mass quite uniformly. The food yolk or oil globules assort themselves in two sizes; first, a few (generally three) very large oil drops, which persist throughout the earlier stages of the embryo; second, smaller globules of apparently the same character, which are quite numerous and form a very considerable part of the contents of the egg. In an egg of about 0.35 mm. in diameter, the largest of the smaller size of oil drops measured 0.029 mm., while the larger three exceeded 0.060 mm. ‘The oil drops are distinguishable by their light refractive power, pellucidity and the intense dark brown or black color assumed when treated with osmic acid. The latter reagent affects the formative yolk but slightly. It will be seen that though the summer egg is nearly as large as the ‘‘Dauerei’’ in some cases, yet the relative amount of formative yolk is more diverse than at first appears. The great similarity between the two sorts of eggs in Daphnia schefferi is throughout striking as compared with Moina, the only one of the Daphnide the development of which is fully studied. In the summer eggs I have not been able to see the complete segmentation 184 GEOL. AND NAT. HIST. SURVEY OF MINNESOTA. described for Moina. The following stages are much as described by Grobben. An invagination occurs and a median swelling appears on the ventral aspect of the egg. Labrum and second antenne bud out and are soon followed by the antennie, mandibles and two pairs of maxille, after which the five pairs of feet soon appear. In an early stage there is present a basal palpus to the second antennz, a fact not before observed, and this per- sists as the small two-bristled wart found on the basal joint of the an- tenna. It is a conspicuous object in the embryo and is thus a true embryonic organ. The eyes of the embryo appear as two separate pigmented flecks which approximate and are covered with an oval refractive body, which later is penetrated by the pigment and divides to form the small lenses. Soon after this the shell grows over the eye as described for Moina. The first indication of the shell appears as two folds of the maxil- lary region of the back, being thickest laterally. These grow forward and backward to form the cephalic and body shield. At a little later stage there appears a very interesting modification of the shell which stands in close relation to the growth of the brood sae. A slight pro- tuberance appears on the margin of the shell in the median dorsal line and extends toward the abdomen. It grows much more rapidly than the other parts of the shell and, in a later stage, forms a compara- tively enormous tail, which curves under the animal between the shell valves which now extend beyond the body. This ‘‘tail’’ extends well along the ventral margin of the shell and reminds, by its posi- tion, of the tail of a frightened dog. The true tail, or post-abdomen, is, in the meanwhile, well developed and is constantly kicking the useless protuberance of the shell upwards. As the animal leaves the egg this projection becomes straightened as in the young D. pulex, finally becoming the still considerable spine, though it is proportion- ately much shorter than in the embryo. The spine becomes shorter with successive moults, and the mature form has only a slight rounded knob in place of a spine more than half the length of the body. The use of the long spine in the young Daphnia is a matter of in- terest. Its length agrees pretty well with that of the brood cavity and it seems possible that it serves to prevent the shell from bending abruptly down when it is only partially removed during the moult and thus breaking off and so leaving a portion of the clothing of the brood cavity therein to become a source of irritation. This is more necessary for the young, since the brood cavity is narrow and the shell weak, so that while the outer shell is removed like a glove from the finger, it cannot be pulled upward or downward, but directly ENTOMOSTRACA OF MINNESOTA. 185 backwards. It is well known that male Daphniw often have the spine while the females may have none, and here again it is possible that the narrower cavity over the abdomen requires this assistance, while this is not the case with the females. The shell gland is early formed and the branchial lamelle of the feet appear almost simultaneously with the feet themselves as distinct lobes. The branchial chamber is not a simple chamber, but is essen- tially a curved tube, as can be very well seen in the last foot of the adult. This tube doubles upon itself and crosses in the manner of a loop and a constant stream flows rapidly through it. The nervous system is, at first, paired from beginning to end and first unites anteriorly, the ocular ganglia fuse after the union of the two pigment flecks in the compound eye, then the cephalic ganglion is formed by the union of the two precesophageal ganglia, and the com- missures passing about the cesophagus. I have not been able to de- termine if the subcesophageal ganglia become fused. From the anterior ganglia spring the nerves to the antenne and jaws, which latter are © larger in the embryo. It is greatly to be regretted that no sufficient revision of Daphnia can now be attempted. This is partly due to the very imperfect nature of the descriptions and partly to the scattered literature of the group. We here supply nothing more than a provisional key and synoptical descriptions. I take pleasure in acknowledging the substantial assistance, in respect to recent literature of the group, received from my friend, Professor Birge, as also for valuable sugges- tions respecting Cladocera in general. KEY TO THE GENUS DAPHNIA. I. Pigment spot present. A. Anal margin of the post-abdomen deeply excavated. . . Schaefferi, 187 B. Anal margin slightly if at all sinuous. a. Head very short and regularly curved from the heart to the beak. . . . . . . . . +. ~»psittacea, 187; atkinsonii, 188 b. Head not very short or regularly curved. * Claws of post-abdomen with a distinct comb of spines. t A strong toothed process from the dorsal margin of the head at some time of life. ii Spinelonsstraisht. . . . 3) ... 4 . elathrata, 188 {i Spine short, curved. . . . . . . . minnehaha, 189 tt No strongly toothed dorsal process at any period in either sex. { Head with a?helmet-like crest. 2 Spine long, springing from the dorsal angle, Curnvedydorsad an pete cunrewoey rae ne 8S VExiiS S190 TAPS 4! eo regs 186 GEOL. AND NAT. HIST. SURVEY OF MINNESOTA. 22 Spine moderate, springing from the middle of the caudal margin. . ... . . . arcuata, 190 tt Head uncrested. 2 Spine short or absent. || Abdominal process united at the base. . gibbosa, 19f \||| Abdominal processes discrete. ‘| Spine near the middle of the caudal margin. ° Anal teeth 20 to 22. . . . . =. +. Ovata, 192 os Anal teeth Sto lO) 7. >. 4). -obtusa,eios | Spine at the dorsal angle. ~ . . . alpina, 192 22 Spine of considerable length. || Spine near the middle of the caudal margin. ‘' Ventral margin of the head convex. . hastata, 192 “ Ventral margin of head concave. ° Eye distant from the margin of the eager °° Eye near the margin of the head. x Abdominal processes united at the base. . . . . . . . Schoedleri, 195 xx Abdominal processes discrete. brevispina, 193 \||| Spine nearer the dorsalangle. . . . . pulex, 193 ** Claws of the post-abdomen without a basal comb of teeth. yj Antennal setze thick, first segment longer than the second. { Spine near the middle of the caudal margin. ventricosa, 195 ornata, 192 ti Spine above the middle of the caudal margin. . caudata, 195 t+} Antennal sete with the second segment longer than the first. tt; Headhelmeted:- 77). :°03. © fe te, £0 vallinagels> tt Head not helmeted. 2 Abdominal processes united. || Dorsal margin strongly carinate. . . . . Sarsii, 198 \||| Dorsal margin slightly or not carinate. ‘| First abdominal process much the longer. ° A deep depression separating head and body. See veo paludicola, 198 °° A very slight depression separating head and body. longispina,199; minnesotensis, 199 “* Abdominal processes nearly equal. ° Anal claws 12 to22. . . . . Gavifrons, 200 °° Anal claws 7 to 23. . . . microcephala, 200 22, Abdominal processes discrete. j | Abdominal processes short, equal. . . . rosea, 200 ||| First abdominal process twice as long as the second. " Beak not greatly produced ventrad. . aquilina, 200 “ Beak greatly produced ventrad. . . lacustris, 201 {it Head with a dorsal toothed crest. 2 Crest just in front of the heart. . . . . dentata, 201 22 Crest over the bases of the antenne. . . dentifera, 202 II. Pigment spot absent. A. Head not helmeted or but slightly so. . . . . . . longiremis, 202 B. Head helmeted. . 7 5 fod ee 7 ewe yee, UJ ENTOMOSTRACA OF MINNESOTA. 187 a, Eye near the end of the head. ye ey AMASHICE pS, 202: b. Eye not near the end of the head. * Abdominal processes free. . . . . . . #£Kalbergensis, 203 ** Abdominal processes united. Nas ae hee eo s Cucullata,.203 [Not in the key: dubia, 196; pennata and curvirostris, 194; thorata,197;. hermani, 198; similis, 204; bolivarl, 205; carinata, 205; lumholtzii, 206. }, Daphnia scheefferi Baird. PLATE LI, Fies. 1-5. Daphnia pennata — Mueller. Daphnia pulec—Straus, Koch (fide P. E. Mueller). Daphnia magna—Lilljeborg, Leydig, ete. The largest species of the genus, is of an elongated oval and ven- tricose form. The head is short and evenly rounded, The spine is. entirely absent in old females and of only moderate length in the young. The antennules of the male are long and have a very long. flagellum. The post-abdomen is narrowed suddenly below the anus so that the spines consist of two sets; the terminal claws are spiny at the base. The species may be recognized at once by the concavity of the dorsal] margin of the post-abdomen. The plate will make any de- tailed description superfluous. A common species in Europe, but not yet found in America, The sole distinction between this species and D. magna Straus is. found in the fact that the intestinal cceca are very long and recurved in D. schefferi and short and thickened at the free extremity in D. magna. We fail to discover sufficient reason for separating them. Daphnia psittacea Baird. Baird 750; Schoedler 758; Fric’72!; Kurz’74; Hellich’77; Herrick ’84; Elymann’873. Daday ’88. Head short, rounded in front, beak very short. A depression sepa- rates the head from the oval, ventricose body. Spine long directed dorsad. Eye distant from the margin of the head. Post-abdomen long, narrowed toward the end, somewhat sinuous in the caudal margin. Anal teeth about ten. Claw bipectinate, rather long. Length 1.8 to 1.9 mm. This species is at once recognized by the head, which is very short and evenly curved, or nearly so, from the heart to the beak. The shell is high, oval, with a rather short spine. The fornices are wide and angled behind. The antennules are longer than in most species; the post-abdomen is very large, but narrows toward the end and has comparatively few anal teeth, which are of unequal size. This is one of the largest of the genus. Not yet found in America. 188 GEOL. AND NAT. HIST. SURVEY OF MINNESOTA. Daphnia atkinsonii Baird appears to us but a variety of this species. There is said to be no depression between head and body and the anal teeth diminish dorsad instead of being nearly equal as in D. psittacea. Considerable disagreement exists in the various descriptions. Daday’s figures show no grounds for separating the species. * Daphnia clathrata Forbes. Forbes ’93. ‘*A species of moderate size, with short, deep head, medium to very long posterior spine, minute pigment fleck, and pectinate tarsal claw. In the immature female there is a prominent angle just above the Swimming antenne, like that of D. dentifera. In the adult female the head, measured vertically across the rostrum, is twice as deep as its length from the base of the antenne to the middle of the front. It is sharply keeled rather than crested, very broadly rounded, its lower margin very slightly convex or quite straight, and its rostrum well marked in the adult. The eye is close to the front, the transparent orbit reaching to the margin of the head, of medium dimensions, its antero-posterior diameter contained twice in the space between the posterior margin of the head. The pigment speck is very minute, placed behind the lower half of the eye and nearer the posterior margin of the head. The fornices are not prominent. Beginning midway between the antenna and the eye, they arch broadly above the base of the former, making an obtuse angle a little beyond the antenna, and continuing as a slight carina backwards and downwards for a little dis- tance on the side of the valve. ‘“The ventral margin of the shell is more broadly arched than the dorsal, the latter being in the immature female nearly straight from the heart backwards. The valves are conspicuously quadrangularly reticulate, spinose on their lower edges nearly to the beak, and on the upper edge to the vicinity of the heart. The posterior spine is very long, straight, slender, spinose to the tip, contained in average cases not more than twice in the length of head and body without the spine. ‘The antenne are rather short, about half as long as the distance from the posterior margin of the eye to the base of the posterior spine. The swimming hairs are two-jointed, the basal joint the shorter. The dorsal abdominal processes arise in immediate connection, but are not united at their base. Theanal furrow has about a dozen teeth on each side, and the caudal claw has a comb of three or four conspicuous teeth at its base besides a little group of smaller ones. Length of ovigerous female 1.7 mm. to the base of the spine; the greatest depth 0.85mm. The male not seen. Occasional in Grebe lake, Yellowstone Park’? ENTOMOSTRACA OF MINNESOTA. 189 * Daphnia minnehaha Herrick. PLATES XLIX, Fias. 1, 2a; L, Fies. 1, 2; LII, Fries. 1-3. Herrick ’84; Birge ’91. This species, which occurs in small pools in autumn (affluents of Minnehaha creek, ete.,) closely corresponds apparently to Sars’ Daphnia carinata but differs in numerous points. It, in fact, is more nearly related to D. pulex than the group under which that species is placed. The form is oval, arched above, narrowed posteriorly, terminating in a rather short spine which curves lightly upwards. In males and young females the spine springs from the upper angle, but in old females having many summer eggs the spine is nearly median. The head is depressed, strongly arched and keeled slightly above the eye, which occupies the extreme end of the forehead. The keel of the head extends into a slight angle over the heart and continues down the back. In young females and in males the slight angle is replaced by a strong knife-like projection which extends into from one to four sharp teeth, the anterior tooth being directed forward. The males, in particular, have this feature emphasized. D. longispina has a somewhat similar projection, but the more nearly related forms seem not to show this peculiarity. The beak is slightly curved and the lower margin of the head is slightly sinuate. The shell has the usual square reticulations and is usually very transparent but in peaty waters becomes brownish. The size is small but variable; 1.8 mm. is a common measurement. The post-abdomen is narrow, the claws are armed with four or more teeth and a series of lateral bristles. The anal spines are eleven or more in full grown females and decrease only moderately upward. The processes of the abdomen are distinct. The males are smaller and Strongly carinated above and of the same form as young females. The antennules are rather long, with a short lateral and a long terminal flagellum, which latter is more than twice the length of sensory set which are partially lateral. The first foot has a strong claw and a long flagellum, while the second feet have a small spiny hook. ‘There is a Single abdominal process which is not hairy as in D. pulex. The following measurements may be added: Female—Length 1.44 mm., spine 0.33 mm., head 0.26 mm., depth of head 0.46 mm. Male—Length 1.0 mm., spine 0.17 mm., head 0.20 mm., depth of head 0.31 mm., length of flagellum of first foot 0.55 mm. Ephippial female —Length 1.64 mm., spine 0.20 mm., head 0.35 mm., depth of head 0.8 mm., greatest depth of shell 0.94 mm. The ephippial females appear in July in the vicinity of Minneapo- lis, and at that time it is rare to find a female with the toothed crest developed. D. dentifera Forbes is closely related but has smooth claws. 190 GEOL. AND NAT. HIST. SURVEY OF MINNESOTA. * Daphina exilis sp. n.? PLATE LII, Fias. 4, 5. It is admittedly undesirable to describe a specimen instead of a species, but the form for which the above name is provisionally pro- posed is so peculiar and its locality so little studied that a description is given based ona single young female. It will be understood that the ovigerous female would differ in the length and position of the Spine, size of crest and form of the abdominal processes. A daphnid of moderate size with crested head, long spine and den- tate caudal claw. Nearly colorless. Head projecting in the line of the axis of the body, crested from the eye to a point cephalad of the heart, but truncate in front. Ventral outline nearly straight, beak not projecting, antennules very short and applied almost at the end of the beak, which does not lie between the valves. Eye of rather large size, with few crystallines, near the ventral margin. Pigment: fleck small, nearer to the caudal margin of the head than to the eye. Cceca narrow, strongly curved. Antenne short and stout, second segment of the setze longer than the basal. Fornix moderate. Valves sub-oval, strongly curved ventrally, dorsal outline straight from in front of the heart to the spine, which is very long and curved dorsad. In this specimen the spine is longer than the entire valve. There is no dorsal emargination between the head and body. Dorsal margin armed with spines beyond the heart, ventral margin spined more than half of the length. Valves marked with the usual quadrangular meshes. Post-abdomen narrowed toward the end. Anal margin sin- uate. Anal teeth about eight, nearly equal. Claw short and moder- ately curved, armed with a continuous series of spinules and a comb of fine spines near the base. Length, exclusive of spine, 1.15 mm.; length of head 0.38 mm., height of head 0.54 mm., height of shell 0.65 mm., length of spine 0.84 mm., diameter of eye 0.10 mm, length of base of antennze 0.26 mm., claw 0.09 mm, The abdominal processes in this specimen are not in their mature form. It is not certain that - the dense hairiness of the anal margin above the teeth is an adult character. It would appear that the crest is normally a strongly pro- jecting cephalic helmet, but this is but conjectural. Found in weedy pools fed by irrigation canals at Albuquerque. * Daphnia arcuata Forbes. Forbes ’93. ‘‘Head helmeted, rounded in front, length one-third that of the shell, front concave, beak produced, extending beyond the sensory hairs of the antennee. Eye small, about midway between the mandi- pends ENTOMOSTRACA OF MINNESOTA. 191 bles and the front of the head, and about midway between the tip of the beak and the dorsal surface of the head. Pigment speck very small, less than half the diameter of a lense of the eye, and placed midway between the eye and the posterior margin of the head. The latter concave, the beak extended backward and applied against the margin of the shell. Swimming antenne reaching the middle of the shell, their hairs moderately robust, the first segment not longer than the second. No emargination separating head from body, but the dorsal surface very slightly sinuate there. Abdominal processes all distinct, anterior much the longest. Caudal claw with accessory teeth, about six in number, the three proximal the largest. Anal spines about ten. Posterior spine of the shell given off from the middle of the valves, in the adult female a third to a half as long as the valve. Shell moderately coarsely marked in quadrangular areas, the lower and dorsal margins spinulose from the middle backwards. Length 2.0 mm., depth 1.0 mm. Heart Lake, Yellowstone Park.”’ Daphnia gibbosa Hellich. Hellich ’74 and ’77; Elymann ’87. Body large, very high. Head depressed, ventral margin strongly concave. Eye large, with few crystallines. Antenne long, scaly. An obvious depression separates head and body. Spine short, above the middle. Abdominal processes united. Anal teeth 17 to 19, dimin- ishing dorsad. Claws with a comb of teeth. Color reddish. Length 2.01 mm. Daphnia ovata Sars. ‘*Caput a latere visum ante oculum fere angulatum, margine inferiore leviter con ¢avo in rostrum longum apicem versus attenuatum, extremitate tenuissima exeunte- spura visum ut in D. pennata cordiforme. Testa cetera a latere visa ovata, margine superiore et inferiore in femina adulta fere eequies arcuatis, postice in medio spinam formans brevissimam vel omnino obsoletam. Processus anteriores duo abdominis dis- juncti. Margo posterior postabdominis in medio sinuatus, utrinque aculeis 20-22 armatus. Color albido—flavescens vel-virescens. Longit. circit 3 mm.’’ No one besides Sars seems to have seen this species. We suspect it is simply D. schefferi. Daphnia obtusa Kurz. Lilljeborg 753 (pulex); Kurz ’74; Hellich ’77; Elymann ’87; Daday ’88. Head short, front rounded, ventral margin slightly sinuate, beak short, acute turned caudad, Eye remote from the margin of head. Crest absent. Body oval, margins convex, spine nearly absent. Post- 192 GEOL, AND NAT. HIST. SURVEY OF MINNESOTA. abdomen not ciliate, of moderate size. Anal teeth 10, nearly equal. Claws bipectinate. Abdominal processes discrete. Length 1.08 mm. It still seems probable that this is an age form of some species with longer spine. Daphnia alpina Daday. Daday ’88. Head short, somewhat produced ventrad, front rounded, ventral margin almost straight; beak rather acute, short, extending ventrad. Eye large, rather remote from the margin of the head. No crest. Shell almost round, ventral margin obviously rounded; spine absent or very short, simply forming an acute angle. Post-abdomen small, laterally setose, bearing 11 to 12 anal spines which are short and curved and slightly diminish in size dorsad. Claw with a comb of long teeth and a continuous series of fine spinules. Abdominal pro- cesses discrete. Length 1.2 to 1.9 mm., depth 0.9 to 1.15 mm. The resemblance to D. obtusa Kurz is very close, but that species has the sides of the post-abdomen smooth, the ventral margin of the head concave and the spine near the middle of the caudal margin of the shell. The shell is longer and more oval in outline. We should wish to be very sure that these are not both old individuals of a spe. cies having the usual spine in younger stages. Daphnia hastata Sars. A large species of reddish color, with strongly depressed head, whose ventral margin is convex. Shell oval, with a long spine. The abdominal processes are long and approximate. Anal spines 1o. Length 3.0 mm. This species was inadequately described by Sars. and probably should be dropped. Daphnia ornata Daday. Daday ’84! (serrulata); 788. Head not separated by a depression from the thorax. Beak rather acute, short, turned ventrad. Eye distant from the margin of the head. Shell oval, margins rounded, with a moderate spine directed caudad. Post-abdomen searcely attenuated apically with eight to ten curved anal spines, diminishing dorsad; sides setose. Claw with a basal series of spines and a continuous series of fine sete. Abdominal processes discrete, ciliate. Length 1.0 to 1.5 mm., height 0.85 to 1.0 mm. The ventral margin of the head in this species is more curved than in D. alpina, and this might well be a younger form of D. obtusa, though the setze on the sides of the abdomen are not noted in that species. ——— Sh nk ie aaa xs ; ENTOMOSTRACA OF MINNESOTA. 193 Daphnia schoedleri Sars. Schoedler ’58 (longispina); Sars ’61; Hellich 77; Elymann ’§7; Daday ’88. Head arched in front, ventral margin gently sinuous, beak acute, projecting ventrad. Eye large, near the margin of the head. Body oval, spine long. Post-abdomen of moderate size, with 12 [14 to 16] anal teeth. Claw with comb of spines. Abdominal processes discrete but approximate [Daday ] or distant from each other [Elymann]. There is wide disagreement between the various descriptions of this species. Daphnia brevispina Daday. Daday ’88. Head short, slightly projecting ventrad, front strongly rounded, ventral margin somewhat sinuate. Beak short, acute, inclined ven- trad. Eye distant from the frontal margin of the head. Shell oval, with a slight depression between head and thorax, margins arcuate, with a very short.spine. No crest. Post-abdomen rather long with delicate lateral setze; anal teeth 12, curved, almost equal. Claw with a comb of spines and a continuous series of fine sete. Abdominal processes discrete, setose. Length 1.2 to 1.8 mm., height 0.75 to 1.2 mm. * Daphnia pulex De Geer. De Geer 1778; Hellich ’77; Lutz ’78 and ’79; Elymann ’86; Daday ’88, Matile ’90. Body large, stout and thick, rather opaque, reddish. Head broad, depressed, front protuberant. Ventral margin of head deeply con- cave. Beak acute, curved backward. Fornix high. Eye small, with few lenses. Antennules short, conical, extending but little beyond the beak. Antenne short, slender, evidently marked with scuta, with long densely pectinate setze. The shell is not separated from the head by a depression in mature females and is oval in outline. The ventral margin is much more strongly arched than the dorsal. Spine very short, straight, inclined upward and inserted above the middle of the posterior margin. Shell margins with short spines. Surface reticulate in fine quadrangles. Coceca short, clavate, curved dorsad. The abdominal processes approximate; the first twice as long as the second; the third small. Post-abdomen long, narrowed toward the end. Its distal end is rounded. Anal teeth 12 to 14, nearly equal. Claws curved, with two combs of teeth, the higher consisting of six to seven teeth, the lower of three to four. Length of female 2.15 mm., height 1.23 mm., spine 0.16 mm. It is at present impossible for the writer to unravel the relations of the numerous varieties and supposed species of the pulex group. Probably most of them are simple syno- nyms. The following American varieties may be mentioned: PAR eae ae ‘y ie Fae ee wy a Barc ‘ athe Pye : eae best a fy : \ > 194 GEOL. AND NAT. HIST. SURVEY OF MINNESOTA. * Daphnia pulex var. denticulata Birge. The lower margin of the head is said to be less convex [concave?] than D. pulex. The abdominal processes are less hairy, there is a continuous series of spinules on the claw and a larger number of anal ‘Spines—18 to 20. Daday figures claws such as Birge describes. * Daphnia pulex var. nasutus Herrick. PLATE XXXYV, Fies. 1-4. This in some respects is more like the type. It has an elongate ‘oval form with spine of variable length arising from above the middle. The impression between head and body is slight. The ventral margin -of the head is concave and the beak is curved caudad. The terminal claw of the post-abdomen is furnished with two combs of fine teeth. ‘The anal spines are 10 to 14. The abdominal processes are hairy. Neither this variety nor the above seems to possess the two teeth on the front margin of the claw. * Daphnia pulex var. pulicaria Forbes. This seems to closely resemble the type. The fact that the antennz are ornamented with spines rather than scales is noticed, The first abdominal process is smooth, as it is also stated to be in the European form by some authors. The male is said to differ more, but compari- son of Forbes’ figure with that of Elymann reveals nothing of impor- tance. (Elymann figures spines rather than scales on the base of the -antennee of the female. ) [Daphnia pennata Sars. ] ‘‘Antecedenti (D. pulex) simillima, caput autem a latere visum latius, rostro bre- viore, supra visum testa cetera parum angustius fere cordiforme, antice acuminatum. Processus anteriores duo disjuncti. Margo posterior postabdominis in medio sinulo parvo et infra hunc utrinque aculeis 16-18 armatus. Color ut in antecedente. Longit 0.24 mm.”’ Although admittedly very close to D. pulex, it is said to differ in the broad depressed head, which is uniformly rounded in front and deeply excavated in front of the beak, which is short and deflected. The post-abdomen has 16 to 18 teeth. The antennules of the male are almost as long as the head, bearing a long pointed flagellum and a short lateral seta. [Daphnia curvirostris Elymann. | The differences relied on to distinguish this species from D. pulex seem to us quite inadequate. The head is more depressed and this gives to it a quite different appearance. The male antennule is thick- ; ened slightly at the middle and the flagellum is longer. The hairy ; abdominal process is absent. ENTOMOSTRACA OF MINNESOTA. 195 Daphnia ventricosa Hellich. Hellich ’77; Elymann ’87. A large pelagic species without the toothed comb of the claw. The head is depressed, small, with rather protuberant front and long beak inclined caudo-ventrad. The short oval shell is deeper than the head, well rounded above and below. Spine long and straight, springing from the middle of the caudal margin. The antennal sete are short and thick and have the first segment longer than the second. The first abdominal process is twice as long as the second, with which it is united. The post-abdomen narrows toward the end and is hairy lat- erally. Anal spines 14. Claws with sete. Length 2.28 mm. Daphnia caudata Sars. Fischer 54 (longispina). A large species without basal spines upon the claws. Head some- what depressed, about one-third as long as the body, ventral margin slightly concave; beak long, inclined caudo-ventrad. Shell oval, with no depression between body and head. Spine long, springing from the middle of the caudal margin. Eye near margin of head, with few crystallines. Antennze with short thick sete whose basa, segment is longer than the second. Post-abdomen narrowed toward the end. Anal spines 9 to 12. Claw with a row of setz on the con- cave, and two spines on the convex aspect. The two cephalic abdominal processes united. Length 2.3 to 2.67 mm. This species is said to resemble D. longispina. It would appear to be closely related to D. ventricosa. *Daphina hyalina Leydig. PLATES XXII, Fieas. 7, 8; X XVII, Fie. 6; XXXV, Fie. 16; XLIX, Fiaes. 3-5; LIII, Fias. 1-4. Leydig ’60; Sars ’64 (galeata); Hellich ’74 (gracilis); P. E. Mueller ’68 (pellucida); Birge ’78 (levis); Herrick 783 The general form and appearance down to the minute details in this species are similar to D. kahlbergensis, with which it is almost always associated, except the head which is subject to an astonishing range of variation. A comparison of Figs 1 and 5 of Plate LIIT, which were drawn by camera upon the same slide, illustrates the simi- larity. The body is pellucid. Shell, sub oval, with long, straight, toothed spine as long as the body without the head, and inserted high up. Post-abdomen narrow with discrete processes, anal teeth about ten, terminal claw finely fringed or smooth. Eye small, either near 13 196 GEOL. AND NAT. HIST. SURVEY OF MINNESOTA. the margin and occasioning a prominence in the ventral outline or retreating from it. Macula nigra small or almost non- pigmented. Gastric ccecca slender, Antenne weak. The typical form of head is that of Fig. 3, Plate LIII, but the outline may be evenly rounded. The range of variation is well shown by the various figures. The young have no horn on the head. The spine of the shell is nearly as long as the whole animal in the young. The male of our form is 1.2 mm. long, excluding the spine which measures 0.47 mm. The flagellum is a very little longer than the sensory sete, and there is a very minute lateral flagellum. A peculiarity of this species is the scattered thorny armature of the spine of the shell. There is but little change in the form of head with age. The form of the last feet is peculiar. The ephippium occupies comparatively a small part of the valves and the spine becomes very short and quite smooth. The sexual period occurs in September and October. (*Daphnia dubia Herrick.) PLATE XLIX, Fias. 7, 8. Our D. dubia may prove distinct. It is nearly related to D. hyalina, but the head is strongly crested all around and the eye is withdrawn, in young as well as old specimens, toward the middle of the head. This peculiarity is shared in this degree by no other Daphnia. The form is as in D. pellucida, but the spine is more slender and directed upward. The head is shaped much as in D. vitrea in the young, but is much less prominent. The older form has a shorter and more slender spine (none were seen in the ultimate or spineless stage). The head is more evenly rounded, but still well crested. The abdomen is very Slender and the anal teeth diminish rapidly in size from below upward. The claws are very short and armed down the whole length with fine bristles. The abdominal processes are well united at the base in old specimens, so that the second seems a small process of the first. The shell is very transparent and the spine is very long. Ina young specimen the spine was 1.0 mm., the body 0.7 mm., and the head 0.4 mm. In this specimen the spine was slightly curved, the head elongate with a slight ridge in front. Another individual had the spine 1.1 mm. long, while the remainder of the animal was 1.3 mm. This specimen also had a knife-like hyaline ridge on the crest, which was obliquely truncate in front; it also had numerous summer embryos in the brood sac. The spine was perfectly straight and but slightly inclined upward. Older individuals have a rounded crest as figured and no ridge. The spine is relatively somewhat shorter but much more slender. The characters which most clearly distinguish eineeneens ENTOMOSTRACA OF MINNESOTA. 197 this species are the well crested head, which in young as well as sometimes older specimens has a median hyaline ridge, the with- drawal of the eye from the margin and the very long spine. It resem- bles D. galeata in earlier stages. It is very much like D. levis or, in other words, is in the group of D. hyalina. This form has only been found in autumn, September to November, Lake St. Croix and Rich- field in Hennepin county. [*Daphnia thorata Forbes. | Forbes 793. _ “This species belongs to the hyalina group, and may possibly be entitled only to varietal rank. The distinctness and constancy of its characters, however, in collections made by us in Flathead and Swan lakes in western Montana, and the number of minor points in which it differs from hyalina, as most recently described, lead me to distin- guish it as a specific form. ‘‘It is oval in outline; the long and slender posterior spine is placed at or a trifle above the middle; the length of the head is about a third that of the valves of the shell excluding the spine, and there is no trace of dorsal emargination between head and body. The head is narrowed toward the base and elongated forward in a way to give it the outline of a bell jar with a flaring base. Its front is broadly and regularly rounded, its ventral margin usually conspicuously concave and closely like the dorsal, although occasionally the head is straight or convex beneath. The posterior margin is either straight or slightly concave, and the beak stands free from the front margin of the valves, and by its extension downward not only covers the antenne but reaches clearly beyond the tips of the sensory hairs. The eye is of medium size, placed far back of the front of the head and equidistant from the tip of the beak and the dorsal junction of the head and body. The pigment speck is of moderate size, placed directly behind the eye, and much farther from it than from the posterior margin of the head. The antenn are moderately stout, entirely smooth except for inconspicuous transverse rows of minute appressed hairs upon both peduncle and rami, and a row of short, tooth-like spinules at the dis- tal end of each segment. The swimming hairs are rather slender, the second joint commonly decidedly shorter than the first. Fornices Slight, arising above and a little behind the eye and terminating directly behind the antennz, above the bases of which they project but slightly. The lower margin of each valve is set with the usual Spinules almost to the beak, and the dorsal margin is similarly armed _ for a distance in front of the spine about equal to half the length of Tay, a ees 198 GEOL. AND NAT. HIST. SURVEY OF MINNESOTA. the latter. The valves are marked off by fine lines into large quad- rate meshes. ‘The dorsal abdominal processes rise separately, the two anterior, however, in immediate contact at their bases. The first of these is decidedly the longer, but the third process is distinct, although low. The anal sete are two-jointed, the second joint the shorter. The abdomen is regularly narrowed backwards, and the anal groove is provided with twelve to fifteen teeth on each side, com- monly the latter number. The terminal claws are without accessory comb. The intestinal cceca are short, not longer than the diameter of the eye, and extend directly forward. Length 2.0 to 2.5 mm.;depth half the length, sometimes a little more. Length of spine variable, but commonly about equal to the depth of the shell.”’ As to the specific rank of this form we suspend judgment for the present. [Daphnia hermani Daday. ] Daday ’88. Head broad, compressed, front rounded, beak round, projecting ventrad. Eye large. Macula nigra absent. Shell oval, with a long spine. Abdominal processes discrete. Claws without teeth but orna- mented with a continuous series of fine sete. Anal teeth six, dimin- ishing dorsad. Length 0.5 to 0.8 mm. This we may unhesitatingly regard as a form of D. hyalina. Daphnia sarsii Schoedler. Sars ’60 (carinata); Schoedler ’77; Elymann ’87 (carinata). A. large yellowish species with a strong dorsal keel. Head uni- formly curved, slightly concave behind the eye, with a long oblique beak. Dorsal and ventral margins curved. Spine short and curved, springing from near the middle of the caudal margin- The abdominal processes long and united at the base. Claws without teeth. Length 2.5mm. The very insufficient description may help to place a form not recognized since Sars described it, When DP. carinata King is finally placed among its congeners this species will preoccupy Sars’ name. Daphnia paludicola Hellich. A large species of a dirty yellow color. Head depressed, front scarcely protuberant, ventral surface slightly concave, beak sharp, short. Antennules very small. Shell deep, oval, with a short curved spine springing from the middle of the caudal margin. First abdomi- nal process much longer than the second, to which it is fused. Post- ee ENTOMOSTRACA OF MINNESOTA. 199 abdomen small. Anal teeth 12 to 14. Claws with a series of fine Sete. Length 2.18mm. In the male the lower margin of the head is excavated and the flagellum of the antennules short and straight. Daphnia longispina Mueller. Mueller 1785; Straus-Durckheim ’19-’20; Baird ’50 (pulex var. longispina); Leydig ’60; Sars ’61, and ’64 (affinis); Mueller ’68; Plateau ’70; Lund ’70-’71; Kurz ’74; Hu- dendorff ’76; Hellich ’77; Lutz ’78 and ’79; Herrick ’84; Elymann ’87; Walter 788; Daday ’88; Matile ’90. A slender species of moderate size and transparent. Head not so deep as the body, from which it is not separated by a depression, slightly concave behind the eye. Beak long and directed caudo-ven- trad. Hye large, near the margin. Shell oval; spine long, situated above the middle line and curved upward. Two largest abdominal processes both directed cephalad and some- what united. Anal spines 10 to 12. Claws with a series of fine setze and two spines on the convex aspect. Length 2.0 to 2.5 mm. Flagellum of the male antennule hardly longer than the sensory setee. The young have three teeth above as in D. minnehaha. There is a great deal of diversity of opinion as to the value of this name. Not that there is any doubt of the existence of a widely dstri buted form which in general is that intended by Leydig and others, but the variation is so great that the possibility remains that more than one species is included under the one title. P. E. Mueller recognizes two varieties depending chiefly upon the length of the spine. * Daphnia minnesotensis sp. n. PLATE L, Fias. 10-12. Herrick ’84 (rosea.) The later descriptions of D. rosea leave no doubt that this is a distinct species. The abdominal processes are somewhat united at the base instead of ‘‘manifeste discretis,’’ and the first is much longer. In many respects the species is near D. longispina. The original de- scription is given: ‘‘In form very like D. longispina, this species, which is the only representative of this smooth-clawed, unkeeled group yet found in America, might perhaps be appropriately united with that species. ‘“Body oval, moderately ventricose; head of moderate size, lower margin nearly straight; eye situated in the anterior prominence. The beak is not very prominent. The upper outline of the head is slightly concave above the eye or rather less convex. The head is separated 200 GEOL. AND NAT. HIST. SURVEY OF MINNESOTA. from the body by a marked depression. The spine of the shell springs from the upper angle or is quite wanting. The post-abdomen is of moderate size, somewhat narrowed toward the end. The claws are smooth, the anal spines nearly equal, straight, about fourteen in number. The abdominal processes are not coalesced or but slightly so. Length 1.50 mm. to 2.0 mm. The species was collected sparingly in a large gathering of D. pulex from a small lake in early spring. ‘“The size and conformation of the abdominal processes are very variable and the long and very slender spine is frequently absent.” The antennules are very short. Males unknown. Daphnia microcephala Sars. A small transparent form, head only half as deep as the shell, slightly concave ventrally and ending in a short blunt beak. Shell elongate oval with a slender somewhat curved spine from the middle of the caudal margin. Abdominal processes nearly equal and united at the base. Analspinesseven. Claws without teeth. Length 0.75 mm. This is also a species requiring farther study. Daphnia cavifrons Sars. A reddish species with the head separated from the body by a depression, depressed, ventral border excavated, beak large. Shell ventricose with a short spine from near the upper angle. Abdominal processes nearly equal and united at the base. Anal teeth 12. Claw without teeth. Length 1.5 mm. I am not sure of this and the preceding. * Daphnia rosea Sars. Of moderate size, reddish in color, and resembling D. longispina. Head depressed and not separated by a depression from the thorax, somewhat excavated in the ventral margin, beak blunt. Shell oval, spine long, springing from above the middle and directed obliquely dorsad. The two abdominal processes thick, equal, discrete. Anal spines 12 to 14. Claw without teeth. Length 1.9 mm. The American form identified with this species is more like D. longispina. Daphnia aquilina Sars. A species of medium size, transparent. Head depressed, protuber- ant at the eye, excavated behind it, the beak lying in the same plane as the frontal projection and strongly curved caudad. Eye large. Shell oval, slightly separate from the head. Spine above the middle ENTOMOSTRACA OF MINNESOTA. 201 line very slender and short, directed dorsad. Abdominal processes long, approximate, the first twice as long as the second. Anal spines 16 to17. Length 1.83 mm. Dapnia lacustris Sars. Very similar to D. aquilina and to D. rosea. The head is depressed and excavated behind the eye, the beak projecting ventrad below the level of the front. The eye retreats from the front and is large. The shell is oval and the spine is straight, springing from the mid- dle of the caudal margin. The abdominal processes are discrete but approximate. Post-abdomen as in D. longispina, with 14 to 16 teeth. Length 2.21 mm. This is doubtless to be reckoned among the varities of D. longispina. Daphnia dentata Matile. Matile ’90. I translate the description, 1. ¢. p. 14. Body transparent. Head low and rounded cephalad; its ventral margin rather short and concave. Apex of beak directed ventrad [nach unten]. Antennal sete three-jointed, the last segment very short. Head separated from the thorax uniformly in adult animals by a tooth-like projection cephalad. Valves oval, extending into a rather short spine which lies somewhat dorsad of the median, longitudi- nal axis. Spine and the caudal half of ventral margins of the valves spined; dorsal edge without spines. Shell reticulated by regularly crossing lines. First two anal processes approximate and of equal length. Borders of the anal groove armed on either side with 12 to 14 spines which diminish gradually in size dorsad, Terminal claws without the comb of spines but armed with a continuous series of very fine sete; on the convex side two small spines. Eye large, with many erystallines; macula nigra point-like. Length 1.20 mm., height 0.70 mm., height of head 0.25 mm., length of spine 0.11 mm. The male is smaller. Antennule somewhat curved; at the free end it bears, besides the sensory threads, a flagellum, which is some- what curved at the end and dark contoured at the base and is at least twice as long at the sensory sete. The lateral seta is situated some- what separated from the flagellum on the front (cephalic) margin of the antennule. There is the same cervical toothed process seen in the female. Abdominal processes absent. Lengtn of male 0.78 mm.; height 0.42 mm. It would appear that Forbes D. dentifera is the American represen- tative of this species. It differs in having the cervical process much APPL EMM aire A Sel 2 p a) Y Pht ya PE bie A 202 GEOL. AND NAT. HIST. SURVEY OF MINNESOTA. further cephalad, i. e., over the base of the antenne rather immedi- ately in front of the heart. The beak in PD. dentifera does not turn ventrad but caudad. * Daphnia dentifera Forbes. PLATE LIIIJ, Fic. 9. Forbes 793. Broadly oval, long beaked, species with a large eye, posterior spine high and with a prominent angle dorsally between heart and eye inthe male and young female. Head broadly rounded, eye near front margin. Fornices short, forming a prominent angle behind the base of the antenne. Lower margin of head concave, beak projecting. Bye large with numerous lenses, its diameter more than half the dis- tance from eye to beak. Pigment fleck immediately behind the eye and nearer it than the posterior margin of the head. Head crested, forming above the insertion of the antenne a rectangular process which in the young may bear two or three teeth. This process is re- duced to an obtuse angle in the adult female, disappearing in ephip- pial individuals entirely. Spine of shell long and slender, one third or one-fourth the length of the shell. Caudal ciaws smooth, anal spines 13. The two abdominal processes approximate. Length of female 1.8 mm. Male 1.0 mm. Very near if not identical with D. dentata Matile. This species differs from D. minnehaha chiefly in having smooth claws. Daphnia longiremis Sars. A species of moderate size and very hyaline. Head small and rounded, ventral margin somewhat concave, beak sharp, directed ventrad. Shell oval, spine short, straight, inclined dorsad. Antenne relatively long, extending to caudal margin of shell. Post abdomen similar to that of D. longispina. Macula absent. Eye small. Length 1.0mm. Apparently a pelagic form. We are not certain that ib represents an adult. * Daphnia magniceps Herrick. The peculiar form figured in the tenth annual report of this survey seems indubitably new and is distinguished by the peculiar shovel- shaped head, which is seareely crested but is broadest beyond the mid- dle. The spine is long, the claws smooth, the abdominal processes united and the shell transparent. The eye is near the end of the rounded head and is large; the pigment fleck was apparently absent. Found with Daphnia minnehaha in a shallow swampy pool in autumn. ws bs 3 és 5 ENTOMOSTRACA OF MINNESOTA. 203- Daphnia cucullata Sars. Kurz (vitrea). Very like the above, but the margin of head is not straight below, is, however, extremely variable and ends in a sharp angle. The eye lies nearly midway between the heart and the end of the head and near the lower margin. The two anterior processes of the abdomen are united for most of their length. Anal teeth five to seven. Claw ciliate. The flagellum of the male antenna is about as long as the ter- minal sete. D. apicata Kurz seems to be a large variety lacking the sharp spine of the head. In the main it agrees quite well. Although the post- abdomen is broader than figured by Mueller, the number of teeth cor- responds with Sars’ description. Length 0.95 to 1.11 mm. * Daphnia Kalbergensis Schoedler. PLATES X XVII, Fias. 1-3; LIII Fries. 5-8. Schoedler (ccederstrcemii, and berolinensis); Forbes (retrocurya). Rather delicate species of moderate size, inhabitants of clear and deep waters. Form oval, with a long nearly straight spine springing from near the middle of the posterior margin. Head very large and produced into an enormous helmet-like crest, which projects cepha- lad and may be somewhat or greatly curved dorsad. The size of the crest and its form are very variable even in the same gathering. Eye small, with few lenses, distant from the ventral margin, macula want- ing. Antenne weak. Post-abdomen narrow, with from six to twelve anal teeth; claws weakly ciliated. Abdominal processes discrete. As above stated, the close association of forms in the same gather- ing ranging from D. vitrea to the extreme of D. retrocurva seems to forbid their separation, even varietally. The case of D. vitrea is most open to doubt. The chief differences seem to lie in the small number (4) of anal teeth and the fusion of the two anal processes. A young specimen from Lake Minnetonka had but four large teeth and two inconspicuous ones and the anal processes were less distinct than in older individuals. All transitions could be found. We agree with Hellich that this, at most, is a depauperate variety of D. kalbergensis. There seems to be absolutely no good reason for separating D. ceder- stremii or D. retrocurva, as the differences are largely a matter of age and freedom to develop typically. P. E. Mueller gives the following measurements for D. kalbergensis: Head 0.9 to 1.0 mm., body 1.0 to 1.1 mm., spine 0.7 to 0.75 mm. 204 GEOL. AND NAT, HIST. SURVEY OF MINNESOTA. Kurz for his D. vitrea gives a length of 0.85 mm. plus 0.25 mm., the length of the spine. Judging from his figure, the head would not measure over 0.35 mm. Forbes says of his D. retrocurva that the head is two-thirds as long as the body. Our specimens measured as follows: No. 1. 1.6 mm.; head somewhat more than half the body and almost exactly like D. vitrea in form. No. 2. Head 0.6 mm., body 0.9 mm., spine 0.5 mm.; about nine anal spines. Head in this case moderately curved upward. No. 3. Head 0.95 mm., body 0.95 or less, spine 0.5 mm.; or the head as long as, or, indeed, considerably longer than, the body and directed upward. The males have the crest much lower, the spine longer, and the form of antennules figured by P. E. Mueller. In the older females the beak is elevated above the antennules, as remarked by Forbes, but in smaller individuals there is very little difference between our speci- mens and Mueller’s figures. The claws of the post-abdomen have, besides the row of fine teeth mentioned by Mueller, a cluster of sharp teeth just at the base. Found, together with typical D. galeata and the rounded form, in a small deep lake or expansion of a creek not far from Medicine lake, Hennepin county, Minnesota. We have since found this species at a depth of 80 feet in Lake Min- netonka, and here also in association with D. hyalina. The range of variation is exceedingly great as indicated by the figures of Plate LITT. Having given as fall a catalogue of the well known and accessible species as our circumstances now permit, it remains to notice the ex- istence of others which are either imperfectly described or the descrip- tions are out of reach. Daphnia similis Claus. PLATE XX XV, Bic. 5; LI, ia. 7: The description of this species, which was bred in confinement from eggs brought in mud from Jerusalem, I am, unfortunately, unable to quote. Judging, however, from the figures which alone I now have access to, it belongs in the group of D. longispina, though in many particulars it resembles D. schefferi. The form is elongate, the spine short and springing from the upper margin. The antennule of the female is very large and flagellate, while that of the male is like that of D. sche fferi. The flagellum and hook of the first foot of male are rather small. ey eae ae ee ENTOMOSTRACA OF MINNESOTA. 205 W. Schmankewitsch described as new D. degenerata and D. rudis, from salt or brackish waters. These he regards as degenerate forms produced by the inferior aeration of dense waters. The author does not appear to recognize the modern distinctions of genera, so that, not having seen the work, even the generic position cannot be definitely stated. His investigations seem to show that the proximity of salt waters influence the form of the body, or, perhaps, that there is a con- stant interchange between the sub-marine and fresh-water species. Daphnia brevicauda Chambers is an incorrectly figured and described Simocephalus. Daphnia bolivari Richard. Richard 788. ‘*Caput a latera visum fere triangulare, latum, margine superiore recto; anteriore cum inferiore lineam usque ad apicem rostri sequaliter ac leviter arcuatam formante; rostro acuto brevi. Testa cetera margine dorsali subrecto inter caput et corpus leviter rinuato, margine ventrali aculeato parum arcuato. Spina teste longa aculeis multis ac validis ornata. In capite a latere viso linea circularis patet insignis distinctissime serie duplo aculeorum acutorum instructa, parte superiore modo levi. Ad apice dorsali et posteriore hugus lineze sequitur linea alia eadem structura marginem supe- riorem testz usque ad apicem caudalis spine. Adest preterea linea alia in medis utriusque lateris teste, aculeis ornata. Antennz lmi paris magne. 2di paris medi- ocres piliis brevibus sed distinctissimis ornate. Setz abdominales mediocres, ad apicem ciliis longis dense obsitz. Oculus mediocris crystallinis paucis perspicuis; macula ocularis rotunda, parva. Longit. fem. spina teste inclusa, 3.35 mm., spine, 0.8 mm.’’ This Spanish species is not sufficiently described to be allotted to its place among its congeners. The armature of the abdomen is abso- lutely essential. Daphnia carinata King. King 752-54, This form, though incompletely described, will be easily recognized when rediscovered. It belongs to the D. scehfferi group and is said to resemble D. similis Claus, being one of the largest of the genus. The head is armed with a crest but is depressed and uniformly rounded, The shell is oval with a long spine from the upper angle in the young female. Abdominal processes thick. Post-abdomen attenuated. De- tails of armature not given. Ephippium with four eggs. The eye ig somewhat distant from the margin. Daphnia gravis Schoedler seems to us but an extreme variation of the above as it was regarded by King. Daphnia kingii Schoedler is a very large species with the head greatly helmeted. The outline is nearly circular and rises above the level of the back. The shell is oval with an extremely long spine which is directed obliquely dorsad. 206 GEOL. AND NAT. HIST. SURVEY OF MINNESOTA. Daphina cephalata Schoedler is named from rude drawings by King, which, if they show anything, seem to prove that they rep- resent an abnormality, probably of D. kingii. The sac like disten- sion of the head is at the expense of the lower part of the head. Daphnia macrura Dana is identified by Schoedler with D. carinata King. Daphnia kisilkumensis Schoedler—D. vitrea Uljanin is apparently D. longiremis Sars. Daphnia newportii Baird, from India, is quite insufficiently de- scribed but belongs to the D. schefferi group. Schoedler mentions Daphnia brasiliensis Lubbock and Daphnia gran- aria Gay, from Chili. Haldemann’s Daphnia reticulata may be D. pulex and his Daphnia abrupta is Simocephalus, Daphnia lumbholtzii Sars. BYVARE Ovi ShiGen6. This species from Australia is well characterized by acute depressed frontal spine and the flaring fornices which end in curved spines of considerable length. The male and ephippial female lack the frontal spine but preserve the long spine springing from the upper angle. Theantennules of the malesare very long and the flagellum two-jointed and about as long as the antennule. The claw of the first foot is greatly developed. The claws have no spines. The anal teeth are 12 or more. Abdominal processes discrete. — FAMILY BOSMINIDE. Small cladocera of remarkable form, due to the great elongation and modification of the antennules, which are seated on a small con- ical beak-like projection of the ventral aspect of the head and form long, jointed, probosis-like appendages curved in various ways. The shell is laterally compressed and not sharply separated from the body. There is frequently a sharp spine at the caudo-ventral angles of the shell. The surface is reticulate, striate or smooth. Feet, six pairs. The first pair hooked in the male. The antenne have three and four jointed rami and are very small. The post-abdomen is trun- cate and the claw is seated on a considerable prominence. Macula cerebri and cceca absent. As there is but the single genus [ Bosmina] we have included gen- eric characters, ENTOMOSTRACA OF MINNESOTA. 207 These curious animals are often found at great depths in the larger lakes, though they may also occur in weedy localities. They are poor swimmers and rarely caught in the net. *Bosmina cornuta Jurine. PLATE LXV, Fies. 3-5. Oval, almost spheroidal. Head high, concave below the eye, Beak long, its flagellum midway between the eye and end of beak. Hye large. Antennules curved like a hook composed of 10 or 11 seg- ments. Antenne as long as the end of the antennules, three-jointed ramus with five sets, the four-jointed ramus with three sets. Shell high, greatest height in middle of the length. Back uniformly curved and forming an obtuse angle, with the straight caudal margin. Spines at the caudo-ventral angle short, turned dorsad. Shell hex- agonally reticulate. Post abdomen short, truncate and excavated api- cally, with two anal spines. Claws finely pectinate. Length 0.4 to 0.54 mm. * Bosmina longirostris O. F. Miiller. PRATES XchV~ Bie 2°) LX V;, Pre. s2: General form oval, shell highest in the middle. Head high, beak short, flagellum arising from near the end of the beak, front pro- tuberant. Antenne longer than in B. cornuta, three-jointed ramus with five, four-jointed with four setw. Spines of shell short and Straight. Post-abdomen short, truncate, unarmed. Claws on a pro- tuberance, pectinate. Length 0.31 to 0.35 mm. Bosmina longicorpis Schoedler. Very similar to B. longirostris, but the front is not protuberant, the flagellum is midway between eye and end of beak. The spines of the shell are long, toothed ventrad and directed obliquely dorsad. Shell unmarked. The finely pectinate claws have at their base sev- eral large accessory spines. Length 0.36 mm. Bosmina brevicornis Hellich. A large species with depressed head having a uniformly rounded front. Shell higher than long and coarsely reticulate, spine short and curved. The beak is short and little curved, the flagellum being quite near the eye. The antennules have seven segments. The post- abdomen is large without anal spines and the claws are simply pectin- ate. Length 0.55 mm. Hellich says this differs from B. brevirostris P. E. Mueller, which has a protuberant front and long serrate spine and the claws have seven accessory spines. 208 GEOL. AND NAT. HIST. SURVEY OF MINNESOTA. Bosmina bohemica Hellich. Body large, slender. Head high, front uniformly rounded, flagel- lum nearer the end of beak than the eye. Beak short, rounded. Antennules long and arched, composed of 16 or 17 segments. The triangular spine above the sensory filaments large and acute. Shell as long as high, highest in the middle. Spine long, curved dorsad and toothed. Shell irregularly reticulate and longitudinally striate. Post-abdomen large, truncate and excavated. Inferior angle ciliate. Claw protuberance long, unarmed. Claw with six spines at the base. Length 0.6 mm. Bosmina microps P. E. Mueller. Oblong, length much greater than height. Front not protuberant. Caudo-ventral angle of the shell without the spine, rectangular. An- tennules long, nearly straight, flagellum nearly midway between beak and eye. Length 0.5 mm. or less. The shell is reticulate and the antenne are very short. Bosmina maritima P. E. Mueller. Oblong, longer than high, front moderately protuberant. Shell strongly arched above; spine long, directed obliquely ventrad. An- tennules slender, gently curved; flagellum near the beak. Shell smooth. Length 0.5 mm. Bosmina brevirostris P. E. Mueller. Oblong, length greater than height, front greatly protuberant. Shell arched above, strongly spined. Antennules moderate, straight- ish but inclined caudad. Flagellum near end of beak, sensory sete remote. Length 0.6 to 0.7 mm. Color reddish. Bosmina diaphana P. E. Mueller. Gibbous, length greater than height, front not protuberant. A slight sinuosity in the dorsal outline over antenne. Shell very strongly arched without the spine, smooth. Antennules very long, curved, converging at the ends. Flagellum near the end of the beak. Length 0.6 to 0.7 mm. Bosmina lilljeborgii Sars. PLATE XLYV, Fia. 3. Very gibbous dorsally, length and breadth nearly equal, front not protuberant. Dorsal outline sinuous over the antennz. Spine ab- sent. Antennules longer than the body, straight or slightly curved, divergent. Flagellum near end of beak. Length 0.6 to 0.75 mm. a “ay ENTOMOSTRACA OF MINNESOTA. 209 Bosmina curvirostris Fischer. Body rounded, length little greater than height, front somewhat protuberant, dorsal margin strongly arched, antennules short and strongly curved. Flagellum midway between eye and end of beak. Seven to eight sets upon the cephalic aspect of antenne, Length 0.39 to 0.4 mm. * Bosmina striata Herrick. PLATE LXV, Fia. 1. Herrick ’82. This form is very imperfectly known, but resembles B. bohemica and may be identical, but that is a much larger form. Oblong, slen- der, greatest height cephalad of middle, front strongly arched. Hye large. Flagellum near the beak. Antennules very long, curved. Shell irregularly marked with anastomosing longitudinal lines pro- ducing a deformed reticulation. Spine large, curved, but not long. Ventral margin sinuous, ciliated cepbalad. Length 0.25 mm. * Bosmina atlantaensis Turner. This is not adequately described. It, however, affords proof of the existence of a fourth type of Bosmina in America. B. longirostris, B. cornuta and B. striata all have the shell marked and _ peculiarities of structure otherwise. The southern form has a smooth shell, long antennules, depressed spine, sinus between nead and body, and fla- gellum nearer to the eye than to the sensory sete. The post-abdomen is broad and the claws toothed. The whole genus requires revision. Other species which cannot now be placed are the following: . gibbera and B. rotunda Schoedler. . levis Leydig, probably the young of longirostris, . londensis Norman and Brady. . obtusirostris Sars, probably is Bb. brevirostris. . lacustris and B. nitida Sars. . coregoni Norman and Brady, is B. lilljeborgii. . macrorhyncha, a species from the Nile. Babe oad FAMILY LYNCODAPHNID Sars ’61; Herrick ’81. This is a rather small family with several genera of minute animals which are abundant only insummer. Many, and indeed most, of the species are among the rarer of fresh water crustaceans of this group, and a few are among the rarities which only now and then reward the 210 GEOL. AND NAT. HIST. SURVEY OF MINNESOTA. collector. This family undoubtedly is the link connecting the Daph- nide with the Lynceide, relationships to which are expressed by Macrothrix, on the one hand, and Lyncodaphiaia on the other. The rank of this group as a family must be, of course, a matter largely of opinion. Sars was the first to adopt this view, sustained by certain curious transition forms leading toward Lynceidw. Later writers seem never to have found these genera and the group was again included with the Daphnidw. The writer (82), npon the discov- ery of the Lyncodaphnia was forced to regard this group as of equiva- lent grade with the above mentioned families and again proposed the family name Lyncodaphnide. The genus Jlyocryptus is a little one side the normal course of the family and seems related to the lynceid genus Leydigia. The waters of the northern United States are very rich in members of this family. The aberrant family Bosminide finds its only connection with other Cladocera through this group by means of the remarkable Maero- thrixv (2) pauper; and here it is only vaguely hinted at in the elongated antennules and angled lower margin of shell, as well as the presence of certain bodies near the base of the antennules. It has been affirmed that none of the Lyncodaphnide have an ephippium, i. e., the saddle- shaped thickening of the shell walls to include and protect the winter eggs; but I have discovered it in the case of Maerothrix tenuicornis Kurz and presume it may occur exceptionally in others. Kurz says that Ilyocryptus has no moult proper, but this probably refers only to the European J. sordidus. The American species differs from the generic description given by Kurz, and may be different in this respect also. In this family the regularity in the disposition of the setze on the antenne is broken and the fringing of these hairs serves the purpose of specific distinction. The antennules are always long and frequently differ considerably in the sexes. The pigment fleck is always present (Kurz is in error in denying its existence in Lathonura). In many forms there is no free posterior margin of the valves, while the lower is generally thickly beset with movable spines. The Lyncodaphnide will be distinguished from Ceriodaphnia, which they resemble, by their motion, which is a succession of quick bounds, while the broader Ceriodaphnie hobble along as though heavily weighted by the enor- mous mass of eggs with which they are generally laden. The abdomen is usually short and the anus is behind the terminal claws, but in J/y- ocryptus the claws are long and spined at the base. In the American J. spinifer the anal opening is elevated to a point nearly underneath the stylets, and there is a rudimentary anal czecum as in Lynceids. ° ENTOMOSTRACA OF MINNESOTA. PALA. The males have the opening of the vasa deferentia in front of the claws, which may be absent; the antennules are also modified, being longer and curved. In Lathonura the abdomen is elongated posteriorly till it begins to suggest a transition to Polyphenwus. The known genera and their distribution is as indicated below. Half of the known species are found in America, one-fourth being peculiar to it. peu) eae nly in Total ENE. ueclee, BoroneaE Amer:can. | hens American. | MIACTODATIXssicsccse cece eee base deus eee 4 3 2 1 3 PALOMITAS ss ccwrcinas scieeine sees stssiaes 1 1 De SualliacsteWoroncees 1 REMAN OGL s2i502 a0 sce ces vecmesocacs il Te Mg a RE es | 2a cecisiasiensclotell Woneescwuke tee MPTEMIOCCTHUS tor ssisncsscecelseetsioncedeese | 1 | Ly Thal Res ee crate | ancreeeteahes eters hie a oes tee Atcantholeberis:.::.5:.2c2+-, s0as-2ecsenl 1 Dee VN CTR social ai densi eee [tree meter eee ORVONUS ite vcthon ssa naevacne foceceecseowes i| 1 RA ante a wceche 1 EVAN COC AP DMTAORE scot ccescelet cieosistie se 1 lirsntets Pesce alts dete estes 1 1 UV OEY PLUS esse caseatines sese se naseeeees 3 | Ps Ball ects 1 1 moe | Se ee 700171 RO es Teh le 210 4 3 "i | GENUS MACROTHRIX Baird. Body oval, pointed behind; head broad; antennee of first pair long, nearly straight, beset with spines, olfactory threads terminal; swim- ming antenne large and powerful, propelling the animal by bounds; three jointed ramus with a greatly elongated sets which is thorned and jointed; labrum with the basal joint enlarged, resembling that of Iynceids; first foot with a hook in both sexes; last foot with a long process (respiratory body); abdomen short; claws short; caudal stylets often with a bush of hairs at tip. The intestine is straight and without ceca in front or behind. The first one to observe a member of this genus, apparently, was O. F. Muller whose Daphnia curvirostris is usually referred to Macro- thrix laticornis. The name Echinisca was proposed by Lievin, but Macrothrix was applied by Baird in 1843. Four species are known, three of which occur in America, and without doubt the fourth will ultimately be found. No males of this genus were known till 1877 when the male of M. laticornis was described and figured (Grube and Weismann ’80. ) Nearly two years later the male of VW. rosea was described from Wis- - consin by E. A. Birge. Descriptions of the male of Lathonura are also — given in both the above mentioned sources. 5 14 212 GEOL. AND NAT. HIST. SURVEY OF MINNESOTA. *Macrothrix laticornis Jurine. PLATES LIV, Fias. 9-12; LVI, Fias. 8, 9. Jurine ’20; Baird 750; Fischer ’52 (Daphnia curvirostris); Lilljeborg 153; Schoedler 58; Leydig ’60; Norman and Brady ’67; P. E. Mueller ’68; Lund ’70-’71; Fric 1721; Kurz ’74; Herrick ’84; Birge ‘91. This ubiquitous species was first reported in America by Birge though it had been encountered by the writer in several instances. It is recorded at Madison, Wis., Minneapolis, Minn., where it is not rare, and in Albuquerque, New Mexico. The body is compactly oval, with a curved or subangular lower margin which is armed with spines which project in three planes, thus producing three series; dorsal margin convexly arched, crenulate or subdentate. Head short, produced ventro-cephalad to form a blunt beak from which the antennules are suspended. Eye of moderate size; pigment fleck large; quadrate. Antennules short, greatly expanded at the tip, provided with the usual sensory sete and flagella and a cluster of spines at their bases, also a second cluster upon a special protuberance posteriorly. Upon the anterior margin are series of bristles and this margin is serrate. The antenne are strong, hairy, and armed as usual in the genus. The feet are sufficiently represented in the figures. The post-abdomen is short, with very small terminal claws, in front of which are several bristles not previously noticed; about the anus are several bristles, and a series of short teeth orna- ments the dorsal margin. The whole shell is hexagonally reticulate except along the dorson where the slight crest modifies the markings. Length 4.7 to 6.0 mm. Birge found this form only rarely and then singly. Fric speaks of it as loving the bottom and occurring singly. We have frequently found it in Minneapolis and abundantly in New Mexico. As the type of the genus, it appropriately occupies a conservative position, as shown by broad tip of the antennules, a feature exhibited by embryos and young of other species. *Macrothrix nova-mexicana sp. n. PLATE LIX, Fias. 3-5. Testa corporis suboblongata, levis, postice non angulata, marginalibus ventralibus eequaliter rotundatus fere rectus, ciliatas gerentibus. Oculus magnus; macula cere- bralis parva sed manifesta. Antenne fere rects, ad apicem versus paulum dilatatx, postice ciliate. Antenne 2-di paris ille M. rosea similes. Cauda brevis, apice rotundato, super anum sinuata, ad apicem versus densa ciliata, margine cetero seribus setarum minimarum armato sive inermis. Longit 1.1 mm. As compared with M. rosea, its nearest ally, this form is not only considerably larger (the largest figures being 0.9 mm. in length by 0.6 PE ee. Pe, wake alu ENTOMOSTRACA OF MINNESOTA. 213 mm. high, while the present form measures 1.1 by 0.7 mm.) but the form and several details noticeably differ. The shell, as seen from the side, is nearly quadrangular, reminding of ZLathonura, and is not produced into a sharp spine as in J. rosea. The head is also shorter and is not excavated between the eye and pigment fleck. The ventral margin of the valves is not obviously sinuous and is spinulus as in WV. rosea. The antennules are straight, and not strongly curved, as fig- ured by Kurz, neither are they spiny in front. At the tip they bear the usual sensory sete and posteriorly a cluster of spines while the posterior margin is ornamented with several clusters of bristles dis- tally. The antenne seem not to differ materially from those of M. rosea. ‘The post-abdomen is shorter than in M. rosea, its terminal claws are small, curved, deep-colored and unarmed; in the protuber- ance formed by the anus are closely clustered spines and bristles while the rest of the margin is either unarmed or furnished with a few minute spines. The long stylets are as usual in the genus. No markings were seen on the shell. Projecting into the brood-cavity are two leaf-like plates which seem to serve an accessory branchial function and contain many blood corpuscles. Details of the feet are wanting. The species has been but once seen, in the clear water of the tank supplying Albuquerque, New Mexico, accompanied by two species of Diaptomus and a Moina. M. rosea occurs in the north, often in considerable numbers (Birge 91) and the present species may take its place to the southward. It may be admitted that it approaches Lathonura more than any other Species of the genus. It is just brought to my notice that Matile describes in an appendix to his paper ‘‘Die Cladoceren der Umgebung von Moskau, 1891,” Macrothrix borysthenica, which is so very close to our species that we suspect intimate comparison will prove the two identical. The atten- nules in Matile’s species are shorter and the dorsal margin is less strongly marked. ‘The armature of the post-abdomen is perhaps slightly different but our description was drawn from very large in- ‘dividuals and considerable variation was observed. I therefore with- draw the name proposed for the present. Macrothrix hirsuticornis Norman and Brady. Norman and Brady ’67; Daday ’88; Matile ’90. Head separated from the thorax by a depression. Shell roundish, caudal angle obtuse, smooth, ventral margin gently rounded. An- tennules dilated toward the end, slightly curved, cephalic margin with five series of small sete. Post-abdomen rounded at the end, having ‘distally seven setee and proximally small teeth. Length 0.55 mm. ee Say IS ee SM Dee 214 GEOL. AND NAT. HIST. SURVEY OF MINNESOTA. Macrothrix serricaudata Daday. Shell rounded, punctate, transparent, obtusely angled caudad. Caudal part of dorsal margin serrate, ventral margin nearly straight, sparsely ciliate cephalad. Antennules long, subeylindrical, attenuate at the end, slightly curved, armed with minute sets. Post-abdomen rounded at the end, sinuous above the anus, serrate with strong teeth. Length 0.9 to 1.0 mm. This species is near to our own J. pauper. *Macrothrix rosea Jurine. PLATES LIV, Fias. 1-3; LVI, Fias. 5-7, 11, 13. Monoculus roseus—Jurine. Lynceus roseus—Desmarest. Daphnia rosea—M. Edwards, Jurrell. Echinisca rosea—Lievin. The body is sub-oval, terminating behind in an acute angle; the lower margin is less conspicuously spined than the last or the following; the antennze are but slightly dilated at the end and nearly straight. The longest seta of the antenne is longer than in the last, reaching beyond the tips of the terminal sete; abdomen more slender, sinuate in front, beset with short hairs. Length 0.6 mm., male 0.8mm. The male has small claws on the end of the post-abdomen, and the antennules are curved and elongated. In a later publication Birge finds small claws on the post-abdomen of the male which resemble that of Bosmina. On the posterior side of the apex of the antennules of the male is a cluster of five or six long sense hairs peculiar to this species. *Macrothrix tenuicornis Kurz. PLATES LIV, Fias. 5-8; LVI, Fias. 1-3, 12, 20. (See Notes on Cladocera of Minnesota, p. 245.) The body is oval, produced posteriorly in a sharp point; the ab- domen is strongly arched, while the upper outline of the head is a regular curve or slightly extended in front of the eye; the antennules are long, nearly straight and a very little narrowed toward the end, just in front of which is a series of short teeth; there is no lateral spine, but a strong terminal one in addition to the sensory filaments; the pigment spot is large, the eye small and the lobus opticus well separated from the ganglion; the antenne have a very powerful basal joint; the elongated seta is very stout and densely spiny, with a tooth at its flexure; two of the terminal sets are spiny, for the basal half; the valves are beset with very long spines in sets of three each, all having different positions; the abdomen is nearly as in MV. rosea, but * ti ENTOMOSTRACA OF MINNESOTA. 215 the posterior margin has a series of long sharp teeth; the mandibles are nearly completely exposed by the arched anterior margin of the valves. The labrum, in this species, is an odd link between that of the Daphnide and Lynceide. The basal segment is greatly enlarged and is sub-triangular in outline, with a movable lip attached to the inner free face; the typical daphnoid structure is preserved, but the enlarged salient angle of the basal portion shows how the transition to the great triangular labrum of Alona, etc., is made. In young specimens the head is proportionately larger, the antennules are broader at the tip, , and the dorsal outline is less convex; the marginal spines of the valves are also proportionally larger, as are the appendages of the first and last pairs of feet. This is one of the largest species of the genus, 0.75 mm. being the length. This is very close to M. rosea but seems distinct. This form is quite commom about Minneapolis, Minn., but is not yet noted elsewhere in America. *Macrothrix pauper Herrick. PLATE LVI, Fie. 4. This species is described from a single specimen from Lake Minne- tonka, and I can add nothing to the very meager notice given then. (Herrick ’82.) The body is broad and very narrow, the lower outline is angled and nearly unarmed; the pigment fleck and eye are small and approxi- mated; antennules very long and curved backward and outward; ab- domen short, ciliate below; claws short, ciliated. This: female had a full complement of eggs but the antennze resemble those of a male. This is unusually interesting and should be rediscovered and studied; for there seems to be some affinity between this species and Bosmina, and it is probable that it requires to be distinguished generically from Macrothrix. GENUS LATHONURA Lilljeborg. The form is oval; the head is curved more than in Macrothrix and the shell is more obtuse behind, sinuate below where it is beset with short spines anteriorly; first antenne long, straight; second antennz with five setze on each ramus; only four pairs of feet apparent; ab- domen short, prolonged upward to the insertion of the caudal stylet; male similar but smaller. a 216 GEOL, AND NAT. HIST. SURVEY OF MINNESOTA. *Lathonura rectirostris O. F. Miller. PLATE LVII. K och ’35-’41 (Pasithea rectirostris); Zaddach ’44 (Daphnia brachyura); Lievin ’48 (Daphnia brachyura); Fischer ’52 (Daphnia mystacina); Lil)jeborg ’53; Leydig 60 (Pasithea rectirostris); Norman and Brady ’67; P. E. Mueller ’68; Schoedler 58 (spinosa); Birge ’78; Gruber and Weismann ’80 (Pasithea rectirostris); Herrick ’82. The only species of the genus is distributed probably over the entire northern temperate zone. It has been found in America at Cambridge, Mass., and in the vicinity of Minneapolis, at both of which places it is very rare. é: The form is a rather quadrangular oval, the head being strongly arched to the beak which is much farther posterior than in Macrothria, in this respect resembling the Daphnide; the eye occupies the center of the lower part of the head margin, and is of moderate size; the pig- ment fleck is near the base of the antennules and well removed from the eye; the antenne are straight and long, with a sensory bristle near the base in front and two bristles athird fromthe end; the second ' antenne are furnished with a powerful basal joint, while each of the main subdivisions of the rami has its bristle, which are nearly equal; two of the terminal sete are toothed for the basal half and pectinate distally, but the others are feathered throughout; the four-jointed ramus has a spine on the second joint and a longer one at the end, and all the joints of both rami are ornamented with triple series of spines; the maxille are three spined at the end and are in almost constant motion; the first pairs of feet have curious comb-like bunches on some of the sete; the abdomen is very short and terminates in inconspicuous teeth, the posterior part of the abdomen being ornamented with teeth flattened longitudinally so as to look like spines from the side; the last foot is simple but bears a large appendage; the posterior third of the shell is fringed by extremely minute spines, but anteriorly by lanceolate stiff spines flattened longitudinally like the spines of the abdomen; the caudal setz are seated on a high prominence of the ab- domen, and are fringed along their whole length, not merely at the end. The female is 1.0 mm. long, the male 0.5 to 0.6 mm., in which sex the antennules have more numerous lateral bristles, the first foot has a claw and the back is less elevated. The semen bodies are irreg- ularly round with small nuclei. GENUS STREBLOCERUS Sars. In form like Macrothrix laticornis, head terminating in a long ros- trum bearing the long, twisted antennules, Antennules very large, curved backward and outward. Head not separated by a distinct ENTOMOSTRACA OF MINNESOTA. 217 depression from the body, very high, slightly arched above, abruptly curved below with spines upon the margins. The antenne are large; four-jointed ramus much the longer, with four sete. Labrum with a large process. Post-abdomen much as in Macrothrix laticornis, serrated or notched behind. Eye near the beak; pigment fleck small, situated below the eye at the base of the antennules. The shell is hexagonally reticulate, arched above and angled below; ventral margin armed with rigid spines. Claws ciliate. Length 0.34 to 0.4 mm. Our Macrothrix pauper seems a near approach to this genus; both have a strong spine or claw on the first foot which projects beyond the shell, but there are many differences. J. pauper is 1.0 mm. long. S. serricaudatus Sars (Plate LX VI, Fig. 1) is the only species. GENUS DREPANOTHRIX Sars. The head separated from the valves by a depression; fornices mod- erate; rostrum rather acute, distant from the anterior edge of the valves. The form is subrotund; reticulate, with the margins of shell fringed below by long movable spines; pigment fleck present; swim- ming antenne with three ciliated setz on the four-jointed ramus, the three-jointed ramus with its basal joint armed with an unjointed, strong, spinous seta and four ciliated sets on the remaining joints. The post-abdomen is broad. Intestine coiled. The male has longer antenne and a hook on the first foot. Drepanothrix dentata Euren. PLATES XLVI, Fia. 9; LIV, Fic. 4; LVI, Fie. 14. Acantholeberis dentata—Euren. Drepanothrix setigera—Sars. Drepanothrix hamata—Sars. * Drepanothrix hamata Norman and Brady. This animal is only 0.5 mm. in length. The antennules are later- ally curved in the middle and ornamented with notches on the mar- gins; the pigment fleck is quadrate and rather large; the post-abdomen is truncate at the end, convex behind and ornamented with a series of small spines. Shell margins with long spines. Birge reports this species from Lake Wingra near Madison, Wis- consin. It seems to be repelled by light and is a bottom-loving form. Though it swims fairly well, the stiff sete are chiefly used as pushing poles. The species has been taken in Denmark, Scandinavia, Eng- land and France as well as America. 218 GEOL. AND NAT. HIST. SURVEY OF MINNESOTA. GENUS ACANTHOLEBERIS Lilljeborg. Body more or less quadrangular, head triangular, acute cephalad, bearing the antennules at the front. Fornix slightly developed. Head scarcely separated by a depression from the body. Antennules elongate, expanded apically. The three-jointed branch of the antenne has five setze, the four jointed ramus has three, all being apical. The seta of the basal joint of the three jointed ramus is elongate. Labrum with an acute process. Feet six pairs. Intestine with a loop. Post- abdomen broad, armed with a series of spines. Margin of the shell with long spines below. Ancantholeberis curvirostris O. F. Miiller. PLATE XLVI, Fias. 1-4. O. F. Miiller 1785 (Daphnia curvirostris); Schoedler ’46 (Acanthocercus rigidus); Lievin 748 (Acanthocercus rigidus); Lilljeborg 52, and ’&8 (1igida); Leydig ’60 (rigidus); Norman ’63; Norman and Brady ’67; P. E. Mueller ’68; Lund ’70-’71; Hellich °77. This rare species has not yet been found in America but may be confidently expected. The aspect is macrothroid, the whole ventral margin being long ciliate, while from near the posterior angle arise a number of greatly elongated sete. The caudal margins are armed with short spines. The macula is present but rather small. The an- tennules are elongate, expanded toward the tip, somewhat curved and armed apically with about eight unequal lanceolate processes and swwaller spinules. The post-abdomen is broad, rounded distally. The claws have two small basal teeth and a series of small sete. The pos- terior margin is armed with a series of small teeth. Length less than 1.5 mm. GENUS OFRYOXUS Sars. Lyncodaphnia—Herrick. Body elongated, somewhat rectangular as seen from the side, great- est width and height of shell a little posterior to the heart; head sepa- rated by a depression from the body, truncate below; antenne and antennules much as in Macrothrix; four jointed ramus of antennee with no lateral setze; eye small, pigment fleck present; intestine twice con- voluted, expanded posteriorly, with anterior but no posterior ceca, opening near the ‘“‘heel’’ of the post-abdomen; post-abdomen large, triangular; terminal claws long, rather straight, with two accessory spines at the base. Ofryoxus is, aS Was suggested, a curious transition form linking the Daphnide with the Lynceide. ENTOMOSTRACA OF MINNESOTA. 219 O. gracilis not only has the dise-like last foot colored but the swim- ming antenne are banded with purple as in Simocephalus rostratus --Herrick and 8S. americanus Birge. The intestine has anterior ceca, which is not the case in Lynceids, nor, indeed, in other Lgncodaphnida. The four-jointed ramus of the antenne approaches Lynceid@ in the absence of a lateral seta, but the other ramus is as in Macrothrix. The convolution of the intestine, the form of the post-abdomen and the situation of the anus are all of a strictly Ivneeid type; moreover, the flattened appendage of the last foot is like that of Hurycercus. Even in the form of the shell there is a combination of characters; the anterior part of the shell has the form peculiar to Lyncodaphnida; but posteriorly it again expands and becomes truncate behind; the form in the adult is not unlike that of some Lynceide, but the young has a long spine posteriorly exactly like the spine of Daphnia. The latter fact is very instructive, for it indicates that the theory proposed (American Naturalist, 1882, p. 815) to explain the origin of this ap- pendage is probably the correct one. Professor Leuckart suggested that this spine was a balancing rod intended to keep the proper equi- poise over the center of gravity; but it is difficult to see why these long-bodied forms, in which the greater part of the weight les ‘‘abaft’’ of the pivotal point—the base of the antennze—should be thus provided while the shorter forms are not. We conceive that it is an apparatus for effecting the moult of the inner lining of the brood cavity of long-bodied and tender-shelled animals such as Daphnia and the present genus. The great development of the head in the crested Daphnide may undoubtedly be explained upon Professor Leuckart’s theory. * Ofryoxus gracilis Sars. PLATES XLII, Fias. 12-15; LVIII, Fias. 1-3; LIX, Fia. 2. Herrick ’82 (Lyncodaphnia macrothroides). Sub-rectangular, greatly elongated, truncate behind, with a slight Spine above; head and eye small, fornix moderate, beak truncate; an- tennules rather long, slightly curved, tapering a little toward the end, whence spring three lanceolate spines and several sensory filaments, five stout spines behind, above the middle, and several more slender ones; Swimming antenne very long, terminal sets smooth to the joint; labrum as in Daphnia; mandible attached behind a salient angle of the front margin of the shell; no abdominal processes; post-abdomen broad above, triangular; terminal claws pectinate, furnished with one very large toothed accessory spine and a smaller one; the first foot has a hook; the last foot consists of a large oval plate which bears poste- ma, a > x b' ay — » oe aa ui Reet Sid 220 GEOL. AND NAT. HIST. SURVEY OF MINNESOTA. riorly the ordinary branchial coil, here shaped like a thumb and fore- finger. The young is of a different shape and bears a long spine, The male is known from figures recently published by Birge (91). GENUS ILYOCRYPTUS. Form compact, short; head short, triangular, with large fornices forming a roof over the head; the posterior margin of shell nearly as long as the inferior; lower angle a broad curve; antennules two-jointed, basal joint very short, second joint straight, rather long; setee termi- nal, but one seta near the base; the four-jointed ramus of the antenna with but three (terminal) sete; six pairs of feet, last pair rudimentary; tail large, as in Lyncodaphnia, anus elevated; intestine straight, with- out eeca, but an expansion near the rectum sometimes simulates one; the margin of the shell is bordered with long spines, which may be branched or simply pectinate. There is often, perhaps generally, a failure to entirely remove the moulted shell; when this occurs the newly-formed shell from each moult remains under the older ones till the animal seems to be wearing six or more overcoats, and the spaces so formed become filled with algze and filth till the animal is no longer able toswim. P. E. Mueller and Kurz, who seem to have seen only I. sordidus, agree that Ilyoceryptus cannot swim, but poles along in the mud on the bottom by means of antennee and abdomen; our J. spinifer, on the other hand, swims freely till loaded up with old clothes and filth. ' This genus is also closely allied with the Lynceida. * Llyocryptus sordidus Lievin. PLATES LV, Fias. 6, 10, 11; LVI, Frias. 15-17. Acanthocercus sordidus—Lievin, Leydig. Body higher than long; head small, terminating anteriorly in almost a right angle; posterior part of the shell margins covered with branching, thorny spines; antennules cylindrical; antenne short; four- jointed rami with no lateral sete; post abdomen large, broad; terminal claws with two spines at the base; anus in the middle of the posterior margin, which is very heavily armed with spines; a hairy abdominal process is present, according to Kurz. There are no anterior ceca (my statement that P. E. Mueller de- scribed such ceca was an error; see Notes on Cladoreca of Minnesota, p. 246). Length 0.78 mm. The tabulated comparison beyond makes a full description unnecessary. Birge reports this species from Wis- consin and it has been encountered in Minnesota. es as ENTOMOSTRACA OF MINNESOTA. 221 * Tlyoeryptus spinifer Herrick. PLATEs LV, Fias. 1-4; LVI, Fias. 18-19, 21. Herrick ’82, ’84, and ’87; Turner ’93. The description given in my Final Report, etc., is very brief, and no comparisons were there instituted with the Z. agilis of Kurz, which is its nearest ally in Europe. The paper by Kurz referred to gives de- tailed descriptions of the three European species, accompanied by ele- gant plates. We are able, therefore, to draw up the following dis- tinctive diagnosis of the species, hoping thereby and by means of the figures to show the relations of the four species at present known. It is almost certain that we have more than one species in America, and the careful description of the known form may make the detection of others easier. The size varies greatly; a full grown female with eggs in the brood cavity is nearly 0.90 mm. long and 0.70 high, while a smaller female measures 0.65 mm. long by 0.44 high. The form of the shell is nearest like that of I. acutifrons, the height being less than in J. sordidus, and the angle between the ventral and posterior margins less than in J. agilis. The entire length of the post-abdomen in the large female is 0.56 mm. measured to the base of the caudal stylets, of which length 0.168 mm. pertains to the claws. The width of the post-abdomen is but 0.14 mm. Thus it is evident that the proportions of the post- abdomen differ greatly from any of the other species, it being very long and narrow. The terminal claws are exactly as in J. agilis, hav- ing two small basal spines and a few sharp serrations near the apex, anteriorly. Near the base of the claw is a cluster of small spines of two sizes, then begins a series of about 16 lateral teeth averaging 0.02 mm. in length and extending to the sides of the anus. Above this point the contour of the margin is convex and is ornamented with nine spines twice as long as the preceding. Then follow the promi- nences which bear the long and simple caudal sete. Besides the above mentioned spines there are four spines on either side upon the lower posterior angle of the post-abdomen which are four times as long as those of the previously mentioned continuous series (i. e., 0.08 mm.). Above, the abdomen is hirsute or thorny as in J. agilis, and the process for closing the brood sac is similar. It will be seen that the post-abdomen differs in armature as much as in form from other species. From J. sordidus it differs in the following points: The claws are not pectinate behind but are serrate in front, the anal open- ing is higher and the details of the spines vary; from J. acutifrons it differs in that the claws are not pectinate, neither is there a spine in front of the claws, and the anus is not terminal; from J. agilis it differs in that the shape is different, there are fewer enlarged spines, and the q ik: 222 GEOL. AND NAT. HIST. SURVEY OF MINNESOTA. Shape of the nine spines above the anus is different. The head is con- vex, resembling J. sordidus most nearly, but the antennules are much longer and more slender than in any other known species. They are 0.17 mm. long and about 0.016 mm. wide, while the longest seta is 0.084 mm. long. The antenn are almost exactly as in J. sordidus. The labrum has the usual shape, as have the jaws and other append- ages. The margins of the shell are ornamented with spines simply pectinate or barbed as in J. agilis. In I. sordidus these spines are variously branched, and in that form alone of the European species, according to Kurz, is there a failure to perfect the moult; in our spe- cies, which has simply pectinate sete, the oid coverings are all but uniformly retained. The spines of the Jower posterior margin are from 0.16 mm. to 0.20 mm, long. Such are some of the chief peculiarities of the species, but, to make the relation between the four species of this little known genus even clearer, if possible, the following comparative table is appended. Ve agilis. esol) moulted periodiealliy.s..2ss.25 tv. cbcaecensssase¥essstcasedetene cease I, acutifrons. f { I. sordidus. Mie wnellenotimonulteduputeretammeds sw ccesseseeseencceeceetone teense eee Lit Soihipee I sordidus, Antennules not more than eight times as long as broad............seeeeee I. agilis. I. acutifrons. Antennules more than eight times as long as broad..........sscseeseceeeees I. spinifer. OW; P : { I. sordidus. @laywot post-abdomen: pectinatesc..css-cec: sseret cee ce veseesecoenceaseeeee eae \T., acutifrons. P I, agilis. Claw of post-abdomen not pectinate ..........c0+..sovesssosensccasssesssacosens L. spinifer. ASSLLONS Spine in! front OLiGlawpece.ssstsvacesessecheacetoeeeeedesee este eet eeaeeee I. acutifrons. I. sordidus. Bing: bristles or none in front off Cla w.....2csseses csearsatsscunp teow tccsaserapeceas I. agilis. I. spinifer. ZAATIIIS OPENID CMEAT THEI CLAW Sa. a. cccteacececcadeccee neces cnemee meee ee toeee ete aaae I. acutifrons. I. sordidus. Anus about midway of the posterior border. ....-............ecsceeseceeeseeees I. agilis. I. spinifer. Marginal'spines of shell much branched. «......22s40%.sscaesseewsvauewteacete st I. sordidus. I. agilis. Marginal spines nowhere much branched.............0:ssecssovsecceecanennens I. acutifrons. I. spinifer. Elongated anal spines on either side, tour or five, very long.............. I. spinifer. I. agilis. Elongated analspines more NUMETOUS «....;....sssccasocestesese+cseesvavtdocns {i acutifrons. I. sordidus. Upper (one to three) spines of the supra-anal series modified and { J. acutifrons. CWVAT LOW es Jos se cmsn> ss -osieicde cect sccvseeseeneseaeue dora sce tiacdeeam ine mentomaeacs I. agilis. Upper'spines like the others... :..scve. scronsecvesuiucs te ensea denchbe. theemameastes i peas . Po aes, Pay te iA ~ ENTOMOSTRACA OF MINNESOTA. De The above is extracted verbatim from the Alabama Crustacea, which Professor Birge should have consulted before saying ‘‘none of the specific characters are mentioned or figured”’ (Birge ’91). Professor Birge is inclined to identify our species with I. longiremis Sars, from Australia. But if the Madison specimens have antennary sete nearly equaling the total length of the animal, they differ from all individuals of J. spinifer yet seen. The armature of the post-ab- domen is also different, for there are but four elongated claws at the inferior angle and a series of about 14 anal spines and six longer supra- anal teeth. We infer from Birge’s figure that the antenne are dif- ferent. It would be well that the Madison form should be more eare- fully described and figured and compared with other American species. Length 0.60 mm., height 0.46 mm., base of antenna 0.19 mm., four- jointed ramus 0.13 mm., post-abdomen 0.19 mm., claw 0.125 mm., long post anal spines 0.06 mm., antennule 0.10 mm. Ilyoeryptus acutifrons Sars. BGA Suivi) EG. a. This species is only mentioned in the appendix to the paper of Sars on the Cladocera from the vicinity of Christiania. The following is a condensation of the description. Head large, acute in front. Shell truncate behind, with shorter setee behind than below. Antennules shorter and thicker than in I. sordidus. Antenne long and robust. Abdomen with a short, obtuse process. Post-abdomen shorter than in J. sordidus, posterior margin continuous, anus terminal; caudal claws straight, very long, with two minute basal spines and a cluster of teeth in front. Pigment fleck almost touching the eye. Length less than in J. sordidus, 0.6 mm. In this species the moult is perfect. (See table above. ) *Tlyoeryptus longiremis Sars. PLATE LV, Fia. 5. Sars ’88; Birge ’91. Professor Birge finds this species abundant near Madison. The original description is not now accessible. It appears, however, that the form of the post-abdomen is very similar to J. spinifer, while its armature is quite different. The sets of the antenne are very long, nearly equaling the length of the body. ‘There are five to seven super-anal teeth, largest in the middle, an outer row of about eight long post-anal spines and an inner row of 11 to 12 post-anal denticles, besides several very small teeth near the terminal claw. There are three or four denticles on each side of the anus. The moult is incom- plete as in J. spinifer. SS NE SE A ei Les vy ; 224 GEOL. AND NAT. HIST. SURVEY OF MINNESOTA. FAMILY LYNCEIDE. This family, which is numerically the largest among the Cladocera, is, in the main, well limited, though there are transitions toward the Iyncodaphnide, which are quite direct. The genera Lyncodaphnia, Ofryoxus and Ilyocryptus lead toward the Lynceide unmistakably. Most of the members of this family are small, comparatively few ex- ceeding one millimeter in length. The head is covered with an arched shield, which frequently passes with no indentation into the shell of the body. This head covering generally extends forward and down- ward to form more or less of a sharp angle in front, while in several genera it is simply rounded in front. It, in either case, arches over the more fleshy lower side of the head from which hang the two short antennules and the labrum, while the strong two-branched antennie spring from well up under its posterior expansion. The rounded sides of this shield, which protect the insertion of the antenne, are called the fornices. Above the insertion of antennules is a dark fleck lying near or on the lower angle of the brain; this is the larval or nauplius eye, which is the first to appear in all these small crustacea. This macula nigra is not infrequently as large as the eye itself,* or even larger, and in one genus it is the only visual organ. The antennules are small and bear on the end several sensory filaments as well as a lateral flagellum. The antennules of the male differ very little from those of the female. The labrum is furnished with a process, which is triangular or semicircular and is usually larger than the terminal portion. The mandibles are as in Daphnidw but usually shorter. Maxille are often conspicuous, but the first pair of feet serve, by a slight alteration at the base, the same purpose. There is rarely an indication of the sixth pair of feet, and the antennie have both rami three-jointed. The terminal part of the body, or post-abdomen, is usually enlarged, and the anal opening is near its base; the armature is usually considerable. The form of the post-abdomen is one of the best criteria for distinguishing genera and species—a process often attended with much difficulty. The shell is of various forms, frequently beautifully sculptured. The number of eggs produced at one time is limited, and the winter eggs are very often laid in the brood-cavity with no preparation of the shell previous to it; in other words, the ephippium may be absent. On the other hand, sometimes the shell is considerably modified, and generally there is a deposit of dark pigment in the upper part of the shell. The males are very rare and until recently few were known. The diligence of Kurz has added a great many, and we now have a * The name “ Lynceus ” is derived from that of the son of Aphareus who was famous for the sharp- nameness of his vision. f* be * TY Oe Faer oS we: + ¥ ENTOMOSTRACA OF MINNESOTA. 225 fair idea of the sexual variations. These consist usually in a narrower body and shorter beak, in a strong hook of chitin on the first foot and certain modifications of the post-abdomen. The hook mentioned is simply an enlargement of one of the terminal bristles of the foot, and serves to fasten the animal to the shell of the female. In one Ameri- can species of Plewroxus we find an approach to this structure in the female—an interesting example of inheritance of sexual peculiarities across the sexes. The alterations in the form of the post-abdomen consist in a narrowing or excavation of that organ to permit its intro- duction into the brood-cavity, and in some forms (Chydorus) this change can only be understood by observing the form of the shell of the female about to produce winter eggs. In general, as in other Cladocera, males are found only at the period when the females are sexually perfect. The ordinary method of reproduction is by virgin- bearing or parthenogenesis. In some cases it would seem, from Weis- mann’s observations, that the sexual method occurs only incidentally. The orifice of the male organs is between, or anterior to, the terminal claws of the post-abdomen (Hurycercus alone excepted). The males are usually but not always smaller. Plate LXI gives views of typical Tynceide. Fig. 1 is particularly instructive, for in it the details which can be usually made out in the living object are represented. The following points may be especially noticed. The large size of the pigment fleck, the large antennules (A'), the keel of the labrum (Lb.), the peculiar modification of the first pair of feet to assist the maxillze (not shown) which are exceedingly small, the largely developed anal gland (A. g.), the form and muscular mechanism of the abdomen, which, however, is better illustrated by Fig. 10 of the same plate. Fig. 1 contains an embryo seen from the side with the partially devel- opedlimb. Fig. 3shows the appearance of a different embryo from be- lowand in anearlierstage. Fig. 2 illustratesthe relation of the brain to the eye and the very small optic ganglion. Fig. 9 of Plate LXIII gives details of the feet in another species, and the modifications seen in the male of the same species are sufficiently shown in Fig. 1 of the same plate, which also well illustrates the various sculpture of the shell displayed by this group. Figs. 4 and 9 of Plate LXIV show curious modifications of the post-abdomen of the male, and Fig. 7 ex- hibits the structural peculiarity of sexually perfect females which is correlated with it, or, perhaps, we may say, occasions it. SUB-FAMILY EURYCERCINE. A single species constitutes the sub-family, and it will be necessary to point out only those points which are distinctive. The Hurycercine differ from the true Lynceide and approach the Iyncodaphnide in having the digestive tract not coiled, with two ceca 226 GEOL. AND NAT. HIST. SURVEY OF MINNESOTA. in front and the anus at the end of the post-abdomen. Many eggs are produced at once. The male opening is at the base of the abdomen, as in Sididw. The general habitus is, however, lynceid. The males appear in autumn or when, by the gradual drying up of the water or other causes, the continued existence of the animals is threatened. GENUS EURYCERCUS Baird. Characters of the sub-family. Eurycercus lamellatus O. F. Miiller. PLATES XLVI, Fies. 7, 8; LI, Fie. 6; LX, Fies. 5, 6; LXII, Fie. 19. Lynceus lamellatus — Mueller, Edwards, Koch, Zaddach, Lievin, Leydig, Zenker. Eurycercus laticaudatus — Fischer, Schoedler. A gigantic Lynceid, reaching the dimension of 3.0 mm. The figure of the male given will sufficiently illustrate the general form. The abdomen is broad and armed behind with a dense row of saw teeth. The eye is larger than the rather small pigment fleck, and the intes- tine is bent upon itself but not coiled. The last foot is found in few other Lynceide. Acroperus has the same, and Plewroxus unidens also has a rudimentary sixth foot. SUB-FAMILY LYNCEINE. Intestine coiled; anus near the end of the post-abdomen; opening of vas deferens nearly terminal. There are no anterior ceca but usually a single anal diverticle of the intestine. Rarely or never more than two embryos produced at once. 10 KEY TO THE SUB-FAMILY LYNCEINE. Head or dorsal line keeled or ridged; abdomen long; shell marked with diagonal striz. Cam ptocercus, 227, 228; Acroperus, 227; Alonopsis, 231 Usually no keel above, or, if keeled, the post-abdomen is not long. The majority are highly arched dorsally, and have comparatively short post- abdomen and pointed beak. The antennie are usually feeble and the motion slow. A. Post-abdomen nearly round in outline, armed with very long, stout spines, terminal claw with one minute basal spine or none; greatest height of shell about equal to the posterior margin. . Leydigia, 233 B. Post-abdomen more or less triangular, armed with bristles; greatest height of shell moderately exceeding that of the posterior margin; shell marked with hexagonal meshes. ENTOMOSTRACA OF MINNESOTA. 227 a. Head nearly horizontal, blunt; post-abdomen prominent in the analerepion.. | 20) . . . Graptoleberis, 235 b. Head depressed, acute; poeeandomen excised near the anus, Dunhevidia (= Crepidocercus), 236 €. Post-abdomen more or less quadrangular, armed with one or two rows of small teeth on either side behind; terminal claws with one or two basal spines; height of posterior shell margin usually less than the greatest height of the shell. . . . : . Lynceus, 237 D. Pcst-abdomen terete; greatest height of shell little jess than that of posterior shell margin; terminal claws very minute. : Phrixura, E. Greatest height of shell more than double that of the posterior margin. a. Eye and first foot normal. . . . . . Chydorus, 260 b. First foot with a claw which extends tend shell. Anchistropus, 264 c. Eye absent, only the pigment spot used for vision. . Monospilus, 264 (Not noticed in the key. . Alona, 238; Alonella, 249; Pleuroxus, 253 ) SERIES A.—This section is proposed for the old genera Camptocercus, Acroperus, and Alonopsis, which seem to form a natural group though passing into Alona. GENUS CAMPTOCERCUS (> Camptocercus Baird). This easily recognizable genus contains two groups, each with sev- eral nominal species, which are distinguished mainly by the width of the post-abdomen. In both the shell is elongated, more or less quad- rangular, longitudinally striate, armed behind with one to four minute teeth. ‘The head and back are keeled and the former strongly arched. The antennules rarely extend beyond the beak and are commonly curved laterally. The eye is proportionately small. The post-abdo- men is long and furnished with a lateral row of scales. The terminal claws have a single basal spine and are serrate. There is an ephip- pium, and the male opening is in front of the terminal claws. SUB-GENUS ACROPERUS Baird. Post-abdomen broad, margins parallel; anal teeth very minute, lateral scales large and usurping their place. Antenne with eight setae (39°). Three species are described, one of which is very abund- ant in Minnesota. *Acroperus leucocephalus Koch. PLATES LX], Fie. 5; LXII, Fie. 9 Lynceus leucocephalus—Koch, Fischer. Acroperus harpe—Baird. Acroperus sp.—Herrick. Acroperus striatus—Jurine, M. Edwards, Lievin, Lilljeborg, Leydig, etc., seems to belong here, but I am able to add nothing to the elucidation of the puzzle. Body rounded above, angled behind; head moderately arched and carinated. Lower margin of the shell pectinate, terminating in two 15 228 GEOL, AND NAT. HIST. SURVEY OF MINNESOTA. teeth. The antenne are long and when reflexed the sete reach nearly to the posterior margin of theshell. The posterior angle is not always as prominent as shown in Fig. 5, Plate LXI. * Acroperus angustatus Sars. PLATE LXII, Fie. 10. This species is distinguished from the former by the head, which is higher and very strongly arched. The dorsal contour is nearly straight. The antenne are shorter. The form of the post-abdomen of the male is jess different from that of the female than in the above. The length of both species is about 0.7 mm. The American form figured in Fig. 5 of Plate LXI differs from both the above slightly. The head is carinated and incurved almost as in ©. angustatus; the antenne fall a little short of reaching the pos- terior margin of the too low and oblong shell; there is an obvious de- pression between the head and the body. However, in the main there is close agreement with C. leucocephalus, to which it has been previously referred. There is always a rudiment of an additional pair of feet. A. cavirostris P. E. Mueller, is not known in the female sex. The male has a twisted caudal claw. It is probably founded on an ab- normal individual. Acroperus alonoides Hudendorff. This species is only known to me from incidental references in Matile. The post-abdomen is said to be broader than in either of the above. The claws have only one basal spine. ‘The crest is low and the macula is nearer the end of the beak than the eye. (Acroperus transylvanicus Daday.) ‘Carina capitis rotundata; testa corporis dorsali leniter rotundato; postice angulo indistincto; margine ventrali fere recto angulum inermem formanti, cauda apice rotundata incisa; unguibus caudalibus magnis, fere rectis. Longit 0.85 to 0.9 mm.”’ The figures do not greatly fill out this hopeless description. The form is short and so is the abdomen, but the armature of the latter has nothing distinctive. SUB-GENUS CAMPTOCERCUS Baird. Although the general form is similar to the last section, the body is usually longer; the post-abdomen narrows toward the end; the anal teeth exceed the lateral row; the antennze have usually but seven setze ($44). The species enumerated are so closely related as almost to baffle y definition. ENTOMOSTRACA OF MINNESOTA. 229 KEY TO THE SUB-GENUS CAMPTOCERCUS (VERUS). I. Beak pointed. A. Head depressed. a. Pigment spot larger than theeye.. . . . . . biserratus, 229 b. Pigment spot smallerthantheeye. . . . . . macrurus, 229 B. Head directed forward... . . . .. . . . rectirostris, 230 MpeeLork truncate below... ss... «- (sis) ea sees s. ») latinestris, 230 III. Beak cleft below or with a forward projection. A. Antennules shorter than the beak. . . . . . . Jilljeborgii, 230 B. Antennules longer than the beak. . . . . . . Yrotundus, 230 Camptocercus biserratus Schoedler. PLATE LXII, Fie. 4. Is very nearly related to the next, from which it is distinguished chiefly by the fact that the pigment fleck is larger than the eye. Schoedler overlooked the fact that in C. macrurus there is a lateral line of scales on the abdomen, and relied upon that character to dis- tinguish this form. (Schoedler says that the pigment fleck in C. mac- rurus is smaller than the eye, P. E. Mueller says they are nearly equal, while in our specimens they are much smaller or nearly equal.) If much variability is found, Schoedler’s species seems to rest on a slen- der basis. The basal spine of the claw, however, seems to be peculiar in sitting on a distinct prominence. *Camptocercus macrurus Mueller. PLATE LXI, Fias. 10, 10a. Lynceus macrurus— Lilljeborg, Schoedler, P. E. Mueller, Kurz, Birge, Herrick. This universally distributed species occurs in our larger bodies of water and is not rare, though hardly abundant. The body is long and nearly rectangular; the head strongly arched and keeled. The keel of the head is extended down the whole dorsal line. The dorsal line is moderately curved, while the shell is but slightly excavated below. The head extends into a blunt beak look- ing downward; the direction of the head is somewhat variable (from vertical to an angle of about 30 degrees). The eye is much larger than the pigment fleck; the antennules are shorter than the beak, and have one elongated terminal seta. The post-abdomen is very long and has numerous anal teeth as well as a lateral row of scales. The basal spine of the claws is large and serrate, the claw itself being nearly straight and armed with an increasing series of spines to be- yond the middle. The lateral scales of the post-abdomen are incon- spicuous. The shell gland is long. The antennules reach to almost 230 GEOL. AND NAT. HIST. SURVEY OF MINNESOTA. the end of the beak, are curved and bear a lateral flagellum. The first foot of the female has a sort of hook (branchial sac?). The la- brum is armed with teeth on the posterior face of the triangular pro- cess. The intestine is very strongly, almost twice, coiled. The lower margins of the valves are feebly spined for three-fourths their length, and armed with from one to four teeth at the angle. Length 0.8 mm- to 1.0 mm. Camptocerecus rectirostris Schoedler. PLATE LXII, Fies. 1-3. Distinguished from the above, which it closely resembles, by the form of the head, which is less rounded and directed anteriorly. It hardly exceeds half the height of the body, The beak is sharp. I am not sure that Weismann’s figures (1. ¢., Plate XI, Figs. 13 and 14) really belong to this species, for the drawing of the post-abdomen does not agree with that of P. E. Mueller fully. Outline copies of the former are given in Plate LXII, Figs. 1 and 2. The male has a hook upon the first foot. Not yet recognized in America. Camptocercus latirostris Kurz. PLATE LXII, Fias. 5-6. C. lilljeborgii, P. E. Mueller (?). Closely allied to the next, but distinguished by the position of the head, which is a little less depressed, and, especially, by the truncate beak. The dorsal margin is convex and crested; the lower outline is also convex. The claws are toothed more as in C. macrurus than the following. The basal spine springs from the claw itself and not from the post-abdomen as in the next. Length 0.9 mm. to 1.0 mm. Camptocercus lilljeborgii Schoedler. PLATE LXII, Fias. 7-8. Head depressed, rounded in front; beak divided at the end by the- extension of the fornices. The terminal claws are pectinate for their entire length, and the basal spine is seated on the end of the post- abdomen. This species, in the main, closely resembles C. macrurus, * Camptocercus rotundus Herrick. The second of the two species found in America is this short, strongly carinated form, which is known from a single gathering. It differs from all the above species, with which it agrees pretty well in shape, by its more compact form; high dorsal keel (which extends the entire length of the body); the long antennules, which extend far below the beak; and the somewhat pointed beak. The head is much as in ENTOMOSTRACA OF MINNESOTA. 231 the last, but it is not certain that the beak is cleft, although it has a peculiar form (not indicated in the figure) near the end. The length is 0.7 mm. The terminal sete of the antennules are very unequal; but in most points, as in the armature of the post-abdomen, the details resemble C. macrurus. [This is probably but a variety. | GENUS ALONOPSIS Sars. This curious genus includes three species of small Lynceids which exhibit a combination of characters. The form of the beak and head is like that of Plewrorus, which the form and sculpture of the shell otherwise resembles. The back is extended more or less in a knife- like ridge above, thus resembling Acroperus, a resemblance heightened by the excavated lower margin. The form of the post-abdomen approaches that of Acroperus, but in that genus it is of about equal width throughout and in this it rapidly narrows. The internal organs and feet are of the typical lynceid form, while the antenne are as in Pleuroxus. The type of the genus, 4. elongata, is apparently much closer to Acroperus than the two species which have been identified in America, Shell sub rectangular, high, produced into a ridge above; lower margin convex anteriorly, concave behind; beak rather long; anten- nules slender; antenne with eight sete; abdomen long, narrowed toward end, incised at the extremity; claw rather large, with median Spines and a basal thorn; third foot with a long bristle. Male smaller, without the carina above; orifice of sexual organs in front of the claw, which is removed from the anterior margin. The young are more elongate and (sometimes) have hexagonal reticulations instead of the usual strong diagonal striz. Motion slow. Alonopsis elongata Sars. Lynceus macrurus—Lievin, Zenker, Leydig. Alono elongata—Sars. Acroperus intermedius—Schoedler. The shell is wide, the upper margin forming an even curve, mani- festly angled behind; ventral margin nearly straight, ciliated through- out, with a single tooth behind. Fornices large; head narrow, not carinate. Post-abdomen compressed, truncate at the end, armed with a Series of marginal spines and of lateral scales; caudal claws large, with a single spine at the base and two median spines followed by a Series of minute setze. This form I have never seen, and it seems somewhat doubtful that the following really belongs with it. 232 GEOL. AND NAT. HIST. SURVEY OF MINNESOTA. * Alonopsis latissima Kurz. PrArEs TX Fics 8 Texts abies sland! +9; Body very high, compressed, with a high dorsal keel or ridge; the upper outline strongly and evenly arched, terminating behind in no angle; lower margin almost angled at the anterior third, rounded be- hind, fringed with long bristles anteriorly, with short ones posteriorly. Head very narrow; beak extremely long; fornices small; antennules nearly as long as the beak, straight and narrow; pigment fleck smaller than the eye. The abdomen is long, somewhat narrowed toward the end, where it is deeply cleft; the terminal claw is furnished with a large and small basal spine, while there is an increasing series of spines extending to the middle. The elongated spine of the third foot is pectinate and reaches nearly to the posterior margin of the shell. The shell is marked by a few strong striz which are diagonal except anteriorly where area few parallel to the front margin. The male is small and lacks the crest on the back, while the lower margin is straight; the antenne are longer than the beak and differ somewhat from those of the female. The first foot has a claw. The post-abdomen lacks the anal teeth. Kurz gives the size as 0.5 mm. The American form varies between 0.45 mm. and 0.55 mm., and seems to have a higher dorsal keel and longer beak. Kurz speaks of but a single accessory spine on the terminal claws; there is, however, a second very minute spine or cluster of hairs in this as well as the following. Found in the same gathering with the following near Minneapolis (marshy off-set from Bassett’s creek near Oak Lake Addition) :* * Alonopsis latissima var. media Birge. PLATE LXI, Fie. 9. I give Birge’s description verbatim. ‘‘Rostrum prolonged, and shell sharp, somewhat quadrangular in shape, marked by strie. The dorsal margin is convex, the hinder margin nearly straight. Its lower angle is rounded and without teeth. The lower margin is concave and has long plumose set. The front margin is strongly convex. The post-abdomen is long and slender, resembling that of Capmtocereus, and is notched at the distal extrem- ity; it has two rows of fine teeth and some fine scales above them. The terminal claws are long, slender, with a basal spine, a spine in Note to Atonopsis Lavissima. (See Fig. 1, Plate LXILL.) Since writing the above the males of our American form have been found; they are shaped as the females, with a high dorsal keel; the post- abdomen is rounded, with transverse series of small bristles; the claw has a minute median spine, and the porus genitalis is anterior and elevated. De so oo aig ib a ea T ENTOMOSTRACA OF MINNESOTA. 233 the middle, and are serrated. The antennules are long and slender, but do not reach to the end of the rostrum. They have each a flagel- lum and sense hairs. The antenne are small and have eight (3¢¢ setze and two (4%°) spines. The labrum resembles that of A. leuco- cephalus, but is slightly prolonged at the apex. The intestine, cecum and color resemble those of Acroperus. There is a trace of a keel pres- ent on the back.’’ The specimens seen in Minnesota resemble this species very nearly, apparently, but there are some differences. The terminal claw of the post-abdomen has an increasing series of spines to the middle; there seems to be no lateral row of scales beside the anal teeth; the abdo- men is rather broad at the base and narrows toward the end. The shell is not square behind. The lower margin has a few long hairs anteriorly which are followed by a series of teeth, and in the concave part a somewhat longer set to a point just before the lower curved angle. The pigment fleck is nearly or quite as large as the eye. The an- tennule is shorter than the beak (which is almost as in Pleuroxus hastatus), and has a flagellum about midway; at its base it. is narrowed and inserted on a prominence. The embryo still in the brood-sae has a more elongate form and hexagonal reticulations upon the shell, while the antennules were longer than the very long beak, and the pigment fleck was smaller than the eye. Length of female 0.52 mm. The color is darker, and the striz more numerous, than in A. latissima. From a private letter we learn that this form is now regarded as simply a variety. SERIES B.—This section includes Leydigia, Graptoleberis, Dunhevidia (—Crepidocer- cus), Lynceus, Alona, Alonella, Pleuroxus, Phrixura, Chydorus, Anchistropus, Monospilus. GENUS LEYDIGIA Karz. In this genus, both the known species of which are found in America, the posterior part of the shell and body is emphasized at the expense of the anterior. The curved posterior margin is equal to the greatest height of the shell. The head and anterior part of the body are of the form characteristic of Alona; indeed, the whole body is in plan like Alona, but in the back part the organs are all enlarged. The general form of the body and abdomen recalls J/yocryptus; the post abdomen, in particular, is very like that genus. The last two pairs of feet are much enlarged. ‘The shell is usually irregularly marked with longitudinal strie; the lower margin is covered with long spine-like sete. The post-abdomenis armed with several sets of 234 GEOL. AND NAT. HIST. SURVEY OF MINNESOTA. long spines and aggregations of bristles and small spines; it is almost. round and enormously enlarged. The intestine is coiled and expanded at the end but the anal cecum is rudimentary. The antenne are heavily spined and have eight sete; the labrum is more or less hairy. The male has a strong hook on the first foot, and between the terminal claws of the abdomen is a peculiar intromittent organ. * Leydigia quadrangularis Leydig. PLATES LIX, Fic. 6; LX, Fia. 4. Lynceus quadrangularis—Leydig, Fric. Alona leydigii—Schoedler, P. E. Mueller. The shell is comparable to that of Alona quadrangularis, but higher behind; the markings are not very distinct; shell transparent. The head is very small; the eye smaller than or of about the size of the pigment fleck. The post-abdomen is very broad, the posterior margin nearly the segment of a circle, armed with numerous very long unequal spines which extend only about half the height, being replaced by short close hairs; the anal opening is very high; the terminal claws are long, straightish, and have a small thorn near the base. The males are smaller than the females, and the abdomen is less. broad; the antennules are longer than the beak and furnished with a flagellum. The sexual period occurs in September or irregularly. This species has only been encountered once, during September, in Poplar river, Cullman county, Alabama. *Leydigia acanthocercoides Fischer. Lynceus acanthocercoides—Fischer, Leydig. Eurycercus acanthocercoides—Schoedler. Alona acanthocercoides—P. E. Mueller. Herrick. Leydigia quadrangularis This species, reported in a previous paper, is, aS was said, nearest like L. acanthocercoides; and I am now able to verify the very incon- spicuous differences upon which the two are separated. Our specimens of the L. quadrangularis have the pigment fleck fully as large as the eye, Kurz to the contrary notwithstanding, and the spine of the claw of the post-abdomen is present, while in the present species the pig- ment fleck is much larger and furnished with lenses; the spine of the claw is wanting; the labrum is densely hairy; the abdomen is narrower, and the shell higher. The shell is very obviously striped in the pos- erior portion. The anus is higher thanin the previous species. In ther respects the two seem alike. ENTOMOSTRACA OF MINNESOTA. 235 [Alona balatonica Daday. | This is apparently simply L. acanthocercoides with unusually sharply marked shell. ‘The figures are very poor. Leydigia australis Sars. PLATE LXVI, Fig. 7. Very similar to L. acanthocercoides. Head comparatively erect, rostral projection not much curved. Body quadrangular, expanded behind and obliquely truncate. Macula nigra at least three times as large as the eye. Antennules reaching nearly to the end of the beak. Abdomen very large, lamellar. Spines about 20, increasing distad. Length 0.84 mm. The points most relied on to distinguish the species are the large size of the macula and the absence of teeth from the claws. A very full description with numerous figures is given by Sars. GENUS GRAPTOLEBERIS Sars. A genus having affinities with Alonella. The shell is entirely re- ticulated, and there is a sort of crest along the back; while, on the other hand, the head is flattened and rounded in front. There can hardly be said to be a beak. Seen from above, the animal resembles some species of Alonella, but the head is larger proportionally and more horizontal. The lower posterior angle is spined. The an- tenne have seven sete and are very long, in this respect resembling Camptocercus. The dorsal contour is not greatly arched. The post- abdomen has short claws and anal bristles, but no teeth. * Graptoleberis testudinaria Fischer. PLATE LXV, Fias. 8, 11, 12. Lynceus testudinarius—Leydig, Lilljeborg. Lynceus reticulatus—Fric. Alona testudinaria—Schoedler. Graptoleberis inermis—Birge. Form trapezoidal; lower margin straight, armed behind with two teeth, thickly beset with long hairs in front; the dorsal margin is not greatly elevated, rounded at the posterior angle, forming a slight “hump” where it unites with the head shield. The head and shell are reticulated with hexagonal or quadrangular markings. The shell gapes below and rises to a sharp ridge above. The antenne have long rami, the antennules being hardly longer than the fornices. The eye is large; the pigment fleck is small. The post-abdomen is narrowed 236 GEOL. AND NAT. HIST. SURVEY OF MINNESOTA. toward the end, rounded in front; the terminal claws are small and have two basal teeth. The dorsal margin of the post-abdomen is coy- ered with tufts of hairs. The winter eggs have noephippium. Length 0.55 mm. to 0.7 mm. The male is smaller and has a lower dorsal keel; the post-abdomen is excavated behind. The only differences between the Minnesota specimens and the typi- cal European form seemed to be the absence of the very minute spines on the front of the terminal claws. The eye and pigment fleck are of about the proportions figured by Kurz. Birge’s figure of the post- abdomen does not agree with his description fully. Our Minnesota specimens have an obvious but not high keel. * Graptoleberis reticulata Baird. Alona reticulata—Baird, P. E. Mueller. Lynceus reticulatus—Liljeborg, Leydig. Alona esucirostris—Schoed ler. Shell almost rectangular, reticulate, ventral margin straight, ciliate anteriorly, with two teeth behind. Pigment fleck smaller than the eye. Post-abdomen short, narrowed towards the end, dorsally cov- ered with clusters of spines; caudal claws with a minute tooth at the base. Length 0.4 mm. to 0.5 mm. The pigment fleck is nearer the end of the beak than the eye, and is smaller than in the previous species, but, on the whole, there is, perhaps, too great similarity. Professor Birge writes that he unites the two species. GENUS DUNHEVEDIA King. Crepidocercus — Birge. The characters of this group place it rather near Alonella or between that and Pleuroxus. Form sub-quadrate with rounded angles; dorsal line uniformly arched, terminating in a sharp angle behind; lower margin convex, armed behind with a single spine as in Pleuroxus unidens, and along the entire length with loose sete. Beak of moder- ate length, acute. Post-abdomen deeply incised in the anal region; lower posterior margin straight,rounded at the apex; ventral margin straight or concave; claws with a single basal spine and a few teeth. The post abdomen is shoe shaped and armed with transverse rows of sete. The antenne are large, having eight setze and the usual spines. Shell smooth or reticulate. Founded by King to include two species from Australia, D. crassa and D. sodagra, ENTOMOSTRACA OF MINNESOTA. 237 *Dunhevedia setiger Birge. PLATE DXIV, Fie. 3: Length 0.4 mm. to 0.5 mm. Minnesota specimens measured 0.5 mm. This species is but rarely encountered, and is so peculiar as to be easily recognized when seen. Alona intermedia has a post-abdomen with clusters of bristles, but in Dunhevidia the post-abdomen is more as in species of Graptoleberis than any other genus. The markings upon the shell are very indistinct. Birge says that the male is simi- lar in form to the female. The first foot has a stout hook. Theclaws are smooth in both sexes. This species has been found by Daday in Hungary. GENUS LYNCEUS O. F. Miller. The perplexing inter-relations between the three genera Alona, Alonella and Pleuroxus give rise to the utmost confusion. No two authors are agreed as to their respective limits, and the points given by Kurz, who has carefully gone over the ground, are obviously in- sufficient. Although there may be practical benefits to be derived from the continuance of the nomenclature in use for groups which in the general view can be distinguished, the value from a theoretical standpoint is reduced to a minimum. The genus Camptocercus (including here Acroperus, which differs solely in the form of the abdomen, as a sub-genus) passes through Alonopsis into the group represented by Alona. Leydigia, although very near such forms as Alona quadrangularis, may be conveniently distinguished as a transition to species like L/yoeryptus. Phrixura, Graptoleberis and Dunhevidia, each containing few species which can be readily recognized, fill a place in the system; but it is practically impossible to distinguish Alona from Plewroxus without in- Stituting the very indefinite genus Alonella to contain a variety of small intermediate forms. Percantha, Rhypophilus, Harporhynchus and Pleuroxus seem to be pretty generally regarded as constituting a single group which may be recognized by the long rostrum, high shell and greater development of the antenna bristles. Alona, on the other hand, with its broader fornices, shorter beak, fairly developed an- tenn, and more rectangular shell, is, perhaps, the pivotal point of the group. According to this view, then, the old name Lynceus is re- vived for the aggregate; and the other names are retained, in part, as titles of largely conventional groups or sub genera, thus: 238 GEOL. AND NAT. HIST. SURVEY OF MINNESOTA. GENUS LYNCEUS. Sus-Genus ALONA—Section A, Alona vera. Section B, Alonelia. Sus GENus PLEUROXUS—Section A, Pieuroxus verus. Section B, Leptorhynchus.* Characters of Percantha and Rhypophilus are combined in the species P. procurvus, Birge, so that one must be dropped or new diagnoses formulated. JI am not sure that the same species is not at first Pleu- roxus verus’ and only later assumes the form known as Rhypophilus. So with Percantha the amount of serrature of the posterior margin is in part a question of age. SUB-GENUS ALONA. This group contains two sections which resemble each other in form and, in general, in detail; but it is exceedingly difficult to formulate a diagnosis that shall strictly limit it. The form is generally sub- quadrangular with rounded corners; the terminal claw is armed with but a single spine at the base; the beak is rather short; and the pre- vailing marking consists of longitudinal lines. Section A, Alona (vera) Baird. This genus contains a large number of minute animals which are widely distributed. The authors who have done the most to elucidate this genus are Schoedler, P. E. Mueller and Kurz. Birge has contributed most largely, thus far, to the knowledge of American species, which are, for the most part, identical or very close to the European. No other genus is so difficult among the Lynceide, for the most minute differ- ences are relied upon to distinguish species. The species of this genus are not greatly altered by the production of the winter eggs. The males are frequently but little smaller than the opposite sex, and are recognized by the altered form of the post-abdomen and the presence of a hook on the first foot. The form is more perfectly rectangular than in the next section; the shell is only exceptionally reticulated and very rarely tuberculate, occasionally smooth. The lower angle of the shell is not armed with spines, but is generally rounded. There is only one basal spine upon the claw of the post-abdomen, which usually bears a row of scales beside the anal spines. The antennze have eight sete. The claw of the male post-abdomen is removed from the lower angle. Many species are known, all of which that seemed recognizably de- fined have been included in the following key, which is believed to 1 Instead of Harporhynchus, a name preoccupied in zoology. 2 Embryos of P. procurvus have the part which is to be curved forward attenuated before leaving the brood cavity, however. ENTOMOSTRACA OF MINNESOTA. 239 more nearly represent our present knowledge of the genus than that of the previous edition. Unfortunately the key must be based on the statements of other authors, and in this genus it is rare to find com- plete agreement between the published descriptions. The best thing a student can do is to disregard much of the synonomy and make an exhaustive study of a species from a large number of individuals in one locality and then cautiously extend the range of work to include adjacent stations. KEY TO THE GENUS ALONA. I. Macula cerebri much larger than the eye... Sanguinea, 239; moniezi, 240 fil. Macula cerebri about as large as the eye. quadrangularis, 240; (affinis, 240 oblonga, 240;) lepida, 242. . . . . (See also intermedia, 244) III. Macula cerebri smaller than the eye. A. Post-abdomen narrowed toward the end, at least not broadly rounded. a, A single series of anal spines. * Striee oblique to the axisoftheshell.. . . . lacustris, 242 ** Strize parallel to the axis of the shell. + Abdomen very long, with long anal spines. (One form of ) tenuicaudis, 242 tt Abdomen not very long. . . ; . « guttata, 243 b. A lateral as well as an anal series of sett Pdcmnial spines, setze or scales. * Post-abdomen long and slender. (Usual form of ) tenuicaudis, 242 ** Post-abdomen of ordinary form. + Anal spines two. Row of sete in addition. . dentata, 244 tt Anal spines represented by transverse clusters of bristles. intermedia, 244 ttt Anal spines large, nearly equal... . . . . pulehra, 245 tttt Lower anal spines larger. . . . . . . . porrecta, 246 B. Post-abdomen broadly rounded below. a. Anal spinesinasingle series. . . . . . . . Stagnalis, 246 b. A double series of anal spines. * Striee of shell close, fine and oblique. . . . . elegans, 247 ** Strie of shell distant. { Strie oblique. . . . . . angulata, 247 {tStrize parallel to the lonpitudinalla: axis of the shell. coronata, 247 (Not noticed inthe key. . . . . . . . costata, 245; barroisi, 248) * Alona sanguinea P. E. Mueller. PLATE LXIJI, Fia. 20: Body nearly rectangular; ventral margin nearly straight, with short setve; posterior angle rounded, unarmed. Beak short; pigment fleck much larger than the eye. Post-abdomen large, the end truncate, broadened; posterior margin rounded, with a series of spines and a 4 r he aa. s = a < > SES in \ . yrs 240 GEOL. AND NAT. HIST. SURVEY OF MINNESOTA. lateral row of scales; terminal claw with a small spine. The shell is ornamented with fine, close, longitudinal striations. Length 0.9 mm. Alona elegans is very near to this and should have followed. In August, 1878, I took an Alona marked as in A. sanguinea and agreeing with Mueller’s description in all points which can be verified in the draw- ing. The small size of the eye is remarkable for so large an animal. I have never again seen this species; it seems to be very rare here and in Europe. Alona moniezi Richard. Richard ’88. ‘Testa antice quam postice latior, striis multis, interdum areis ornata, supine sat arcuata, postice fere truncata, angulo inferiore rotundato, inferne subrecta, ciliis longis, hic obsita. Antenne 1mi paris apicem rostri fere attingentes. Articulus ultimus utriusque rami antennarum 2 di paris, setis 5 longis et aculeo forti pieditus. Rami exterioris articulus penultimus longa seta instructus. Macula nigra oculo major, inter hune et apicem rostri in medio sita. Post-abdomen breve latitudine fere eequali, ad angulum posteriorem et inferiorem rotundatum, seriebus (8-9) aculeorum (4-5 quorum exterior multo major) fusiformium, preterea aculeis minutis «qualibus fasciculatim usque ad processum obtusum positis, armatum. Adest denique series lateralis squamarum spinis gracilibus ac longis compositarum. Ungues terminales sat longi, usque ad apicem ciliis minutissimis obsiti, dente basli gracile, et sat magna. Setze abdominales longee. Mas femina majore paulo dicrepans. Postabdomen brevius, latum, spinis unguibusque terminalibus multo brevioribus quam infemina, ornatum. Pedes 1 mi paris in hamulo valido curvato ad basin crasso, apicem versus acuto ex- euntes. Longit. fem., 0.5-0.55 mm.; mas., 0.45-05 mm.”’ Found near Vichy. * Alona quadrangularis Miller. PLATE LXI, Fias. 1, 2. Alona oblonga—P. E. Mueller. Alona affinis—Leydig. Alona suleata—Schoedler, Hudendorff. The group of forms included under the above names is in inex- tricable confusion. Hellich evidently describes the same species as quadrangularis and affinis. A ffinis falls little short of one millimeter in length while quadrangularis is less than 0.75 mm. A. oblonga is said by Kurz to measure 0.8 to 0.9mm. He, however, did not know A. afinis. Hellich says that there is a secondary marking of the shell in 4. affinis. The claws are smooth in quadrangularis and ciliate or toothed in affinis. Statements of various authors differ respecting the relative size of eye and pigment fleck. The American form, which most closely approaches «affinis, has the claws denticulate and the pigment fleck smaller than the eye. In the figure (Plate LXIV, Fig. 14) the head is somewhat protruded by bei: ENTOMOSTRACA OF MINNESOTA. 241 pressure, but there is nevertheless greater proportional length than in ordinary specimens of A. quadrangularis, and we may have to do with a new species. Accordingly we quote our original description. ‘‘Rorm sub-quadrangular; height about once and one-half in length; the dorsal outline forming a regular and low curve from end of head to upper posterior margin; lower outline very slightly sinuate, ante- rior one not at all; posterior angles rounded; head nearly horizontal; eye of moderate size; pigment fleck considerably smaller; antennules rather large, with unequal sensory hairs at the end, one spine just above the end in front and a bunch of minute hairs near the base behind; antenne comparatively large, basal joint spiny, outer ramus with three sete, two of which have thorns at their middle, also a termi- nal spine; inner branch with two of the terminal sete thorned and the upper lateral setee reduced. The post-abdomen is very broad and short, expanded below and rounded at the end; the terminal claws are straightish, denticulate, and the spine at the base is also dentate; there is a series of heavy spines on the upper margin of the post-ab- domen, accompanied by a series of scales on the side. The shell is unornamented and fringed below with short bristles. Length 0.9 mm., or more. This fine species is recognized by its smooth shell, the hori- zontal position of the head, and the form of the post-abdomen; it be- longs among the largest of the genus. Lakes near Minneapolis not rare. ‘*Birge quotes A. spinifera from Wisconsin. In all probability that species is the younger stage of the above.”’ The American form, which we identified with Alona oblonga, was said to differ from A. quadrangularis in the following points: “The greatest height of the shell is anterior to the middle; the lines are less evident, and all confined to the lower part of the shell, while the centre of the valves is marked with very minute strie; the pigment fleck equals the eye, and the post-abdomen is of about the same width throughout and hardly as round below. This and the preceding species have a well-marked keel on the process of the labrum, The size is greater, this being one of the largest and most abundant, as well as one of the most striking species. It, perhaps, should rank as a well-marked and permanent variety of the above. Length 0.9 to 1.0mm. The abdomen of the male is narrowed at the end and lacks the teeth. Lakes about Minneapolis. ‘CA small form of 4. quadrangularis in Lake Calhoun had the eye and pigment fleck equal and the terminal claw smooth. )’’ We are satisfied that a wide range of variation must be allowed for. The presence or absence of markings is unreliable. 242 GEOL. AND NAT. HIST. SURVEY OF MINNESOTA. * Alona lepida Birge. General shape of the genus. Head depressed, rostrum sub-acute, nearly reaching the level of the ventral margin of the shell. Valves quadrangular, dorsal margin arched, caudo-dorsal angle obtuse, well marked. Caudal margin oblique, bearing a row of spinules. Caudo- ventral angle rounded, very slightly emarginate. Ventral margin with plumose sete. Valves marked by closely-set, conspicuous, longitudinal strice, alternately stronger and weaker, occasionally anas- tomosing, parallel to the dorsal and ventral margins and converging to a reticulated area at the cephalo-ventral portion of the valves. The antennules extend nearly to the end of the beak, are small, spin- dle-shaped. Antennary setze 32°. The terminal sete are of unequal length. All are plumose and without spines. The eighth seta is of moderate length, bi-articulate and plumose. Spines of antennze 4}. Eye moderate. Macula about as large as eye, angular, and somewhat nearer to eye than to apex of rostrum. Post-abdomen enlarged pos- teriorly, lower angle rounded, bearing 15 to 17 serrate post-anal den- ticles and about the same number of squame. ‘Terminal claws smooth. Basal spine rather large. Abdominal sete of ordinary length. Length0.8 mm.; male 0.6 mm. Obviously this species is near to A. elegans. Alona lacustris Daday. Daday ’88. “‘Rostro brevi; macula cerebrali oculo minore; Jabro processu mediali glabro; testa corporis striis longitudinalis dense vestita, linea dorsali parum arcuata, margine ventrali subrecto, setas postice breviores gerenti, postice angulum obtusum inermem formanti; cauda brevi, apicem versus rotundatum attenuata serie fere marginali aculeorum sensim minorum armata, unguibus caudalibus unidentatis. Longit. fem., 0.4-0.5 mm.; altit. 0.35-0.4 mm.’’ It is questionable whether this form is sufficiently differentiated from A. parvula; it is also very like A. guttata=A. intermedia. Alona tenuicaudis Sars. PLATE LXII, Fie. 11. Alono camptocercoides—Schoedler. Form nearly rectangular; ventral margin rounded, with long sete, posterior angle rounded. Beak short, pigment fleck smaller than the eye. Post-abdomen with sides parallel, long, incised below; lower angle armed with about six strong teeth, remainder of the series small; a lateral line of scales present; claws with a strong basal spine. The shell is striate with longitudinal lines. Length 0.5 mm. One of the most easily recognized species; not identified in America. dl « b ENTOMOSTRACA OF MINNESOTA. 243 It would appear that the lateral line of scales upon the post-abdo- men may be absent. There is often, if not always, a cluster of fine spinules above the spine on the otherwise smooth claw of the post- abdomen. Alona guttata Sars. Norman and Brady ’67 (Lynceus guttatus); Kurz ’74 (parvula and tuberculata); Hellich ’77 (anglica, and guttata); Matile ’90. A small species of sub-quadrangular form. The beak is very short; the eye small, but larger than the minute pigment fleck. The shell is short, with a rounded posterior angle and marked by hexag- onal or rectangular meshes running about parallel with the lower margin. The post-abdomen is of moderate size, rounded at the apex, with a series of stout teeth behind; the terminal claw has a minute basal spine. P. E. Mueller, in Danmark’s Cladocera, confused this with A. intermedia, which he described under this. The post-abdo- men in that species is larger, less rounded behind, and armed with clusters of spines instead of teeth. The length is about 0.3 mm. in both. In males the hook is small and the anal spines are absent. *** Alona parvula Kurz is said to have the body sub quadrangular, arched above; ventral margin straight, rounded behind. Shell marked by longitudinal, feeble and irregular lines. The post-abdomen is nar- rower toward the end, with eight or more teeth; the row of scales is absent; at the end it is sharply truncate and incised; the claws have short basal spines. Hardly to be distinguished from the next. ** Alona parvula var. tuberculata Karz (Alona tuberculata Kurz) de- seribed by Kurz in 1874, and more at length by Lutz under a different name (Alona verrucosa) in 1878, appears to be simply a tuberculate variety of the above. Observations upon the American representa- tives of the two forms indicate a close relationship between them. The shell is covered with rows of tubercles (or depressions?) which vary in number greatly. ‘‘T do not know how to distinguish *Alona glacialis Birge (Plate LXIII, Figs. 2,3 and 8) certainly from A. parvula. It, however, seems to have the lower angle of the post-abdomen less squarely truncate and the incision less obvious. Birge says that the abdomen is rounded. I have found specimens which apparently belong here, with the post- abdomen rather sharply angled and deeply incised; there were about fourteen teeth with a row of hairs in front. The form is hardly to be distinguished from another variety which has a shorter post-abdomen, rounded below, and with only about seven or eight teeth and with a smooth shell. This form passes directly into a tuberculate variety, having the post-abdomen similar but the shell covered with numerous 16 244 GEOL. AND NAT. HIST. SURVEY OF MINNESOTA. rows of tubercles. Sometimes a transition from a lined shell to a tuberculate shell is seen (asin Plate LXII, Fig. 14). Alona tuberculata Kurz is said to have a truncate and incised post-abdomen with no lateral row of hairs. Birge thinks these identical; if so, our form re- ferred to A. glacialis is identical with A. parvula. There is also a form found with the above in which no markings are visible and the shell is considerably arched; these were, however, nearly all ephippia females or approaching that period. ** Alona glacialis (2) var. tuberculata Herrick (Plate LXIII, Figs. 4-7 and 14) will, then, be our tuberculated a/ona with a lateral row of scales and a series of fine spines along the anus. Alona glacialis (2) var. levis Herrick is the smooth form with higher dorsal margin. ‘‘The antennz of the two last have spines at the end of the rami of the antennze, a circlet of spines on the outside of the second joint of the setose ramus, and a spine on the basal joint of the other ramus; two of the sete at the end of the setose ramus have spines at the angles. The males found among the above small forms have the same characters as var. /evis and the abdomen is rounded at the end; the claw is situated in the middle of the lower margin, in front being the opening of the porus genitalis and behind a cluster of hairs; the spines are absent, but there is a lateral row of long bristles. A strong hook is found on the first foot. Length 0.3 mm.” To the above, which expressed my opinion in 1884, I can only add that | am more than ever convinced that all should be united (probably with A. guttata). Alona dentata P. E. Mueller. PLATE LXII, Fias. 12, 13. Form sub-rectangular, somewhat arched above, obscurely longi- tudinally striated; lower angle obtuse, margined below with short setce. Post-abdomen small, slender, armed with a lateral line of scales and two strong teeth at the lower angle; claw with a minute basal spine. The form of the post-abdomen is identical with Harporhynchus falcatus Sars, which this species also resembles in having the pigment fleck larger than the eye, and in general form and the character of the striation. The beak, however, is very short. In size P. E. Mueller Says it is among the smallest of the genus. Alona intermedia Sars. ~ Prats LXII, Fic. 15. Alona guttata—P. E. Mueller. Form sub-rectangular, rounded below; beak short; shell marked by longitudinal lines, which may be broken into indistinct rectangular ENTOMOSTRACA OF MINNESOTA. 245 meshes. Post-abdomen short and wide, rounded at the end, orna- mented by seven or eight clusters of minute spines behind as well as a lateral row of scales. Length 0.43 mm. Hellich says the pigment fleck is larger than the eye and is farther from the end of the beak than from the eye. Alona pulchra Hellich. Sars ’61 (rectangula and lineata); Hellich ’74 and ’77 (lineata); Matile ’90. We are influenced by Matile in not recognizing A. lineata Fischer and substituting Hellich’s name. Alona lineata of Kurz is said by Matile to be A. costata Sars. Body small, elongate oval, truncate behind and of a pale color. Greatest height near the middle. The upper margin is rounded, the lower one somewhat sinuate, with sete of moderate length. The beak is short, reaching nearly to the level of the lower margin of the shell; the pigment fleck is one half the size of the eye, to which it is much nearer than to the end of the beak. Post-abdomen short, broad and tapering toward the end, truncate, armed with seven to eight large teeth; short caudal claws with a small basal tooth. Shell marked with distinct lines running horizontally. The ephippial females are recognized by a deep color and the greater elevation of the back Length 3.8 to 4.00 mm. I am unable to satisfactorily differentiate the species of this group. * Alona costata Sars. PLATE LX, Fie. 3. Alona lineata—Schoedler, Kurz, P. E. Mueller. Alona modesta—Herrick. We need not attempt to unravel the perplexing synonomy. As thus defined the species seems to be common in Europe and America. Shell quadrangular, widest behind the middle. Beak of moderate length. Pigment fleck smaller than the eye and midway between eye and beak. Antenne with only seven setze. Labrum small. ‘The shell is strongly and coarsely striped parallel to the shell margins. Lower margin straight or concave, armed with rigid sete. Ccecum long. Post-abdomen rather short, acute and excavated at the distal end. Anal spines nine or ten, equal, with a secondary series of scales. Claws smooth, except for a basal spine. Length 0.55 to 0.65 mm. The claw of the male lacks the basal spine. The Minnesota representative of this widely distributed species differs in some respects. The lower margin is nearly straight and 246 GEOL. AND NAT. HIST. SURVEY OF MINNESOTA. rather sparsely hairy; the beak is blunt, but, on account of the spread- ing of the extremely wide fornices, does not appear so except under pressure. The beak reaches nearly to the lower shell margin. The antennules are narrow, one or more of the setw being elongated. The dorsal margin is either nearly straight or strongly arched behind; in either case the greatest height of the shell is back of the middle. The pig- ment fleck is large. The post-abdomen is just as in A. costata, but the lateral row seems to be of spines rather than fringed scales. The shell is marked by rather evident or indistinct lines. The form agrees pretty well with Schoedler’s figure, except that the posterior shell margin is much higher. The antenne have eight sete, but the last one is very weak. ‘The terminal sets seem sometimes to be spined, as figured by Schoedler, but in some specimens they are perfectly smooth. There is a circlet of spines on the second joint of the setose ramus. There is a hair on the inner aspect of the protuberance of the labrum. The eye is somewhat nearer the pigment fleck than is the end of the beak. There seems to be no occasion for separating the American form (Plate LX, Fig. 3), in which the length varies between 0.41 mm. and 0.55 mm. The smaller forms have the back most rounded, while a specimen 0.55 mm. long will appear very like A. quadrangularis. Males are elongate; hook of first foot strong, accompanied by a heavy growth of small spines; terminal claw of abdomen with a minute spine. * Alona porrecta Birge. Sub-rectangular; ventral line nearly straight; valves marked by longitudinal strizw; beak short. Post-abdomen truncate, with about twelve teeth, three or four of which at the end are larger, and a row of hairs above the teeth. Male similar. Length 0.34 mm. Distinguish- able from the following small species in the armature of the post- abdomen. The lower angle of the post-abdomen is acute. The claws are not serrate, but possess the basal spine. The post-abdomen is said to re- semble that of A. tenuicaudis in its armature, but not otherwise. This species is not enumerated by Professor Birge in his List of Crus- tacea Cladocera from Madison, Wisconsin [1891], and we are left in doubt whether the species is abandoned or not. Alona stagnalis Daday. ‘*Rostro longisculo, paulum curvato, acuminato; macula cerebrali oculo minore3 jabro processu mediali glabro; testa corporis longitudinaliter, manifeste striata, linea dorsali rotundata, margine ventrali medio parum arcuato, setas ubique me- ng Junaid _ al Ao ea ae ar Wes eo . ENTOMOSTRACA OF MINNESOTA. 247 diocres gerenti, postice angulum obtusum, inermem formante; cauda brevi, apicem versus rotundatum dilatata, margine dorsali utrinque serie muarginali aculeorum 7-8 sensim minorum et pleuribus minimorum equalium armata; unguibus caudali- bus inermibus dente basali uno. Longit. fem., 0.4-0.48; alt. 0.18-0.22 mm.”’ While doubting the integrity of this species we are unable to place it and quote the author’s description. Alona elegans Kurz. PLATE LXII, Fia. 14. Form rectangular; back slightly elevated, posterior margin high, lower margin straight. Shell covered with minute striations spring- ing from the region of the attachment of the head shield. Head rather large, pigment fleck smaller than the eye. The antennze have eight sets anda circlet of spines on the second joint of the inner ramus, and a single thorn on its first joint. The post-abdomen is short and broad, rounded at the end, and is armed with about ten anal teeth and a lateral row of scales. Length 0.4 mm. to 0.5 mm. *Alona angulata Birge. Dorsal margin considerably arched, terminating in a more or less obvious angle at the hinder corner; the hinder edge is convex, as is also the front margin; the ventral margin bears plumose sete. Beak pointed, extending nearly to level of ventral margin of the valves. Fornices broad. Shell obviously striated diagonally and less obviously marked by cross lines. Post-abdomen broad, truncate; about twelve anal teeth, with a series of scales and hairs back of them. The pig- ment fleck is much smaller than the eye. Male smaller; beak shorter; post-abdomen with a lateral row of hairs; anterior feet hooked; Sculpture less distinct. [Birge.] Length of female 0.4 mm.; male 0.35 mm. Whether Professor Birge still continues this species does not ap- pear, but it is dropped from the list of Madison Cladocera. Alona coronata Kurz. Hellich identifies this with his A. pulchra, but with Matile we re- gard this as doubtful. The resemblance to 4. pulchra [lineata] is very close, the outline being identical. The lower margin is sparsely hairy. The beak is blunt. A half cirelet of teeth ornaments the end of the middle segment of the inner ramus of the antennae, The macula is but little smaller than the eye. The post-abdomen is broad as in A, elegans, not narrowed at the end, but broadly rounded. The anal 248 GEOL. AND NAT. HIST. SURVEY OF MINNESOTA. spines are represented by clusters of hairs and there is a secondary series of scales. Kurz lays great stress on the fact that the intestine is flexed rather than coiled. Length 0.35 to 0.42 mm.; male 0.3 mm. Abdomen only armed with a series of delicate hairs, Alona barroisi Moniez. We quote the description of Alona barroisi Moniez (’88). This form is very incompletely described from a single specimen. Itis said to be very small and finely striate. ‘Tl est extremement petit, beaucoup plus bombe sur le dos qu’aucun autre Alona et la bord inferieur de la carapace est fortement arrondi, rappelant ainsi les Leydigia. Ce bord est muni de courtes soies; l’ocelle est environ moitie plus petit que 1’ceil, Vappendice labial est large et arrondi sur les trois cotes libres; le post-abdomen est court, son crochet terminal depourvu d’anguillon a la base, les dents laterales en sont courtes et larges et il y a sur les cotes serie de plaques, la carapace est finement striee.’’ Island of Terceira, Azores. It is doubtful whether it can be recognized. I venture to add a few memoranda respecting the long list of names which have appeared within this genus and which for various reasons are not included in the above list. Unfortunately the list is incom- plete and can only serve at best as a sort of guide to the perplexities of the synonomy. A. anglica Hellich is A. guttata. A. acanthocercoides of various authors is A. Leydigia. A. aculeatus is Alonella exigua. A. angusticaudata Hudendorff is Alonopsis latissima. A. balatonica Daday is A. Leydigia. A. camptocercoides Schoedler is A. tenuicaudis. A. esocirostris Schoedler is Graptoleberis. A. excisa is alonella. A. elongatus Sars is Alonopsis. A. faleata Sars is Leptorhynchus. A. grisea is Alonella. A. glacialis Birge is a variety of A. guttata. A. inornata Hudendorff is A. coronata. A. insculpta is Alonella excisa. A, leydigia is Leydigia. A. lineata Fischer is unrecognizable. A. latissima is Alonopsis. A. minuta Poggenpol is insufficiently described. A. modesta Herrick is A. costata. A. nanus is Alonella pygmea. A. ovata Baird is uncertain. ENTOMOSTRACA OF MINNESOTA. 249 A. pygmeea is Alonella. A. parvula Kurz is A. guttata. A. rectangularis is A. pulchra. A. rostrata is Alonella. A. reticulata Bd. is Graptoleberis. A, striata is Alonella. A, suleata is A. quadrangularis. A, spinifera Schoedler is the young of some species. A. socors O. F. Muller is uncertain. A, tuberculata Kurz is A. guttata. A, tuberculata Hudendorff is A. coronata. A. transversa is Alonella pygmea. A. testudinaria is Graptoleberis. A. verrucosa Lutz is A. guttata. Section B, Alonella Sars. In this group are included small species with a combination of characters, forming the link between dA/ona and Pleuroxus. An obvious character is the fact that the shell is usually partly marked by oblique strie, which run in two directions: first, a set extending forward and upward from the lower posterior angle of the valves; second, a set springing from the anterior and lower angle, running across the others. At the central part where these two series intersect, they each become zigzag; the result is a series of hexagonal markings, which may extend to the middle of the lower margin. The beak is short and the fornices broad; the shell is more or less rectangular, but somewhat elevated in the middle above. There are usually but seven sete on the antenne, or the eighth is a minute hair; on the ramus having the lateral setz one of the terminal sete is frequently reduced. In many cases the whole shell is marked by minute strive in addition to the proper markings, but this is also found in some species of the true Pleuroxus. Kurz gives, as a character of Alonella, the presence of but a single basal spine to the claw of the post-abdomen; but P. E. Mueller figures two spines on the claws of one of his species (4. exigua), and Schoedler figures eight setze on the an- tenna of A. ercisa. American specimens of A. excisa and of A. pygincea both certainly have a very minute eighth seta. There remains, there- fore, positively no point which can be relied upon to distinguish these little Zynceids from Pleuroxus or Alona. Perhaps, however, these Species, aS a group, may be recognized by what has already been said. Three species are found in Minnesota. \ 250 GEOL. AND NAT. HIST. SURVEY OF MINNESOTA. KEY TO THE GENUS ALONELLA. I. Rostrum long, bent backwards. bw hws 8 pales pie eh RO SUE has eee II. Rostrum short. A. Lower posterior angle toothed. a. Shell more or less reticulate. * Reticulated areas minutely striate. pulchella, 250; excisa, 251 ** Reticulated areas smooth. {i kleadidepressedis 0 Ua rt oe sepa teller Ota Ne XTC Meese timeleadshori zontal iy. eens acne. cen grisea, 252 b. Shell marked by lines running diagonally upward and backwards tse 3c Pah peer Seeks Ye renee pygmeea, 253 B. Lower posterior angle smooth, shell longitudinally striate. striata, 253 Alonella rostrata Koch. Lynceus rostratus—Koch, Lilljeborg, Schoedler. Alona rostrata—P. E. Mueller. Pleuroxus acutirostris—Birge. Pleuroxus affinis—Herrick. Body long, rapidly narrowed behind; dorsal line strongly arched in front toward the depressed head; the lower margin straight, with 0-3 small teeth at the angle. The fornices are broad, but the beak is sharp; the pigment fleck is but little smaller than the eye, to which it is three times nearer than to the beak. The post-abdomen is long, very much as in dA. excisa, but longer. Length 0.4 to 0.5 mm. Schoedler says the lower margin is concave and the angle unarmed, a condition not inconsistent with specific identity, as can be seen in many other species. The shell seems to be variably marked, but most conspicuous are the diagonal, curved strixe. Schoedler compares the sculpture to P. exiguus; Kurz, however, leaves the impression that only slight reticulation is present in the female. The male -has the post abdomen narrowed, ornamented with clusters of hairs behind, and the small claws have no basal spine, while the genital opening is in front of the claws. *Alonella pulchella Herrick. PLATE XIII, Fics. 1-3. A minute form very recently obtained is described under the above name. Although closely allied to A. evigua, this species is more like Graptoleberis than any other member of the genus. It is the smallest of the Lynceids, excepting A. pygmea. The shell is high and rather strongly arched; the posterior margin is short and armed with four teeth below, which point in different directions as in Graptoleberis. The head is short and the antennules long. The pigment fleck is of ENTOMOSTRACA OF MINNESOTA. 3 251 moderate size, but smaller than the eye. The post abdomen is short, rounded below, and armed with sharp and small anal teeth, besides which is an inconspicuous row of minute sete. The claw is very small, and has a single very minute tooth. The shell is marked by reticulations, which below are regular hexagons but above pass into elongated meshes, and finally on the beak and head become longitud- inal striations. ‘The areas are lined as in 4. exvcisa. Thus this species combines the form of abdomen of 4. exigua with the teeth of Grapto- leberis and the markings of A. excisa. Length hardly 0.27 mm. Motion active. The specimen figured contained a single large ovum. ‘The head may possibly have been somewhat protruded by pressure. Habitat, vicinity of Minneapolis. * Alonella excisa Fischer. PLATES XXII, Fie. 10; LXI, Fias. 6-7; LXIII, Fias. 10, 11. Lynceus excisus—Fischer. Pleurovus excisus—Schoedler. ? Pleuroxus insculptus—Birge. This species is closely allied to Alonella exigua; yet that species shows appreciable differences (which can hardly be claimed, per- haps, for Pleuroxus insculptus). The various authors who have written of this Lynceid have all laid emphasis upon the sculpture of the shell, almost to the exclusion of other points in the description. Professor Birge has found a quite different form, apparently, which has the same peculiar markings; and even the common Alona oblonga has a part of the valves covered by minute striations. Schoedler’s figure of this species is unrecognizable; but, as identified by Kurz, the species seems undoubtedly the same that is common in shallow pools in Min- nesota, during autumn, and probably also in Massachusetts. The variations to which this species is subject are considerable and may account for the marked disagreement in the accounts of our dif- ferent authors. Schoedler gives his specimens a length of 0.20 to 0.25 mm., while Kurz says 0.35 mm. Birge gives 0.27 mm. for the length of Pleuwroxus insculptus, and our specimens varied in the same gathering between 0.24 mm. and 0.40 mm. Schoedler figures three teeth at the lower posterior angle; Kurz says ‘‘several (4)’’; Birge describes one or two, and Minnesota specimens show gradual transitions from an in- conspicuous angle to three or perhaps four teeth. These teeth are the extensions of some of the strong ridges or crenulations which mark the shell. P. E. Mueller’s figures of the shell and abdomen of P. exigua would apply to our species perfectly, save the absence of minute striations; Kurz’s statements with reference to the differences between these two forms seem to agree only in part with those of 252 GEOL. AND NAT. HIST. SURVEY OF MINNESOTA. Schoedler. I must here express my suspicion that the Pleuroxus aculeatus, P. exiguus and P. excisus all belong under this species. I have seen a small form which lacked the fine striations; and there ap- peared to me to be, at times, a slight indication of a second series of hairs upon the post-abdomen. The form is oblong, truncate behind, variously arched above, but usually with a rather low, evenly curved dorsal contour; the lower shell margin is either nearly straight or convex in front and concave along the posterior third, and is heavily beset with very long pectinate bristles. The head is moderately depressed, with a very broad, blunt and short beak (in some positions this beak seems acute, but it is an optical delusion); the fornices are very broad, covering the antennules completely; seen from above the head is broad and truneate in front; the eye is larger than the large pigment fleck, which is nearer it than the end of the beak. The antenne have eight set, the last of which is minute; the five spined ramus has a strong thorn on the end, and the inner terminal seta is reduced. The post abdomen is rather broad and truncate or somewhat rounded below; its length is very variable, being short in small individuals; its form is subject to concomitant variations. Theseven to eleven anal spines extend in a series of minute bristles above the anus. The lower posterior angle of the shell bears one to four teeth; the marking consists of wavy ridges and strig, pro- ducing, by the crossing of two sets springing from the two lower angles, a reticulation covering more or less of the entire shell. The head-shield and the spaces between these markings are densely striated. Color yellowish, often opaque. Length 0.24 to 0.40 mm. At times abund- ant. Birge alone has seen the males; his description agrees with Kurz’s account of the male of A. evigua, save that the former speaks of spines, and the latter of thorns, along the post abdomen. Alonella exigua Lilljeborg. Lynceus exiguus—Lilljeborg, Leydig, Fric. Pleuroxus exiguus—Schoedler, P. E. Mueller. ? Lynceus aculeatus—Fischer. Aside from the differences in the male sex as above indicated, this form is said to have a convex lower margin, a rounded post-abdomen, and the pigment fleck nearer the end of the beak than the eye. The absence of the fine striation, finally, is the most marked characteristic: Length 0.30 to 0.83 mm. Not identified in America. (?) Alonella grisea Fischer. This species is included here on the authority of Kurz. The shell may or may not be toothed at the lower corner, and is partly lined and partly reticulate; but the only character which at all separates this Pe ee ee ENTOMOSTRACA OF MINNESOTA. 253 species from the above seems to be the position and form of the head, which is said to be blunt and nearly horizontal, as in Camptocercus rectirostris. Is this a transition to Graptoleberis ? * Alonella pygmzea Sars. PLATE LX, F14. 7. Pleuroxus transversus—Schoedler. Alonu transversa—P. E. Mueller. Lynceus nanus—F rie. Alonella pygmxa—Kurz. The form is rotund, much like species of Chydorus in the highly arched dorsal outline; the beak is rather short and depressed; the lower outline of the valves is very convex in front, and barely sinuate behind, where it terminates in a minute spine. The shell is marked, as in no other Lynceid, by lines running diagonally backward, and only on the lower part reticulated, if at all. The post-abdomen is short, broad and rounded below; the claw has a single basal spine. Length 0.20 to 0.28 mm. This is the smallest member of the Cladocera. In form it so nearly resembles Chydorus that upon first sight the writer took it for a member of that genus. Our one specimen measured 0.25 mm. The shell is marked by plica- tions rather than strize, which arch over the back. Alonella striata Schoedler. This species is said to resemble 4. exigua in habit and sculpture of shell; the form is quadrangular and not greatly elevated in the middle; the lower margin is nearly straight and fringed with bristles; the posterior angle is rounded and unarmed. The antennules with their sete extend beyond the beak; the pigment fleck is smaller than the eye and half way tothe beak. The post-abdomen is long and nar- rowed toward the end; there are seven or eight anal spines, and two spines on the terminal claw. Length about 0.5 mm. SUB-GENUS PLEUROXUS. Section A, Pleuroxus (verus) Baird. This group of Lynceids is most obviously defined by the long beak, formed by the extension of the chitinous covering of the head. (There is rarely a beak in the sense of that word as applied in the ease of Scapholeberis or Daphnia, but the antennules are simply attached to low prominences on the under side of a broad shield-like projection of the shell.) This beak-like projection is acute and often long and either curved backward or even bent forward. The fornices, or lateral E ~~ eo 254 GEOL. AND NAT. HIST. SURVEY OF MINNESOTA. projection of the head-shield, are narrow. ‘The form varies much, but is almost always very strongly convex above, and the posterior margin is thus only a fraction of the whole height of the animal. In some American species the body is very much elongate, and these also depart from the characteristic habitus of the genus in having strong longitudinal striz instead of reticulations. The lower posterior shell angle has teeth which, in a few cases, extend across the entire posterior margin. The post-abdomen is slender, usually truncate and armed behind with a single set of sharp teeth on either side; the terminal claw has usually two spines and may be serrate. . ?, The male has a shorter beak, the post-abdomen is more or less modi- fied, and the first foot has a powerful hook. The winter eggs frequently have a true ephippium; and sometimes this structure is like that of Chydorus, toward which the round forms of this genus seem to lead. There are upwards of a dozen valid species, several of which are American. KEY TO PLEUROXUS VERUS. Beak not curved forward. A. Shellreticulate. . . . . . . . hastatus, 254; (?) stramineus, 255 B. Shell smooth, except upon the front margin. . . . . . adunctus, 255 C. Shell striped. a. Shell very long and low. * With one tooth below. . . . . gracilis, 257 * Without a tooth; female witha HOGI upon the first foot. hamatus, 257 b. Shell high. * The whole posterior margin of the shellspined. . . . truncata, 258 ** The lower angle of the shell spined. 7 Antennz with eight setee; the anterior margin of the valves toothed... sc. ao - Bu an ade ts © ee Cee. -Centieulatusticos ;+{ Antenne with seven sete. . . . . . . =. +. ~. bairdii, 256 Beak procurved (Rhypophilus). A. Shell reticulate (either strongly or quite faintly). . . . personatus, 259 B. Shell striped. The posterior margin of the shell toothed. /) sea procurvus, 258 2 Only the lower angle of the shell toothed. . . . . . uncinatus, 259 (Not noticed in the key, .-... 4. % os 3S ee.” trigonelius,-5o Pleuroxus hastatus Sars. PLATE LXII, Fic. 16. Pleuroxus lzevis—Sars. Form somewhat oval, dorsal line strongly curved, posterior mar- gin short, with a tooth below; head short, beak very long, straight- ish; shell obscurely reticulate. Post-abdomen very long, narrow, +h ae ENTOMOSTRACA OF MINNESOTA. 255 with small teeth; claw with two basal spines. Color corneous. The sculpture consists of faint reticulations. The ephippium forms a truncation of the upper part of the shell. Length 0.50 to 0.55 mm. The male has a shorter beak; the first foot has a weak hook; and the spermatozoa are spherical. Pleuroxus stramineus Birge. This form is the American representative of the preceding, if not identical with it. Birge mentions minute striz in the meshes. P. stramineus is said to be lower than P. hastatus, while its beak is shorter. Undoubted specimens of P. denticulatus exhibit the same differences, an increase in the convexity of the shell accompanying an increase in the length of beak. The form of the abdomen appears nearly identical, if we compare P. E. Mueller’s Plate IV, Fig. 18, with the outline given by birge at Plate II, Fig. 11. The color in both is deep» especially during the period when the winter egg is forming. The direction of the reticulations is said to differ, but P. E. Mueller’s figure does not furnish positive evidence of this. Length 0.6 mm. ~leuroxus trigonellus O. F. Miiller. Lynceus trigonellus—O. F. Muller, Lievin, Lilljeborg, Leydig, Fric. ? Pleuroxus ornatus—Schoedler. Dorsal line strongly arched; the beak rather long, straightish, pigment fleck smaller than the eye. Shell faintly reticulate, the mark- ings consisting of transparent ridges. Post-abdomen widest in the middle, attenuated slightly toward the end, which is truncate; claw large, with one long and one very small basal spine. The anal margin of the post-abdomen has a series of small spines, and the lower shell-margin is hairy. The post-abdomen of the male is somewhat as in Crepidocercus, and densely hairy; the first foot has a moderate hook. To judge from Kurz’s statements, P. ornatus Schoedler is not specifically distinct. Not yet identified in America. Pleuroxus adunectus Jurine. Monoculus adunctus—J urine. Very like P. trigonellus, but with the back more strongly arched. The anterior part of the shell is striped. The beak is shorter than in P. trigonellus, but no other permanent differences are discoverable. The temptation to believe this a mere varietal form of P. trigonellus is great. Indeed, four species (the two here noted, P. bairdii and P. denticulatus Birge) are very nearly related. The ephippium, where known, is marked by minute punctation and a darker color. 256 GEOL, AND NAT. HIST. SURVEY OF MINNESOTA. Pleuroxus bairdii Schoedler. Pleurovus trigonellus—Baird. This form, so far as can be gathered from Baird’s brief description and figures, differs from the others in having the shell marked by straight parallel lines running diagonally back and upwards, and in lacking one of the terminal bristles on the 5-setose ramus of the an- tenne. The first is a possible but unusual structure, while the second might result from an overlooking of the very small seta which fills this place in the other forms. Baird himself did not distinguish it from P. trigonellus. *Pleuroxus denticulatus Birge. PLATES XLV, Fic. 8; LXIII, Fies. 10a, 12, 13. Resembling very closely P. adunctus, which, however, has a broader post-abdomen than the ordinary P. denticulatus. The posterior angle of the shell is armed with from one to four (generally three) teeth. The beak is very long. The character most emphasized by Birge is a series of teeth along the anterior margin of the valves. The same thing is found in P. pro- curvus, aS I have repeatedly satisfied myself. In certain positions these teeth do not show, or the smaller teeth on the lower margin only appear. P. adunctus, as figured by Schoedler, has similar teeth on the lower margin, and very likely has them anteriorly. The edges of the valves are heavily fringed with pectinate setze. The male has a shorter beak and the post-abdomen simply rounded without the peculiar modifications seen in P. adunctus. There seems to be two varieties in Minnesota, both of which have the characteristic irregular striations, which radiate from an irregu- larly marked or unmarked area in the centre of the shell toward the edges; both have the toothed posterior angle and the serrated posterior angle and the serrated anterior margin. But the common form is much longer, with the dorsal margin less convex and the beak shorter. The robust form has a larger pigment fleck, while the post-abdomen is shorter and more robust, resembling more nearly Schoedler’s figures of the abdomen of P. adunctus. There is another variation or abnor- mality, in which the lower margin is quite concave. The resemblance to P. procurvus is remarkable in some phases. I have collected this species in Blount springs, Ala., in the St. Croix river, and at various intermediate points, as well as very often in Minnesota. adie eae vi an ) ea dln re ¥ ENTOMOSTRACA OF MINNESOTA. 257 *Pleuroxus hamatus Birge. PLATE LX, Fie. 1: This species is smaller than those of the preceding group and forms a transition to the two next, to be described, in the greater elongation of the shell, which is, however, higher and more strongly arched. The head and beak are much as in P. denticulatus. The lower margin is concave posterior to the middle and slightly convex at the posterior angle, which is unarmed. The lower margin is hairy. The markings are as in P. denticulatus, but, in addition, there is a set of horizontal strie all over the shell. The post-abdomen is widest in the middle and almost exactly as in P. denticulatus. The first foot bears a claw such as ordinarily distinguishes the males. The only specimens which I have seen were from the Tennessee river, near Waterloo, and near Decatur, in Alabama. My notes con- tain no reference to the minute striations, which could perhaps be hardly seen with the instrument employed. The process of the labrum is long and rather acute, the beak moderate, and the pigment fleck very large. The markings on the anterior of the valves are irregular and are inter-connected by cross lines or anastomoses. Ova two. (The genus Anchistropus has a hook upon the first foot, but is like Chydorus. ) *Pleuroxus gracilis Hudendorff. PLATE LXIV, Fias. 15, 15a. Pleuroxus unidens—Birge. An extreme among these elongated species, the length of body fall- ing little short of double the height. The dorsal line is very flat and slightly but evenly arched; the lower margin is evenly convex or nearly straight, covered by long pectinate bristles. The head is short, and the beak is long and sharp; the antennules are of moderate size, with a lateral seta one-fourth from the end; pigment fleck less than the eye; antenne rather long, with strong thorns on the termina] joints. The post-abdomen is long, as in P. hastatus, sides nearly par- allel; anal teeth sharp, small and numerous; claws pectinate, with two strong basal spines. The shell is strongly striate with longitudinal strie, which are parallel with the different margins. Birge says that there is a reticulated area. The lower angle is rounded, and anterior to it is a small tooth directed backward. This species is distributed throughout the Mississippi valley. I have notes of it from Swan lake, near Decatur, Ala. It is often rather abundant about Minneapolis, but it is thought by Birge to be absent from the Eastern states. Almost all the specimens I have seen are very dark, often brown, so as to ap- pear to the eye like dark specks as they swim about. The length 258 GEOL. AND NAT. HIST. SURVEY OF MINNESOTA. varies from 0.55 mm. to 0.85 mm. About 0.60 mm. is a common size, according to my observation. Birge mentions a rudimentary sixth foot in this species. This organ is found in Hurycercus and other Tynceids, according to Schoedler. Pleuroxus truneata O. F. Miiller. Lynceus truncatus—Miiller, Koch, Zaddach, Lievin, Fischer, Lilljeborg, Leydig, Fric. Percantha truncata—Baird, Schoedler, Kurz. Pleuroxus truncatus—P. E. Mueller. Percantha brevirostris—Schoedler. This species is widely distributed in Europe, but is replaced in America by the following. The shell is high, the dorsal contour arched; beak rather long and straight; lower margin slightly convex, setose; posterior margin straight, armed with very strong teeth en- tirely across it; the anterior margin also is dentate, as in the next. ‘The valves are covered with strong striz, springing from the anterio- central part and radiating toward the free margins. The post-abdomen is of moderate size and in form much as in the next. The ephippium causes a considerable change in form and coloration. In the male the beak is shorter, and the abdomen has finer teeth. The first foot has an extraordinarily large hook. The length is about 0.5 mm. to 0.6 mm. Percantha brevirostris Schoedler differs in the length of the beak only. *Pleuroxus procurvus Birge. PLATE LXI, Fies. 3, 4. In size and general appearance this most interesting species is similar to the above, and, especially, to P. denticulatus. The general form and even the details of structure agree almost to identity with the latter. The structure of the posterior margin is like Percantha, while the rostrum is bent abruptly upwards as in Ihypophilus. In small individuals the length is greater proportionaliy. The lower margin is slightly convex or nearly straight, and fringed by bristles whieh are strongly pectinate; the anterior and lower margins are toothed as in Percantha. The shell gland is more as in the Daphnide than most Lynceids. The number of posterior teeth is variable. The ephippium is as in P. denticulatus. Length 0.40 mm. to 0.50 mm. Not rare, but less common than P. denticulatus. The male post-abdo- men is like that of P. denticulatus; the rostrum is as in the female. Of the species following it may suffice to say that they are corpu- lent, filth-loving representatives of P. trigonellus, P. adunctus and P, bairdii, respectively, which have turned up their noses at a superficial existence and buried themselves in the mire and debris at the bottom of the pools. It might be fanciful to assume that the curved snout is used for ‘‘rooting,’’? but the fact that these ‘‘Schmutzpeterchen”’ Lynceids would find a long straight beak in the way is suggestive. Pa ee, = ENTOMOSTRACA OF MINNESOTA. 259 Pleuroxus personatus Leydig. Leydig ’60 (Lynceus personatus); Schoedler ’62, ’63 (Rhypophilus personatus and glaber); Norman and Brady ’67 (Lynceus uncinatus); Muller ’68; Frie ’72 (Lynceus personatus); Hellich ’77 (personatus and glaber); Herrick ’84; Daday 788; Matile ’90; Kurz ’74 (glaber). Shell high, oval, smaller caudad. Head small, depressed, with narrow, long, procurved beak. Macula quadrangular, half the size of the eye, to which it is nearer by half than to the end of the beak. The shell is either hexagonally reticulate or smooth. The lower margin is flexed cephalad of the middle and bears long cilia. The ventro-caudal angle bears two curved spines. The post-abdomen is rather broad, narrowed toward the end. Anal teeth 10-11, very large. Claw serrate, and with two basal spines. There are seven sete and a spine upon the antenne. The antennules are fusiform. Length 0.65 to 0.67 mm. There seems to be no reason to doubt that P. glaber is only a condi- tion of P. personatus not even worthy of a varietal name. Pleuroxus (Rhypophilus) uneinatus Baird. The shell is ridged with lines running upward and backward, as in P. bairdii; the lower angle of the shell has three teeth, and the beak is more horizontal than in the above. In size and characters this is almost identical with P. bairdii, with which it occurs in Eng- land. This completes the list of swine-like members of the genus; these well deserve to be studied from a morphological standpoint. The following names may be mentioned, though the list of syno- nyms cannot claim to be exhaustive. Pleuroxus nasutus Gay is a poorly described form from Chili, re- sembling, according to Schoedler, P. ornatus = trigonellus. A species of Percantha (Lynceus armatus Gay) is found in Chili. P. exiguus Lillj. is Alonella. P. griseus is possibly Alonella pygmea but is said to have two teeth on the ventro-caudal angle of the shell which is faintly reticulated as well as striate. striatus Hellich is P. gracilis Hudendorff. striatus Schoedler is Alonella. balatonicus Daday is insufficiently described. excisus Fischer is Alonella. nanus Baird is Alonella pygmea. levis Sars is P. hastatus. ornatus Schoedler is the young of P. trigonellus. trigonellus Mueller is P. bairdii Schoedler. 17 nol Jeefalashetae sae iais ae aa 260 GEOL. AND NAT. HIST. SURVEY OF MINNESOTA. P. glaber Schoedler is P. personatus. P. brevirostris Schoedler is P. truncatus. P. aculeatus Fischer is Alonella exigua. P. convexus Poggenpol is doubtful. SECTION B. Leptorhynchus Herrick.!—The species for which Sars formed the genus Harporhynchus is of Alona-like habit, but has a beak which ‘exceeds that of any known Pleuroxus in length, being sim- ulated in this respect by the American P. acutirostris, which is, how- ever, in other respects more nearly allied to Plewroxus. Leptorbynchus faleatus Sars. Harporhynchus falcatus —Sars. Alona falcata—Sars, P. E. Mueller. Body oblong, arched above; ventral margin nearly straight, setose, with a spine at the posterior angle; beak strongly curved, folded laterally; pigment spot larger than the eye. The post-abdomen is wide, sides nearly parallel, armed with a few strong teeth below and a lateral line of spines; caudal claw with a single small basal spine. GENUS CHYDORUS Leach. This genus, if it be really of generic value, contains minute rotund animals which appear in the water like animate pin-heads of small size. Their motion is a rolling, wavering hobble; and they live by preference upon vegetation, or in slime at the bottom of pools. Occa- sionally they may be seen in sunshiny weather, disporting themselves near the surface in immense numbers. There are two common species, and six more which are more rare or in part not valid. The sexual period occurs at two different periods (i. e., May-June and December), but probably is not confined to any periods. The males, which only rarely are found even in these periods, have the abdomen narrowed or excavated to accommodate it to the peculiar alteration of the brood cavity which takes place in the sexually ma- ture female. The connection takes place by the insertion of the abdo- men within this chamber, which is facilitated by the reduced size of the abdomen. The modification of the shell of the brood-cavity above referred to consists in the thickening of the wall posteriorly, which may or may not result in the deforming of the shell as shown in Plate LXIV, Fig. 7, taken from Kurz. This may be termed an ephippium, although it differs somewhat from the modified shell so called in Daphnia. The male element consists of nearly round nucleated cells, and the opening of the vas deferens is anterior to the terminal claws. 1 Harporhynochus is preoccupied in ornithology. a ENTOMOSTRACA OF MINNESOTA. 261 The members of this genus are among the most minute forms of the family or the entire group. Concisely put, the characters are as follows: Form globose, not obviously truncate behind; head terminating in a Sharp, long, curved beak, which lies close upon the anterior margins of the valves; antennz short; eye larger than the pigment fleck; abdo- men flattened, excavated in the male; intestine with no anterior ceca, doubly convoluted, with an anal cecum. Three species found in Min- nesota. * Chydorus sphzericus Mueller. PLATE LXIV, Fias. 4, 7, 8, 10. Lynceus sphxricus—O. F. Muller, M. Edwards, Koch, Zaddach, Lieven, Fischer, Lill- jeborg, Leydig, Toth, Zenker, Fric. Monoculus sphericus—J urine. Chydorus muelleri— Leach. Form nearly spherical, as seen from above broadly oval; in young Specimens truncate behind; antennules of moderate size, in the male very large, with curved flagellum near the middle of anterior margin; pigment fleck often nearly as large as eye; beak of moderate length, blunt in the male; first foot strongly hooked in the male; post-abdomen Short, broad, rounded at the end, armed with eight or nine sharp teeth; shell reticulated with polygonal meshes. Color light, unspotted. Length 0.50 mm. This species occurs in spring elie: than most forms, and is ranked as the most abundant of the micro crustacea, being found over the whole circumpolar land-area. The ephippium for the winter egg was observed by Kurz, but the period at which it is formed seems variable. C. spheericus of a previous report seems to have been the following Species, which is more common in Minnesota in the clearer lakes. A small form in our large lakes measures 0.5 mm.; it may be distinct. * Chydorus globosus Baird. PLATES X XI, Fic. 23; LXIV, Fies. 1-3, 9. Form globose, very broad; antennules very large with a strong lat- eral seta on a small elevation; swimming antenne exceedingly small; the shell gland is well developed; the pigment fleck is much smaller than the eye; beak very long and incurved; post-abdomen rather long, more slender than the last, broader near the end which is truncate, bearing about 20 spines on the margin near which is a lateral series of minute bristles; the terminal claws are straightish, spined along the basal half, and have an accessory spine; the shell is very indistinctly 262 GEOL. AND NAT. HIST. SURVEY OF MINNESOTA. reticulated and spotted; color dark; length 0.7 to 0.8 mm.; male 0.55 mm. The males have the abdomen very narrow for the entire length. This species is considered rare elsewhere, but is not infrequent near Minneapolis during August. Chydorus ovalis Kurz. PLATE LXIV, Fie. 11. Form oval, nearly twice as long as high; beak long; antennules two-thirds as long as the beak, with one elongated sensory filament above the others; pigment fleck nearly as large as the eye; antenne small; shell margins heavily fringed anteriorly; post-abdomen of mod- erate size, rounded at the end, with about eight teeth near the end; shell smooth. Length 0.4 mm. This species is rather near C. sphericus, differing in having the shell smooth, antennz shorter and beak longer. This species is not yet known in America. From C. Jatus it differs in the single anten- nulary flagellum and number of anal teeth. * Chydorus czelatus Schoedler. PLATE LXIV, Fie. 12. Chudorus adunctus—Schoedler. This small species is about 0.4 mm. long and resembles the young of C. globosus in form, from which as well as from all known species it is distinguished by the markings of the shell, which consist of series of rounded elevations (or depressions?) arranged parallel to the lower margins of the shell and head. The description is very incomplete, and the only other author who appears to have seen the animal is Kurz, who adds that the sensory filaments of the antenne are unequal in ‘height, and that the so-called elevations are really depressions. A form with a few depressions about the edge and characters of this species was once seen in the vicinity of Minneapolis. This is probably a variety of OC. sphericus. Chydorus nitidus Schoedler. PLATE LXIV, Fias. 5, 6. Shell smooth and regularly punctate; the head resembles C. speri- cus, but the pigment fleck is much smaller than the eye, to which it is much nearer than to the end of the beak; the post-abdomen is broader near the end, and bears a row of 10 to 12 teeth on either side. Chydorus latus Sars. Of moderate size, oval, rounded behind. A slight depression be- tween head and body. Beak long, slender and curved. Macula quad- ENTOMOSTRACA OF MINNESOTA. 263 rangular, smaller than the eye and half as far from it as from the beak. The conical antennules bear two flagella, one near the end, the other near the basal third. Shell longer than high, strongly arched above, surface smooth. Anal teeth 13 or 14. Claws short and smooth except for the two basal spines. (Matile says the claws are slightly ciliate.) Length 0.54 to 0.59 mm. Chydorus piger Sars. Sub-rotund, prominent above, sinuate behind; lower and posterior margins rounded, lower margin ciliated. Head movably united to the body; beak long, separated by an indentation from the head shield. The shell is broad, as seen from above. Shell punctate anteriorly and marked below by indistinct oblique striz. Antennules with seven setze and two small thorns on the end of each ramus. Post-abdomen truncate; the terminal claws with a minute tooth at the base, posterior margin sinuated, rounded below and there densely armed with minute teeth. Abdominal sete long and flexible. Pig- ment fleck of medium size, much nearer to the eye than to the beak. Length about 0.33 mm. (2) Chydorus latifrons Dana. (U. S. Exploring Expedition, Rep. on Crust., Vol. II, p. 1274.) Very tumid; inside view rotund, head not separate, very short- beaked; beak slender and close to the body, acute; in upper view animal very broad, truncate anteriorly, the front thereby nearly as broad as the body; behind low, triangular and obtuse. Feejee Islands. (2?) Chydorus albicans Gay. From Chili. Is imperfectly described; but it is interesting to note the occurrence of this genus there. Chydorus punctatus Hellich. Very small, tumid, truncate caudad. Head low, with rather short, sharp beak. Macula round, as large as the eye, to which it is nearer than the beak. Antennules tumid at the middle, with lateral seta above the middle. The ventral margin of the shell is very convex, with long pectinate sete. Hexagonal reticulations, each with a cen- tral elevation (?) mark the shell. Post-abdomen short, broad. Anal teeth eight or nine, of uniform size. Claw with one basal spine and a row of sete. Length 0.44 to 0.47 mm. The abdomen of the male is curved and deeply excavated apically. Claws short and smooth. Length 0.42 mm. ‘This is probably only a variety of C. sphericus. Sey od es Poe ey Se 1 ER = q vw, 264 GEOL. AND NAT. HIST. SURVEY OF MINNESOTA. Chydorus letourneuxi Richard. Richard ’88. Testa a latera visa subrotundaia, sulcis curvatis (10-12) e medio exeuntibus, ad margines anticos liberos porrectis, antice manifestis ut in Pleuroxus adunco, ornato; testis cetera levis, margine superiore prominente, postice leviter sinuato, marginalibus posterioribus et inferioribus rotundatis. Valoulorum margines inferiores postice ciliis longis instructi, margines superiores dentati. Rostrum breve et obtusum. Antenne 1 mi paris ad basin crassze, rostro breviores, setis squalibus. Antennz 2 di paris setis 7 preedite. Macula nigra oculo duplo minor, inter oculum et apicem rostri fere in medio sita. Postabdomen apicem versus rotundatum, unguibus termi- nalibus brevibus levibus ac robustis, aculeis ad basin 2, quorum interior altero multo brevior, armatis; margo superior in medio sinuatus supra medium processum obtusum format et infra hune aculeis minutis dense obsitus. Spinulis mintutissi- mis sparsim in lateribus post-abdomen instructum. Color corneus. Longit. circit 0.6 mm. Mas ignotus. Algeria and Tunis. Ohydorus alexandrowii and C. tuberculatus of Poggenpol are confess- edly imperfectly described. We incline to the belief that there are not more than four good species in this genus, but extended study of the conditions of variation are necessary. GENUS ANCHISTROPUS Sars. (2) Very similar in form to Chydorus; valves gaping below anteriorly; antennules small; process of labrum rounded. Post-abdomen atten- uated toward the end, densely covered with fine teeth; terminal claws denticulate. First foot with a powerful claw, protruding beyond the Shell. Eye very large. Shell indistinctly reticulate. Sars says of his Anchistropus emarginatus that on cursory inspection it would be taken for the young of Chydorus globosus. He found but few speci- mens, about 0.35 mm. long. The suggestion is still possible that the young males of some Chydorus are here mistaken for a new genus. The males of Chydorus globosus were not known till 1878, and their | early form is still unknown. The young females have a tolerably strong claw, though it is not much curved. I once found a peculiar Lynceid measuring 6.46 mm., with unevenly but distinctly reticulate shell, slender abdomen, and a strong claw which was dentate. There were several young (more than two), and the shell in these was more regularly reticulate. All efforts to find a second specimen failed, and the one seen was somewhat mutilated; hence I am unable to determine its real position. GENUS MONOSPILUS Sars. Head separated by a depression from the body; shell high, com- pressed, posterior margin somewhat less than the greatest height of the shell. Post-abdomen broad, ornamented with lateral and posterior ENTOMOSTRACA OF MINNESOTA. 265 spines; claws large, with a single basal tooth. The compound eye is absent, its place being taken by the pigment fleck, which is the fune- tional eye.* *Monospilus tenuirostris Fischer. PLATE LXII, Fic. 21, 21a. Fischer 754 (Lynceus tenuirostris); Sars 61; Norman and Brady ’67; Mueller ’68; Hellich ’77; Herrick ’84 and ’87 (dispar). Shell roundish; ventral margin setose; posterior angle rounded, marked above with numerous impressions. Antennules small; anten- ne long, with seven sete. Post-abdomen short and broad, bearing a series of Spines along the excavated posterior margin, and ornamented on the sides with clusters of bristles. The shell in old individuals is not moulted but remains as in Jlyocryptus, covering the greater part of the new shell. The figure shows an old individual with its succes- Sive coverings still clinging to it. Like Ilyocryptus, this animal passes its life in filth at the bottom of pools and rarely emerges to the light of day. What little visual function. there may be is vested in the larval organ. The specimen from which the drawing was made measured 0.45 mm. The first glance at this rarest of all entomostraca affords proof of its unique character. The strongly arched shell is so compressed as to bear little resemblance to Chydorus. The dorsal line passes with little angle into the high posterior margin. There is a rounded angle below, armed with two teeth—the shortened representatives of the fringing spines of the straight lower margin. The head is depressed and very short; but the narrow beak is produced to below the margin of the valves. It is rounded so as to resemble, as seen in front, a duck’s bill. The fornices are narrow and flare so that the eye is left partly exposed upon the side. The antennules are not long but slender. The labrum has a very large lamella, which is crenulate in front and acute below, the labrum proper being large. The systematic position of this genus is a matter of considerable interest, for it is the only member of the whole order in which the larval eye is the only one *So much interest attaches to this species that we reproduce the latin description of Sars: ‘‘ Testa in adultibus valvulis composita pluribus, altera alteri imposita, a latere visa lata, latitudine maxima in parte antica sita; margine superiore antice valde prominente, posteriore et inferiore ciliato rotundatis, Caput mobile, perparvum et valde depressum, supine impressione parva sed distincta, a testa cetera dis- junctum, deorsum in rostrum rectum et breve apice obtuso exiens. Animalsupravisum sat compressum, latitudine maxima capite majore ante medium sita. Pars superior teste et capitis impressionibus nume- rosis rotundatis notata. Antenne 1-mi paris minute structura ut in ceteris Lynceidis; 2-di paris sat long, ramo altero setas 4 et aculeum unum apicalem altero setas 8 et aculeos duos,quorum alter longus articulo primo ejusdem rami adfixus est, gerunte. Postabdomen breve et latum, apicem versus truncatum; margine posteriore supra obtuse angulato, ad angulum inferiorem rotundatum seriebus Guabus aculeo- rum inque lateribus setis vel spinulis brevyibus numerosis preditum; ungues terminales ad basin aculeo longo armati. Intestinum, ut in ceteris Lynceidis, in thorace laquem fere duplicem format. Macula nigra unica minima prope basin antennarum 2-di paris; maculz infra oculariin ceteris Lynceidis simillima, in capite conspicitur, quze, quum oculus verus compositus in omnibus ceteris Crustaceis Cla- doceris distinctus omnino absit, organum quamquam rudimentare visus habenda est. Animal parum pellucidum, colore fulvescente. Longit. parum supra 14 mm.” 266 GEOL. AND NAT. HIST. SURVEY OF MINNESOTA. developed, and the first thought would be that this must be a primi- tive synthetic type; in other words, historically the oldest of Cladocera. Closer study does not warrant the theory. There is much to indicate that, though essentially lynceid, it stands in close connection with the higher members of the family and perhaps has more than a superficial resemblance to such degraded Lyncodaphnids as Ilyocryptus. All things considered, however, our diagram stands with this genus as a degraded offshoot of the more typical stem of Lynceide. SUB-ORDER GYMNOMERA. This group is easily recognized by the almost entire absence of the shell, which forms so conspicuous a part in the greater number of the Cladocera. Here it serves simply to form a pouch or brood-sac for carrying the eggs and embryos. The feet are nearly terete and pre- hensile, with but slight indications of branchial appendages. FAMILY POLYPHEMIDE. Feet five pairs. Antenne with the rami three- or four-jointed. GENUS POLYPHEMUS De Geer. Head very large, separated by a depression from the compact body; shell covering but a part of the dorsal region. Feet all with an inter- nal dentate and an external lamellate appendage. Caudal seta upon a long process of the post-abdomen. * Polyphemus pediculus Linn. PuLatTeEs LVIII, Fies. 4-6; LXIX, Fie. 1. Monoculus pediculus—Linnzeus, 1746. Gmelin, Linn. Syst. Nat. Fabricius, Ent. Syst., etc. Sulzer, Insecten. Manuel, Encyclop. Meth. Monoculus pediculus ramosus—De Geer, Mem. pour serv. a |’ Hist. des. Ins. Polyphemus oculus—Mueller, Zool. Dan. Prod. et Entomost. Cuvier, Tab, element. Latreille, Hist. Nat. Crust., ete. Leach, Edin. Encyc. Polyphemus stagnorum— Leach, Dict. Se. Nat. Latreille, Cuv. Reg. An. Demarest, Cons. Gen. Crust. Polyphemus pediculus—Straus, Mem. Mus. d’Hist., etc. M. Edwards, Hist. Nat. Crust. Monoculus polyphemus—Jurine, Hist. Nat. Monoc. Cephaloculus stagnorum—Lamarck, Hist. An. Vert. Bosc, Man. d’Hist. Nat. Crust. Monoculus oculus—Gmelin, Linn. Syst. Nat. Sealicerus pediculus—Koch, Deutsch. Crust. Polyphemus pediculus—Baird, Brit. Entom. Polyphemus oculus—Lievin, Branch. d. Danz. Polyphemus stagnorum—Fischer, Ueber die in d. Umg. von. St. Petersburg vorkom Crust. ENTOMOSTRACA OF MINNESOTA. 267 Polyphemus pediculus—Liljjeborg, De Crust. ex ord. trib. Polyphemus oculus—Leydig, Naturg. d. Daph. Polyphemus pediculus—Schoedler, Neue Beitr. zur Naturg. d. Cladoceren. Polyphemus kochiti—Schoedler, Neue Beitr. zur Naturg. d. Cladoceren. Polyphemus oculus—Schoedler, Neue Beitr. zur Naturg. d. Cladoceren. Polyphemus pediculus—P. E. Mueller, Danmark’s Cladocera. Kurz, Dodekas neuer Cladoceren. Weismann, Beitr. zur Naturg. der Daphnoiden. Birge, Notes on Cladocera. Polyphemus occidentalis—Herrick. There are two well-marked varieties of this species: one is found commonly in the clear lakes; the other, which I have only once seen, was found ina very shallow weedy marsh. The difference in size is quite remarkable. Our ordinary form measures less than 1.0 mm. The larger form, including the stylets, is 16 mm. The ordinary variety, although highly colored, is yet transparent, while the large variety is deep red and quite opaque. The relationship between the two forms is quite like that maintaining between Diaptomus stagnalis and D. sanguineus. Some slight structural differences are observable between the two varieties, as in the form of the antennules, yet quite insignificant when compared with the striking difference in size and coloration. The feet of this species have not been fully figured hitherto and are accordingly given on Plate LXIX. Some minor differences may be noted between these figures and those given by Lund. *Polyphemus stagnalis Herrick. In order to make the relation clear between these forms, I add measurements of this species, following each with the corresponding measurement of P. pediculus in parenthesis; animals of the same age, as far as possible, being chosen. Head (capsule of eye) 0.3 mm. (0.2 mm.); head and thorax 0.7 mm. (0.45 mm.); abdomen 0.7 mm. (0.56 mm.); caudal stylet 0.386 mm. (0.26 mm.); caudal filaments 0.36 mm. (0.3 mm.) Whole length of antenne 0.54 mm. (0.42 mm.); first, second and third joints of the three-jointed ramus 0.08, 0.06 and 0.10 mm., respectively. The formation of the resting eggs or ‘‘dauer-ei’’ seems to go on at the same time with the parthenogenetic repro- duction. ; GENUS BYTHOTREPHES Leydig. Much like Polyphemus, but the external appendage of the feet is rudimentary, and the abdomen extends out into a most enormous spine. The single species is that described by Leydig as Bb. longimanus, which was found in the stomach of Coregonus wartmanni. B. ceder- stromii of Schoedler and P. E. Mueller, the latter author now identifies 268 GEOL. AND NAT. HIST. SURVEY OF MINNESOTA. with the above, and concludes that the supposed differences arose from ‘‘Vetat de maceration des exemplaires examines.’’ (Les Cladoceres des Grands Lacs dela Suisse, p.11.) This species may be looked for in the depths of the Great Lakes. (See Plate XX VII, Fig. 10.) GENUS PODON and GENUS EVADNE. These are compact oval forms confined to the sea. See Claus, Zur Kenntniss des Baues der Polyphemiden, Vienna, 1877, for the best account of the anatomy. FAMILY LEPTODORIDE. Feet six pairs. Antenne with both rami four-jointed. Body elongated, not curved, shell very much reduced. *Leptodora hyalina Lilljeborg. BATH SXGXOX Vey DIGS.7 Gs de The only species, is found rarely in the larger lakes of Europe and America. See Bau und Lebenserscheinung von Leptodora hyalina, Weismann, 1874; also, Omen dimorph Udvikling samt Generationsvexel hos Leptodora, G. O. Sars, 1873; also, Bidrag til Cladocerenes Forplantningshistorie, Pp: . Mueller. The work of Sars is particularly valuable, showing that the young produced from the winter eggs pass through a metamorphosis not ex- perienced by the summer or parthenogenetic brood. P. E. Mueller mentions the pathological condition induced by the plants of the Saprolegnia. ie AS Tele NOU Ow leeeb sl» ele -NOTESONTHECLADOCERA _ OF THE og SOUTHEASTERN PART OF THE UNITED STATES 1BNe (Gy Tele JO SURNaIEY hte canes ot eee > ¥ . ORDER CLADOCERA. FAMILY SIDIDE. GENUS SIDA Straus. Sida crystallina Miller. Sida crystallina—C, L. Herrick, Final Report on Minn. Crust., p. 20. Habitat: Cincinnati, Ohio. Rare. Occurs in deep canal basins. FAMILY DAPHNIDE. GENUS MOINA Baird. Moina rectirostris Miiller. Moina rectirostris—C. L. Herrick, Final Report on Minn. Crust., p. 34; Pl. A., Figs. 2, 5, 8, 10, 11. Length of female 0.94 mm.; height 0.63 mm. Habitat: Atlanta, Ga. Moina paradoxa Weismann. Moina paradoxa—C. L. Herrick, Final Report on Minn. Crust., p. 34; Pl. A, TOMS ILS eels 7G 43)s Habitat: Cincinnati, Ohio. During the latter portion of summer this species is very abundant in foul pools. GENUS CERIODAPHNIA Dana. Ceriodaphnia consors Birge. Ceriodaphnia consors—E. A. Birge, Notes on Clad., p. 5; Pl. 1, Figs. 3, 4. Length 0.55 mm.to 0.61 mm.; height 0.40 mm. The reticulations on the shell are singly contoured. Habitat: Atlanta, Georgia. Winter and summer. Ceriodaphnia megops Sars. Ceriodaphnia cristata—E. A. Birge, Notes on Clad., p. 6; Pl. II, Figs. 8, 9. Length 0.64 mm.; height 0.50 mm. Habitat: Kent county, Dela- ware; Atlanta, Georgia. > 272 GEOL. AND NAT. HIST. SURVEY OF MINNESOTA. GENUS SCAPHOLEBERIS Schoedler. Scapholeberis mucronata Miller. Scapholeberis mucronata—C. L. Herrick, Final Report Minn. Crust., p. 42; Pl. J, Fig. 5. Habitat: Atlanta. Georgia; Cincinnati, Ohio; Lockland, Ohio. Abundant in shallow grassy ponds and sluggish creeks. GENUS SIMOCEPHALUS Schoedler. Simocephalus vetulus Miller. Simocephalus vetulus—C. L.. Herrick, Final Report Minn. Crust., p. 46. . Habitat: Cincinnati, Ohio; Kent county, Delaware. Simocephalus serrulatus Koch. Simocephalus americanus—E. A. Birge. Notes on Clad., pp. 6-8; Pl. I, Fig. 6. Length 1.7 mm. to 1.9 mm.; height 1.43 mm. This species is often covered with vorticellide. Habitat: Atlanta, Georgia; Baxley, Georgia; Cincinnati, Ohio; Kent county, Delaware. GENUS DAPHNIA Schoedler. * Daphnia pulex Miller. Dapnnia pulec—C. L. Herrick, Final Report Minn. Crust., p. 56. Habitat: Cincinnati, Ohio; Covington, Kentucky. ‘This species is fond of foul water and is often associated with Moina paradoxa. Daphnia longiremus Sars. (?) Daphnia longiremus Sars—C. L. Herrick, Final Report Minn. Crust., p. 63. Length 1.70 mm. This is a non-crested, hyaline specimen, marked with rectangular meshes and devoid of pigment fleck. It resembles the species under which I have placed it in all respects excepting siez. I do not consider this alone sufficient to establish a new species. It may, however, be a variety of the above. FAMILY BOSMINID©. GENUS BOSMINA Baird. Bosmina cornuta Jurine. Bosmina cornuta—E. A. Birge, Notes on Clad., p. 15; Pl. I, Fig. 10. Length 0.26 mm. Habitat: Tusculum, Ohio. Rare. Found} in grassy pools. ENTOMOSTRACA OF MINNESOTA. 273 Bosmina atlantaensis Turner. Bosmina atlantaensis—C. H. Turner, Notes on the Clad. of Ga., p. 23; Pl. VII, Figs. Leto: Length 0.46 mm.; height 0.36 mm. Habitat: Atlanta, Georgia. Obtained in the middle of winter from pools that dry up in dry weather. FAMILY LYNCODAPHNIDE. GENUS MACROTHRIX Baird. Macrothrix laticornis Jurine. Macrothrix laticornis—C. L. Herrick, Final Report Minn. Crust., p. 68; Pl. C, Figs. 8, 9. Length 0.37 mm. to 0.39 mm.; height 0.25mm. Habitat: Atlanta, Georgia, GENUS ACANTHOLEBERIS Lilljeborg. Acantholeberis curvirostris Miiller. Acantholeberis curvirostris—C, L. Herrick, Final Report Minn. Crust., p. 73. Length 0.97 mm.; height 0.61 mm. Habitat: Baxley, Georgia. GENUS ILYOCRYPTUS. Ilyoeryptus sordidus Lievin. European observers have never found more than a few specimens of this species at any one time. At two different times this summer I have found this species in great numbers in the mud at the bottom of a small pool on the Clark University campus at South Atlanta, Georgia. This pool is a tank about four feet deep, fed by a cool spring. At one end a shallow grassy creek flows outward from it. This creek at its origin is less than a foot deep and has a mud bottom. In this creek, at its source, is where the specimens were obtained. The American specimens tally in all essential respects with the European Specimens. Habitat: South Atlanta, Georgia. Ilyocryptus longiremus Sars. Ilyocryptus longiremus—E. A. Birge, List of Crust. Clad. from Madison, Wis., p. 392; lek, SQUOE dorpesailsy This species agrees in all essential respects with the species found by Professor Sars in Australia and by Professor Birge in Wisconsin. Habitat: Baxley, Georgia. It seems to be present in almost all of the ponds near Baxley. This species is very closely related to J/yocryptus spinifer Herrick. At one time I was fully convinced that they were two distinct species, Q74 GEOL. AND NAT. HIST. SURVEY OF MINNESOTA. but the more I study this species the more I am led to believe that this and J. spinifer are varieties of one and the same species. If this surmise be true then Professor Herrick’s name has precedence. FAMILY LYNCEIDE. SUB-FAMILY EURYCERCINEE. GENUS EURYCERCUS Baird. Eurycercus lamellatus O. F. Miller. Eurycercus lamellatus—C. L. Herrick, Final Report Minn.Crust., p. 80; Pl. H, Figs. 5, 6. Length 1.67 mm.; height 1.16 mm. Habitat: Kent county, Dela- ware. SUB-FAMILY LYNCEINE. GENUS CAMPTOCERCUS Baird. Camptocercus macrurus O. F. Miller. Camptocercus macrurus—E. A. Birge, Notes on Clad., p. 33. The specimen here tabulated under this genus is smaller than those found by Professor Birge in Wisconsin and by Professor Herrick in Minnesota; but, since they agree with Professor Herrick’s description in all other respects, it is thought that this is the right place for it. Habitat: Lockland, Ohio. Length 0.63 mm.; height 0.42 mm. GENUS LEYDIGIA Kurz. Leydigia quadrangularis Leydig. Leydigia quadrangularis—C. L. Herrick, Final Report Minn. Crust., p. 88; Pl. H, Fig. 4 Length 1.00 mm.; height 0.5mm. Habitat: Clifton, Ohio; Lock- land, Ohio; Atlanta, Georgia. GENUS DUNHEVIDIA King. Dunhevidia Setiger Birge. Crepidocercus setiger—E. A. Birge, Notes on Clad., p. 26; Pl. I, Fig. 18. Length 0.43 mm.; height 0.831 mm. Habitat: Cincinnati, Ohio. GENUS ALONA Sars. Alona quadrangularis Miller. Alona quadrangularis—C. L. Herrick, Final Report Minn. Crust., p. 97; Pl. E, Figs. 1, 2. Length 0.76 mm.; height 0.46 mm. In the specimen here assigned to the above named species the pigment fleck is as large as the eye and the spine on the terminal claw of the post-abdomen is pectinate at its base. Habitat: Baxley, Georgia. ENTOMOSTRACA OF MINNESOTA. 275 Alona affinis Leydig. Alona afinis—C. L. Herrick, Final Report on Minn. Crust., p. 98; Pl. F, Fig. 14. Length 0.79 mm.; height 0.46 mm. The specimens here tabulated are smaller than those found by other writers; but since they agree in all essentials with A. affinis they are placed here. In all probability they are immature individuals. Habitat: Kent county, Delaware; Fayetteville, Georgia. Alona porrecta Birge. Alona porrecta—E. A. Birge, Notes on Clad., p. 29; Pl. I, Fig. 16. Length 0.37 mm. to 0.58 mm.; height 0.22 mm. to 0.24 mm. Habi- tat: Atlanta, Georgia; Cincinnati, Ohio. Alona glacialis Birge. Alona glacialis—E. A. Birge, Notes on Clad., p. 30. Habitat: Cincinnati, Ohio. Rare. Alona intermedia Sars. Alona intermedia—C. L. Herrick, Final Report Minn. Crust., p. 101; Pl. I, Fig. 15. Habitat: Cincinnati, Ohio. GENUS PLEUROXUS Miller. Pleuroxus acutirostris Birge. Pleurocus acutirostris—E. A. Birge, Notes on Clad., p. 23; Pl. II, Fig. 15. This species seems to be very rare. I have only encountered it once. Then it was associated with Pleuroxus hamatus Birge, which it closely resembles in shape. The specimen resembled in all respects the specimens described by Professor Birge. Habitat: Atlanta, Georgia. Pleuroxus hamatus Birge. Pleurowus hamatus—E. A. Birge, Notes on Clad., p. 22; Pl. II, Figs. 13, 14. Length 0.46 mm. to 0.52 mm.; height 0.23 mm. to 0.33 mm. Habi- tat: Cincinnati, Ohio; Atlanta, Georgia. Im the northern part of Georgia specimens of this species are more plentiful than those of any other member of this genus. Pleuroxus denticulatus Birge. Pleuroxus denticulatus—E. A. Birge, Notes on Clad., p. 20; Pl. I, Fig. 21. Length 0.57 mm.; height 0.43 mm. Habitat: Cincinnati, Ohio; Kent county, Delaware; Atlanta, Georgia. 18 we’! J a ks Ae 2, © eee pa felh an Ml 276 GEOL. AND NAT. HIST. SURVEY OF MINNESOTA. GENUS CHYDORUS Leach. Chydorus spheericus Miiller. Chydorus sphericus—C. L. Herrick, Final Report Minn. Crust., p. 116; PI.!jF, Figs: 4, 7, 8, 10. Length 0.36 mm. to 0.42 mm.; height 0.31 mm. to 0.36 mm. Habi- cat: Ohio, Kentucky, West Virginia, Georgia. This species is very abundant. At Atlanta, Georgia, it can be found any time during the year. FAMILY POLYPHEMIDE. GENUS POLYPHEMUS De Geer. Polyphemus pediculus De Geer. Polyphemus pediculus—C. L. Herrick, Final Report on Minn. Crust., p. 121; PJ. B’, Figs. 4-6. Habitat: Baxley, Georgia. IP-ALR fe EGE STATES One ERs CINE TURNER Jel. BenG: PREFACE, Perhaps no other class of animals has been so much neglected by scientists as the American Ostracoda. With the European Ostracoda it is quite different. In Great Britain, Norway, Germany, Bohemia and along the shores of the Mediterranean Sea able naturalists have devoted many years of their life to the study of the Ostracoda of their respective countries. A perusal of the bibliography given below will show how well they have done the work. In his late monograph (221) Professor Wenzel Vavra devotes several pages to a historical resumé of the work that has been done upon the European Ostracoda. A1l| that has been done upon the recent American Ostracoda can be included in a Single paragraph, and a small one at that. The first scientist to study American Ostracoda was De Kay (58). In 1844 he described a few specimens from New York. This was fol- lowed in 1852 by an article by Professor Dana (57). In 1855 Lubbock (123) published a short article on South American Ostracoda. Next comes a paper by Chambers (41) on Colorado Crustacea. Between 1879 and 1881 Professor Herrick (83, 84, 85, 86) published several papers on this subject. His paper on ‘Alabama Crustacea”’ is by far the best article yet published on recent United States Ostracoda. Professor Moniez (142) has recently added a paper on Lake Titicaca Crustacea. Between 1892 and 1894 the present writer has contributed his mite (212, 213, 214, 215, 216) towards furthering the good cause. In 1893 Forbes (67*) published a description of a new species. The fossil Ostracoda have been studied by Jones (89,92) Brady (29) and Ulrich (217). In the present communication it is proposed to give complete de- scriptions of all known recent United States Ostracoda. In most cases the descriptions are made from dissections made by the writer. When this has not been possible the description of some American author has been incorporated. In all such cases the description is surrounded by quotation marks and the name of the author is mentioned. I here tender my thanks to Messrs. A. B. Whitby and L. D. Hile- land, who have so kindly collected for me material which otherwise would have been inaccessible. Mr. Whitby collected in Texas and southern Georgia, while Mr. Hileland coliected in Delaware. I here acknowledge my great indebtedness to Professor C. L. Her- rick, not only for the loan of rare literature and for the use of Plates LX, LXIII, LXIV, but also for the careful drawings of Cypris albu- querquensis and for alcoholic specimens. 280 GEOL. AND NAT. HIST. SURVEY OF MINNESOTA. BIBLIOGRAPHY. Baird, W. 1. Trans. Berw. Nat. Club., Vol. I, 1835. 2. Natural History of the British Entomostraca. (Mag. Zool. and Botany, Vol. II, 1838, p. 132.) 3. Description of some new species and genera of British Entomostraca. (Ann. and Mag. Nat. Hist., Ser. I, Vol. XVII, 1846, p. 410.) 4, Notes on the genus Cypridina, M. Edw. with description of two new species. (Ann. and Mag. Nat. Hist., Ser. I, Vol. I, 1848, p. 21.) 5, Natural History of the British Entomostraca. (Ray Society, 1850.) 6. Description of several new species of Entomostraca. (Proc. Zool. Soc., Lon- don, Vol. XVIII, 1850, p. 254.) 7. Monograph of the family Apodide and description of two new species of Cypris. (Proc. Zool. Soc., London, Vol. XX, 1852, p. 1.) 8. Some new species of Cypridina. (Ann. and Mag. Nat. History, Ser. III, Vol- VI, 1860, p. 139; and Proc. Zool. Soc., London, Vol. XXVIII, 1860, p. 200.) Barrois, Th., and R. Moniez. Matériaux pour servir a ]’étude de la faune des eaux douces des Acores. IV. SE Crustacés. Lille, 1888. 20 pp. Bosquet, J. 10. Description des Entomostracés fossiles des terrains tertiares de la France et de la Belgique. Bruxelles, 1850. Brady, G. S. 11. Species of Ostracoda new to Britain. (Ann. and Mag. Nat. Hist., Ser. III, Vol. XIII, 1864, p. 59.) 12. Undescribed Fossil Entomostraca from the Brick-earth of the Nar. (Ann. and Mag. of Nat. Hist., Ser. III, Vol. XVI, 1865.) 13. Report on the Ostracoda dredged amongst the Hebrides. (Brit. Assoc. Report, 1866, p. 208.) 14. New and imperfectly known species of Marine Ostracoda. (Trans. Zool. Soc., London, Vol. V, 1866, p. 359.) 15. Entomostraca. (Intellectual Observer, 1862, p. 446.) 16. Synopsis of recent British Ostracoda. (Intellectual Observer, 1867, p. 110.) 17, Crustacean Fauna of the Salt Marshes of Northumberland and Durham. (Nat. Hist. Trans. Northumberland and Durham, Vol. III, 1868, p. 1.) 18. Monograph on Recent British Ostracoda. (Trans. Lin. Soc., Vol. XXVI, 1868, p. 353.) 19. Contribution to the study of Entomostraca. (Ann. and Mag. Nat. Hist., Ser. IV, Vol. II, 1868, pp. 30, 178, 220; Vol. III, 1869, p. 45; Vol. IV, 1870, p. 450. ) 20. Descriptions of Ostracoda. (Berchon, De Folin, and Perier, Les Fonds de la Mer., Vols. I, II, and IV, 1867-86.) 21. Notes on the Ostracoda. (Nares’ Narrative of a Voyage to the Polar Sea, 1875-6, in H. M.S. S. ‘‘Alert’’ and ‘‘Discovery,’’ 1878, p. 253.) pris ENTOMOSTRACA OF MINNESOTA. , 281 22. Notes}onjEntomostraca taken chiefly in the Northumberland and Durham dis- trict. (Nat. Hist. Trans. Northumberland and Durham, Vol. III, 1870, p. 361.) 23. Review of the Cypridinidz of the European Seas. (Proc. Zool. Soc., 1871, p. 289, ) 24, Monograph of the Ostracoda of the Antwerp Crag. (Trans. Zool. Soc., Vol. X, 1878, p. 379.) 25. Report Voyage of H. M.S. ‘‘Challenger’’-— Ostracoda, 1880. 26, Notes on Entomostraca collected by Mr. A. Haly in Ceylon. (Lin. Soc. Jour- nal, Vol. XIX, 18835.) 27. Notes on Freshwater Entomostraca from South Australia. (Proc. Zool. Soc., 1886,) 28. Notes on Entomostraca. (Fifth Ann. Rep. Fishery Board of Scotland, Ap- pendix F, 1887, p. 328.) Brady, G. S., and Crosskey, W. H. 29, On. Fossil Ostracoda from the Post-tertiary Deposits of Canada and New England. (Geol. Mag., Vol. VIII, 1871.) Brady, Crosskey, and Robertson. 30. Monograph of the Post-tertiary Entomostraca of Scotland, and parts of Eng- land and Ireland. (Palzontographical Soc., 1874.) Brady and Norman. 31. A monograph of the marine and freshwater Ostracoda of the N. Atlantic and ofjN. W. Europe. Section I, Podocopa. (Trans. R. Dublin Soc., 1889:) Brady, G. S., and Robertson, D. 82. Notes on a Week’s Dredging in the West of Ireland. (Ann. and Mag. Nat. Hist., Ser. IV, Vol. III, 1869, p. 353.) 33. Ostracoda and Foraminifera of Tidal Rivers. (Ann. and Mag. Nat. Hist., Ser. IV, Vol. VI, 1870, p. 1.) 34, On the Distribution of British Ostracoda. (Ann. and Mag. Nat. Hist., Ser. IV, Vol. TX, 1872, p. 48.) 35, Ostracoda taken among the Sicily Islands, and on the Anatomy of Darwinula stevensoni. (Ann. and Mag. Nat. Hist., Ser. 1V, Vol. XIII, 1874, p. 114.) 86. Report on Dredging off the Coasts of Durham and North Yorkshire. (Brit. Ass, Rep., 1875, p. 185.) Braun, M. 37, Faunistische Untersuchungen in der Bucht von Wismar. (Arch. Freunde Naturg. Mecklenburg, 42. Jahrg. 28 pp.) Brown, Dr. H. G. 38. Die Classen und Ordnungen des Thier-reichs. V. Bd. Arthropoda, I. Halfte, Crustacea von Dr. A. Gersteecker, Leipzig und Heidelberg, 1866-1879. Carriere, Dr. Justus. 39. Die Sehorgane der Thiere vergleichend-anatomisch dargestellt. 1885. Carus, J. V. 40, Prodromus Faune Mediterranee. Arthropoda. 1885. Chambers, V. T. 41, On some new Entomostraca of Colorado. (Bull. United States Geological Survey, Vol. III, Art. IX.) 282 GEOL. AND NAT. HIST. SURVEY OF MINNESOTA. Chyzer, C. 42. Uber die Crustaceen-Fauna Ungarns. (In: Verhandl. d. k. k. Zoolog.-botan. Gesellschaft in Wien, p. 505, 1858.) Chyzer, C., and Toth, Alex. 43. Die Crustaceen der Pest-Ofener Gegend. (Naturfreund Ungarns, 1. Bd., 1857. 5. Heft, p. 84.) Claus, C. 44, Ueber die blassen Kolben und Cylinder an den Antennen der Copepoden und Ostracoden. (Wurzburg naturw. Zeitschr., 1. Bd., 1860, Taf. VII, Figs- 1, 2, 5.) 45, Ueber die Organisation der Cypridinen. (Zeits. f. wiss. Zool., Vol. XV, 1865, p. 143.) 46. Zur naheren Kenntniss der Jungenformen von Cypris ovum. (Zeits. f. wiss. Zool., Vol. XV, 1865, p. 391.) 47, Ueber die Geschlechts differenzen von Halocypris. (Zeits. f. wiss. Zool., Vol. XV, 1865.) 48, Beitrage zur Kenntniss der Ostracoden. (Schrift. der Gesells. z. BefOrd. d., gesam. Naturwiss. zu Marburg, Bd. IX, 1868, p. 151.) 49. Neue Beobachtungen iiber Cypridinen. (Zeits. f. wiss. Zool., Bd. XXIII. 1873, p. 211.) 50. Die Gattungen und Arten der Halocypriden. 1874. 51. Untersuchungen zur Erforschung der genealogischen Grundlage des Crusta- ceen-Systems. Wien, 1876. 52. Bemerkungen iiber Marine Ostracoden aus den Familien der Cypridinen und Halocypriden. (Arbeit. Zool. Inst. Wien und Zool. Stat. Trieste, T. VIII, Heft I, 1888, pp. 149-154. Wien. 53. Uber die Organisation der Cypriden. (Ausz. im Anzeig. kais. Akad. Wiss. Wien. VIII, 1890, pp. 55-60. Costa, 0. G., and A. 53a. Fauna del Regno di Napoli. Crostacei. Daday, E. 54, Beitrige zur Kenntniss der Crustaceen-Fauna der Umgebung von Klausen- burg. (Berichte Klausenburger medicin.-naturw. Vereins, 1881.) 55, Catalogus Crustaceorum Faunze Transylvaniz, 1884. Dahl, F. 56. Die Cytheriden der westlichea Ostsee. (Zool. Jahrbuch, Bd. III, Abth. f. Systematik, 1888.) Dana, J. D. 57. Crustacea of the United States Exploring Expedition, 1852. De Kay. 58, Nat. Hist. New York, VI, 1844. De Saussure, H. 59. Mémoire sur divers Crustacés nouveaux des Antilles et du Mexique. (Mem. de Soc. de Phipique et d’ Histoire Naturelle de Genéve, 1858.) 1 Desmarest, A. G. 60. Considerations Générales sur la classe des Crustacés. (Paris, 1825.) Egger, J. G. 61. Die Ostracoden der Miocain-Schichten bei Ortenburg. (Stuttgart, 1858.) pO, me, lacie Saar NS Te ENTOMOSTRACA OF MINNESOTA. 283 Ferrussac, Daudebert de. 62. Mémoire sur deux nouvelles Espéces d’Entomostracés et d’ Hydrachnes. (Cyclops miuilleri et Cypris reniformis). (Ann. et Mus. Hist. Nat., VII, 1806. ) Fischer, S. 63, Ueber die in der Umgegend von St. Petersburg vorkommenden Crustaceen aus den Ordnungen der Branchiopoden und Entomostraken. (Mém. des Sav. Etrangers, VII, 1847.) 64, Abhandlung tiber das Genus Cypris, (Mém. des Sav. Etrangers, VII, 1851.) 65, Beitrag zur Kenntniss der Ostracoden. (Abhandl. d. mathemat.-physik. Classe der KOniglich-Bayerischen Akad. der Wissenschaft., VII, 1855, pt. 3.) Fischer, Dr. Paul. 66, Crustaceés Ostracodes Marins des Cétes du Sud-Ouest de la France, 1877. Folin, Marquis De. 67. Faune lacustre de ancien Lac d’Ossegor, 1879. Forbes. S. A. 67a, A Preliminary Report on the Aquatic Invertebrate Fauna of the Yellow- stone National Park, Wyoming, and of the Flathead Region of Montana. Bull. U. 8. Fish Comm. for 1891, p. 207-258, pl. XXXVII-XLII. Pub- lished April 29, 1893. 2 Forel, F. A. 68. Die pelagische Fauna der Siisswasserseen. (Biol. Centralblatt, Jahrg. IT, 1883.) Fric, A. 69. Die Krustenthiere BOhmens, 1872. Fric, A., and Nekut, F. 70. Korysizemé Ceské. Prag. (Zeits. Ziva, v. J., 1867.) Frenzel, J. 71. Ueber die Mitteldarmdriise der Crustaceen. (Mittheil. Zoolog. Station. Neapel. V. Bd., 1884, 1. Heft.) Garbini. 72, Contrib. all’ Anatomia ed alla Istologia delle Cypridinz. (Boll. Soc. Entom. Ital., XIX.) Giard, A. 73. Le laboratoire de Wimereux en 1888, recherches fauniques. (Bull. Soe. France. Belg., 1 Année, 1888, pp. 492-513.) Gissler, Chas. F. 74, Contributions to the Fauna of the New York Croton Water. Microscopic observations during the years 1870-71. (New York, 1872, 23 pp., 5 pl.) Guerne, J. de. 75, Note sur la faune des Acores. Diagnoses d’un Mollusque, d’un Rotifére et de trois Crustacé nouveaux. (Naturaliste, Paris, 1887, 7 pp.) 76, Compagnes scientifiques du yacht monégasque L’Hirondelle. 3 Année, 1887. Excursions zoologiques dans les iles de Fayal et de San Miguel (Acores). (Paris, 1888, 110 pp., 1 Taf.) 284 GEOL. AND NAT. HIST. SURVEY OF MINNESOTA. 77. Un Ostracode nouveau pour la faune francaise. La distribution geographique de Cypris bispinosa Lucas. (Revue Biol.!Nord. France, 4 Année, 1893, No. 12, pp. 518-519.) Haldeman, C. 78. Proc. Phil. Acad., 1841 and 1842. Hallez, Paul. 79. Dragages effectués dans le Pas-de-Calais pendant les mois d’aofit et septembre 1888 et 1839. (Revue Biol. Nord. France, Lille, 1 Année, pp. 102-108; 2d Année, pp. 32-40.) Haupt. 80. Ueber Cypris im Allgemeinen nebst Beschreibung zweier neuer Arten. (Cor- respondenzbl. d. zoolog-mineralog. Ver. in Regensburg, 1850.) Heller, C. 81. Untersuchungen tiber die Crustaceen Tirols, 1870. Hellich, Boh. 82. O pohlavnim Ustroji rodu Cypris. (Oznamovatel I. sjezdu ceskych lékaru a prirodozpyteu, 1880. ) Herrick, C. L. 83. Microscopic Entomostraca. (Geol. and Nat. Hist. Survey of Minn., 7 Ann Report, 1879, pp. 81-123; pl. I-X XI.) 84. On New Forms of Copepod and Ostracod Crustacea from the Fresh Waters of the State of Minn. (Ann. Rep. Geol. and N. H. Survey for 1881.) 85. On Notodromas and Cambarus. (Minn. Geol. and Nat. Hist. Survey, 10th Ann. Rep., 1882, pp. 252-254; 1 fig.) 86. Contribution to the Fauna of the Gulf of Mexico and the South. List of Fresh Water and Marine Crustacea of Alabama, with Descriptions of the New Species and Synoptical Keys for Identification. (Memoirs of Denison Scientific Ass., Vol. I, 1887, No. 1.)} Imhof, 0. E. 87. Die pelagische Fauna und die Tiefseefauna der zwei Savoyerseen: Lac du Bourget und Lac d’Annecy. (Zool. Anz., 6 Jahrg., 1883, pp. 655-657.) Jeffreys, J. G. 88. Mediterranean Molluska and other Invertebrata. (Ann. and Mag. Nat. Hist., Vol. II, 1883, pp. 393-401, T. 16.) 89. Monograph on the Tertiary Entomostraca of England. (Palzeont. Soc., 1856.) 90. Notes on the Tertiary Entomostraca of England. (Geological Mag., Vol. VII, 1870.) 91. On some Fossil Ostracoda from Colorado. (Geological Mag., Decade II, Vol. III, 1886.) 92. Contributions to Canadian Micro-Palentology. 5. On Some Ostracoda from Cambro-Silurian, Silurian and Devonian Rocks. (Geol. Nat. Hist. Survey Canada, 1891, pp. 57-100, T. 10-13.) 93. On Rheetic and Liassic Ostracoda. (Quart. Jour. Geol. Soc., London, Vol. 50, 1894, P. II, pp. 156-168.) ‘ 94. Onsome Palzoic Ostracoda from Westmoreland. (Quart. Jour. Geol. Soc., London, Vol. 50, P. II, 1894, pp. 288-295.) he : “Sa ENTOMOSTRACA OF MINNESOTA. 285 Jones, T. R., and Sherborn, C. D. 95, Further Notes on the Tertiary Entomostraca of England. (Geol. Mag., De- cade III, Vol. IV, 1887.) Joseph, Gust. 96. Erfahrungen im wissenschaftlichen Sammeln und Beobachten der den Krainer Tropfsteingrotten eigenen Arthropoden Berlin. (Separat-abdr. aus der Berliner entomologischen Zeitschrift, Bd. X XV, 1882, Heft II, und Bd. XXVI, Heft I.) Jourdain, S. 97. Recherches sur les poils 4 batonett de l’antenne interne des Crustacés, précé- dées de quelques remarques sur les poils dit 6lfactifs. (Jour. Anat. Phys., 17 Ann,, 1881, pp. 402-418, F. 23 und 24.) Jurine, L. 98. Histoire des Monocles, qui se trouvent aux environs de Genéve, 1820. Kertesz, K. 99, Daten zur Ostracoden-Fauna der Umgebung Szeghalom’s. (Természetr. Fuzetek, Bd. XVI, 1894, Hefts 3 u. 4.) Kerville, G. de. 100. Les Crustacés de la Normandie, espéces fluviatiles, stagnales e terrestres. Bull. Soc. Amis Sc. N. Rouen, 1888, pp. 133-158.) King, R. L. 101, On Australian Entomostraca. (Proc. Roy. Soc. Van Diemen’s Land, Vol. III, pt. 1, 1855.) Koch, C. 1. 102. Deutschlands Crustaceen, Myriopoden und Arachniden, Heft 10, 1837; H. 11, 1837; H. 12, 1837; H. 21, 1838; H. 36, 1841.) Kolmodin, L. 103. Ostracoden silurica Gotlandie cum tab. (In Ofvers. k. vet. Akad., Forhdlgr. Stockholm, 1879, No. 9, pp. 133-139.) Korschagen, A. N. 104. Fauna of the neighborhood of Moscow, Entomostraca-Malacostraca, 1887. 4to (in Russian). Krause, Aurel. 105, Die Ostracoden der Silurischen Diluvialgeschiebe. (Berlin, 1891, 24 pp.) 106. Beitrag zur Kenntniss der Ostracoden-Fauna in Silurischen Diluvialge- schieben, mit 5 Taf. (Zeits. d. deutsch. Geol. Ges. 43 Bd., 2 Hft., pp. 488-521.) 107. Neue Ostracoden aus mirkischen Silurgeschieben, mit 2 Taf. (Zeits deutsch. Geol. Ges., 44 Bd., 1893, pp. 383-399.) Lang, Arnold. 108. Text-book of comparative anatomy, trans. by Bernard. (London, 1891, p. 290, etc.) Ledermuller. 109. Microscopische Gemiiths- u. Augen-erg6tzungen. I.S. 141, Taf. 43, Fig. d, 1761. ese ta we es ae ae eee: Bee eT ens SP ny Renee ale Ee Bi ak | ee aE CR ER : eat i er eS he Pee ey bem : ED oe ‘ Bator eee anys 2 see ig 5 H : MYR At * : aA ha ares et Cs eee eel oe A iz a g- 286 GEOL. AND NAT. HIST. SURVEY OF MINNESOTA. Lereboullet, A. 110. Note concernant l’ovaire de Cypris. (L’Institute XVI, nro. 773, 1848, p. 329.) \ 111. Note sur l’ovaire de Cypris. (Mémoires du Muséum @hist. nat. de Strass- bourg, IV, 1850, p. 211). Leslie, Geo., and Herdman, W. A. 112. The Invertebrate Fauna of the Frith of Fourth. (Edinburgh, 1881, pp. 42-52.) Leydig, F. 113. Naturgeschichte der Daphniden. (Tiibingen, 1860.) 114. Ueber Amphipoden und Isopoden. (Zeits. f. wiss. Zool., Supp. XXX, 1878, p. 225.) 115. Ueber Verbreitung der Thiere im Rhéngebirge und Mainthal mit Hinblick auf Eifel und Rheinthal. (Verh. nat. ver. d. preuss. Rhein]. w. Westf., 38 Jahrg., 1881.) Lienenklaus, E. 116. Ueber die Ostracoden des nordwestdeutschen Tertiars. (Verhdlgn. natur- hist. ver. preuss. Rheinl., 49 Jabrg., 1893, 1 Halfte Korr.-Blatt, pp. 58-59.) Lievin. 117.. Die Branchipoden der Danziger Gegend. Ein Beitrag zur Fauna der Provinz Preussen. (4° mit 11 Taf., Danzig, 1848.) Lilljeborg, W. 118. De Crustaceis ex ordinibus tribus Cladocera, Ostracoda et Copepoda in Scania occurrentibus, 1853. 119. Beskrifning ofver tva Grter Crustacea af ordningarna Ostracoda och Copepoda. (Ofvers. af K. Vet. Akad. Forhand, 1862, p. 291.) 120. Collections of chiefly Freshwater Crustacea from Sweden. (International Fisheries Exhibition, London, 1883. Sweden Special Catalogue, p. 140.) 121. De under Svenska vetenskapliga expeditionen till Spetsbergen, 1872-3, derstiides samlade Hafs-Entomostraceen. (Kongl. Vetenskaps.-Akad Forhandl, XXXII., No. IV., p. 3, 1874.) Linne, C. 122. Systema nature, VII vyd., 1748. Lubbock, J. 123. On the Freshwater Entomostraca of South America. (Trans. Entom. Soc., Vol. III, N. S., pt. IV, 1855.) 124. Onsome Entomostraca collected by Dr. Sutherland in the Atlantic Ocean. (Trans. Entom. Soc., Vol. IV, N. S., 1856, pt. IT.) 125. On some Oceanic Entomostraca collected by Capt. Toynbee. (Trans. Lin. Soc., Vol. XXIII, 1862, p. 173.) McIntosh, W. C. 126. Pelagic fauna of the bay of St. Andrews during the months of 1888. (7th Ann. Rep. Fish. Board of Scotland, pp. 259-310, T. 3-6.) Malcomson, S. M. 127. Recent Ostracoda of Belfast Lough. (Proc. Belfast Nat. Field Club, 1884-5, p. 259. ) ENTOMOSTRACA OF MINNESOTA. 287 Martens, Ed. 128. Ueber einige beim Finkenkrug gesammelte Sitisswassercrustaceen. (Sitz- ungsberichte Ges. Nat. Fr. Berlin, 1881.) May, Konv. 129. Ueber das Geruchsvermégen der Krebse nebst einer Hypothese tiber die analytische Thatigkeit der Riechharchen. Mit1 Taf. (Kiel, 1887.) Marsson, Th. 130. Die Cirripedien u. Ostracoden der weissen Schreibkreide der Insel Riigen- Mit 3 Taf. (Mittheil. naturwiss. Ver. von New. Vorpominern, 12 Jahrg., 1881, pp. 1-50.) Metschinkoff. 131. Arb. erst. Vers. russ. Naturf. Abth. d. Anat. und Physiologie, 1868, p. 56. Milne, Edwards. 132. Histoire naturelle des Crustacés. Tome III, p. 409, pl. 36, 1840. Mobius, K. 133. Systematische Darstellung der Thiere des Plankton, gewonnen in der west- lichen Ostsee und auf einer Fahrt von Kiel in dem Atlantischen Ocean bis jenseit der Hebriden. (5 Ber. Komm. Unters. d. Meere, Kiel 12-16. Jahrg. 1887, pp. 109-124, T. 7, 8.) Moniez, R. 134. List des Copépodes, Ostracodes, Cladocéres et quelques autres Crustacés recueilles a Lille en 1886. (Bull. Soc. Zool. de France, XII, 1887.) 135. Notes sur des Ostracodes, Cladoceres et Hydrachnides observés en Norman- die. (Bull. Soc. d’ Etudes Scient. de Paris, 1887.) 136. Faune des eaux souterraines de department du Nord et en particulier de la ville de Lille. (Revue Biol. Nord France, Lille, 1 Année, Crustacea, pp. 175-182, 241-257.) 137. Sur la faune de Hable d’Ault. (Revue Biol. Nord France, Lille, 1st Année, pp. 277-280, 346-350.) 188. Les males chez des Ostracodes d’eau douce. (Compt. rend. Ac. Se., Paris, T. 112, No. 13, pp. 669-672, and abs. in Journ. R. Micro. Soc., London, 1891, B:)3; p; o46-) 139. Faune des lacs salés d’Algérie. (Mémoire Soc. Zool. France, T. 4, P. 3-4, pp. 246-257.) 140. Les males chez les Ostracodes d’eau douce. (Revue Biol. Nord. France, 3 Ann., No. 9, 1893, pp. 354-356.) 141. Description d’une nouvelle espéce de Cypris vivant dans les eaux thermales du Hamman-Meshkontine, 7 figs. (Bull. Soc. Zool. France, T. 18, No. 3, 1893, pp. 141-142.) 142. Quelques Cladocéres et sur un Ostracode nouveaux du Lac Titicaca. Avec 13 figs. (Revue Biol. Nord. France, 1 Ann., No. 11, 1893, pp. 419-429.) 143. Sur la présence en Asie du Cypris Madarazi, Orley. (Revue Biol. Nord. France, 4 Ann., 1893, No. 2, p. 80.) Marzek, Al. P i 144. Ocysticerkoidech nasich korysu sladknovodnich. (Véstnik kral. Ceské spolecnosti nauk., 1890, Tab. V and VI.) 288 GEOL. AND NAT. HIST. SURVEY OF MINNESOTA. Muller, Fritz. 145. Bemerkung iiber Cypridina. (Jenaische Zeits., V., Heft 2, 1870, p. 255.) 146. Descripcao do Elpidium bromeliarum, crostaceo da familia dos Cytherideos. (Archiv. d. Mus. Nacional. Rio de Janeiro, 1V, 1879, p. 27.) Muller, 0. F. 147. Fauna insectorum Fridricsdalina, 1764. 148. Zoologix Danicze Prodromus, 1776. 149. Entomostraca, 1785. Muller, G. W. 150. Die Spermatogenese der Ostracoden. (Zool. Jahrbiich. Herausgeg. v. Spen- gel, III. Bd., 1889. Pp. 677-726; 2 pl.) 15]. Ueber Lebenweise und Entwicklungsgeschichte der Ostracoden. (Math. w. Nat. Berlin Akad., 1893, Heft V, pp. 239-266. ) Muller, Wm. 152. Zur niheren Kenntniss der Cytheriden. (Archiv. fiir Naturgesch., 1884, p. 1.) 153. Beitrag zur Kenntniss der Fortpflanzung und der Geschlechtsverhaltnisse der Ostracoden. (Zeitsch. f. d. gesamm. Naturwiss., 1880, p. 21.) 154. Ueber die Function der Antennendriise der Cytheriden. (Zeitsch. f. gesamm, Naturwiss., 1880, p. 213.) Nordquist, Osc. 155. Beitrag zur Kenntniss der inneren mannlichen Geschlectsorgane der Cypriden. 156. Die pelagische und Tiefsee-Fauna der grosseren finnischen Seen. (Z, An- zeiger, 10. Jahrg., 1887, pp. 339-345, 358-362. ) Norman, A. M. - 157. Contributions to British Carcinology. (Ann. and Mag. Nat. Hist., Ser. III, Vol. VIII, 1861.) 158. Species of Ostracoda new to Britain. (Ann. and Mag. Nat. Hist., Ser. III, Vol. IX, 1862.) 159. Reports Deep-Sea Dredging, Coast of Northumberland and Durham. Crus- tacea. (Nat. Hist. Trans. Nerthumberland and Durham, Vol. I, 1865.) 160. Report of Committee for Exploring the Coasts of the Hebrides. (British Ass. Report, 1866, p. 198.) 16l. Last Report of Dredging among the Shetland Isles. (Brit. Ass. Report 1868, p. 248.) 162. Report Valorous Expedition. (Proc. Roy. Soc., No. 173, 1876, p. 202.) 163. Notes on the Marine Crustacea Ostracoda of Norway. (Ann. Nat. Hist., (7) Vol. 7, pp. 108-121.) Orley, S. 164. Ueber die Entomostraken—Fauna von Budapest. (Természetrajzi Fuzetek X, 1886, pp. 7 and 98.) Pavesi, P. 165. Della mie annotorioni zoologiche. IV. Prime linee di uno studio zoologico delle nostre acque minerali. (Renconditi R. Instituto Lombardo, Vol. 14 1882, pp. 7-11.) 166. Altra serie di ricerche e studi sulla fauna pelagica di laghi italiani. (Atti. Soc. Veneto-Trent, Padova, Vol. 8, 1883, pp. 340-403, T. 8-14.) ete te Nae Tn eee te ENTOMOSTRACA OF MINNESOTA. 289 Peach, B. N. 167. On some new Crustaceans ‘from Lower Carboniferous Rocks of Eskdale and Liddesdale. (Trans. Roy. Soc. Edinburgh, Vol. 30, 1882, pp. 73-91, T. 7-10.) Pelseneer, P. 168. Note sur la présence de caridina desmaresti dans les eaux de la Meuse. (Bull. Mus. H. N. Belg., Tome 4, 1886, pp. 211-222.) Plateau, F. 169. Recherches sur les Crustacés d’eau douce de Belgique. (Mem. Couronnés et Mem. des Savants Etrangers, XX XIV, 1868.) Poggenpol M. J. 170. List of the Copepoda, Cladocera and Ostracoda of the Environs of Moscow. Russian. (Translation in: Trans. Kansas Acad. of Science, Vol. VIII, 1883. ) Poppe, S. A. 17]. Notizen zur Fauna der Stisswasserbecken des nordwestlichen DeutsehJand mit besonderer Berticksichtigung der Crustaceen. (Abh. Nat. Ver. Bre- men, 10. Bd., 1888, pp. 295-300.) Ramdohr, K. A. 172. Beitrige zur Naturgeschichte einiger deutschen Monoculus-arten, Halle, 1805. 173. Ueber die Gattung Cypris Miill. und drei derselben gehdrige neue Arten. (Mag. d. Gesell. naturforsch. Freunde in Berlin, Jabrg. II, 1808, pp. 83- 93, Taf. III.) Rehberg, H. 174. Beitrage zur? Naturgeschichte niederer Crustaceen [Cyclopiden und Cypri- den]. (Abhandlung herausg. vom naturw. Vereine zu Bremen. Bd. IX, 1884.) Reuss, A. E. 175. Die fossilen Entomostraceen des osterreichischen Tertiarbeckens. (Natur- wiss. Abhandlungen, III, 1847, p. 41.) Robertson, D. 176. Notes on the Ostracoda and Foraminifera of the Firth of Clyde. (Trans. Geol. Soc. Glascow, Vol. V, pt. I, p. 112, 1874.) 177. Notes on a Raised Beach at Cumbre. (Trans. Geol. Soc. Glasgow, 1875.) 178. Notes on Cypris levis and its habit of perforating the leaves of Victoria regia. (Proc. Nat. Soc., Glascow, Vol. II, 1875, p. 7.) 179. Post-tertiary Deposits by Tunnel at Arkleston near Paisley. (Trans. Geol. Soc., Glascow, 1876, p. 292.) 180. Garnoch Water Post-tertiary Deposits. (Trans. Geol. Soc., Glascow, 1876 p. 281.) 18]. Post-tertiary Deposit at ;Misk-Pit and Kilwinning. (Trans. Geol. Soc. Glascow, 1877, p. 297.) 182. Noteson the Fauna and Flora of West Scotland, p. 38, 1876. 183. Ostracoda of Scotland. (Append. to Pt. I of Proc. Nat. Hist. Soc., Glascow, TV, 1880.) 290 GEOL. AND NAT, HIST. SURVEY OF MINNESOTA. Forse 184. Fauna of Scotland, with special reference to Clydesdale and the western dis- tricts; Fresh and Brackish Water Ostracoda. Glascow, 1880. 185. Post-tertiary Beds of Garvel Park, Greenock. (Trans. Geol. Soc., Glascow, 1883, p. 1.) Rochebrune, A. T. 186. Observations sur la Cypris fusca. (Act. Soc. Lin. de Bordeaux, XXIV, 1861, p. 77.) Saccardo, P. D. 187. Cenni Storico-naturali intorno agli animaletti Entomostracei, etc. Treviso, 1864. Sars, G. 0. 188. Om eniSommeren 1862 fortagen Zoologisk Reise. Christiania, 1863. 189. Oversigt of Norges marine Ostracoder, 1865. 190. Nye Dybvandscrustaceer fra Lofoten. (Vidensk-Selks. Forhand, 1869, p. 170.) 191. Undersdgelser over Christianiafjordens Dybvandsfauna, 1869. 192. Undersdégelser over Hardangerfjordens Fauna. I. Crustacea. (Vidensk- Selks. Forhand, 1871, p. 278.) 193. Den Norske Nordhavs-Expedition 1876-1878, Vol. 15, Crustacea II, 1886; 96 pp. 194. Nye Bidrag til Kundskaben om Middelhavets Invertebratfauna. IV, Ostra- coda Mediterranea. (Archiv. f. Math. og Naturvidenskab, 1887.) 195. On some Freshwater Ostracoda and Copepoda raised from dried Australian mud. (Christiania Vid. Selsk. forh. f. 1889, No. 8, 79 pp., 8 Taf.) Sars, Michael. 196. Om dei Nordge forekommende fossile dyrelivningen fra Quartzerperioden. Christiana, 1865. Schneider, Rob. 197. Ueber Eisenresorption in thierischen Organen und Geweben. (Abh. Akad. Berlin, 1888, 66 pp., 3 Taf.) Schnur. 198. Systematische Aufzaihlung der Crustaceen, Arachniden und Myriopoden in der Umgebung von Trier. (Ges. f. niitzliche Forschungen zu Trier, 1856.) Schwarz, 0. G. 199. Ueber die sogenannte Schleimdriise der madunlichen Cypriden. (Berichten der Natur. f. Gesells. zu Freiburg, Bd. III, 1888, p. 5.) Seguenza, G. 200. Le Formazioni Terziarie nella provincia di Reggio (Calabria), 1880. 201. II Quaternario di Rizzolo. II. Gli. Ostracodi. (II. Naturalista Siciliano, Anno III, 1883.) Sostaric, Dragutin. 202. Prilog poznavanju faune slatknovodnih korepnjaka hrvatske. (Prést. iz XCII, knjige Rada jugoslavenske akademije znanosti i umijetnosti, W. Zagrebu, 1888. ) Speyer, 0. 203. Die Ostracoden der Casseler Tertiarbildungen. Cassel., 1863. ENTOMOSTRACA OF MINNESOTA. 291 Stimpson, W. 204. Synopsis of the Marine invertebrata of Grand Manan. (Smithsonian Con- tributions, 1853.) Straus, H. E. 205. Mémoire sur les Cypris. (Mém. du Museum, Vol. VII, 1821.) Stuhlman, F. 206. Beitrage sur anatomie der inneren madnnlichen Geschlectsorgane und Sper- matogenese der Cypriden. (Zeits. f. wiss. Zool., X LIV, 1887, p. 536; and Zoologischen Institut. zu Freiburg, I. B , 1886.) Terquem, M. 0. 207. Les Foraminiféres et les Entomostracés-Ostracodes du Pliocéne supérieur de l’lle de Rhodes. (Mém de la Soe. Géol. de France, Sér. III, Vol. I, 1878.) Terrigi. 208. Sulla fauna microscopica del calcare zancleano di Palo. (Atti. R. Accad. Lincei-Transunti, Vol. 6, 1882, pp. 253-256.) Thompson, G. M. 209. New Zealand Entomostraca. (Trans. New Zealand Institute, Vol. XI, 1878.) Toth, Alex. 210. Die in neuester Zeit zu Pest-Ofen gefundenen Schalenkrebse und ihre anat- omischen Verhiltnisse. (Verhdlgn. d. Zool.-bot. Gesell. Wien, XIII, 1863, p. 47.) Treviranus (both). 211. Abhandlung iber den inneren Bau der ungefltigelten Insecten. (Vermischte Schriften anatomischen und physioloischen Inhalts, 1816.) Turner, C. H. 212. Notes on the Cladocera, Copepoda, Ostracoda and Rotifera of Cincinnati, with des. of new sp. (Bull. Sci. Lab. of Denison Univ., Vol. VI, pt. II, 1£92, pp. 57-74; pl. I-11.) 213. Additional Notes on the Cladocera and Ostracoda of Cincinnati, Ohio. I Systematic Part, with des. of new species. II Late Larval History of Cypris herricki. (Bull. Sci. Lab. Denison Univ., Vol. VIII, Part 1, 1893, pp. 1-18, pl. I-I1.) 214. Preliminary Note on the Nervous System of the Genus Cypris. (Jour. of Comp. Neurology, Vol. III, 1893, pp. 35-40; pl. III and IV.) 215. Notes on American Ostracoda, with Description of new species. (Bull. Sci. Lab. Den. Univ., 1894, Vol. VIII, Part II, pp. 13-25, pl. VII and VIII.) 216. List of Known American Ostracoda, with description of new species. (Amer. Naturalist, 1894. [?]) 217. Ulrich. __v. La Valette St. George. | 218. Ueber die Genese der Samenkédrper. Dritte Mittheilung. (Arch. fiir mikroskop. Anatomie. Bd. X, 1874, p. 497.) _ Vavra, V. 219. Uber das Vorkommen einer Siisswasser-Cytheride in BOhmen. (Zool. Anz., XIV, Jahrg. No. 357, 1891, p. 77.) 19 292 GEOL. AND NAT. HIST. SURVEY OF MINNESOTA. 220. Kritisches Verzeichnis der Ostracoden Bohmens. (Sitzgsber. Kgl. bohm. Ges. d. Wiss., 1891, pp. 159-168. ) Vavra, Wenzel. 221. Monographie der Ostracoden BOhmens. (Prag, 1891.) Vernet, H. 222. Acanthopus, un nouveau genre d’Ostracodes. (Forel, Matériaux pour servir a l’étude dela Faune profonde du Lac Leman, 1Ve Série, 1879, p. 408.) Vejdovsky, F. 223. 0. povodu fauny studnicné, Slavnostni predndska ve vyroenim sezeni krAl. (Ceské spol. nauk v Praze dune 3. Cervna 1880.) 224. Thierische Organismen der Brunnenwasser v. Prag. Mit 8 Taf. 1882. Wagner, R. 225. Beitrage zur Kenntness der Samenfitissigkeit der Thiere. (Arch. f. Naturg. von Wiegmann (Troschel). II Jahrg., 1836, 1 B., p. 369.) Weismann, A. 226. Parthenogenese b. d. Ostracoden. (Zool. Anz., Vol. III, 1880, p. 82.) Weismann, A., and Ischikava, C. 227. Ueber die Bildung der RichtungskOrper bei thierischen Eiern. 4 Taf. (Be- richte der Naturforsch. Ges. zu Freiburg, Bd. III, 1887.)” Wierzejski, A. 228. Materialen zur Kenntniss der Fauna der Tatraseen. (Ber. physiograph. comm. Acad. Krakau, 1882, 16 Bd., pp. 1-24 (Polish).) Woodward, H. 229. A Catalogue of the British Fossil Crustacea. British Museum, 1887. Zacharias, 0. 230. Die Thierwelt der Eifelmaare. (Biol. Centralbl., 8 Bd., 1888, p. 574.) 231. Zur Kenntniss der Fauna des Siissen und Salzigen Sees bei Halle a|s. (Zeit. f. wiss. Zool., 46 Bd., 1888, pp. 217-232.) 232. Bericht liber eine zoologische Excursion an die Kraterseen der Eifel. (Biol. Centralblatt, 9 Bd., 1889, pp. 56-64, 76-80, 107-113.) 233. Faunistische Untersuchungen in den Maaren der Eifel. (Zool. Anz., 11 Jahrge., 1888, pp. 705-706. ) Zaddach, E. G. 234. Synopseos Crustaceorum Prussicorum Prodromus, 1844. Zenker, W. 235. De natura sexuali generis Cypridis. (Dissert. inaug. Berolini. ¢. tab. 1,. 1850.) 236. Ueber die Geschlectsverhiltnisse der Gattung Cypris. (Archiv, fiir Anatomie u. Physiologie. Herausg. von Dr. J. Miiller, pp. 193-202, Taf. V, 1850.), 237. Anatomisch-systematische Studien iiber die Krebsthiere. Berlin, 1854. 238. Monographie der Ostracoden. (Weigmann’s Archiy. f. Naturg., Tome XX,. I. Bd., 1854, pp. 1-87, Taf. I-VI.) INTRODUCTION. The Ostracoda form a well-defined division of the Hntomostraca. Like the Lamellibranchiata the body is always enclosed in a bivalve shell, which is closed by powerful abductor muscles. No doubt the casual observer often mistakes the Ostracoda tor miniature mollusks. Yet the resemblance is all on the surface; for, although the structure of the enclosed Ostracodan is quite primitive, yet it is decidedly crus- tacean. The body always bears seven pairs of articulated appendages. The first five of these belong to the head; but, in different groups, either or all of the last three of these cephalic appendages may be modified for walking. The last two pairs of members belong to the body and are properly called legs or feet. In some cases, however, (Cypris) the last pair of legs is never used for locomotion. In most cases the abdomen bears a pair of appendages, which usually resemble one-jointed legs. Morphologically they probably are legs which have been arrested in their development. It is thought that a brief resume of the steps by which the Ostra- codes have been assigned to their present taxonomic position may be of interest. Linneeus (or Linné) Hered all of the lower Crustacea in his genus ~ Monoculus. O. F. Muller divided the lower Crustacea into several genera, Col- lectively they were called the ‘‘Entomostraca.”’ Latreille and Cuvier were the first to separate the Crustacea from the Jnsecta. Basing their judgment upon the morphology of the ‘mouth parts, they divided the lower Crustacea into two artificial groups, the Branchiopoda and the Poecilopoda. The first division included the Phyllopoda and Lophyropoda, while the Ostracoda fell into the second division. Following in the footsteps of Latreille, Milne-Edwards, with the / mouth parts for criteria, established an artificial system of classifica- tion for the Crustacea. Separating the Copepoda and Ostracoda from Latreille’s Branchiopoda, he united them in the group Entomostraca. Dana modified slightly Latreille’s system. The first attempt to form a natural system of classification for the ever Crustacea waS made by Zenker. He separated the Copepoda 4 294 GEOL. AND NAT. HIST. SURVEY OF MINNESOTA. from the Ostracoda and used the name Hntomostraca as a group name for the Siphonostoma and Lernaeoda. Claus used the word Hntomostraca in a different sense. The Phyl- lopoda, Ostracoda, Copepoda and Cirripedia were collectively called the Entomostraca. Professor G. O. Sars has divided the Ostracoda into the following four sections: 1. Podocopa, 2. Myodocopa, 3. Cladocopa, 4. Platycopa. All of the members of sections 2, 3 and 4 and a portion of those belong- ing to section 1 are marine, Brady and Norman have divided the Podocopa into the following families: Family I.—Cypridide. Family U.—Bairdiide. Family I11.—Darwinulide. Family 1V.—Cytheride. Family V.—Paradoxostomatide. This article treats exclusively of the first and third families. FAMILY CYPRIDIDE. ‘Shell generally thin and horny; valves equal or but slightly une: qual in size, surface usually smooth, or simply punctated; ventral margins more or less sinuated; hinge margins edentulous. Eyes sim- ple, usually confluent, sometimes wanting. Antennules (first anten- ne) slender, usually seven-jointed, very flexible, usually provided with a number of long hairs forming a dense brush. Antenne (sec- ond antenne) pediform, geniculated, four- or five-jointed, clawed at the apex, second joint mostly bearing an apical brush of hairs. Man- dibles strong, apex strongly toothed, palp four-jointed, with a setifer- ous branchial plate at the base. Two pairs of maxille, the first pair four digitate; its external branch distinctly two jointed, bearing a large setiferous branchial plate; second pair small, composed of a | single prehensile lobe and palp, which in the female is generally sim- — ple, rarely pediform, is in the male prehensile. Two pairs of feet dis- similar in structure, the anterior pair strong, ambulatory, directed | downwards, and having a long curved apical claw; posterior bent backwards within the shell, and not used for motion. Caudal rami — usually well developed, elongated, very mobile, and bearing two or three apical claws. Intestine forming two dilations, of which the an- ; terior is provided with ececal appendages. Generative organs large, — and of complex structure, and partly extended within the valves; in ~ the male frequently a whorled sac connected with the testis; copula- ENTOMOSTRACA OF MINNESOTA. 295 tory organs symmetrica!, and of moderate size.’ (Brady and Norman. ) It is thought that the following modification of Wenzel Vavra’s key will serve to differentiate the genera. KEY TO THE FAMILY CYPRIDIDE. I. The second foot terminates with a cylindrical joint that bears two backwardly directed setz. A. The second foot of the female and the male six-jointed. No branchial plate attached to the second maxillez. Notodromas, 295 B. The second foot of the female five-jointed and of the male six-jointed. The second maxilla bears a branchial plate. a. The branchial plate is feebly developed in the form of two pectinated bristles. * The eye is developed. . : : ; : Candona, 298 ** The eye is absent. ; ; 5 *Typhlocypris. b. The branchial plate is Ae elonedi in the form of three pec- tinated bristles. P . . *Candonopsis. ce. The branchial plate is in ‘ne fred of six x pachinated bristles. * The palp of the second maxilla is rudimentary. . *Ilyocypris. ** The palp of the second maxilla is normally developed. { The terminal joint of the second foot is as long as one-third of the fourth joint. : : : Cypria, 304 tt The terminal joint of the second foot is as long as two-thirds of the fourth joint. . : Cycloeypris, 310 II. The second foot terminates in a beak-shaped joint that bears one backwardly directed claw. A. Caudal rami are rudimentary. : : : Cypridopsis, 312 B. Caudal rami are cylindrical with two corminial claws. * Natatory sete of the antenne short. {t These setce not reaching to the tips of the terminal claws. Erpetocypris, 315 tt These set not reaching to the base of the terminal claws. *Scottia. ** Natatory sete of the antenne long, reaching to or beyond the tips of the terminal claws. {+ Parthenogenetic. . ‘ : j : : : Cypris, 319 Tt Sexual. : ; : : : : : Cyprinotus, 329 (*Not noticed in the text. ) In the above table an attempt has been made to tabulate all known freshwater genera of the Cypridide. The genus Stenocypris Sars has. been omitted because the data at my disposal do not seem to warrant its separation from the genus Hrpetocypris Brady and Norman. Of the twelve genera here mentioned, nine have been found in America. GENUS NOTODROMAS Lilljeborg. 1853. In shape the shell of the male is quite different from that of the female. ‘ The antennules are seven jointed. 296 GEOL. AND NAT. HIST. SURVEY OF MINNESOTA. In both males and females the antenne are six-jointed. The nata- tory sete extend to beyond the tips of the terminal claws. There is no branchial plate on the second maxilla. The palp of this jaw is two-jointed. In the female the distal joint is short and cylindrical, bearing at its apex two short sete; in the male the distal joint forms a long scythe-shaped appendage. The second foot is five jointed, terminating in three sete, two of which are directed backwards. The two eyes are not confluent. The abdominal rami are long and slender. Males are numerous. The cylindrical core of Zenker’s organ (verticillate sac) is ornamented with numerous closely set whorls of short stout spines. Notodromas monacha (O. F. Miller). PLATE LXXII, Fie. 4-45. 1785.—Cypris monacha O. F. Miller (149), p. 60, Taf. V, Figs 6-8. 1820.—Monoculus monachus, Jurine (98), p. 173, Pl. XVIII, Figs. 13-14. 1837.—Cypris variabilis Koch (102), H. 10, 3. 1837.— ‘‘ lencomela Koch (102), H. 10, 4. 1837.— ‘* monacha Koch (102), H. 11, 1. 1837.— ‘* bimuricata Koch (102), H. 11, 2. 1837.— ‘‘ nubilosa Koch (102), H. 12, 4. 1814.— ‘* monacha Zaddach (234), p. 31. 1850.— ‘‘ monacha Baird (2), p. 153; Pl. IV, Figs. 1-11. 1851.— ‘‘ monacha Fischer (64), p. 146. 1853.—Notodroma monachus Lilljeborg (118), p. 95; Taf. VIII, Figs. 1-25; Taf. XII, Figs. 13; Taf. XXV, Fig. 16. 1854.—Cyprois monacha Zenker (233), p. 80; Pl. III, C. 1868.— ‘ monacha Plateau (169), p. 60; Pl. I, Figs. 22-23. 1868.—Nolodromas monachus Brady (18), p. 379; Pl. XXIII, Figs. 1-9; Pl. XXXVIL Fig. 3. 1870.—Notodromas monachus Heller (81), p. 78. 1872.—Cypris monacha Fric (69), p. 228. 1880.—Notodromas monachus Robertson (184), p. 22. 1882.— st monachus Herrick (85), p. 252. 1885.— © monachus Nordquist (155), Pls. I, I] and IV. 1887.— es monachus Korschagen (104), p. 24. 1888.—Cyprois monacha Schwarz (199), p. 11. 1889.—Notodromas monacha Brady & Norman (31), p. 96. 1891.— oy monacha Wenzel Vavra (221), pp. 32-39; Figs. 7 9. This species does not seem to be as abundant in America as in Europe. I have never encountered it. The figures that accompany this description are Professor Herrick’s (86), and the following diag- nosis is due to Professor Brady (18): ‘“MaLp.—Carapace obliquely sub-quadrangular, greatest height equal to two thirds of the length, situated in the middle. Anterior ENTOMOSTRACA OF MINNESOTA. 297 margin broad, rounded at the angles, and expanded into a flattened lamina or flange. Ventral margin straight for about two-thirds of its length, then bending upwards at an obtuse angle. Dorsal margin arched, almost angular in the middle, whence it slopes steeply to the anterior border and with a bold curve towards the posterior extremity, joining the ventral margin at an acute angle. Seen from above, the carapace is ovate, pointed in front, and rounded behind; the greatest breadth in the middle. The ventral surface is bounded by two con- Spicuous, elevated, arcuate ridges, one at each valve, which together enclose a flattened lozenge-shaped area. Parallel to the contact margin of each valve runs another straight but much less conspicuous ridge, which towards the front curves outward, and joins the external ridge at an acute angle, the union of the two forming a slight eleva- tion, from which a single ridge runs forward, gradually merging in the flattened encircling flange of the anterior border. Seen from the front, the shell is sub-triangular, the sides convex, but flattened, the dorsum forming a flattened arch; the ventral border perfectly flat, and bounded by the projections of the outermost ventral ridges; the inner ridges form also conspicuous projections, which run obliquely upwards and inwards towards the flattened anterior flange. Lucid spots, about six, oblong and irregularly placed, their long diameters pointing transversely across the valve. Surface of the shell smooth and shining, marked by fine impressed lines forming a pattern simi- lar to the imbrications of fish-scales. Color pale greenish or white, transparent, with large and irregularly spread patckes of deep olive- green or black. ‘*WEMALE.—Sub-quadrangular. Anterior border flattened, flanged, forming with the ventral margin a well-marked angle; rounded above. Dorsal margin boldly arched, highest at the posterior third, whence it sweeps round with a deep curve to the postero-ventral angle. Ventral margin straight, slightly rising behind, and terminating in a flattened squamous plate, which projects backwards, with the appear- ance of aspine. The other aspects are similar to those of the male shell, except that the ventral surface of the left valve has at the pos- terior extremity of its contact margin a flattened squamous plate, which is received into a corresponding depression of the opposite valve.”’ - Professor Brady (18) states that the branchial plate of the mandib- ular palp arises from the lower side of the palp, thus differing con. siderably from other Cyprididw. Professor Vavra (221), however, says that the branchial plate arises from the upper side of the mandibular palp. ‘The first foot in both sexes terminates in three curved SEN the central one being the strongest and longest. * * * * * * % , 4 ta \ es «Se Cer ee ERS TR Oe 298 GEOL. AND NAT. HIST. SURVEY OF MINNESOTA. “The ‘glandular mucosa’ [Zenker’s organ] consists of a central eylinder, closely beset with radiating filaments, arranged in 50 to 60: transverse rows, the whole organ being imbedded in a sort of glairy matrix. The two glands are connected each by an efferent duct with the ‘bursa copulatriz,’ an organ of very complicated structure, and con- sisting ofa much convoluted canal (? vesicula seminalis), an intromittant organ or penis, and two hooked appendages. The whole organ is very dense in structure, consisting probably of chitin, deep brown in color, and, with the ‘glandulz mucosz,’ constitutes a very considerable por- tion of the male carapace. It should be noted that the ‘bursa copula- trix,’ as well as the testis,* is a double organ, one on each side of the median line. The two burse lie closely in apposition but are not in organic connection except at the upper margin, where they are held together by a ligamentous tissue. Length . in. (1.1 mm.), height ay in. (0.78 mm.).’? Habitat: Minnesota (Herrick ’85). GENUS CANDONA Baird. 1850. This genus, which was founded by Professor Baird (5) has recently been more restricted by Mr. Wenzel Vavra (221). In this connection the genus is used in Vavra’s restricted sense. In the female the antenna is five-jointed. In the male, owing toa division of the fourth joint, the antenna is six-jointed. At the division between the fourth and fifth joints of the male antenna two character- istic olfactory hairs are situated. The distal extremity of the third joint is not supplied with a brush of natatory sete. The rudimentary branchial plate of the second maxilla is composed of two, unequal, pectinated setce, which are attached directly to the basal portion of the maxilla. In the female the palp of this maxilla is two-jointed, and terminates with three unequal pectinated bristles. In the male this palp, which is then unjointed, differs in shape from that of the female- The second foot, which may be either five or six-jointed, terminates with three sete; two unequally long, backwardly directed, sete and one forwardly directed seta. The strong post-abdomen (abdominal ramus) bears two terminal claws. The seta on the caudal border of the ramus is quite remote from the end. At the origin of this ramus the dorsum of the body terminates in a short seta. The eye is small. Males are common, larger than the females. Seven circles of chitinous spines are arranged around the central cylinder of Zenker’s organ. The copulative organ is not so complex as that of Notodromas. * Dr. Brady uses testis as a synonym for Zenker’s organ. It is now well known that this organ is not the testis. a ENTOMOSTRACA OF MINNESOTA. 299 The absence of natatory set from the antenne prevents the mem- bers of this genus from swimming. They creep along the bottom and frequently burrow in the mud or sand. Candona fabzeformis (Fischer. ) PLATES LXXV, Fias. 10, 11; LX XVI, FIas. 6, 8. 1851.—Cypris fabeformis Fischer (64), p. 146; Pl. III, Fig. 6-16. 1853.—Candona fabeformis Lilljeborg (118), p. 207. 1870.— ‘' diaphana Brady and Robertson (33), Pl. V, Figs. 1-3. 1889.— ‘* fabeformis Brady and Norman (31), p. 103; Pl. IX, Figs. 1-4. 1891. ‘*‘ = fabseformis Wenzel Vavra (221), pp. 45-48; Figs. 6, 2; Figs. 12, 1-9; Fig. 13. Length 1.03 mm. Height 0.49 mm. Width 0.38 mm. The shell is more than twice as long as high and nearly three times. as long as wide. The shell being pellucid, the color of the enclosed body shines through the lorica and gives it a greenish yellow tint. Viewed from the side the shell of the female is sub-reniform; great- est height situated behind the middle; obtusely and evenly rounded in front, obliquely rounded behind. Ventral margin sinuated. Viewed from above the shell is compressed, tapering equally and suddenly to the two pointed extremities; sides almost parallel. Near each extremity a process from the left valve overlaps the right. The projection near the caudal extremity is much more pronounced than the other. The antenne are stout; the smooth terminal claws are slightly curved and are not quite as long as the combined lengths of the last three joints. Natatory sete are absent. For the arrangement of sete consult the figures. : The second foot is six-jointed. The abdominal rami are strong. In the female they are curved. The terminal claws are stout, curved and pectinate; the shorter claw is a little more than three-fourths as long as the other. The longer claw is about half as long as the entire ramus. Habitat: The only specimens yet found in America were found in a small spring-fed water tank on Clark University campus, Atlanta, Georgia, Aug. 30, 1894. Candona acuminata (Fischer. ) PLATE LXXI, Fia. 34. 1851.—Cypris acuminata S. Fischer (64), p. 148; Pl. IV, Figs. 12-16. 1854.— ‘ or Zenker (238), p. 74; Pl. II, D. 1889.— ‘ es Brady and Norman (31), p. 104; Pl. IX, Figs. 9-10; Pl. X, Figs. 5-6. 1894.— ‘* 4 C. H. Turner (215), p. 19; Pl. VIII, Fig. 34. 300 GEOL. AND NAT. HIST. SURVEY OF MINNESOTA. Length 1.25 mm. Height 0.58 mm. Width 0.46 mm. The shell is smooth, white, and elongated. It is more than twice as long as high and about three times as wide. Viewed from the side, the shell is sub-reniform, highest in the middle. Viewed from above, the shell is sub elliptical with pointed extremi- ties. The widest portion is in the middle. One valve is a trifle longer than the other. The antenne are stout. The natatory sete are absent and the ter- minal is long and non-pectinated. The post-abdomen (Fig. 34) is curved and slender. The terminal claws are slender and pectinated. Habitat: San Antonio River, Texas. I have seen only three speci- mens of this species. They were collected for me by Mr. A. B. Whitby. Candona crogmani Turner. PLATES LXXI, Figs. 24-33; LXXXI, Fias. 4-5. Candona crogmaniana—C. H. Turner (215), p. 20; Pl. VIII, Figs. 24-33. Length of female 1.52 mm. Height 0.76 mm. Width 0.58 mm. This form is about the size of the elongated variety of Candona can- dida. The two most obvious differences are: 1, the inequivalve shell with pointed extremities; 2, the second foot is six-jointed. The shell is very thin, so thin that the ova and spermatozoids are visible through it. It is glossy and is covered with short scattered hairs. These hairs are more numerous around the margins than else- where. In the living specimen the body shines through the pellucid shell and gives it a greenish yellow tint. Numerous Vorticellide are usually found attached to the lorica. Viewed from the side (Fig. 33), the female is sub-triangular, the caudal third being the highest portion. The caudal, dorsal and ceph- alic margins are convex. The ventral margin is slightly sinuate, be- ing concave in the middle. Viewed from above (Fig. 32), the shell is an elongated ellipse, pointed at both ends. One valve is longer than the other and over- laps it at each extremity. The antenna (Fig. 25) is five-pointed in the female. Near the proximal end of the lower margin of the first joint there is one elon- gated filament and one short, pectinated, dagger shaped filament. The terminal claws are slender, non-pectinated and long—longer than the combined lengths of the last three joints. The antenna of the male is six-jointed. ae ENTOMOSTRACA OF MINNESOTA. 301 The mandibular palp (Fig. 31) is five-jointed. The first joint is large and bears at the distal angle of its inner margin a short dagger- like seta (Fig. 31). The distal half of this seta is pectinate. The mandibular blade is stout. The spines of the first mandibular process of the first maxille are non-pectinated. The first foot (Fig. 29) is long and slender and is composed of five joints. The second joint is about as long as the next two joints. The third and fourth joints are of about the same length. The fifth joint is the smallest of all. It is conical and from its distally directed apex arises the terminal claw. The terminal claw is slender and long. It is longer than the combined lengths of the last three joints and the distal portion is flexuose, The fourth joint of the second foot (Fig. 30) is somewhat obscurely divided into two joints, so that the second foot appears, under a high power, to be composed of six joints. The foot terminates in two long flexuose filaments and one shorter filament. The post-abdomen (Fig. 28) is of medium size. The terminal claws are slender, pectinated and curved. The terminal claw is about half as long as the abdominal ramus. The adjacent claw is a little shorter than the terminal claw. The filament in the caudal margin is about one-third the length of the ramus from the distal extremity of the post-abdomen. Habitat: Atlanta, Georgia, December, 1893. Abundant in the shallow ponds near South River. The ponds in which these speci- mens were found dry up in warm weather. Candona Peircei sp. n. PLATE LXXX. Length 0.70 to 0.79 mm. Height 0.33 to 0.37 mm. Width 0.22 to 0.31 mm. The color of the shell is white tinged with yellow. The surface is highly polished and bears a few scattered hairs. The muscle impressions are sub central and the eye is not visible through the shell. The animal is about half as high as long, but is not quite so wide as high. Viewed from the side the shell is sub-reniform, the greatest width being a little caudad of the middle. The two extremities are rounded and are of about the same width. The dorsal margin is feebly convex, in some specimens it is nearly flat. The ventral margin is somewhat sinuous, the middle being slightly concave. In some speci- mens this margin is almost straight. De cara eT ap 302 GEOL. AND NAT, HIST. SURVEY OF MINNESOTA. Viewed from above, the shell is sub-elliptical with pointed extremi- ties. The cephalic extremity is more sharply pointed than the caudal. The sides are convex. The hinge-line throughout the greater part of its course is straight, but near the cephalic extremity of the valve there is a slight sinuosity. Viewed from below the shell has the same general appearance as when viewed from above. The con- tact line is quite sinuous. The antenna of the female is five jointed. Near the distal extremity of the inner margin of the second joint there is a long seta, which ex- tends about to the base of the fifth joint. Near the proximal extremity of the inner margin of the third joint there is the usual biarticulate olfactory hair. Near the proximal extremity of the outer margin of the same joint arises a long seta which extends almost to the base of the next joint. From the distal extremity of the inner margin of this joint there arise one long and one short seta. The long seta reaches way beyond the tip of the fifth joint, while the short one does not reach to the extremity of the fourth joint. From the middle of the inner margin of the fourth joint there arise one long and one short seta. The long seta extends to beyond the tip of the terminal joint. while the other extends to a little beyond the base of the same joint. From the middle of the outer margin of the fourth joint there arises a short seta which extends to about the base of the next joint. The tip of the fourth joint bears two long and one short claw. The two long claws are stout and are longer than the combined lengths of the last. two joints. The short claw is only about twice as long as the terminal joint. From the tip of the fifth joint there arise one long and one shorter claw. The shorter claw is about two-thirds as long as the other claw. The tip of this joint bears also a biarticulate sensory filament. The antenna of the male is six-jointed. In structure and append- ages the first three joints resemble the corresponding portion of the female antenna. From the distal extremity of the fourth joint arise two peculiar biarticulate sensory filaments which extend to beyond the tip of the terminal joint. From the distal extremity of the outer margin of this same joint arises a short seta which extends to about the tip of the fifth joint. From the distal extremity of the fifth joint arise two long curved claws and one medium seta. The claws, which are of equal length, are longer than the combined lengths of the last three joints. The claws arise from the outer portion, while the seta springs from the inner angle of the margin. The seta is about one- half as long as one of the claws. From the distal extremity of the sixth joint there arise one long terminal claw and one biarticulate sensory seta. The claw extends to the tips of the claws that spring from the fifth joint, but the seta extends less than half so far. ENTOMOSTRACA OF MINNESOTA. 303 The palp of the mandible is stout, the terminal joint of the same is short. The blade of the female mandible is stouter than that of the male. The first maxilla bears a large leaf-like branchial appendage. The second maxilla of the female has the usual generic form, the palp being two-jointed and bearing at its tip three short sete. In the male the palp of the second maxilla is peculiarly modified and the palp of one side is larger than the palp of the other. The first foot is of the usual type. The second foot, as is always the case in this genus, bears at its tip two long and one short sete. The post-abdomen of the female is quite stout and bears at its tip two strong claws. This appendage is strongly curved. One claw is only about two-thirds as long as the other. The post-abdomen of the male is straighter than that of the female, but its borders are more irregular. The terminal claws are slender and of about the same size. The verticillate sac of the male bears seven whorls of chitinous spines. Habitat: Fayette county, Georgia. These specimens were found in the weedy shallows of a large millpond near Fayetteville, June 21, 1894. Candona delawarensis Turner. PLATE LXXI, FieGs. 35-40. 1894.—Candona delawarensis C. H. Turner (215), pp. 21-22; Pl. VIII, Figs. 35-40. Length 0.95 mm. Height 0.54 mm. Width 0.43 mm. The color of this form is greenish yellow variegated with blotches of brown. Viewed from the side (Fig. 39) the shell of the female is sub-reni- form, the greatest height being about two-thirds the length of the animal from the cephalic extremity of the shell. The cephalic, dorsal and caudal margins are convex. The ventral margin is undulating, ‘concave in the middle. Viewed from above (Fig. 37) the shell is an elongate ellipse with its greatest width in the middle. The extremities are pointed. The hinge-line is sinuous. Near the cephalic extremity there is a very pronounced sinuosity. Viewed from below (Fig. 38) the general outline is the same as when viewed from above. The contact line is more sinuous than the hinge- line. Viewed from the end the shell is elliptical. It is widest in the middle and the extremities are rounded. 304 GEOL. AND NAT. HIST. SURVEY OF MINNESOTA. The antenne bear no natatory sete on the antepenultimate joint. The terminal claws are non-pectinated and long. They are about as long as the combined lengths of the last three joints. The lower margin of the antepenultimate joint bears a modified sensory seta. The antenna of the male is six-jointed. The mandibular palp of the female is large. The antepenultimate joint bears, in addition to the usual long sensory sets, one short and stout sensory seta which is sub-rectangular in form with truncated ends and convex sides. It is about four times as long as wide. The spines on the first mandibular process.of the first maxilla are not toothed. The post-abdomen of the male (Fig. 36) is slender and sub-triangu- lar. The terminal claws are slender and curved. Habitat: Jones’ Creek, Kent County, Delaware. The specimens that I have were collected by Mr. L. D. Hileland, March 3, 1894. GENUS CYPRIA Zenker. 1854. This genus, which was founded by Zenker (238), has been revised by Wenzel V4avra (221). Antennules are seven-jointed. Antenne in the female are five jointed; in the male they are six- jointed. The distal extremity of the fourth joint bears two olfactory sete. The natatory sete on the third joint are very long, extending way beyond the tip of the terminal claws. The mandibular palp is much elongated; this is especially true of the terminal joint. The palp of the first maxilla is strongly developed. The second maxilla bears a well-developed branchial plate. In the female the palp of this member is unjointed and terminates with three sete. In the male the palp of the second maxilla forms a hooked pre- hensile organ. In that case the left palp differs somewhat in size and configuration from the right. The small terminal joint of the second foot, which is about one- third as long as the fourth joint, bears two equally long backwardly directed setie. The abdominal rami are robust; the caudal seta is situated about midway the caudal border. The eye is large. Muscle impressions four. Males are numerous. The central cylinder of Zenker’s organ is surrounded by seven whorls of chitinous sete. The upper part of the organ forms a blind dilated sac; the lower forms the funnel-shaped origin of the vas deferens. The copulative organ is triangular, The species of this genus are all small ovate or reniform creatures. Bilinear ENTOMOSTRACA OF MINNESOTA. 305 Cypria exculpta S. Fischer. PLATES LXX, Fias. 1-8; LX XII, Fie. 3. 1853.—Cypris elegantula Lilljeborg (118), p. 206. 1854.— *‘ exculpta Fischer (65), p. 18; Pl. XIX, Figs. 36-38. 1854.— ‘‘ puncetata Fischer (65), p. 77; Pl. III, Figs. 1-6. 1864.— ‘‘ striolata Brady (11), p. 60; PI. III, Figs. 12-17. 1868.— ‘‘ striolata Brady (18), p. 372; Pl. XXIV, Figs. 6-10. 1880.— ‘* granulata Robertson (184), p. 18. 1887.— ‘ — striolata C. L. Herrick (86), p. 29; Pl. LV, Fig 3. 1889.—Cypria exculpia Brady and Norman (31), pp. 68-69; Pl. XI, Figs. 1-4. 1894.— ‘ exculpta C. H. Turner (215), p. 13; Pl. VII, Figs. 2-8. 1894.— “ exculptaC. H. Turner (216), p. —. Length of female 0.54 to 0.64 mm. Height 0.33 to 0.43 mm. Width 0.26 mm. The shell is thin and somewhat transparent and is covered with a meshwork of sub longitudinal lines (Fig. 5). Viewed from the side (Fig. 3), the shell is orbicular, highest in the middle, the two extremities being of about equal height. The cepha- lic, dorsal and caudal margins are convex. The ventral margin is slightly sinuate, being concave in the middle. Viewed from above the shell is an elongated, laterally-compressed ellipse. The two extremities are of about the same width and the line of contact is straight. The natatory sete of the antenne (Fig. 6) extend far beyond the terminal claws and are much longer than the entire limb. The claws on the tip of each antenna are long and slender. They are longer than the last three joints. In the male the second maxille (Fig.8) are dissimilar. The tip of the second foot (Fig. 2) bears two short ectally project- ing sete and two long sete which project backwards as far as the base of the antepenultimate joint. The post-abdomen (Fig. 7) is short, stout and curved. The ter- minal claw is strong and about half as long as the ramus. About the middle of the caudal margin of each abdominal ramus there is a short filamentous seta. Habitat: This species is quite abundant in shallow ponds and slowly flowing shallow creeks. In America this species has been found at: Atlanta, Georgia (Turner, 215); Burlington, Ohio (Turner, 215); Alabama (Herrick, 86); Kent County, Delaware (Turner, 215); Fayette County, Georgia (Turner). The specimens from Delaware were collected for me by Mr. L. D. Hileland. 306 GEOL. AND NAT. HIST. SURVEY OF MINNESOTA. Cypria opthalmica Jurine. PLATES LXXV, Fias. 1-3, 7; LX XVI, Fias. 1-3, 5. 1820.—Monoculus opthalmicus Jurine (98), p. 178; Pl. XTX, Figs. 16, 17. 1835.—Cypris compressa Baird (I), p. 100; Pl. III, Fig. 16. 1837.— ‘‘ punetata Koch (102), H. 21, p. 23, Fig. 23. 1837.— ‘‘ tenera Koch (102), H. 12, p. 3. 1850.— ‘‘ compressa Baird (5), p. 1&4; Taf. XIX, Figs. 14, 14a-c. 1851.— ‘ elegantula Fischer (63), p. 161; Pl. X, Figs. 12-14. 1853.— ‘‘ compressa Lilljeborg (118), p. 112; Pl. X, Figs. 16-18. 1854.—Cypria punctata Zenker (238), p. 77; Taf. III, A. 1868.—Cypris compressa Brady (18), p. 372; Pl. XXIV. Figs. 1-5; PJ]. XX XVI, Fig. 6. 1868.— ‘* ovum Fric u. Nekut (70), p. 48, Fig. 30. 1872.— ‘‘ ovum Fric (69), p. 213, Fig. 28. 1875.— ‘‘ compressa Brady, Crosskey, and Robertson (30), p. 123; Pl. I, Figs. 5, 6. 1879.—? Cypria neglecta Herrick (83), p. 112; Pl. XVII, Fig. 2. 1885.— Cypris punctata Nordquist, (155) p. 150. 1888.— ‘‘ punctata Schwarz (199), p. 18. 1888.— ‘‘ compressa Sostaric (202), p. 47. 1889.—Cypria opthalmica Brady and Norman (31), p. 69; Pl. XI, Figs. 5-9. 1891.— ‘* opthalmica Wenzel Vavra (221), pp. 63-66; Figs. 19, 191-19°, 20, 20!-20+. Length 0.55 to 0.58 mm. Height 0.37 to 0.40 mm. Width about 0.30 mm. The American representative appears to be somewhat wider than the European type. The translucent shell is covered with irregularly scattered large puncta. Near the two extremities, the shell bears long hairs. Viewed from the side the shell is reniform, widest back of the mid- dle. Near the two extremities, the dark puncta are often so clustered as to form dark blotches. Caudal, dorsal and cephalic margins con- vex. Ventral margin is somewhat sinuate. Viewed from above the shell is ovate, the cephalic end somewhat more narrow and more pointed than the caudal extremity. Hinge line is straight. Viewed from below the contact line is sinuate. Viewed from the end the shape is oval, much higher than wide. For the structure of the female antenna consult Fig. 1. For the structure of the mandible consult Fig. 5. For the structure of the second foot consult Fig. 2. For the structure of the abdominal ramus consult Fig. 3. Habitat: ? Minnesota (Herrick, 83); Baxley, Georgia. The speci- mens from Baxley were collected for me by Mr. A. B. Whitby. The figures were drawn from Baxley specimens. ENTOMOSTRACA OF MINNESOTA. 307 Cypria mons (Chambers). PLATE LXXXI, Fias. 6-12. ? .—Cypris mons Chambers (41), pp. 153-154, Fig. 3. 1887.— ‘* mons C. L. Herrick (86), p. 32. Length 0.70 mm. Height 0.45 mm. ‘‘Ovoid; tumid; highest immediately before the middle. Length gz; inch; height 3,. Dorsal margin regularly arched, sloping more rapidly behind the highest point than before it. Extremities rounded; the anterior widest ventral margin very slightly sinuated. Seen from above, ovate, but less tumid than Cypridopsis vidua as figured by Baird and Brady (Brit. Ent. and Trans. Linn. Soc.). But little or not at all narrowed in front; widest a little behind the middle. Lucid spots seven, near the middle of the valve; the three lower ones in a line and small; one of them very small. Valves white, shining smooth, with numerous almost confluent puncta. The sete of the lower antenne extend beyond the apex of the claws, and the articulate appendage of the third joint has its apex swollen or enlarged. Superior antenne with two long and one short seta from the end of the fourth joint; two from the end of the fifth joint; four long ones from the end of the sixth; two long and two short from the end of the seventh (there are also other short sete on the different joints). The last joint of the inferior antenne is small, almost rudimentary, bearing a single large claw. (Indeed, it seems to be bifid, with a claw from each branch.) There are three other claws articulated to the end of the penultimate joint, from which also arise four sete shorter than the claws; two moderately long sete arise from about the middle of the fourth joint above, and three longer ones below; the usual fascicle of five long and one short sete from the third joint, just behind which is a bunch of short cilia and another bunch on the under side. Abdominal ramus straight, slender, with two claws, one under the other. The mandib- ular palpus, with branchial appendage and two large plumose and one simple sete from the end.’’ (Chambers. ) I have never seen specimens of the above. It is certainly very closely related to Cypria opthalmica (Jurine), yet it seems to be dis- tinct. Habitat: Pond on Mount Elbert, Colorado; altitude 11,000 feet. (Chambers, 41.) Cypria inequivalva Tumer. PLATE LXVIII, Fias. 1-8. 1893.— Cypria inequivalva C. H. Turner (213), pp. 6-8; Pl. I, Figs. 1-8. 1894.— ‘* inequivalva C. H. Turner (215), p. 14. 1894.— ‘* inequivalva C. H. Turner (216). 20 308 GEOL. AND NAT. HIST. SURVEY OF MINNESOTA. Length 0.46 mm. to 0.52 mm. Height 0.35 mm. to 0.36 mm. Width 0.26 mm. Shell inequivalve, one valve overlapping the otherin front. Valves glossy, finely pubescent. In fresh specimens, near the cephalic end of the shell, there is an irregular cross-shaped dorsal dark spot (Figs. 1, 2), the arms of which extend latero-ventrad along each valve for about one-half the height of the valve. Near the caudal extremity of the shell there is another irregular dorsal dark spot. This spot is somewhat fan-shaped, with the expanded portion directed caudad. Occasionally, on the ventral surface, about one-third the length of the valve from the cephalic ex- tremity, asmall dark spot is seen. In fresh specimens these markings are very pronounced; but in alcoholic specimens, they are usually more or less obscured. Viewed from the side (Fig. 1) the shell is sub-reniform, higher near the middle. It is about twice as long as high. Dorsal margin, feebly convex; cephalic margin, convex; ventral margin, nearly straight, slightly concave in the middle; caudal margin convex. Viewed from above (Fig. 2) the shell is sub-elliptical, inequivalve, one valve overlapping the other in front. Shell widest near the mid- dle. Cephalic extremity about as wide as the caudal. All margins convex. Hinge-line straight. Viewed from below (Fig. 3) shell presents the same outline as when viewed from above, but the line of contact of the two valves is sinuated. Viewed from the end, the shell is oval, widest in the middle, ventral margin about as wide as dorsal. Antennules typical for the genus. Antenne of female (Fig. 4) composed of five joints, the joints diminishing in size from the second to the most distal joint. The second joint bearing at about the middle of its ental margin a long seta. The next joint bears at about the middle of its ental margin the usual biarticular sensory hair and at its disto-ental angle a moderately long plumose seta, this seta extends to about the base of the terminal claws. From the base of the penultimate joint arise five very long non-plumose set, these setze extending far beyond the tips of the terminal claws. At the middle of its ental border this joint bears a short seta, and opposite this on the ectal border there is a slightly longer seta. From the disto-ental angle of this joint arise two short sete. From the ectal half of its distal margin arise two long claws; one of these claws extends beyond the tip of the claws springing from the terminal joint, while the other extends nearly to the tip of those claws. At the extremity of the terminal joint there are two large ENTOMOSTRACA OF MINNESOTA. 309 claws and two short setie; one of these sete is located at the disto-ental angle and the other at the disto-ectal angle of the joint. The claws are smooth. In the male the antenna is six-jointed, and the terminal claws are longer and more flexible than in the female. Mandible resembles that of Cypria exculpta Fischer. First foot of female (Fig. 5) long and slender, composed of five joints. The most proximal joint large, the broadest of all. The next joint the shortest of all. The antepenultimate joint about as long as the most proximal, but more slender. From the margin of this joint arise two short sete. From the disto-caudal angle of this joint arises a long seta which extends to beyond the base of the terminal claws. From near the disto-cephalic angle of this joint arises a short seta. Along the cephalic margin of the penultimate joint there is a longi- tudinal row of fine hairs. From the disto-caudal angle of this joint arises a Seta of medium length. From the extremity of the terminal joint arises a long claw; this claw is much longer than the joint and appears to be composed of two portions; a short proximal and a long distal portion. From the cephalic margin of the proximal portion arises a short seta. Second foot of female (Fig. 6) composed of five joints, the joints diminishing in size from. the second to the most distal joint. The most proximal joint bears at about its proximo-caudal angle a long plumose seta which is as long as the joint; and from the distal third of its cephalad margin arises a somewhat shorter seta. From the distal fourth of the cephalic margin of the antepenultimate joint arises a seta. From a corresponding point on the penultimate joint there also arises aseta. From the extremity of the terminal joint arise two long and two short sete. The two long sete are about as long as the entire limb. 5 The two shorter sete are but little longer than the terminal joint. Post-abdomen (Fig. 7) is curved, bearing one terminal claw and at its base a short terminal spine. On the convex surface there is a sub- terminal claw. Verticillate sac (Fig. &) of male as usual in this genus. It seems to be enclosed by a transparent capsule. Habitat: This species is abundant among the grass and weeds of many Shallow ponds. It has been found at the following places: Cincinnati, Ohio (Turner, 213); Atlanta, Georgia (Turner, 215); Fay- ette County, Georgia (Turner, 216). 310 GEOL. AND NAT. HIST. SURVEY OF MINNESOTA. GENUS CYCLOCYPRIS Brady & Norman. 1889. This genus, founded by Brady and Norman (31), has been amended by Wenzel Vavra (221). Antennules are seven-jointed. The antenne of the female are five-jointed; of the male, six-jointed. There is no olfactory organ on the fourth joint. Natatory sete are very long, reaching far beyond the tip of the terminal claws. The palp of the mandible and of the first maxilla normally developed. The second maxilla bears a branchial plate and a palp. In the female this palp is unjointed; in the male it forms a hooked prehensile organ. The last joint of the second foot is unusually long, being two-thirds as long as the fourth joint. Males are numerous. Zenker’s organ is similar to that of Cypria. The proximal side of its central cylinder is flat. Vas deferens is long and convoluted. The copulative organ is quadrangular. The abdominal ramus is robust, the caudal seta is situated at about one-third the length of the caudal border of the ramus from its distal extremity. Cyclocypris levis (O. F. Miiller.) PLATE LXX, Fias. 9-11. 1785.—Cypris levis Miller (149), p. 52; Pl. III, Figs. 7-9. 1820.—Monoculus ovwm Jurine (98), p. 179; Pl. XIX, Figs. 18, 19. 1835.—Cypris minuta Baird (1), pp. 99; Pl. III, Fig. 9. 1837.— ‘‘ brunnea Koch (102), H. X., Fig. 5. 1837.— ‘* lepidula Koch (102), H. X. 6. 1850.— ‘‘ minuta Baird (5), p. 155; Pl. XVIII, Figs. 7 and 8. 1851.— ‘‘ pantherina Fischer (64), p. 163; PI. XI, Figs. 6-8. 1853.— ‘* ovum Lilljeborg (118), p. 113; Pl. X, Figs. 13-15. 1868.— ‘‘ ovum Brady (18), p. 373; Pl. XXIV, Figs. 31-34, 43-45; Pl. XXXVI, Fig. 8. 1868.— ‘* ovum Claus (48), Pl. I, Figs. 1-5. 1874.— ‘‘ ovum Brady, Crosskey & Robertson, (30), p. 125; Pl. I, Figs. 29, 31. 1888.— ‘‘ ovum Schwarz (199), p. 18. 1888.— ‘‘ ovum Sostaric (202), p. 46. 1889.—Cypria levis Brady and Norman (31), p. 69. 1891.— ‘* levis Wenzel Vavra (221), pp. 68-71, Figs. 21, 217-21. 1894.— ‘* Jexvis C. H. Turner (215), pp. 14, 15; Pl. VII, Figs. 9-11. 1894.— ‘S levis C. H. Turner (216). Length 0.51 mm. to 0.57 mm. Width about 0.4 mm. The somewhat translucent shell is hispid and very tumid, being about as broad as it is high. Viewed from above the shell is ovate with rounded extremities. The eye, which is situated near the cephalic extremity of the animal, is easily seen through the shell. ENTOMOSTRACA OF MINNESOTA. 311 The five large sete on the antepenultimate joint of the antennee extend way beyond the tip of the terminal claws (Fig. 9). The distal extremity of each seta is plumose. According to Professor Brady* in Cypris ovum (Jurine) only two of the natatory sete of each antenna are long. In this respect Cypris ovum (Jurine) differs from the specimen under consideration; but since they are similar in all other features I consider them to be of the same species. The terminal joint of the mandibular palp is short. The terminal claws of this palp extend to the tip of the mandibular teeth. The slightly curved terminal claw of the first foot is slender and is about as long as the combined lengths of the three distal joints. The terminal joint of the second foot is about two-thirds as long as the fourth joint (Fig. 11). The long, slender, backwardly directed seta upon the distal extremity of this joint is longer than the combined lengths of the three distal joints. This joint bears at its apex two other set; one, about the same length as the joint is directed back- ward, the other is very short and is directed forward. The short post-abdomen is about twice as long as its terminal claws. The stout claws are feebly curved. Habitat: I have seen only three specimens of this species. These Professor L. D. Hileland collected in Jones’ Creek, Kent County, Dela- ware, March 31, 1894. Cyclocypris modesta (Herrick. ) PLATE LXXII, Fies. 5, 5*, 5a, ETc. Cypris modesta C. L. Herrick (86), p. 28; Pl. IV, Fig. 5. This species has never been seen by me. Probably its nearest ally is Cypria inequivalva Turner. The figures as well as the text of this species are taken from Professor Herrick’s work (86). ‘Shell sub-reniform, greatest height behind the middle, upper out- line somewhat obliquely truncate, especially in the male; color yellow- ish, scarcely maculate, nearly smooth. Antenne short, with long non-plumose filaments, two from the apical and four from the penulti- mate segment very long, others half as long; second antennze with three toothed claws on the penult segment, one together with three smaller ones, on the apical, antepenult segment armed only with small bristles, preceding one with six long setz exceeding the claws; first foot slender, apical segment long conical, with a long serrate claw and bristle, other setze short; second foot (in male) with a short terminal Segment armed with two very long set and one shorter one; caudal stylets very slender, with a terminal claw, a sub-terminal claw some- * Recent British Ostracoda, p. 373. 312 GEOL. AND NAT. HIST. SURVEY OF MINNESOTA. what smaller and a weak pectinate seta one-fifth the length of the stylet from the end; palp of mandible very bristly. The intromittant organ of the male is more simple than those hitherto described, con- sisting of a broad, flat basal segment on either side, with a coiled ductus ejaculatorius and a funnel-shaped terminal portion consisting of two opposable flaps. The basal segment is indistinctly two jointed and those of both sides are seated on a common prominence. ‘‘Length of male 1.70 mm., of female 2.16 mm.; height of male 0.84 mm., of female 1.24 mm. The above measurements are too large, but express the correct proportions. It is one of the smaller species.”’ Habitat: ? Alabama (Herrick, 86). GENUS CYPRIDOPSIS Brady. 1868. The antennule is seven-jointed. The antenna is five-jointed. The five natatory sete on the third joint are plumose. The branchia of the second maxilla consists either of a plate bear- ing five plumose sete or else of two setse which are inserted directly on the blade. The second foot is five-jointed and bears, near its extremity, a strong chitinous claw. The abdominal rami are rudimentary. The members of this species seem to be exclusively parthenogenetic. Cypridopsis vidua (0. F. Miller.) PLates LXXII, Fias. 1-lg; LX XV, Fias. 5, 6, 8, 9; LX XVI, Fias. 4, 7. 1785.—Cypris vidua O. F. Miller (149), p. 55; Taf. IV, Figs. 7-9 1820.—Monoculus vidwa Jurine (98), p. 175; Pl. XIX, Figs, 5-6. 1837.—Cypris maculata Koch (102), H. 10, 2. 1841.— ‘‘ — strigata Koch (102), H. 36, 19. 1844.— ‘* vidua Zaddach (234), p. 35. 1850.— ‘‘ vidua Baird (5), p. 152; Pl. XIX, Figs. 10-11. 1850.— ‘‘ sella Baird (5), p. 158; Pl. XIX, Figs. 5, 5a. 1851.— ‘‘ vidwa Fischer (64), p. 162; Taf. XI, Figs. 1-2. 1853.— ‘ vidua Lilljeborg (118), p. 111. 1854.— ‘ vidwa Zenker (238), p. 79. 1868.—Cypridopsis vidua Brady (18), p. 375; Pl. XXIV, Figs. 27-36, 46. 1868.—Cypris vidua Claus (48), Pl. I, Figs. 6-8. 1868.— ‘‘ vidua Fric and Nekut (70), p. 48, Fig. 29. 1869.— Cypridopsis obesa Brady and Robertson (32), p. 364; Pl. XVIII, Figs. 5-7. 1870.— A obesa Brady and Robertson (33), p. 15. 1870.—Cypris vidua Heller (81), p. 90. 1872.— ‘‘ vidua Fric (69), 227. 1874.—Cypridopsis obesa Brady, Crosskey and Robertson (30), p. 128; Pl. I, Figs. 1- 4. 1879.—Cypris vidua C. L. Herrick (83), p. 112; Pl. XVII, Fig. 1. 7 «= ENTOMOSTRACA OF MINNESOTA. 313 1887.— Cypridopsis vidua C. L. Herrick (86), p. 33; Pl. IV, Fig. 1. 1888.— Cypris vidua Sostaric (202), p. 46. 1889.—Cypridopsis vidua Brady and Norman (31), p. 89. 1891.— a vidua Wenzel Vavra (221), pp. 75-77; Figs. 23, 231-234. 1892.— vidua C. H. Turner (212), p. 73. 1894.— a vidua C. H. Turner (215), p. 19. 1894.— S vidua C. H. Turner (216). Length 0.54 mm. to0.7 mm. Height 0.34 mm. Width 0.37 mm. to 0.49 mm. The color of the tumid shell is yellowish green. The shell is cov- ered with short sparse hairs and is marked with three characteristic dark bands (Pl. LX XV, Figs. 5,8). These bands are confined to the dorsal surface. Viewed from the side (Pl. LX XV, Fig. 5) the shell is sub-reni- form in outline, widest in the middle. Excepting a slight concavity at the middle, the ventral margin is straight. The other margins are strongly convex. Muscle impressions sub central. Viewed from above (Pl. LX XV, Fig. 8) the shell is broadly orvid, being widest caudad of the middle. The two extremities are round- ed, but the cephalic extremity is much more narrow than the other. The sides are strongly convex and the hinge-line is straight. Viewed from below (Pl. LX XV, Fig. 6) the shell has the same general shape as when viewed from above. ‘The contact line is sinuous and there is a slight depression in the centre. Viewed from the cephalic end (Pl. LX XV, Fig. 9) the shell is a broad oval, being wider than high. Contact line straight. The antenna is five-jointed (Pl. LX XVI, Fig. 7). The terminal joint is small. A projection from the outer angle of the distal ex- tremity of the penultimate joint extends half way the length of the ter- minal joint. Two of the terminal claws are stout and one of them bears, on its inne margin, blunt teeth. The natatory sets extend toa little beyond the tip of the terminal claws and are plumose. The mandible is stout. The claws of the mandibular palp extend to the tips of the mandibular teeth. The antepenultimate jointof the palp bears a short, pectinated, dagger-shaped seta. As far as my ob- servations go, the penultimate joint does not bearsuch aseta. The fact that the dagger-shaped seta found on the penultimate joint of some Cppride oceurs on the side renders its detection quite difficult. The abdominal rami (Pl. LXXVI, Fig. 4) are rudimentary, the long slender terminal claw being longer than the ramus. In addition to the terminal claw there is a shorter and more slender claw. Habitat: This species occurs in all kind of fresh water. I have found it in small tanks, pools, ponds, lakes, creeks and small rivers. Tt usually occurs in great numbers. 314 GEOL. AND NAT. HIST. SURVEY OF MINNESOTA. In America it has been found in the following localities: Eastern United States (Herrick, 86), Georgia (Turner, 215, 216), Ohio (Turner, 212, 213), Texas (Turner 215, 216), Minnesota (Herrick, 83), West Virginia (Turner, 215). The Texas specimens were collected by Mr. A. B. Whitby. Cypridopsis newtoni Brady and Robertson. PLATE LXXII. Fic. 6-6h. 1870.—Cypridopsis (?) newtoni Brady and Robertson (33), p. 14, Pl. VII, Figs. 14-16. 1874.— ae newtoni Brady, Crosskey and Robertson (30), p. 129; Pl. II, Figs. 20-21. 1887.— ae hystrix C. L. Herrick (86), pp. 30, 31; Pl. IV, Fig. 6. 1889.— ss (2) newtoni Brady and Norman (31), pp. 90, 91; Pl. VIII, Figs. 16, 17. 1891.— ce newtoni Wenzel Vavra (221), pp. 77-79; Figs. 24, 241-24°. 1894.— 7 C. H. Turner (216). Not having met this species, I here give Professor Herrick’s de- scription. The figures are his also. ‘‘Length equal to about twice the greatest height which lies just behind the anterior third, anterior outline much higher than the pos- terior, and evenly rounded, posterior margin acutely angular, lower Outline slightly concave, upper margin twice angled; shell covered with long curved spines; color yellowish, with eight lucid spots. An- tenne (first antennze) slender, composed of seven segments, of which all but the basal are short and sub-equal. * * * * * Antennules (second antenn) with very short apical segment with two strong un- equal claws and a minute seta, penultimate with two equal toothed claws and a number of slender sete, third from end with five long and several short sets, preceding segment large, with three slender sete. First foot five-jointed, second joint elongated, third and fourth equal, each with a single short seta, apical segment small, with two sete and a long toothed gently curved claw; last foot moderately slender, termi- nal joint with a small claw and two set at the apex and a lateral Spine. Caudal stylets reduced to minute papillie bearing a slender claw and a flexuous spine. The mouth parts bear the characters of the genus Cypris. ‘‘Tn this species there is an aureole-like lucid zone about the an- terior of the shell and a similar, but triangular, appendage behind. ““The species may be regarded as forming a transition to Cypris proper, as the form if not the size of the stylets is more as in that genus.”’ Habitat: Minnesota (Herrick, 86). Sito ENTOMOSTRACA OF MINNESOTA. 315 GENUS ERPETOCYPRIS Brady and Norman. 1889. ‘‘General characters of the animal closely approaching those of Cypris; but the sete of the third joint of the lower antenne are short, not nearly reaching the apex of the terminal claws, and are not plumose. The second pair of jaws have branchial plates as in Cypris. The power of swimming is lost, and the habits of the animals, which creep along the bottom, are thus very different from those of Cypris.’’ (Brady and Norman). Erpetocypris minnesotensis (Herrick. ) PLATE LXXII, Frias. 2-2h. 1887.—Cypris minnesotensis C. L. Herrick (86), p. 28; Pl. IV, Fig. 2. Length 1.60 mm. This species is closely related to Hrpetocypris fasciata (O. F. Muller). In FH. fasciata the caudal margin of the abdominal ramus is smooth) but in L. minnesotensis it is pectinate. In FH. fasciata the length is three times the width, but in 2. minnesotensis the length is two and one-half times the width. The figures and the following description are from Professor Her- rick (86). ‘‘From any of the American species it is at once known by the great proportionate length of the valves, which are about two and one-half times as long as broad. Lower margin nearly straight, gently sinuous near the middle, dorsal margin gently curved, highest back of the middle, then gently curved; color light, with two inconspicu- ous dark transverse bands on either side at about the anterior and posterior thirds; scattered hairs upon prominences are found near the margins. Antenne (antennules) slender, seven-jointed, apex with two very long and one short spine, penult segment with tour long Setie, antepenult segment with two long plumose sete above, preceding segment with shorter sete; second antenne with the apical segment very short and armed with one (?) serrate claw and a seta, the preced- ing with two claws and a few short sete, antepenult segment with three (four?) shortish sete, not reaching end of claws; mandible with strong lobed teeth and a Jarge palp; first foot with a large claw; sec- ond foot slender, ending in a small hook with a single weak seta; cau- dal stylets rather short and wide, with two strongly serrated claws, the other spines being obsolescent (?); posterior margin serrulated. Lucid spots of the shell seven in number, two being minute. Length ; of shell 1.6 mm.?’’ Habitat: Minnesota (Herrick, 86). 316 GEOL. AND NAT. HIST. SURVEY OF MINNESOTA. Erpetocypris barbatus (Forbes. ) PLATE LXXVII. 1879.—Candona ornata (2?) C. L. Herrick (83), p. 113; Pl. XX, Fig. 1893.—Cypris barbatus 8. A. Forbes (67a), pp. 244- 246; eal seta Figs. 2-3; Pl. XXXVIII. This, which is probably the largest freshwater ostracode, is known to me only through the paper of Professor 8. A. Forbes. The follow- ing description, as well as the figures, is copied from his paper. ‘‘An extremely large, very hairy, oblong Cypris, with rounded ends and dorsal and ventral margins nearly parallel. Length 4.0 mm. Width 1.6mm. Depth 2.0 mm. A very little deepest at hind end of hinge margin. (Depth across eye 95 per cent of greatest depth. ) ‘Dorsal margin about straight for a great part of its length, the ventral margin very slightly emarginate or sinuate at its anterior third. ‘The anterior end broadly and smoothly rounded, more obliquely above than below, the posterior somewhat obliquely rounded, the ventral margin being thus nearly half as long again as. the dorsal. Seen from above the shape is symmetrical, a slender oval, a little more flattened at the sides behind than before; thickest, con- sequently, before the middle. ‘‘Color a dirty yellowish brown in alcohol, with a reddish-brown patch on either side above and behind the middle. Surface of valves opaque, very minutely roughened, and well covered with conspicuous hairs, which give this Cypris | Erpetocypris| a decidedly hairy appear- ance to the naked eye. Hairs longest before and behind and length- ening generally towards the margin, where they project as a fringe, the most prominent part of which is a row of hairs borne on slender conical tubercles within the margin of the valves, The valves are equal and the shell fairly fall, but not plump. “Anterior antenna with the basal segment obliquely channeled, partially dividing it into two, the distal part of which bears a single bristle on its superior surface, and two long, more slender ones, springing together from tip of the ventral surface. A short, subquad- rate second segment bears a single seta, about as long as the segment, on the dorsal surface, near the tip. From the distal end of the fol- lowing segment spring two long, slightly plumose seti, one dorsal, one ventral, the former much the longer. The fourth segment bears at its tip four long sets, two of which arise from the ventral angle and two from the outer dorsal. The following segment is similarly armed, and the distal extremities of the sixth and seventh are densely set with long plumose sete forming a stout fascicle, which extends beyond the end of the antenna a distance equal to the length of the antenna itself. a ENTOMOSTRACA OF MINNESOTA. se ‘The terminal segment of the palp of the first maxilla is a little more than a fourth the length of the basal, the latter with one subter- minal bristle without, and several terminal ones. Tip of last segment with two stout, curved, claw-like sete, and four or five smaller, softer ones. Outer lobe of maxilla proper reaching to tip of first segment of palp, nearly equaling it in diameter, also with two curved claws, shorter but much stouter than those mentioned above, three-fourths as long as the lobe itself. Besides these, two smaller sete and three or more sub-terminal ones, two of which are smooth, like the terminal group, one strongly plumose. A single plumose seta also springs. from near the base of the concave surface of this lobe. ‘The second and third lobes similarly armed at the tip, but with a larger number of curved sete, all of which are soft. Two of these, on the short inner lobe, are much longer and stouter than the others, and project directly backwards. The base of this lobe bears two plumose setze about as long as those just mentioned. The length of the inner lobe is half that of the outer, the middle one being intermediate. ‘‘The second maxilla with about 12 terminal setee, which diminish in length inward, most of them slightly plumose, and two long slender Sete, one Springing from the middle of the inner margin and the other from the base, Palp thick, slender ovate, twice as long as the masti- catory lobe, fringed with a soft silky pile. and bearing three more or less plumose setie at its tip, the middle one of which is the longest. Branchial lobe very small, semicircular, with three fully developed plumose sete nearly as long as the palp, and two much shorter ones, one delicate and smooth, the other stout and plumose. ‘“The basal segment of the second antenna trigonal, with one mod- erately long hair beneath, and two of similar length springing together from the inner side of the apex. The second segment subcylindrical, with two hairs diverging from the middle of the outer side of the apex, the under one of which is very short and weak, about as long as the third segment is wide, while its companion reaches about to the tip of that segment. On the inside of the tip of the second segment is another hair, similar to the above, and of about the same length. The third segment bears, at the union of its basal with its middle third, on the under side, set beyond a slight tooth-like projection, a jointed olfactory club, whose length is about two-thirds the diameter of the segment. Otherwise this segment bears no hairs except at the tip, where, upon its inferior angle, is one long, stout hair, reaching beyond the tip of the last joint, and upon its inner surface a fascicle of five plumose hairs, the four longer of which are curved and parallel, while the fifth is short and straight. The third segment is slightly longer than the second and about two-thirds as thick. The fourth segment is three- 318 GEOL. AND NAT. HIST. SURVEY OF MINNESOTA. fourths the length of the third and about two-thirds its diameter, slightly enlarged at the middle, where it bears, on the under side, a group of three long hairs, and upon the upper side two shorter ones. At the tip of the segment are a group of three long plumose hairs and a stout, curved, concave, acute claw, nearly three times the length of the last segment, doubly dentate on both edges. At tip of last segment the usually strong, curved bidentate claws, five in number, three of equal length, as long as the two last segments of the antenna, and two others about half that length. ‘*Mandible with a row of six dark corneous teeth, more or less bifid, the series continued in an irregular cluster of tooth-like spines, and terminating in two highly plumose sets. The series of teeth with numerous accessory smaller teeth and spines, and two transparent la melle—slender, but as long as the teeth themselves—inserted between the first and second and second and third series, respectively. The lat- ter lamella is recurved and serrate on its concave edge. Basal segment of palp longest, the third next, second and fourth sub-equal in length, the second as broad as the first. The latter bears at its posterior tip three plumose setze of unequal length, in a cluster, and a fourth larger, stouter, decurved articulate one, inserted on the outer side of the tip of the segment, ‘The second segment has in front a group of three slender sete inserted a little behind the tip; and opposite to them upon a stout tuberosity another group of three long equal sete, to which a fourth stands in the same relation as on the preceding seg- ment. On the third segment is a group of five set similar to those on the anterior margin of the segment preceding, and, in addition, a circlet of six, attached around the posterior and inner margin of the end of this segment. At the tip of the palp are three curved claws, averaging as long as the two preceding segments together, with some slender sete intermixed. The so-called branchial appendage is about as long as the basal segment of the palp, and bears four stout plumose setee with a small accessory seta in front. ‘First leg with basal segment columnar, distal portion partially separated, without hair or bristle. Second segment cylindrical, its surface smooth except for numerous transverse rows of exceedingly fine short sets, present also on the two succeeding segments of this leg. A stout bristle at anterior distal angle. Third and fourth seg- ments nearly equal (the third, however, somewhat the longer), together slightly longer than the second, the length of each about twice its transverse diameter. The third with a single apical hair at the ante- rior angle, and the fourth with but two, one of which is as long as the segment itself, and the second about half that length. ‘Terminal seg- ment with a very long, slender symmetrically curved, regularly taper- re ENTOMOSTRACA OF MINNESOTA. 319 ing claw, with two short soft sete springing from its base. The entire claw somewhat longer than the last three segments conjointly. ‘‘Caudal rami long and slender, slightly sinuate, the transverse diameter of each not more than one-twentieth its length; the basal fifth, however, considerably thickened. Rami smooth, except poste- riorly, where the margin is closely set with stout, short spines, length- ening toward the distal end of the ramus. Terminal claw slightly curved at the tip, contained two and a half times in the length of its ramus. Subterminal claw nearly two-thirds the length of the terminal, also slightly curved. Claw-like seta almost immediately above the latter, more slender, but two thirds its length. Besides the above, a short slender seta springs from in front of the base of the termina] claw. ‘The first and last segments of the second pair of legs sub-equal, each two-thirds the length of the second; basal segment straight, its length five times its width, with three slender set, one borne upon the middle of its exterior side, and two near the apex, opposite each other. Second segment slightly curved, with a single slender seta near the apex, on its outer margin. Third segment with two terminal sete, one nearly straight, claw-like, about three-fourths the length of its segment, and the other curved and blunt.’’ Habitat: Yellowstone River, Yellowstone Park, Wyoming (8. A. Forbes); (?) Minnesota (Herrick). To my mind Candona ornata Herrick belongs here. But since the figure given by Professor Herrick is about all I have to base my Opinion upon, it is not thought wise to enforce this opinion upon the public. GENUS CYPRIS O. F. Miller, 1785. In both sexes the antenna is five-jointed. The natatory sete on the third extend to the tip of the terminal claws. The mandibular palp does not extend beyond the tip of the man- dibular teeth. The branchial plate of the first maxilla is large, bearing stiff, plu- mose sete. The first mandibular process is armed with two biarticu- late thorns. The second maxilla bears a branchial plate. The second foot resembles that of Cypridopsis. The abdominal ramus is stout, and terminates with two more or less stout claws, in front of which occurs a short and behind which a long seta. Males are unknown; propagation parthenogenetic only. 320 GEOL. AND NAT. HIST. SURVEY OF MINNESOTA. Cypris fuscata Jurine. Puiatrs LXXI, Fias. 41-46; LX XII, Fies. 7-7p; LX XVI, Fie. 9. 1820.— Cypris fuscata Jurine (98), p. 174; Pl. XIX, Figs. 1-2. 1837.—? ‘‘ adusta Koch (102), H. IT, 3. 1838.— ‘ galbinea Koch (102), H. XXI, 19. 1844.— ‘‘ fuseata Zaddach (234), p. 32. 1850.— ‘‘ fusea Baird (5), p. 154; Taf. XIX, Fig. 7. 1850.—Candona hispida Baird (5), p. 161; Taf. XIX, Fig. 4. 1853.—Cypris fuscata Lilljeborg (118), p. 114; Pl. X, Figs. 6-9; Pl. XII, Fig. 5. 1868.— ‘ fusca Brady (18), p. 362; Pl. XXIII, Figs. 10-15. 1887.— ‘* dugesiC. L. Herrick (86), p. 26; Pl. IV, Fig. 7. 1888.— ‘‘ fusca Sostaric (202), p. 47. 1889.— ‘‘ fuscata Brady and Norman (31), p. 73; Pl. XII, Figs. 3-4. 1891.— ‘‘ fuscata Wenzel Vavra (221), pp. 98-99, Figs. 83, 33!-33°. 1894.— ‘ fuscata C. H. Turner (215), pp. 16-17; Pl. VII, Figs. 41-46. 1894.— ‘* fuscata C. H. Turner (216). ; Length of the female 1.40 mm. to 1.50 mm. Height 0.9 mm. Width 0.67 mm. to 0.73 mm. The greatest height of the animal is about two-thirds of the length, while the greatest width is less than the height. The color is greenish brown. ‘The shell usually has attached to it furfaceous mat- ter, which Professor Brady thinks is desquamating epidermis. Viewed from the side the cephalic third of the shell is wider than any other portion. The caudal, dorsal and cephalic borders are con- vex. The cephalic and caudal margins have a narrow hyaline edge. The valves are not very transparent and are covered with short, scat- tered hairs. Muscle impressions near centre of the valve, about seven. Viewed from above the shell is oval, rounded behind and bluntly pointed in front. The greatest height is in the middle. The natatory sete of the antenne extend to the tips of the terminal claws. The terminal claws are stout, curved and longer than the last two joints. The distal half of the inner margin of each claw is pecti- nated with a double row of fine teeth. The two enlarged spines upon the first mandibular process are toothed. The extremity of each spine and the two adjacent teeth are blunt. The first foot is five-jointed, the third and fourth joints being dis- tinct. The terminal claw is long and stout, longer than the combined lengths of the last three joints. The second joint is stout and about as long as the combined lengths of the next two joints. The terminal claw of the second foot (Fig. 43) is about twice as long as the terminal joint. ENTOMOSTRACA OF MINNESOTA. oui The feebly-curved post-abdomen (Fig. 46) is stout and short. The terminal claw is a little more than half as long as the abdominal ramus. The adjacent claw is about three-fourths as long as the ter- minal claw. Habitat: Cincinnati, Ohio (Turner, 213); Guanajuata, Mexico (Herrick, 86); Albuquerque, New Mexico. Cypris virens Jurine. PLATE LXXIV, Fias. 3-3e. 1820.— Monoculus virens Jurine (98), p. 174; Pl. XVIII, Figs. 15-16. 1838.—Cypris qibberala Koch (102), H. X XI, 20. 1844.— ‘* virens Zaddach (234), p. 35. 1844.— ‘* »ilosa Zaddach (234), p. 36. 1850.— ‘* tristriata Baird (5), p. 152; Taf. XVIII, Figs. 1, 1a-1i, 2-3. 1851.— ‘‘ ornataS. Fischer (63), p. 157; Pl. IX, Figs. 7-10. 1853.— ‘“ virens Lilljeborg (118), p. 117; Taf. VIII, Fig. 16; Taf. IX, Figs. 4-5. 1868.— ‘ virens Brady (18), p. 364; Pl. XXIII, Figs. 23-32; Pl. XXXVI, Fig. 1. 1868.— ‘‘ pubera Fricand Nekut (70), p. 46, Fig. 26. 1870.— ‘ ventricosa Brady and Robertson (33), p. 12; Pl. IV, Figs. 1-3. 1872.— ‘* pubera Fric (69), p. 226. 1874.— ‘‘ virens Brady, Crosskey and Robertson (30), p. 124; Pl. II, Figs. 27-28. 1887.— ‘‘ Helena Moniez (135), p. 2. 1887.— ‘* virens C. L. Herrick (86), pp. 24-26; Pl. VI, Fig. 3. 1889.— ‘‘ virens Brady and Norman (31), p. 77. 1891.— ‘* virens Wenzel Vavra (221), pp. 102-104, Fig. 3; Figs. 4, 41, 42, 44; Figs. 5, 51-52; Figs. 36, 361-364. Only once have I encountered an American form which I supposed was Cypris virens. Then the specimens were accidentally destroyed before accurate drawings were made. Mr. Deming, however (Her- rick, 86), claims to have found this species to be quite abundant at Granville, Ohio. The following description is due to Mr. Deming. I have taken the liberty to omit much that is merely generic and to add, in brackets, some specific characters. ‘*Valves sub-reniform, the two ends almost equal, the dorsal side evenly curved, the ventral side sinuated, highest in the middle. The valves are covered with minute hairs. The hinge-line is sinuated and unbroken. ‘The outer part of the shell is slightly lined. The shell as seen on end is oval; seen from above, oblong-ovate. Lucid spots, about seven in number, are found in about the centre of the valves; these are oblong and irregular in shape, often pointing towards the ventral margin. Isolated spots are found near the dorsal side. The color is olive or yellowish green, with dark brown spots near the dorsal margin and scattered throughout the shell * * * * * * % [The two biarticulate spines on the first mandibular process of the _ first maxilla are smooth. ] ses 322 GEOL. AND NAT. HIST. SURVEY OF MINNESOTA. ‘“The post-abdomen forms two long, movable rami, which are well developed and terminated by two claws of unequal length, and in fine Specimens are serrated on their inner edge near the apex. The rami themselves are also serrated.”’ [In European specimens and in speci- mens taken by the present writer to belong to this species the abdomi- nal rami are not serrated. | Mr. Deming claims to have found the male of Cypris virens. I have reason, however, for supposing that he has confounded the males of some other species (perhaps C. crena) with Cypris virens. Habitat: Granville, Ohio (Herrick, 86). Cypris perelegans Herrick. PLATE LXXIII. 1887.—Cypris perelegans C. L. Herrick (86), p. 27; Pl. III, Figs. 7-12. 1894.—Cypris perelegans C. H. Turner (216). Length 3.60 mm. Height 1.72 mm. Width 1.40 mm. ‘*Carapace of largest size, elongate sub-oblong, sides nearly parallel, upper margin nearly straight, lower outline with two sinuses and two slight convexities, produced to form a slight tooth behind; greatest height at one-fourth the length from the posterior, equal to less than half the length; width greatest somewhat in advance of the middle, about four-tenths the length; color clear, pale yellow, with a well-de- fined pattern in deep brown, pattern consisting of a sigmoid band crossing the middle of the valves, giving off spurs at each flexure, and sundry other spots, as well as an anterior marginal band; surface shining, minutely dotted, slightly hairy at margins; lucid spots con- sisting of two large irregularly pentagonal approximated spots, with three smaller ones grouped below; appendages very similar to C. virens; antenne seven-jointed, slender, basal segment very large, third elongated, four succeeding nearly equal in length, fourth and fifth segments each with two long sets above, sixth with four long and one shorter setee, apical segment with four very long sete, fifth segment with two sete of moderate length below; antennules (antennze) slender, apical segment with two serrate claws and two slender set, fourth (antepenult) segment the same, third segment with four long and two shorter sets, second segment with six long pectinate sete reaching to end of terminal claws; labrum with claw-like appendages bearing seven teeth, the inner being double, medianly the labrum appendaged with pectinate plates; the mandibles furnished with six strong teeth, two pectinate sete and several small spines, the palp being well-de- veloped; first maxilla with short lobes, the anterior of the one-jointed lobes with four very strong toothed spines; first foot with five seg- ments, the apical one being very small and bearing a single very long b). er q ENTOMOSTRACA OF MINNESOTA. 323 serrated claw, the third and fourth are equal and much more slender than the second; second foot slender, apical segment with two small claws and one delicate seta, caudal stylets elongated, narrow, serrate behind, with two straight, unequal serrate claws, lateral spine sub- terminal.’’ (Herrick, 86.) Habitat: Mobile, Ala. (Herrick 86.) Cypris altissimus Chambers. PLATE LXXIX, Fiaes. 10-13. 18—.—Cypris altissimus Chambers (41), pp. 152-153, Fig. 2. 1887. —Cypris altissimus C. L. Herrick (86), v. 27. Length 1.26 mm. Height 0.63 mm. ‘‘Valves oblong, slightly subreniform, highest about the middle, rounding regularly before and behind; the side view resembling some- what Baird’s figure of C. tristriata, but less distinctly reniform, perhaps rather resembling in the form of the dorsal margin Cypridopsis vidua; it is, however, much more elongate in proportion to height. Brady’s figure of C. virens (=C. tristriata Baird) is a little nearer to this species, but is too distinctly reniform. C. virens also agrees with this species in the number (seven) of the lucid spots, and approaches it in their position on the shell, and in relation to each other, but they differ in shape. In this species, the extremities are more nearly equally rounded than in virens, the dorsal margin being evenly rounded before and behind the middle, and the ventral likewise, both before and be- hind the slight sinuation in the middle. But the anatomy of the ap- pendages differs more decidedly from that of virens, as will be seen by a comparison of the following account with Brady’s figures. Superior antennée with only twelve instead of fourteen long sete, arranged as follows: There are two short setie (one longer than the other) from the third joint, which has none in Brady’s figure; two short and two long ones from the fourth joint, where virens has four long ones; three long ones and one shorter one from the fifth joint, which in virens has four long ones; four long ones from the sixth joint, where virens has only three, and three long ones and one short one from the last joint, where virens has three long ones. In the inferior antenne similar differences are found, and in the mandibular palpus even greater ones. The feet of the first pair appear to be identical in the two species, ex- cept that this species has a short seta on each of the joints three and four, which are not represented in Mr. Brady’s figure. His figure, however. shows one seta more on each of the joints two and three of the feet of the second pair than I find in this species, which likewise is much smaller than ©. virens, being only one-twentieth of an inch long and one-fortieth high instead of one-fourteenth of an inch long and 21 = er 3 eee 324 GEOL. AND NAT. HIST. SURVEY OF MINNESOTA. one twenty-fifth high, as in virens. In ventral and dorsal view it also resembles virens. Surface smooth pubescent, with minute punec- tures. Color bright deep green.’? (Chambers. ) This species has not been seen by me. It certainly is very closely related to Cypris virens, and may prove to be that species. For the present, however, it is thought best to regard it as a distinct species. Habitat: Pond fed by melting snow, Mount Elbert, Colorado. A1- _titude, about 12,000 feet. (Chambers, 41.) Cypris herricki Turner. PLATES LXVII, Fies. 1-10; LXVIII, Figs. 40-42; LXIX, Fics. 32-39. 1892.—Cypris Herricki C. H. Turner (212), pp. 71-73; Pl. II, Figs. 1-10. 1893.—Cypris Herricki C. HW. Turner (213), pp. 11-15; Pl. I, Figs. 33-39; Pl. II, Figs. 40-42. Length 3.0 mm. Height 1.70 mm. Width 1.45 mm. In a lateral view, the shell is sub-triangular, highest near the mid- dle. The ventral margin is straight, excepting at the cephalic ex- tremity, where, after a shallow concave notch, the margin is convex. The remainder of the margin is strongly convex. From the above described ventral notch, a well defined, feebly convex, line passes dorsad to the opposite margin. That portion of the shell which lies cephalad of this line is usually curved laterad. From within the eephalic and caudal extremities of the valves numerous hairs pro- trude. In a dorsal view, the shell is sub-fusiform, being widest caudad of the middle. At their caudad extremity the valves are slightly divari- cated, while at their cephalad extremity they are closely approximated. The shell is covered with fine reticulations and minute hairs. In addi- tion to these, it is marked with conspicuous dark green bands. These bands are arranged as follows: One, parallel to and almost adjacent to the mesal border of the shell, extends from the caudo-ventrad angle of the shell dorso-cephalad almost to the cephalad extremity of the valve. There it divides. One portion continues in the same course to the cephalo-ventral extremity of the valve. The other, turning laterad, passes ventrad for a short distance and terminates in a sharp point. At the origin of this line there is a large, convex blotch, which extends ventrad ashort distance. Near the centre of the figure several bands fuse in such a manner as to form a hollow, sub-square figure. From the cephalo-dorsal corner of the square a tongue passes ventro- _ caudad into the square. The length of this tongue and the angles it makes with the sides of the square vary slightly in different individ- uals. Usually it extends almost to the centre. From this same angle of the shell a band projects ectad. After passing cephalad a short is, oN mt i: me ENTOMOSTRACA OF MINNESOTA. 325 distance, this band forms a convex curve and passes caudo-dorsad almost to the margin of the shell. From the caudo-dorsal angle of the square a short band passes dorso caudad and fuses with a broader band which passes caudad, approximately parallel to the dorsal margin of the shell. From this same corner another band passes caudo-ventrad almost to the caudal margin of the shell. This band is approximately parallel to the band just described. From the caudo-ventral angle of the square a band passes caudo-ventrad almost to the caudo-ventral extremity of the shell. In the caudal portion of its course this band curves dorsad, otherwise it is approximately parallel to the band last described. From the cephalo-ventral angle of the square, a short band projects ventrad and then broadening, forms a boot-shape band. The short heel of this boot projects caudad and terminates in a point, the long toe extends cephalad and terminates bluntly. From the same corner of the square, a second band projects cephalad to about the level of the toe of the boot. There it fuses with a spike-shaped band which extends cephalo-ventrad from near the cephalo-dorsal angle of the square to about the cephalo-ventral extremity of the shell. The head of the spike is at the caudo-dorsal extremity of the band. The two bands fuse near the head. The number of lucid spots is about eight. They are situated in the centre of the valve and ordinarily are inclosed within the square above described. Viewed from the ventral surface one valve overlaps the other in front. The contact line is sinuous, being laterally convex at the mid- dle. Viewed from the end the shell is oval in shape, the greatest width being near the dorsal surface. Antenne slender; the natatory sete on the distal extremity of the third joint reach almost or quite to the tip of the long and slender terminal claws. The mandible is stout. Among other sete, the antepenultimate joint of mandibular palp bears a short, pectinated, dagger-shape seta; so does the penultimate joint. The two biarticulate claws on the first mandibular process of the first maxilla are smooth. ‘The extremity of that same process bears two sete as long as the biarticulate claws; one, which is curved and smooth, is situated at the outer angle and the other, which is straight and pectinated, is situated about the middle of the extremity. The terminal claw of the first leg is almost as long as the entire dimb. The distal two-thirds is pectinated. The post-abdomen is long, slender and straight. The distal portion -of its outer margin is pectinated. The terminal claws are curved and -are a little longer than half the length of the abdominal rami. MON « . , 326 GEOL. AND NAT. HIST. SURVEY OF MINNESOTA. Habitat: Cincinnati, Ohio. Very abundant in a shallow canal basin in Camp Washington. Up to date it has not been found in any other locality. LATE LARVAL HISTORY OF CYPRIS HERRICKI. PLATES LXVIII, Fies. 40-42; LXIX, Fias. 33-39. In this connection it is not intended to discuss the early stages of Cypris Herricki. These remarks will be confined to what corresponds to the seventh to ninth ecdyces of Cypria opthalmica Jurine. Not only that, but the remarks will be restricted to the external morphology. It is hoped to discuss the internal anatomy in a subsequent paper. The earliest stage here discussed has been compared to the seventh stage of Cypria opthalmica Jurine, because in that stage the appendages have attained about their permanent form; but it- must not be sup- posed that in this Cypris there are only two subsequent larval stages. These stages are tabulated in the following table: Stages.| Length. Height. Position of Dorsal Hump, Ete. Form of Post-abdomen. —| | Rudimentary; fewer spines. A 0.90mm. | 0.57mm. /| Some distance in front of middle. vale aa fica Gananee Teeth on caudal margin of shell. than remainder of the ap- pendage. 4 - z 4 : | Form normal; number of % 1 Sa Oy mm Approaching middle. spines normal : ratio of 1he 1.38 mm | 0.84 mm Teeth on shell much larger. weten nH aie ae P | Ratio of the length of ter- | 1.98 mm 1.20mm, | Near the middle. | minal spine to the lergth of Cc Teeth hell] post-abdomen more uearly | eeth on shell large. normal than in B. | 2.79 mm 1.64 mm At middle. About as in adult. Dat Teeth disappearing. ‘ Adult. | 3.00 mm. At middle. No teeth on shell. In Cypria opthalmica (Jurine) Claus found that by the time the seventh stage was reached, the shell had practically assumed its final form. Inthe form here described there are pronounced differences between the earliest stage here considered and the adult. In the adult of Cypris Herricki the dorsal border of the shell is almost uniformly convex and the cephalic border of the shell is about the same height as the caudal. In stage A (Fig. 33), however, the shell is highest near the cephalic extremity, and the cephalic border of the shell is higher than the caudal. As the animal passes through stages B to D, the highest point of shell moves gradually towards the middle and the height of the caudal margin of the shell approaches more and more the height of the cephalic margin. he RRO eg ee eh aS Pci. tae Pisa te ap Ae ee £ gril, ENTOMOSTRACA OF MINNESOTA. oat In the adult Cypris Herricki the caudal margin of the shell is entire. But in stage A, the caudal margin of the shell is bordered with minute teeth (Fig. 34). In this stage the teeth are quite small and might easily be overlooked; but in stage B (Fig. 35), these teeth have become very conspicuous. Indeed, they are the characteristic feature of the shell. These teeth are present throughout stages A to D, but in stage D they have begun to disappear. In the adult stage there is no trace of these teeth. A careful study of the adult shows that the shell is covered with hairs. These hairs are very conspicuous in stage A. The shell of the adult is marked with very conspicuous dark bands. An effort has been made to discover at what period these bands appear, and to see if they conform to the rules laid down by Professor Eimer. The characteristic bands on the shell may be present in any stage from A to the adult; and when they are present they do not differ essentially from the markings on the adult. The chief points of dif- ference being variations in the width of the bands. In all examples of stages Cand D examined, these characteristic markings were found; but in stages A and B, they were occasionally absent. An examination of Fig. 35 will show that some of these bands are longitudinal while others are oblique. Professor Eimer has attempted to establish the following rule for the formation of oblique markings on animals.* Oblique markings first appear as longitudinal lines. These lines become resolved into dots, these dots, in turn, rearrange themselves in oblique lines. If these laws were applicable to the markings on Oypris Herricki, in stages A and B, where we have some specimens with bands and others without them, we ought to find some transition stages—some stages in which the oblique markings were represented either by parallel lines, or by series of dots. But such is not the case. The shell is either un- marked by bands, or both oblique and longitudinal bands are present. As stated above, in stage A the appendages have practically as- sumed their permanent form. The post-abdomen is a notable excep- tion. This appendage is quite rudimentary; not only has it not yet acquired the typical number of set, but the longest terminal seta is as long as, or longer than, the remainder of the post-abdomen. This great relative length of the terminal seta is due, not to an over-devel- opment of the seta, but to an under-development of the body of the post-abdomen. That the post-abdomen appears to be the last append- age to development is rendered more striking by the discovery of C. _ Claus that the post abdomen appears before the formation of the sec- es ae. Stree = Pare y *G, H. Th. Eimer. Organic Evolution as the Result of the Inheritance of ee Characters According to the Laws of Organic Growth. Translated by J. T. Cunningham, 1890, P.7 3 a et en SA) my ye LY J 4 ee ‘ y tia Ss Ma are Ie pg : EPRI OLS LS Ae i SL es et =. o 1 *> ree? epee } 328 GEOL. AND NAT, HIST. SURVEY OF MINNESOTA. ond pair of legs. In stage B the post-abdomen has developed the per- — manent number of set, but the ratio of the length of the terminal seta to the length of the body of the member is much greater than in the adult. In passing through stages C and D, the parts of the post- abdomen gradually assume the proportions of the adult. Every precaution has been taken to be sure that all the stages. above described were stages of one and the same animal. A definite number of each stage was isolated in saucers of water and a record kept of the number placed in each saucer, and also of the stage of growth exhibited by each set at time of isolation. The water used was collected from a pool which did not contain any Ostracodes which in the least resembled those under consideration. As a further pre- caution the water was allowed to stand in the laboratory a couple of weeks. The loss in volume was replaced by river water, taken from the city hydrant. I never have found any Ostracoda in said river. Thus there was no possibility of the water containing the eggs of Cypris herricki. The larval stages which were placed in this water were examined from time to time. In every case the specimens devel oped into the adult form. The morphological differences between the shell of stage B and the shell of stage A, and between the shell of stage B and the adult, are certainly as great as the morphological differences between the shells of closely allied species. The morphological differences between stage A and the adult are differences, not only in the shell structure, but also in the structure of the post abdomen. And these differences. are as great as those between the genus Cypris and the genus Cypri- dopsis. These facts show that shell structure of Ostracodes, when taken alone, is of almost no taxonomic value. These facts also have phylogenetic significance. These various. larval stages are resting stages in the development of Cypris herricki. Since it is true that the ontogenetic development of an individual is a rapid and compact repetition of its phylogenetic history, these larval forms must represent past stages in the evolution of Oypris herricki. As has been stated above, stage A corresponds very closely to the genus Cypridopsis. The main distinction between the genus Cypris and the genus Cypridopsis is the difference in the form of the post-abdo- men. In the genus Cypridopsis the body of the post-abdomen is but slightly developed, while the sets are quite long. In stage A, in the larval history of Cypris herricki the post-abdomen is in this rudiment- ary condition; thus it corresponds very closely to the genus Oypridop- sis. Not only that, but the unbanded forms of this stage correspond very closely to Cypridopsis hystrix Herrick.* Indeed, when this stage " *0. L. Herrick. Contribution to the Fauna of the Gulf of Mexico and theSouth. 1887. P. 30, Pl. y, Fig. 6. J Meter che <, ‘ > ENTOMOSTRACA OF MINNESOTA. 329 was first encountered, it was supposed to be a Cypridopsis. While working at its anatomy a specimen with the markings characteristic of Cypris herricki was discovered. This led to an investigation of the larval history of the crustacean. These facts give us avery strong hint that the genus Cypris has been evolved directly from the genus Cypridopsis. Should future research show that all members of the genus Cypris have a Cypridopsis stage, the discovery would give much weight tothe hint. And if, at the same time, the internal structure should prove to be similar, the evidence would be conclusive. Cypris (?) albuquerquensis sp. n, PLATE LXXVIII. Length 0.5mm. Height 0.28 mm. Width 0.35 mm. This is asmall greenish hirsute shell about twice as long as high and much wider than high. Viewed from the side (Fig. 1) it is sub-reniform. The two extremi- ties are rounded, but the cephalic is broader than the eaudal. The dorsal margin is convex, the ventral nearly straight. Viewed trom above (Fig. 2) the shell is a broad oval, widest near the middle. The cephalic extremity is a trifle narrower than the caudal. Hingeline straight. The terminal claws of the antenna are long, slender and non-pecti- nate. The natatory sete on the antepenultimate joint do not extend beyond the tip of the terminal claws. The feet are stout. For details consult Plate LX XVIII, Figs. 1-7. This species has not been encountered by the author. The deserip- tion is based on drawings furnished by Professor C. L. Herrick. Habitat: Albuquerque, New Mexico. The data at my disposal render it impossible for me to rightly classify or characterize the following species: C. agilis Haldeman (78), C. discolor Haldeman (78), C. scabra Haldeman (78), C. simplex Hal- deman (78), ©. vitrea Haldeman (78), C. hispida De Kay (58). . / GENUS CYPRINOTUS Brady. 1885. This genus was first established by Professor Brady (26) in 1885 to include a peculiar form that had been discovered by Mr. A. Haly in Ceylon. Professor Sars (195) in 1889 amended the genus in such a F: way as to make it include all the sexually propagated forms of the old { ‘ ' q genus Cypris. In this paper Professor Sars’ description has been Raat WT hes ¥ 330 GEOL. AND NAT. HIST. SURVEY OF MINNESOTA. sufficiently modified to include the American forms that propagate sexually. It is presumed that Professor Wenzel Vavra, who objects to the genus Erpetocypris (221), will also object to this one. The species of this group, however, are closely related both anatomically and physiologically, and it is thought that most workers will welcome the division of the old genus Cypris into the several genera here given. Shell rather thin, compressed, oval or sub-triangular, height ex- ceeding half the length, dorsal margin strongly arched, ventral almost straight. Valves usually unequal, the left valve overlapping the right. The free edges of left valve smooth, cephalic and caudal extremity usually bordered with a hyaline flange. The free cephalic end of right valve usually armed with tuberculiform teeth. Natatory setze of antennze reach beyond the tip of the terminal claw. Abdomi- nal rami are slender, with smooth or very finely pectinated claws. Propagation is sexual. Copulative organs are small, with an outer linguiform obtuse plate. The cylindrical core of Zenker’s organ bears numerous wreaths of spines, Cyprinotus incongruens Ramdobr. PLATE LXVIII, Figs. 9-16. 1808.—Cypris incongruens Ramdohr (173), p. 86; Taf. III, Figs. 1-12, 15, 16, 18-20. 1820.—Monoculus conchaceus Jurine (98), p. 171; Pl. XVII, Figs. 7-8. 1820.— ruber Jurine (98), p. 172; Pl. XVIII, Figs. 3-4. 1820.— ‘ aurantiacus Jurine (98), p. 173; Pl. XVIII, Figs. 5-12. 1821.—Cypris fusca Straus (205), p. 59; Taf. I, Figs. 1-16. 1844.— ‘‘ aurantia Zaddach (234), p. 37. 1844.—? ‘‘ opthalma Koch (!02), H. 36, p. 17. 1850.— ‘* aurantia Baird (5), p. 159; Taf. XIX, Fig. 13. 1853.—. ‘‘ incongruens Lilljeborg (118), p. 119; Taf. IX, Figs. 6-7; Taf. XI, Figs. 1-4; Taf. XII, Fig. 6. 1855.— ‘* aurantiaS. Fischer (65), p. 650; Pl. I, Figs. 29-31, 60, 61. 1868.— ‘‘ incongruens Brady (18), p. 73; Pl. X XIII, Figs. 16-22. 1868.— ‘‘ fusca Fric and Nekut (70), p. 47, Fig. 28. 1872.— ‘* fusca Fric (69), p. 212, Fig. 26. 1889.— ‘‘ incongrwens Brady and Norman (31), p. 73; Pl. XII, Figs. 8-9. 1891.— ‘* incongruens Wenzel Vavra (221), pp. 95-98; Figs. 32, 321-32°. 1893.— ‘* incongruens C. H. Turner (213), p. 8; Pl. I, Figs. 9-16; Pl. II, Figs. 17-21. Length 1.35 mm. Height 0.75 mm. The shell is equivalve, one valve overlapping the other in front. The shell is yellowish brown in color and is covered with scattered hairs. Viewed from the side (Fig. 9) the shell is sub-reniform, widest near the middle. Both extremities rounded and of nearly the same width; the cephalic extremity may be a trifle narrower than the caudal. Ventral margin nearly straight, other margins convex. ee ENTOMOSTRACA OF MINNESOTA. 331 Viewed from above (Fig. 10) the shell is ovoid, pointed in front and rounded behind. The greatest width is caudad of the middle. Hingeline straight. Viewed from below (Fig. 11) the contact line is straight. The claws on the antenna (Fig. 13) are toothed. The plumose natatory sets reach to the extremity of the terminal claws. No dagger-shaped seta visible on either the penultimate or ante- penultimate joint of the mandibular palp. The biarticulate claws on the first mandibular process of the first maxilla toothed. The claw of the first foot is long, slender, finely pectinated and curved, The abdominal ramus is short, feeble and slightly curved. The terminal claw is long, slender, slightly curved, pectinated near the end. The claw is about two-thirds as long as the entire ramus. I have never encountered any males of this species; but since Wen- zel Vavra (221) has found males of this species in Bohemia, and since it is anatomically closely related to the other members of this group, I include it in this genus. Habitat: Rare. Cincinnati, Ohio (Turner, 213). Cyprinotus crena Turner. PLATES LXVII, Fiaes. 11-13; LXIX, Fias. 22-31. 1892.—Cypris sp. (?) C. H. Turner (212), p. 71; Pl. II, Figs 11-13. 1893.— ‘ crenata C. H. Turner (213), p. 9; Pl. II, Figs. 22-32. Length of female 1.23 mm. Height 0.63 mm. Width 0.60 mm. Length of male 1.14 mm. Height 0.60 mm. Width 0.45 mm. The shell is equivalve, very thin, the free margins of one valve are bordered with blunt teeth. The ventral margins of both valves bear hairs. Shell reticulated with contorted lines; the reticulations are most distinct on the cephalic portion of valve. Lucid spots about nine, sub-central. Color, various shades of greenish yellow. The caudal half of shell of male appears to be marked with concentric retort shaped lines. Since the shell is very thin this appearance is due to the presence of Spermatozoa or spermatophores within the shell. Viewed from the side (Fig. 22) the shell is sub-reniform, highest about the middle, cephalic and caudal extremities about the same width. Caudal, dorsal, and cephalic margins convex; ventral margin nearly straight, slightly convex at the middle. Viewed from above (Fig. 23) the shell is sub-oval, widest behind the middle. Caudal margin rounded, cephalic margin bluntly pointed. Hingeline sinuate. i) & bs ’ *y 7 ¥ 5 5 “ae ( 332 GEOL. AND NAT. HIST. SURVEY OF MINNESOTA. Viewed from below (Fig. 24) same as when viewed from above. Line of contact of valves sinuate. Viewed from end (Fig. 25) shell is oval, a little higher than wide. Antennules (Fig. 25) and antennz as usual in genus Cypris. The mandible (Fig. 26) terminates in four large teeth; between each two of these teeth there is a short, slender rod. The mandibular palp consists of four joints. The first joint is very large, about as large as the combined lengths of the other three; it bears about the middle of its dorsal surface a branchial appendage, which in turn bears four long sete; and from the distal fifth of its ventral surface arise two long setee. The antepenultimate joint is very short; from the distal half of its dorsal surface arise two long sete and one short one. The penultimate joint is long; from its disto dorsal extremity arise three long and one short sete; from the disto-ventral angle of the shell arise two short sete. The terminal joint is very narrow and about as short as the antepenultimate joint; at its tip it bears four short claws. The biarticulate claws on the first mandibular process of the first. maxilla are smooth. The first foot of the male (Fig. 27) is composed of five joints. The second joint is large. The antepenultimate joint is about as long as the preceding joint. From its disto-caudal margin arises a medium sized seta, and from its disto-cephalic margin arises a somewhat smaller seta. The terminal joint is about the same size as the penul- timate. From its disto-caudal margin arise a medium size seta and a small spine; from its disto-cephalic margin arises a very short spine. From the distal end of joint arises a long claw; the claw is about as long as the combined lengths of the three distal joints. The claw is composed of a short basal and a long terminal portion. At the disto- caudal portion of the basal joint of claw there is a short seta; at the disto-cephalic margin of the same joint there is a somewhat smaller seta. A row of fine hairs extends along the middle portions of the caudal margin of the terminal joint of the claw. In the second foot of the male the antepenultimate joint is medium sized. From about the middle of this joint arises a median seta, and from the disto-caudal margin a long seta. The penultimate joint is the longest joint; from its disto-cephaliec margin arises a median spine. The terminal joint is about as long as the antepenult; from the middle of its cephalic border arises a short seta; from its tip arises a short seta; from its tip a more or less curved short claw and a median seta. The post-abdomen (Fig. 29) of male is curved. At its tip there is — a long claw and a short seta. Entad of this terminal claw is another long claw; further entad arises a short seta. Post-abdomen of female is straighter, otherwise the same. ENTOMOSTRACA OF MINNESOTA. 333: In the male there is a pair of verticillate sacs (Fig. 30). From the distal extremity of each arises a vas deferens. Length of sac 0.385 mm. ; width 0.11 mm. The copulative organ of male consists of distinct halves, each half of which is composed of a large basal and a small terminal portion. The basal portion of each division receives at its proximal end a vas deferens. Length of copulative organ 0.37 mm. ; width 0.11 mm. Habitat: Small weedy ponds or canal basins. I have not found these very often; but whenever found they were very abundant. On one occasion I found a pool containing millions of males, but not a single female. Specimens of this species have been found at Cincin- nati, Ohio. (Turner, 213.) Cyprinotus burlingtonensis Turner. PLATE LXX, Fias. 14-23. 1894.—Cypris burlingtonensis C. H. Turner (2:5), pp. 17-19; Pl. VII, Figs. 14-23. 1894.— ‘‘ burlingtonensis C. H. Turner (216). Length of the female 1.6 mm. Width 0.89 mm. Height 0.93 mm. Length of the male 1.8 mm. Width 0.7 mm. Height 0.7 mm. The length of the shell is a little less than twice the width and the height is about equal to the width. The shell is very thin and is covered with long hairs (Fig. 15). The shell is also marked with certain dark bands, which are due, in part at least, to the internal organs shining through the translucent shell. Viewed from the side (Fig. 17) the shell is sub-oval, but the cephalic extremity is wider than the caudal. The dorsal margin is convex, the greatest convexity being nearer the cephalic than the caudal ex- tremity. The cephalic and caudal margins are convex. The ventral margin is nearly straight. Viewed from above the shell is sub-elliptical, the two extremities being more or less pointed (Fig. 17) and of about equal width. In some specimens the ends are round. ‘The sides are feebly convex, indeed in some parts they are almost straight and nearly parallel. Viewed from the end the shell is nearly circular, the sides being very convex. The antenna consists of five joints (Fig. 20), the fourth joint being very long and slender. The distal joint is narrow, being no wider than the base of the terminal claws. ‘The terminal claws are slender _ and the distal portion of each is fringed by a longitudinal row of very _ fine teeth. The natatory sete extend to a short distance beyond the tip of the terminal claws. a \ 4 aii AEA ‘ 334 GEOL. AND NAT. HIST. SURVEY OF MINNESOTA. The second joint of the mandibular palp bears, in addition to the usual sete, a short, plumose, dagger-shaped seta (Fig. 18). The ter- minal claws of the palp are slender and smooth. The two prominent spines upon the first mandibular process of the first maxilla bear teeth (Fig. 16). The palp of the second maxilla terminates’ in three long flexible spines. The middle spine is longer than the whole palp, but the lateral ones are only about two-thirds as long as the middle one. The first foot (Fig. 21) is five-jointed, the third and fourth joints being distinet. The second joint is broad and is as long as the united lengths of the next three joints. The terminal claw is longer than the united lengths of the last three joints. The distal third of the cephalic margin of this claw is finely pectinated. The claw upon the last joint of the second foot (Fig. 23) is curved and is about twice as long as the terminal joint. The post-abdominal rami (Fig. 19) are slender and straight. The terminal claws are long and slender, being about half as long as the ramus. They are straight and one margin of the tip of each is finely pectinated. The lower claw is fully three-fourths as long as the distal one and resembles it in structure. Habitat: These are found in great numbers in a shallow grassy pool at Burlington, Ohio. They were found in the early part of March, 1893, just after the close of a long and severe winter; indeed, there was a light snow-fall the day before the collection was made. Judging by the lay of the land, I think that the pool dries up in summer. At Atlanta, Georgia, just after some heavy rains in January, 1894, large numbers of these active creatures were found in several shallow pools in the South River bottoms. These pools dry up in warm weather, The specimens remained for about two weeks and then dis- appeared. Length 1.58 mm.; height 0.94 mm.; width0.91mm. Jones Creek, Kent county, Delaware, March 3, 1894, collected by Professor L. D. Hileland. These were immature specimens about 1.4 mm. long. Cyprinotus grandis Chambers. PLATE LXXIX, Fias. 1-9, —.—Cypris grandis V. T. Chambers (41), pp. 151-152, Fig. 1. 1887.—Cypris grandis C. L. Herrick (86), p. 32. Length 3.60 mm. Height 2.09mm. Width 1.39 mm. ‘‘Valve oblong, slightly sub-reniform, highest behind the middle, sloping thence regularly toward the anterior end, with a slight bulge ~ on the hinge-margin just where it rounds off in front. Greatest thick- ness about the middle. In side view somewhat resembling Brady’s Fe ce i ENTOMOSTRACA OF MINNESOTA. 335 figure of (C. tessellata (Trans. Linn. Soc., v. 26, Pl. 23, Fig. 39), but this species is longer in proportion to height and has the highest point of the dorsal margin a little farther behind. Ventral margin very slightly emarginate. In dorsal and ventral view somewhat resembling Brady’s figure of Macrocypris minna (loc. cit., Pl. 28, Fig. 34). Right [? left] slightly overlapping the left [? right]; surface smooth, with minute punctures and short hairs, but with a group of scattered, large sordid, yellowish punctures about the middle of each valve. Color bluish-white (nearly that of thin milk), though some specimens show a decided pale greenish tinge. Basal joint of superior antenn with two short sete above and one below; second joint with a single short one below; third with two short unequal setze above and one below; fourth with two above like those of the third, and two long ones below; fifth as the fourth; sixth with the two upper sete as in the third and fourth, but with four long ones below; seventh with two long and two shorter sete. Inferior antenne with one moderately long and two short claws, and two sete from the end of the last joint, and with four long claws (one shorter than the other three), and one moderately long Seta, and one long one from the end of the penultimate joint, besides four rather long ones above, and two beneath about its middle. Third joint with the usual single stout seta from its end beneath, and the usual fascicle of five long and one short one above near the end, and the usual articulated process. Post-abdominal ramus similar to that of C. incongruens as figured by Brady (loe. cit., Pl. 23, Fig. 20), but longer, having three unequal setie, the terminal one longest. Seminal gland very Similar to that of Notodromas monachus (loe. cit., Pl. 37, Fig. 36). Length + of an inch; height -;';; greatest thickness ;. Probably the largest known species of the genus. It is abundant in the ponds along the upper Arkansas river in the Mount Harvard region, at an altitude of about 8,000 feet. When first taken, my specimens were brownish from adhering mud, but alcoholic specimens have the livid white color above mentioned. The lucid spots are indistinct and difficult to make out; there are about nine, the two anterior obliquely transverse and long, the two posterior small.’’ (V. T. Chambers. ) Habitat: Upper Arkansas river in Mount Harvard region. (V.T. Chambers. ) FAMILY DARWINULIDE. ‘‘Antenne destitute of swimming sete and of poison gland and duct. Mandible-palp three-jointed; the basal joint large and densely setiferous. Two pairs of jaws, the first bearing a large branchial plate, the second a smaller branchial plate and a pediform palp. Two pairs of feet external to the valves. Post-abdominal lobes sub-conical, small.”’ (Brady and Norman. ) 336 GEOL. AND NAT. HIST. SURVEY OF MINNESOTA. GENUS DARWINULA Brady and Robertson. 1870. ‘*Shell smooth, thin, and fragile. Carapace oblong, higher behind than in front; lucid spots ten to twelve in number, linear-oblong or wedge-shaped, arranged in a subradiate manner in front of the centre of the valve. Seen from the side, compressed, oblong, sub ovate. Seen from above, ovate, acuminate in front, obtusely rounded behind. Valves unequal, the right much larger than the left. Antennules very short, six-jointed, and stout, strongly armed with short and stout curved sete. Antenne four-jointed, and bearing four or five strong terminal claws; entirely destitute of poison gland or urticating sete, the place of which is occupied by a single curved seta of moderate length. Mandible broad, truncated at the distal extremity, which is provided with six or seven small spiniform teeth; palp three jointed, its basal joint very wide and fringed with several curved set, bearing also a small lamina, fringed with branchial filaments; second joint long, slender, and nearly four times as long as broad, slightly curved and dilated at the distal extremity, where it bears one long and two small setze; terminal joint more slender, about two-thirds of the length of the foregoing, and bearing at the truncate apex about six slender curved spines. First maxilla divided into four short setiferous seg- ments, and bearing a very long oblong palp, which is fringed with about twenty-four long branchial filaments, and has also four other long sete at its base. Second maxilla simple, short, and broad, trun- cate at the apex, and fringed on the distal margin with several slender spine-like hairs, bearing also a large, three jointed, pediform palp, and an ovate branchial appendage of moderate size. Two pairs of feet of moderate size, five-jointed; second pair much the longest, and hav- ing the last joint armed with one long and two small curved sete; first three joints of nearly equal length; fourth and fifth, respectively, about one-half and one third as long as the preceding. Abdomen ending in a short conical process. Copulative organs of the male of complex structure, the basal portion of an irregularly-shaped plate produced laterally into an aliform process, and on the distal margin into a short, strong hook. Female probably viviparous.” (Brady and Norman, 31.) Darwinula improvisa sp. n. PLATE LXXXI, Fi@s. 1-3, 13. Length of female 0.68 mm. Height 0.27 mm. Width 0.24 mm. Length of male 0.70 mm. Height 0.23 mm. The right valve is larger than the left and overlaps it on the ven- tral side. In the female the height is more than one-third of the ¥5 ne ei ti atliad 3 — ~ “ ‘ fees ENTOMOSTRACA OF MINNESOTA. 337 length and the width is less than the height. In the male the height is about one-third of the length. The color is yellow, with two green blotches, one on each side, in front of the middle. These patches of pigment are on the animal but show conspicuously through the trans- lucent valves. The female carries her young in the enlarged caudal portion of the valves. These are white and show distinctly through the valves. Viewed from the side the shell is oblong, depressed in front, broad- est caudad of the middie. The two extremities are rounded, the cephalic end is narrow, while the caudal one is broad. Viewed from above the shell is ovate-acuminate, widest near the caudal extremity. The cephalic extremity is pointed while the caudal is broad and notched where the two unequal valves meet. The antennules are stout and appear to be composed of only five joints. In this respect as well as in the arrangement of the sete this member differs from the corresponding member of D. stevensoni. The antenn are stout and are composed of five joints. The long terminal claws are as long as the combined lengths of the last three joints. The antepenultimate joint bears a conspicuous one-jointed appendage which terminates in one long and one short filament. Here we have another marked difference between this species and D. stevensoni, The mandible bears a three-jointed palp, to the termiral joint of which is appended a lamina bearing several long curved filaments. The second maxilla bears a leg-like palp. The first foot is stout and five-jointed. Thesecond foot is not bordered by a fringe of hairs, For arrangement of the setze consult the figures. The second foot consists of five joints; the terminal claw is longer than that of the first foot. Like the first foot, none of its members are bordered with short hairs. For the arrangement of sete consult the figures. The abdomen terminates in a pointed process. Habitat: The only specimens yet found were collected in a sand bottom reservoir at Atlanta, Georgia, Sept. 1, 1894. This reservoir is about three miles in circumference and is fed by creeks which arise a short distance off at the watershed of the state. pis Sik ’ q 4 ; . A om , a A “i yX a wy ’ 4 lft 4 c > 12 { < j -- \ > r . 7 i Z s a - aie 1 © t 1 ' , ve PP ie . y ect ; t ~~ f ity 7 ue 1 ; ’ 5 y + i A> ' ‘ ' ‘ + iy f ‘ ;, - " ly i ‘ q - ¥ ‘ +] i 7 i - rt L, p> . =a he ! 7 ¥ fener . \ ie 7 “. { is. | - ; y , } u 4 7 ’ » eo * ‘ ¥ mi ; Fx ob d .7 Pay ‘ t j i ‘ F ' ‘ Limnocalanus macrurus Sars. 1. Left foot of the fifth pair in the male. 2. Right foot of the same pair. 3. Foot of the fifth pair in the female. 4. Abdomen. Eurytemora affinis Poppe. Female from above. Right antenna. Fifth foot of female. Feet of fifth pair in the male. First foot. 10. One of the swimming feet. fH IH OH Pseudodiaptomus pelagicus Herrick. 11. Lateral view of female with ovisac and spermatophore. 12. Fifth feet of female. 13. Fifth feet of male. 14. Portion of right male antenna. 15. One of the swimming feet. 16. Abdomen of male. 17. Antennules. Notr.—All details are from females unless specified, and where the parts in the sexes are alike the drawing is always from the female. fel yENO WO, dle ZOOL. SURVEY OF Minn., II, 1895. y N ™~ [yi} or i eee 44 bs . Who hes at ae et Or kt qe - EXPLANATION OF PLATE IL Diaptomus leptopus Forbes. Fic. 1. Lateral view of female. Shaded portions purple. 2. Dorsal view of the male. To the same scale. 3. Abdomen of the female from above. 4. Fifth foot of the female. 5. Maxilliped. 6. Antennule. 7. Fifth foot of the male. 8. Fourth foot of the female. 9. Right antenna of the male. 10. First foot. All the figures are from specimens taken near Minneapolis, Minne- sota. Mostly camera lucida drawings copied mechanically. —— PICASE Tl 1895. b) eh SURVEY OF MINN., AOOls ~—_™ — ie a “me Siw he re / ' EXPLANATION OF PLATE II ae a ay. ig 7 AES, 6 P it Be y ~] a “"* vir AY 7" ah ie ee Diaptomus stagnalis Forbes. ‘ ‘2 G. a oe 1. Female from above. rea) ss 2. Male from above. ; --—s-8.-s« Portion of male right antenna—a variant. : 7. 4. Stylet of the female. _ 5. Fifth foot of the female. 6. Fifth feet of the male. 7. Antennule. 8. Maxilliped. 9. First foot of the male. 10. First foot of the female. dl. Third foot of the male. 12. Fourth foot of the male. > A of f ne All the figures from camera drawings. From specimens secured in — Granville, Ohio, in spring. ; “i DUB PEW iy 1305. ZOOL. SURVEY OF MINN., EXPLANATION OF) PLATE! IV. 7] OU Gobo rs 4 Diaptomus pallidus Herrick. Lateral view of preimago (immature) female. Right antenna of male. Fifth feet of the male as they usually appear. Fifth feet of the female. From Minneapolis specimens. Feet of fourth pair. Fifth feet of the male, showing the true nature of the appendages of the left foot. The inner ramus of the left foot is not shown in the figure. Diaptomus oregonensis Lilljeborg. Right antenna of the male. Fifth feet of the male. Fifth foot of the female. Palpus of the mandible. Left foot of the fifth pair according to Lilljeborg. End of the female antenna. All but Fig. 11 from specimens from Lake Minnetonka, near Min- neapolis, Minnesota. ZOOL. SURVEY OF MINN., bd apenieSo)te PEASE VY: EXPLANATION OF PLATE V. Fig. Diaptomus sicilis Forbes. Dorsal view of the female. Dorsal view of the male. Right antenna of the male. Fifth foot of the female. ica) 4 y ~ Qa CON SMR WD HE : “ah 4 Dorsal view of the female. Appendages omitted. Camera. Lateral view with antenna and egg sac. Camera. hort, Dorsal view of the abdomen. Camera. an, One of the feet of the fifth pair in the female. Camera. | Second antenna. ae Jaw and its palp. ‘og i Outer maxilliped. es Foot of the first pair. Foot of the second pair. | SS Extremity of the male right antenna. Ke The fifth feet of the male. Camera. * i ao sat ¢ Age Voie 1895. P. MINN. \ ZOOL. SURVEY OF a 5 ect a bo eee oe ee eo eer Stars gibber Poppe. Fifth foot of male. roubaui Richard. Fifth foot of male. salinus Daday. Fifth foot of male. wierzejskii Richard. Fifth foot of male. richardi Schmeil. Fifth foot of male. incongruens Poppe. Fifth foot of male. lobatus Lilljeborg. Fifth foot of male. mirus Lilljeborg. Fifth foot of male. minutus Lilljeborg. Fifth foot of male. siciloides Lilljeborg. Fifth foot of maie. theeli Lilljeborg. Fifth foot of male. franciscanus Lilljeborg. Fifth foot of male. signicaudatus Lilljeborg. Fifth foot of male. serricornis Lilljeborg. Fifth foot of male. Jaciniatus Lilljeborg. Fifth foot of male. franciscanus Lilljeborg. Antepenultimate joint of right male antenna. trybomi Lilljeborg. Antepenultimate joint of right male antenna. PACE, Velulele ZOOL. SURVEY OF MINN., Ly 895% SOU re Ne ap UoMUs gracilis Sars. Fifth foot of male. amblyodon Marenzeller. Fifth foot of male. oregonensis Lilljeborg. Fifth foot of male. trybomi Lilljeborg. Fift foot of male. castor Jurine. Fifth foot of male. lilljeborgi De Guerne and Richard. Fifth foot of male. coeruleus Fischer. Fifth foot of male. glacialis Lilljeborg. Fifth foot of male. leptopus Forbes. Fifth foot of male. signicaudatus Lilljeborg. Abdomen. roubaui Richard. Abdomen. serricornis Lilljeborg. Antepenult joint of right male antenna. wierzejskii Richard. Antepenult joint of right male antenna. EL AMINES Xe > My ta CVA Riis Yr a he ea) ara oe ie KE aie DA erie ie + a - Ao : Pte tN. : A Pocket (Re Me le ae pe it + U ; IW ” Ne da) Vee ’ : 1a a ee, . eed ) vie ey aE te VGncanh a ake Y ee or PAACor ¢ fume iv DS aia diel it sear ee a ya Dik “er ‘ mee ; : a é oe ne are Aun ~ a) _ 2 Pi) fig Jb rea ay [vac - EXPLANATION OF PLATE X. ic ~ Q eee epee a ee ee Diaptomus,lumholtzi Sars. Fifth foot of male. : baccillifer Koebel. Fiftii foot of male. “3 pectinicornis Wierzejski. Fifth foot of male. “ denticornis Wierzejski. Fifth foot of male. a orientalis Brady. Fifth foot of male. ; sy zachariasi Poppe. Fifth foot of male. 4 asiaticus Uljanin. Fifth foot of male. tatricus Wierzejski. Fifth foot of male. a tyrrelli Poppe. Fifth foot of male. affinis Uljanin. Fifth foot of male. rs eiseni Lilljeborg. Fifth foot of male. me laciniatus Lilljeborg. Abdomen. ch trybomi Lilljeborg. Abdomen. Heterocope saliens Lilljeborg. Fifth foot of male. : borealis Fischer. Fifth foot of male. Broteas falcifer Loven. Third maxilliped. PAu Bie. SURVEY oF Minn., II, 1895. ZOOL. i a hee ea et ene) a = a a a Ponds tt SDM Epischura neyadensis Lilljeborg. Fifth feet of male. Cy nordenskiceldi Lilljeborg. Fifth feet of male. Heterocope appendiculata Sars. Fifth feet of male. Bo Sanat nevadensis var. columbizwe Forbes. Fifth feet of male. nordenskieeldi Lilljeborg. Abdomen. nevadensis Lilljeborg. Abdomen. re columbiz Forbes. Abdomen. cr neyadensis Lilljeborg. Fifth foot of female. ss nordenskiceldi Lilljeborg. Fifth foot of female. i nevadensis var. columbizw Forbes. Fifth foot of female. Poppella guernei Richard. Fifth feet of male. Kurytemora velox Lilljeborg. Fifth feet of male. Beckella brasiliensis Lubbock. Right fifth foot of male. fe triarticulata Lubbock. Right fifth foot of male. Centropages brevicaudatus Brady. Abdomen. ie brevicaudatus Brady. Fifth feet of female. Fe un ES Te Ile T8095. ZOOL. SURVEY OF MINN., ay i A rr Oba T dthent ey , i) “fe eo), : 7 ta = —_= 7 a - oh) j - je Tar re, % C Bee x Ory : a 3 7 0) all Hiaase, a m4 a) Pee Shoe NS Osphranticum labronectum (Potamoichetor). Male. Antennule. Maxilliped. Fifth feet of the male. Palp of the mandible. End of the abdomen. Feet of the first pair. Eye. Cyclops ater. Female. Abdomen. Mavxilliped. Antenna. Osphranticum labronectum. Maxilla. - labronectum. Antenna. ZOOL. SURVEY oF Minn., II, 1895. PAT Ee xele wher s Alonella pulchella. Female. Reticulations. Post-abdomen. Alona modesta. Male. Diaptomus similis. Female . Jaw. Fifth foot of the male. Fifth foot of the female. Diaptomus minnetonka., Fifth foot of the male. Fifth foot of the female. Abdomen of the female. Diaptomus stagnalis. Margin of the last thoracic segment. Ssanguineus. Margin of the last thoracic segment. ne stagnalis. Fifth foot of the male. Epischura fluviatilis. Abdomen of the male. sh lacustris. Fifth feet of the male, io fluviatilis. Fifth feet of the male. Diaptomus pallidus. Inner ramus of the fifth feet of the male. me sicilis. Inner ramus of the fifth feet of the male. ZooL. SURVEY OF Minw., II, 1895. BAL ‘ \ oN BEADS) XGhT. ty Rear See Sore ream ee Rel real Cyclops viridis var. americanus Marsh. Female from above. Antenna and antennule. Foot of the first pair. Foot of the third pair. Foot of the fourth pair. Caudal stylet. Fifth foot. Sixth foot of the male. Antenna of the male. Specimens from Albuquerque, New Mexico. - Zoot. Survey or Miny., II, 1895. PLATE XIV. SS Paes SS SNA =z et > = rf Se - SS a Pe ae tf //' srl” ee en PLD aL OT Te ea EXPLANATION OF PLATE XV. e| a aS sore Cyclops signatus var. coronatus. Outline from above of a mature female. Outline of a male. Fifth foot. One of the fourth pair of feet. Cyclops signatus var. tenuicornis. Tip of the antenna of the female. Fifth foot. Stylet of the female. Cyclops serrulatus. Foot of the second pair. Foot of the fourth pair. Fifth foot. Stylet of the female. Type. ae =A « 95 18; Zs JOT Su VEY Ok M ’ 5 tc . im, c L006 Gat ee Sessa PPP Po | Ras | deh aah | ; —) = PA <>) = | = Au cy oO Zz Oo lem! = x Zz < = — > i<) by eeey ee Or er es ma a ta) Cyclops leuckarti Sars. Camera outline of body seen from above. Antenna. Camera. Caudal stylet. Camera. Terminal segments of antenna to show armature. Fifth foot. Camera. Outer maxilliped. Camera. Inner maxilliped. Camera. Foot of first pair. Camera. Foot of second pair. Foot of fourth pair. Camera. Opening of the spermatheca. PAG Saves Ti Rso55 ZOOL. SURVEY OF MINN... SSS S We, Pa E Eo Pa c) ieee AS = a lee eee eee ff — y 2 Tae aN ~~ _ EXPLANATION OF PLATE XVII. ae ace ape 4c, (> ors rs *« A dt ~ aie Cyclops phaleratus. Outline of the male from above. Stylet of the male. Fifth and sixth feet of the male. Antenna of the male. Antenna of the female. Fifth foot of the female. Fourth foot. Cyclops fimbriatus. Stylet. Antenna of the female. Cyclops languidus. Antenna of the female. Fifth foot. PAGE Sova: ZooL. SURVEY OF Minwn., II, 189s. EXPLANATION OF PLATE XVIIL TAQ W 3d. 3e. Cyclops leuckarti. Slender form. Abdomen. Labrum. Antenna. Fifth foot. Feet of fourth pair. Feet of second pair. Feet of first pair. Antenunule. Maxilliped. Mandible. Cyclops phaleratus. Ventral view of female. Part of the abdomen of the male with sixth foot. Antenna. Labrum. Pair of feet. Cyclops bicolor. Lateral view. Abdomen. Foot of the fourth pair. Antenna. Labrum. Receptaculum. Re By Neh a 8 ita toe Seth eae ae ZooL. SURVEY oF Minw., II, 1895. PAE ASE GWT Sao ee i ane. Or 13. Cyclops phaleratus. Female. Cyclops serrulatus. Male. Under surface of abdomen. Last joints of antenna of the female. First foot. The spine of the distal segment of outer ramus is incorrectly shown as curved. Cyclops diaphanus. Fourth foot. Stylets. Fifth foot. Antenna. Cyclops gracilis. Abdomen. Fifth foot. Cyclops varicans. Stylets. Antenna. PIA BaxIoe II, 1895. ZOOL. SURVEY OF MINN., a a SIS TR go tO Cyclops signatus var. tenuicornis. Female. Mandible. Mavxille. Stylet. Fifth foot. Maxillipedes. Antenna. Cyclops signatus. Abdomen. Antenna. Fifth foot. Male antenna. Cyclops parcus. Abdomen. Antenna. Fifth foot. Receptaculum seminis. Cyclops adolescens Abdomen. Foot. Antenna of female. Kye. Antenna of male. Cyclops signatus. End of antenna. wy AUIS XOX I 0895. ZOOL. SURVEY OF MINN., Cyclops modestus. 1. Side view. 2. End of the abdomen. 3. Outer ramus of first foot. 4, Outer ramus of second foot. 5. Fifth foot. Cyclops phaleratus. 6. Fourth foot. 7. Outer ramus of first foot. 8. Fifth foot. 9. Caudal stylets. 10. Antenna of young, otherwise perfect. il. Cyclops fimbriatus. End of abdomen. Ws se bicolor. Abdomen. Cyclops ater. 13. Inner ramus of first foot. 14. Outer ramus of first foot. 15. Outer ramus of fourth foot. 16. Cyclops signatus. Fourth foot. 17. ; ater. Inner ramus of fourth foot. 18. é ater. Stylet. 19. ‘© sp. First foot. 20-21. ‘* sp-2 Terminal segments of fourth foot. 9° “c 22. parcus. Fifth foot. 23. Chydorus globosus. First foot of male. PAGE. XE ZOOL. SURVEY OF Minn., II, 1895. tt I ae SSS es? EXPLANATION OF PLATE XXIL Les pee igte i. 13. 14. 15. SOMDABDAPWN ES Canthocamptus minnesotensis. First foot. Stylets. Antenna of female. Fifth foot of female. Fifth foot of male. Antenna of male. Daphnia hyalina (D. galeata). Young. cd sé ss Male. Camptocercus leucocephalus. Male. Alonella excisa. Male. Cyclops insignis. Outer ramus of the first foot. Fifth foot. Fourth foot. Sty let. Worm parasitic in arterial sinus of Daphnia schaefferi. Leva NS) POGUE ZooL. SURVEY OF MINN., TT 8o 5: WT/7 wey, ed ji, y re] = ps < ica] = < 4 AY xy S Z ) | an Hy = Z, < 4 a b eal Cyclops brevispinosus. Stylet. Antenna. Outer ramus of fourth foot, terminal segment. Fifth foot. Cyclops xquoreus. After Brady. me insignis. Abdomen. . insignis. Receptaculum, after Schmeil. ? pareus. Fourth foot. a bisetosus. Receptaculum, after Schmeil. oy bisetosus. Stylet. = bisetosus. Fifth foot. ~ strenuus. Receptaculum, after Schmeil. é strenuus. Fifth foot. si abyssorum. Fourth foot. AC xexoie ZOOL. SURVEY OF Minn., II, 1895. IZA Cue ag iif a ra Sz St =< (J L- ———a ' \ _ EXPLANATION OF PLATE XXIV. . Ergasilus depressus. Male. Peo. eae Cyclops leuckarti, deep-water variety, = C. tenuissimus.— ¥ f see ‘Stylets. Fifth foot. Antennule. Fourth feet. Antenna of male. Cyclops brevispinosus. Stylet. Inner maxilliped. Swimming foot. Fifth foot. Antennule. Opening of receptaculum. Cyclops sp.? Nauplius. PLATE XXIV. ZOOL. SURVEY oF MInN., II, 1895. e=. wc EE SSS SSS SEES Ss SSS SS SSS OOPSLA ALOE OO jh i tA f | PPP FS Sea EXPLANATION OF PLATE XXV. Cyclops ingens. First segment of abdomen of female. Antenna. | Fifth foot. Antenna of young male. — Stylets of mature female. Stylets of young male. Maxilliped. Mandible. Cyclops fimbriatus. i Female from above. Antenna. Terminal portion of abdomen. Female fifth foot. Second antenna. Nauplius form. ZOOL. SURVEY OF MINN., II, 1895. PICA E, aXxexe Ve - > a carta el ero . yore f ’ ne og ; 4 e f EXPLANATION OF PLATE XXVI._ . m > Ki RNS Sah; bang gh om, by ad > Cyclops fluviatilis. Female from above. Antenna. — Antenna of young. _ Abdomen of young. Foot of young. — Foot of adult. Fifth foot. Eye. je (Should have been cut out.) Cyclops serrulatus. Young from above. Daphnella brachyura. Female. Lateral view. Male. . Edge of valves. Abdomen of male. Abdomen of female. Antenna of male. BAW i XOXC Vale MSOs: ZOOL, ‘SURVEY (OF MInN., RS —< N \ | _ Ax nig ee VE , eZ ae 4 eT LK) OS i Ugiesooff: 2 SEI Ll SO WHA << \ af ‘ ee ee Ga’ ian ae 5 A, / EXPLANATION OF PLATE XXVIL Daphnia kalbergensis. Of moderate’ size. Antennule of male. Head of variety. Cyclops pulchellus (thomasi). Fourth foot. ** pulchelIns (thomasi). Outer ramus of first foot. Daphnia hyalina (D. galeata). Typical form. Cyclops thomasi. Fifth foot. * thomasi. Stylet. Cyclops (insectus?). Fourth foot. Bythotrephes longimanus. Female. A curious large protozoan; a. infundibulum frame work; 0). pulsating vacuole; ¢. nucleus; d. food and digested matter; e. protective rods; lla. spicules of the infundibulum. PARP En XOxS Vel ZooL. SURVEY oF Minn., II, 1895. | EXPLANATION OF PLATE XXVIII. ! Female. Leg of the fourth pair. The ter is represented too broad. Leg of first pair. ; ey Fifth foot. th | Cyclops pulchellus (« thomasi’’). Leg of first pair. Leg of second pair. Leg of fourth pair. a Fifth foot. 5 All the figures are copied from Forbes. ZOOL. SURVEY OF Minn., II, 1895. AE x Obi i iM a EOS oe Ma) vie Car a ad bd * B H < ml Ay = 2) Z =) eS : va eo a a: ca CoS a 12. 15. 21. 22. SCORN Ss Canthocamptus illinoisensis. Antenna of female. Fifth foot of female. Antennule. First foot. Caudal stylet. Canthocamptus northumbricus var. americanus. Fifth foot of female. Antenna of female. Maxilliped. Caudal stylet. Antenna of maie. First foot. Fourth foot. Fifth foot of male. Frontal area. Canthocamptus tenuicaudis. Stylets. ne tenuicaudis. Fifth foot of female. Cyclops serrulatus. Fifth foot. Fourth foot. Outer ramus of first foot. Canthocamptus northumbricus. Inner ramus of third male foot. Beak. Maxilla. BAG AB, VOX XG ZooL. SURVEY OF Minn., II, 1895. Aus Toa y AP) Oe i yO Pint ry ° Zi S) |= = =< a < = Ay r = PLATE XXX. ‘ Cyclops fluviatilis Herrick. Immature female. Cyclops varicans Sars. «2 »~=0- Female from above. --8.~=~ Caudal stylets. ee ees -- 4,.-~ Antenna of female. ’ rae 5. Maxillipedes. x K une 6, Feet of first pair. RY me os 4. Feet of fourth pair. ae ae 8. Fifth foot. ee Cyclops affinis Sars. — < ee 9. Caudal stylets, after Schmeil. 10. Receptaculum. Play pe foot. EAE OX. ZOOL. SURVEY OF Minn., IT, 1895. _ | EXPLANATION OF PLATE XXXL. j } Marshia albuquerquensis Herrick. Antenna of female. — : Antennule. ‘ i End of mandible. ) BMH? Anterior maxilliped. ee: C4 Posterior maxilliped. . ae Caudal stylet of female. J : First foot of female. — ' Outer ramus of second foot. er Third foot. . 2 . Fourth foot. ue ’ 11. Fifth foot, (a) variety, (b) type. | 12. Caudal stylet of male. The union of the two setae is imperfectly / figured. They form a ee shaped symmetrical union. SOMNDAP WN ZooL. SURVEY oF Minn., II, 1895. Fae AEB XOX XT: | "ial ae ie ber Lo ahi ae 7 hh eae (hie 1a “a a, ees Marshia albuquerquensis. Antenna of male. Antennule. ae Fifth foot of male. Ad. Fourth foot of male. | Hl First foot of male. er Marshia brevicaudata Herrick. Male. Caudal stylet of male Fifth foot of male. Fifth foot of female. Antenna of female. Posterior maxilliped. Antenna of male. Second foot. GAS Ha Xe XoKe Te rs9st ZOOL SURVEY OF MINN., EXPLANATION OF PLATE XXXUIt £ Ve rh bite 4 hi, - he bee ll ef wat t . ig CALCU ale #25 tee ee ae ae Py Fic. - 10. as Cyclops signatus var. tenuicornis. Caudal stylet. where the inner aspect is ciliate. Fourth foot of same. Canthocamptus northumbricus var. americanus. Caudal stylet. Maxilliped. Fifth foot. Diaptomus hircus. Left fifth foot of male. Right fifth foot of male. Fifth foot of female. Diaptomus; sancti-patricii. Fifth foot of male. Fifth foot of female. Appendages of penultimate joint of right male antenna. Figs. 6-11 are after Brady. 2 Oe . * J Ky A ease READE: SOXX iT SURVEY oF Minn., II, 1895. ZOOL. LEE say io i Tap aaa SE gee SSS aN me ASS IS = SSS Lay SSS ONS White ANE ad int Pi - 7 ae es ante an Rac! a) — _ if Posh Y A 7 ok a's _ oo | ty a - ~. . wa nt tT iF i A - cn : - , 1. : a » Sur x tid <1 ype : ue Fi Vy ay en ; Less es. - - is i : as Be’. @ ph miele oR ae Suman oe: oP i Alin ua ee See ah Ty pata) a 5 re: ‘ ct iy aN pa ‘ae un al; rag mee ae BOs 4 » ates 2 5 8 wade i Rib a Pera Peat 1) Rau ee i Cyclops pareus Herrick. 1. Camera outline of female, elongate form. 2. Antenna of female. The relative length of the sete of the apical ! joint is not quite accurately figured. | 3. Caudal stylet of elongate form. ‘3 4. Receptaculum seminis. eee 5.) Fifth foot. . 6. Foot of first pair. 7. Foot of second pair. 8. Foot of fourth pair. PLATE XXXIV. Eso: Zoot. SURVEY OF MINN., = Ses Ah lll! L. tp Jf, = 2. * aan aan metas) ek ' 7 naa oe . a a at n ? a "] a eh yO By ‘v 7 pert as i. bay ” ua no oi : 7 ~ 7 ' Lis oo 1 a Ve 7 » . t a, rs ee 2S oe °° _ 7 ; | ae a —_ om , . 4 Ae ae : 7 fe ¥ - _ ak oie 6 Te GPO snare tas oat B. : _ 7 7 ni aa ne 7 “ Ts = 7 : ; | _—, 1‘ *: ie : . 7 oat - “th rT — a mt ae a) - a ? ie tel , ; ‘2 - ‘? eS . - + ed TU V3 ‘ wa por 7 oe hoe . “Ae oan ie - : Fae ee i - ve cr 2 we : on OP in! i 7 4 o >t a a, ue a ¥ Ll . a 7 : - t a my i: D a es ae a 6 me = 7 7 : 3 , - : : ; ar al ans i} a) a ar t! a 2 _ ied — - - rf oO c e 7 7 Ww — : | ‘ On J we 7 2 : 7 : 7 ‘i re a ‘ 1 rl i of - 77 bes * U - 7 i " a tal Vale x \. ae a a | | ' - os PL be 4 oe | . ; Ps — a ; , oa vy. oan it a ‘ 7 ; 7 = i - } i =e ee uM - a 7 : , ad ; | oa os a ° n ¥ a Ly t ets ; ; > _ : : hy eo - > ao : . 5 : : 7 a : . i 7 ¥ 7 - vie 7 i . ae a ee a 7 7 : cn : mae : + . a td - 7 »s Dale _ Db . : ' os . : __ 7 iv : ™~ 7 ; 7 7 7 a ; ee 2 0.0e'4) Sa A ; i 7 7 — a : ’ a i : _* ea : . rs Prat t ihe ry : : iy. 4h : ‘ ie | ie 7 - | : 7 i ; - w -_ : | ; : i} =~ wy m 7 7 | : Ww aa “a / > 7 . 7 . - 7 - m7 _ . i? ’ 4 _ 5 Ts oT ve on ; : 7 .— ne 5 | a ta 7 : | | . : - > 1 J) | | yn. a a - ‘ : y . es ad a - oo 7 : ie 7 r} 7 . | | eae a ; : ae . ; ei a t - . : an 7 | a ; ; iar » a ae aA > : " ry = 7 : ’ . | oe a : 7 {= - wh ) : 7 wae 4 aw ee aa i ri % wey oe Ce ee ge ; ye vi ae > a _ 7 4.5 - Daphnia pulex var. nasutus. oe similis. Outline of head and (a) beak. Leptodora hyalina. Seen from above. - hyalina. Larva. Latona setifera. Female. Limnosida frontosa, Female. e frontosa. Antennule of male. Holopedium gibberum. Female. Sida elongata. Head outline. ‘* erystallina. Head outline of young female. ‘“ erystallina. Antennule of male. “ erystallina. Antennule of female. ; (Daphnia hyalina) “PD. galeata.” Outline of head. ra 1). vitrea.” Outline of head. ZOOL. SURVEY OF Minn., II, 1895. PILATE RON } a 1 2 7 ara ' ts] COS, D ha y ot we ry ee | | us " ye wey ie aa ee et ane eee EXPLANATION OF PLATE XXXVI. Alona sp? Pseudosida tridentata. Female from above. Antennule of female. End of post-abdomen. First foot. Mavxilla. Moinadaphnia alabamensis. Post-abdomen. Antenna. Female viewed from side. Antennule. One of the feet of Pseudosida. Ee AGIEEy XeXe Xe Will SURVEY OF Minn., II, 1895. EOOn Pa A Rl te Sida crystallina. Female. First foot. Daphnella brandtiana. _ Side view. Antennule. Inferior angle of shell. Claw of post-abdomen. ZOOL.. SURVEY OF Minn., II. 1895. PATE XXXVI 8 pe Wa! Oe a ; “en r in i i aug Vale Y leer : Vine ‘ ‘) Padi ie a - iG) EXPLANATION OF PLATE XXXVIII. Latonopsis occidentalis. Female from above. Ephippial (?) female from the side. Ordinary female from the side. Antenne with usual armature. Inferior angle of shell. Antennule. Eh OXeX Veli rss: ZOOL. SURVEY OF MINN., ea = S ) LE = ROE Bisa | Pa "yt ' ul} 4 wie, ay if Moina rectirostris Mueller. Female with summer ova. Portion of the shell near the postero-inferior angle. Post-abdomen. | Antennule. Moina brachiata Jurine. Female with summer ova. Antennule. The lateral flagellum is omitted. Post-abdomen. First foot of female. Moina paradoxa Weismann. Ordinary form. ZooL. SURVEY oF MINN., IT, 1895. PCA XOXGGIOS. S Ni kK, & S A SD FIG, (tae ake ik Av dle Va Moina paradoxa Weismann. Adult female with ephippium. Antenne omitted. Male, from the side. Adult female with summer eggs, seen from below. View ofthe head, from the side. St, stomach; cw, ccecum of same; Br, brain; ant, antennule; f/f, flagellum of same; /b, labrum; @s; cesophagus; ey, eye; mb, mandible. First foot of male. Antennule of male. First foot of female. All the figures are camera drawings from New Mexican specimens. —_- ae ZOOL. SURVEY OF Munwn., II, 1895. PAA Xs, SSS i ee WaPAY Be - ' 9 eye Die 7 ye Sa 1 ‘Co Seer), ° ‘ &¥ - 1 ee eccaue Au te ek: 4 Tre vie ee 7 ia Abe : € we ey = oe ee ee 7. foal Me a in ; at Ss ia \ \ " (Variety...) a Post-abdomen. oe pulchella. megops. reticulata. laticaudata. ae rotunda. ‘ ire after P. E. Mueller.) First foot of male. First foot of male. Male. (From Weismann). Ceriodaphnia rotunda. Head. (From Weismann). te - ZOOL. SURVEY OF Minn., II, 1895. PCAREY Sel: 1 ar $+) ¢ __- EXPLANATION OF PLATE XLIL ft % “4. Ceriodaphnia rotunda. Male (after Kurz). vant Fhe et $s alabamensis. Female. | “cg bir 3: 33 reticulata. Post-abdomen of male with opening of of é vas deferens (after Weismann): & ks: male - cousors? Bye: Ceriodaphnia scitula. Head of female. 6. Post-abdomen. ages ees ~ 7. Antennule of male. ; 8. Semen cells of male. cee ecapholeberis angulata. Adult female. we, 92, angulata. First foot. Rees 10. a armata. Adult female. 2) ib eine ie armata. From below. , Ofryoxus gracilis. 12, Young. r | 13. Labrum, ’ ; 7 " a 14. Antennule. ; ¥ 15. Last foot. Purple pigment in lower part. aM Py ‘a by ZOOL. SURVEY OF Minn., II, 1895. Pea, xe il: WSS) AY YS =e WAVOO FOBT XO ONO SCO La @@) S585 AY @= Ta NIEHS ~/ Sy S550 Sea = L@) Lee : WH z EXPLANATION OF PLATE XUIII. * ! Moina brachiata . Leg of fifth pair, after Lund. — ee . Leg of third pair, we ice: Thee Ceriodaphnia reticulata. Leg of fifth pair. Scapholeberis mucronata. | Post-abdomen. | Foot of second pair. . Foot of fourth pair. Female, seen from above. Zoo. Survey oF Mrnn., II, 1895. PIAUHT XLII, t \ es _ =) vas ea & = — ae ies O EXPLANATION Ae - Ceriodaphnia scitula. © ‘ Ceriodaphnia reticulata. 8. Post-abdomen. 4. Head. Ceriodaphnia consors. | 5. Post-abdomen. 6. Head. , ‘ Simocephalus vetulus. Foot of second pair. ‘ ‘ ~ ZOOL. SURVEY OF Minn., II, 1895, Ase xo Vie “ ‘EXPLANATION OF PLATE XLV, a i = a k ~ rasj (a) 9.0) = Y=2 > OV MOS OW Ee ‘eriodaphnia scitula (small variety). Ephippial female. Bosmina longirostris. es lilljeborgii. After P. E. Mueller. ay Hook on the first foot of male. Seapoleberis mucronata. ia cornuta. Head. x angulata. Head. es angulata. Angle of shell. Pleuroxus denticulatus. Male. Simocephalus americanus. Head of female. Bosmina. Post-abdomen of male (after Weismann). ZOOL. SURVEY oF Minn., II, 1895. PEATE Sle Ve y y et eat ana: ye ed ere ; ti ay) b 7 Me ve Wi A Nae: Wk Pe oy *. Takia a aes cy re ues, a aie 7, —_ ry a fee Wi Pree A — eo soe ie n 5 ' 7s 4 : a0 : ii. gre - ety: HN) Poe ee tees — oo | a a XPLANATION OF PLATE XLVL Veal : % W a Vik tu! Or KP Acantholeberis curvirostris. — First foot. Fourth foot. Fifth foot. ; ‘Lateral view of female. Simocephalus daphnoides. Lateral view. Lower posterior angle of shell. EBuryeercus lamellatus. First foot. a Caudal claws. ' i: ea 28 a Bhan 4; '9. Drepanothrix dentata. Post- abdomen bf male. ve “Alter Bi ze ZOOL. SURVEY OF Minn., BOOK AWE exe Le Vale C, a Whee Jin \\ hyn Nyy sl . pS Git Aw So) 7 ns \ .e 4 Beall | Mit onite Maat ihe veh : 1 Ba nog r 9 ee iy, 7 Ay " re dog : : “ie aby ee es heute nc on ) eae ; - yi a uM ; twas ey Si tic gi 4 an ] _ EXPLANATION OF PLATE XLVIL 5 “ oh 5 Diaptomus mississippiensis Marsh. Fifth foot of male. Abdomen of female. Fifth foot of female. Diaptomus birgei Marsh. Fifth foot of male. Fifth foot of female. Terminal joints of male antenna. Canthocamptus minutus. Lateral view of male. [‘‘a, testis; b, cephalic ganglion; c, blood sinus or dorsal vessel surrounding the intestine; d, anus; e, cesophagus; f, frontal sensory plate.’’ | Caudal stylet. Antenna of male. Antennule. Foot of first pair. Foot of second pair. Foot of third pair. Foot of fourth pair. First maxilliped. Mandible. Spermatophore. Foot of third pair of male. Foot of fifth pair of male. Foot of fifth pair of female. Maxilla. Zoou. SuRvey or Minn., II, 1895. PATE a xeleivel ls * \ —_ J 4 = =p = see Ay Ne S Z © — cy = Zz < Sp meyer, ia FiGe tS as Hee te — woes © & Phyllopod Larvee. Larva of Limnetes 0.33 mm. long. A}, first antenna; 4?, swim- ming antenna; Md, mandibular palp; e, eye; l, lens; L, liver budding from anterior part of stomach; s, sensory a m, muscles of rectum. Larva of Chirocephalus. View from below. Caudal stylet. Head, showing organs of one side. J, liver. Muscles of swimming antenne. Maxilla. End of abdomen of an older individual. Mandible and palpus (p) in this stage. Antenna of female. Antenna of male. p, inner ramus; g, frontal organ. Part of Limnetes older than Fig. 1. First abdominal segment of female seen from below. illustrates the relation between the Phyllopoda and the Cladocer on one hand (Limnetes) and the Copepoda on the other (Chiro- cephalus). meee ene Ee This plate PI Ae Xl VN Te 1895. ° Os f 29,90 2 af —— ZOOL. SURVEY oF Minn., IT, “EXPLANATION OF PLATE XLIX. Daphnia minnehaha. : Piet le 7a. Young female. Le ‘Head of female. 2a. Post-abdomen. it ‘Daphnia hyalina. Young female. Young. Post-imago. Young. Older female. PVA TE obi xe Zoot. SuRvEY or Minn., II, 1895. eee | i.) 22a Vee «EXPLANATION OF PLATE L. A * / Bytes. bine dts oe t ‘ J f x oA : Z ; 2 5. -. ‘6; ee Te ot eo gate 8. a. ¥ Ty | aye a rk) 10: ney aed ape 11. 4 ‘ sf ’ TDs a me =" . a +% r ‘ eee is Sy Daphnia minnehaha. Male. | ee ‘* minnehaha. Part of feet of first and second pair. ae 3 on Canthocamptus hibernicus. Antenna of female. mk ah e hibernicus. Fifth foot of female. | aa at es palustris. Antenna of male. TY ade ae z. trispinosus. Fifth foot of female. oe i minutus. Young. e of minutus. Nauplius form. Serie e> Pseudo- sida tridentata. Adult female, antennule, labrum, angle y of Shell, and post-abdomen. an Daphnia minnesotensis. Young female. | ‘* —minnesotensis. Post-imago. ‘* minnesotensis. Beak. ZoOL. SURVEY OF Minn., Iirso5. Je) by IR ey | ow a a “am i \ EXPLANATION OF PLATE LI. oh Pe Daphnia scheefferi. Post-abdomen of female. Post-abdomen of male. Male antennule. Brain and nerves. Inf. c. g., infra-cesophageal ganglion with nerves to antenne; c., cesophagus; n. f., frontal nerve; g. opt., optic ganglion; m. opt., muscles which move the eye; p. f., pigment fleck; n. opt., optic nerve. Posterior part of embryo. Eurycercus lamellatus. Heart, showing the anterior bifid por- tion between the lobes of which is the arterial opening and valve. The vaned arrows represent deeper currents while the unvaned indicate superficial ones. The dotted line rep- resents the position of the pulsating membrane separating the venous from the arterial currents and seen in section at (a). Daphnia similis. Anterior part of the nervous system seen from below. a, optic nerve; b, optic ganglion; c, frontal nerve; d, nerve to antennules; e, commissure connecting upper and lower cesophageal ganglion; f, nerves to antenne and mandi- bles. [After Claus. ] ZOOL.” SURVEY OF Minwn., II, 1895. Jee, IIe ¢ - ‘ H _ EXPLANATION OF PLATE LIT. oo to he oi. Daphnia minnehaha. Ephippial female. Post-abdomen. Antennule of male. Daphnia exilis. Female. Post-abdomen. Simocephalus vetulus. Caudo-ventral angle of shell. The markings are on the outer lamina. Margin of shell cephalad. Post-abdomen. Head. "eek to eee ZOOL. SURVEY OF Minn., II, 1895. ieAS Eee ble c I 2 : . Teer era? SG : NEE i re Ai He EXPLANATION OF PLATE LIIL. fa eT pe Daphnia hyalina Leydig. Outline of female from Lake Minnetonka drawn to the same scale as figure 5. Head of a common form of the above species. Extreme development of the crest. Embryo illustrating the early development of the helmet. Daphnia kalbergensis Schoedler. Typical form, from Lake Minnetonka. A form of the above taken from the same gathering. Post-abdomen of the above. Extreme development of head resembling D. retrocurva Forbes, from same gathering as the above. Daphnia dentifera Forbes. Copy from ‘‘Aquat. Invert. Wyoming.” ZOOL. SURVEY OF MrnNN., II, 1895. Ae one lille, Mri i i‘ AAT A Foe ir cee WN BUT ANDE iar a? / a Ny Uk EXPLANATION OF PLATE LIV. 7 Retwre oo a gt 2b Be 12. Macrothrix rosea. Antennule. Post-abdomen of female. Post-abdomen of male. Drepanothrix dentata. Post-abdomen of male. Macrothrix tenuicornis. Head. Post-abdomen. First foot. Antennule of female. Maecrothrix laticornis. Head. Post-abdomen. First foot. Portion of dorsal ridge of shell. _ al wy ZOOL. SURVEY oF Minn., II, 1895. AUB se Vs a3; © bab’ taro ay es ‘ ‘ , , EXPLANATION OF PLATE LV. Ilyocryptus spinifer. eee FIG. 10 Bane ea 1. Lateral view. . ei ee 2, ~—Head, from below. ids Aa 3.“ Post-abdomen. | dad C- Cee 4, Embryo. : a eee gis Hyoeryptus longiremis. \ ae 6. sordidus. Post-abdomen. ) me as * acutifrons. Post-abdomen. \ a 8: ‘© agilis. Post-abdomen. cae, 9. “ir. ggilis. “Head: . ports ee a10. sordidus. Antennule. Sg ae ag Ee oh) sordidus. Spines on free seta of shell. ae 4 aad ZOOL. SURVEY OF Minn., II, 1895. Pile ATE Lv. EXPLANATION OF PEATE GL Vi. . Macrothrix tenuicornis. 1. Lateral view. la. Labrum. 2. First foot. 3. Antenne of young. 4. Macrothrix pauper. Macrothrix rosea. — Antenna of male. Spines of shell margins. 7. Post-abdomen. oD Macrothrix laticornis. 8. Male. 9. Semen cells. 10. Pasithea rectirostris. Male antenna. 11. Macrothrix rosea. Post-abdomen. 2: e tenuicornis. Post-abdomen. tee Be rosea. Post-abdomen of male. 14. Drepanothrix dentata. Antenna. Ilyocryptus sordidus. 15. Marginal spines. 16. Antenna. 17. Post-abdomen. Ilyoecryptus spinifer. 18. Lateral view. 18a. Marginal spines. 19. Antenna. 20. Macrothrix tenuicornis. Heart and accompanying vessels. 21. Ilyocryptus spinifer. Post-abdomen. ZOOL. SURVEY oF Minn., II, 1895. , PS “il & tr Ug» ZA Ae, LIP GqM ry fy Th» fi 4 { GR oN & & Os Pe Abe evel EXPLANATION OF PLATE LVII. Fie. OS TP ow Lathonura rectirostris. Female, from above. a, eye; b, optic ganglion; c, muscles of eye; d, muscles of antenna; e, dorsal sucking dise; f, stomach; g, young in brood cavity; h, heart. Female, from side. Head seen from below. Maxille. First foot. Ovary. Antennule Last foot. ZOOL. SURVEY OF Minv., II, 1895. PEACE EVAL. a aR ps’ ma en they ; pce )/ " ny aan > \ 7 re i . _ : oy ‘ i r a Shean odd © : of : - f “a. ‘a “ip 1 i 2) wy ore EXPLANATION OF PLATE LVIII. i Pac Ofryoxus gracilis. Fic. 1. Adult female, showing coiled intestine, elevated anus, long an- tennule, elongated seta of second antenna, anterior ceca, ete. 2. Post-abdomen. 3. Antennule. 4-6. Polyphemus pediculus. Young and adult females. ZOOL. SURVEY OF Minne) List 895. PA Ate Tey al lle en > 4 ———— | | dud \\ E> ? / At ah in hace a ee EXPLANATION OF PLATE LIX. SU oe Polyphemus pediculus. Swimming feet. Ofryoxus gracilis, First foot. Macrothrix nova-mexicana. Female. End of post-abdomen. Antennule. Leydigia quadrangularis. First foot. Osphranticum lJabronectum. Antennule. Fifth foot of female. Zoo. SURVEY or Minn., IT. 1895. Aya wll) eas), @ — 7 us eos Painy At raed ira n heer et Cie ct Je EXPLANATION OF PLATE LX. Ss 2 Pleuroxus hamatus. Post-abdomen and antenna. ef affinis. Alona costata. Leydigia quadrangularis. Euryecercus lamellatus. Male. . Posterior margin. Antenna of female. Alonella pygmea. Eurytemora affinis Poppe. Female. Female abdomen, Male. Male abdomen. Fifth feet of male. Vifth feet of female. Jaw. Antennule. Nauplius larva of this or a related species. Pe Aw Ee 1x: Zoou. SURVEY OF Minn., II, 1895. EXPLANATION OF PLATE LXI. Alona quadrangularis. FIG. 1. Female. » se) eth - ei2 4 is J 7 ae > . ie de — 5 . - & % , >“ s a a ~. ~~ -- EXPLANATION OF eee See oe © 10. 14. 15. 15a. Side view. First foot. Chydorus globosus. End of post-abdomen. Chydorus sphericus. Post-abdomen of male. 66 nitidus. Post-abdomen of female. nitidus. Head. sphericus. Ephippial female. sphericus. Female. globosus. Post-abdomen of male. sphericus. From above. ovalis. celatus. Dunhevidia setiger. Alona affinis. Pleuroxus gracilis. be gracilis. Antenna. Zoot. SURVEY oF Minn., II, 1895. Ee AWlGH acl. Poe as 30 iow 5. . ; 1 : _ EXPLANATION Bosmina striata. cS longirostris. #8 cornuta. Pleuroxus procurvus. Graptoleberis testudinaria (var. inermis). Acroperus sp. . Graptoleberis testudinaria (var. inermis). PIGAT HE XxCV, ZOOL. SURVEY or Miny., II, 1895. in aie ee Sraee ak D Streblocerus serricaudatus. Female. Macrothrix borysthenica. Antennule. Pleuroxus griseus. Female and post-abdomen. Ceriodaphnia cornuta. Head. Post-abdomen of same species. Daphnia lumholtzii. Female. Leydigia australis. Post-abdomen. ZOOL. SURVEY OF Minwn., II, 1895. PISA OV sea a * titel kg oy iy is 7 ee OE)” aa nae) + ‘eat is oe eR ve aH — beg é deh) aha Au - ed ae ales - , a nee ony mas leap - ats. tape Ae ee, bare!) y : f ey a] rhe 4 ‘ ‘ ae apt EXPLANATION OF PLATE LXVII. 3 + 4 Pa et Q SiS Serer Bes = Fat SOR 1 LZ, 13. Cypris herricki. Dorsal view. Lateral view. One of the first pair of antenne. One of the second pair of antenne. Mandible. First maxilla. Second maxilla. First foot. Second foot. Post-abdomen. Cyprinotus crena. Lateral view. Mandible. Feet. ZOOL. SURVEY OF Minn.,’ IT, 1895. PG AW Le Xevenn, ey % nee core 2 ita i ae re dr: ai ea > ; - yy cin te a2 iv nay ian Ae ay ” yi : ta i b 5 en ae Ohba) Or, ae 7 i oS ais ye See ih ala eae, a . ees eee Mineo ae ene | > & _-BXPLANATION OF PLATE LXVIII. 4 Ons Vine Ra ew eens Cypria inequivalva. Lateral view, female. Dorsal view, female. Ventral view, female. Antenna, female. First foot, female. Second foot, female. Abdominal ramus. Verticillate sac. Cyprinotus incongruens. Lateral view. Dorsal view, female. Ventral view, female. Antennule, female. Antenna, female. Mandible, female. First maxilla, female. Second maxilla, female. Cypris herricki C. H. Turner. Larval stage A, end view. Larval stage A, dorsal view. Larval stage A, ventral view. Zoou. SURVEV oF Minn., IT, 1895. PAC ATE Ee XO Te » ee aia, i a on ol, ge, -¥ a. oe | ms.e Fie. 7. 18. ita 20. 21. 22. 23. 24, 24A. 25. 26. 27. 28. 29. 30. 31. 32. 33. o4. 35. 36. 37. 38. 39. Cypris incongruens Ramdohr. First foot, female. Second foot, female. Post-abdomen, female. Portion of shell. Lucid spots. Cyprinotus crena. Lateral view, female. Dorsal view, female. Ventral view, female. End view, female. Antennule, male. Mandible, female. First foot, male. Second foot, male. Post-abdomen, male. Verticillate sac, male. Copulative organ, male. Cypris Herricki C. H. Turner. Portion of ventral margin of shell, female. Stage A, lateral view. Stage A, teeth on caudal margin of shell. Stage B, lateral view. Stage B, dorsal view. Stage A, post-abdomen. Stage B, post-abdomen. Stage B, ventral view. ZOOL. SURVEY OF Minn., II, 1895. PACT I XCXe. Ate ss .@ & wo a oo Ana are ae a 5 Ay - " cay) S.? Na SO ho — 2 Ws a : y AD ane tare’ ane 7 if ih se hs t: fu Aen 4 MU - phat. elt tarde Oe ; aot ahs ry . aid bd ne Ce 2 esti Bi gas ne - ie Bia oe ieee eee. Ae) Pyne en 1) ee a ie es a, oo ees Sih: - Ci a ee ay 4 « a wig K aay i fy 4 ny 4% a mi . aaanr ft 7% Pi ae | ey Oy ae Le Le y autos ne a 7 _ mm 7 7 7), an we Pia ve = ite ie A 7 a Sate ae Ae cae ,. a Peaks P woeer) 2 Fic. 20. 21. Cypria exculpta Fischer. Lateral view of the shell of a young specimen. Second foot. Lateral view. First foot. Shell markings. Antenna. Post-abdomen. Second maxille of male. Cycloecypris levis Miller. Antenna. Post-abdomen. Second foot. Cyprinotus burlingtonensis Turner. Antennule. Bit of shell. Tip of first maxilla. Dorsal view. (Fig. marked 692, middle of plate.) Mandible. Post-abdomen. Antenna. First foot. Lateral view. Second foot. Figures 12 and 13 have been cut out. Zoo... SURVEY OF Minn., II, 1895. PRAWE TX xX: EXPLANATION OF PLATE LXXI. Candona crogmani Turner. Mandibular teeth. Antenna. Sensory seta from mandibular palp. Antennule. Post-abdomen. First foot. Tip of second foot. Mandibular palp. Dorsal view. Lateral view. Candona acuminata Fischer. Post-abdomen. Candona delawarensis Turmer. First maxilla. Post-abdomen. Dorsal view. Ventral view. Lateral view. Antenna. Cypris fuseata Jurine. First maxilla. Antenna. Second foot. Mandible. First foot. Post-abdomen. ole ) <5 4 PAGE SURVEY oF Minn., II, 1895. ZENON, >. Cee eo oles ota ae a ; — = ei, io) o~ = < tar 7 : - r 7 jet ve ? mays? Iv am Pe c A tae a a ne ee 9 » ee Sa en at . “a MEAT Sal Te Oe oy . ae ate y - Tos ay e, “Dp 7 -_ 4 4 = " 4 7 oe. ¥ 17579 Ton a 7 en ee LB e, a »- 1} x pal eal ay se i> Oe AS : _ 4 a 7 a - ~~ \y EXPLANATION OF PLATE LXXII. Fic, oO & Se ae “I “1 +) Cypridopsis vidua. Female from above. Antennule; 1b, antenna; 1c, first foot; 1d, second foot; le, man- dible; 1f, maxilla; 1g, labrum. Erpetocypris minnesotensis. Female from side. : Antennule; 2b, second antenna; 2¢, first foot; 2d, second foot; 2e, mandible; 2h, abdominal ramus. Cypria exculpata. Lateral view. Notodromas monacha, 4d, second foot; 4f, second maxilla; 4f,} second maxilla; 4h, post-abdomen. Cyclocypris modesta. Male from side. * Female from side. Antennule; 5b, antenna; 5e, first foot; 5h, abdominal ramus; 5x, copulative organ. Cypridopsis newtoni. Side view of female. . Anterior and posterior margins. Antennule; 6b, antenna; 6¢, first foot; 6f, maxilla; 6y, lucid spots; 6h, abdominal ramus. Cypris fuscata. Side view. Female. Dorsal view. Antenna; 7d, second foot; 7h, abdominal ramus; 7y, lucid spots; 7p, a magnified portion of the anterior margin of the shell. Figures drawn by C. L. Herrick. Alabama Crustacea. PEATE: Exch: i ve iY. row Pies ead ral DP igre emai" ha aS ss toy ios Ay’ iy led re Ys ar are pe Ramat ; any ee ey f en ne iyo OM we a ry aa v ns : ee bef if prs roe i Zz Une “X ‘ > < oe er. oe Py is cae es a na ; 7 a 7 4 ein is i 7 7 es ) re Pc : ieee, 7 7 at - Me se nr a ° o- x e etishe Geld aah Be ees een: ; Ow a ae i. >. v v anh Mae 4 ~ a ~ yt ; Avie od ‘> ee i int, ale ne La a oll is ay ah . : Vs aa re Se of aera =. iC Ale —% “aa ; i > Oo ae hee Ys! i” od 7 : a a ~ > ae | oo ¥ 7 7] i a > 7 a ao » cis Figs fe - % a , hy eae yo 4 P s Be ie eee ay seg? bie of a Pin ath ee Lateral view. Dorsal view. Labrum. Jaw. Abdominal ramus. Natural size. Cypris perelegans Ae IxXex is Zoou. SuRVEY or Minwn., II, 1895. | Din a Lt ee ae Ao eo x ve 4 ge Eerie hat 7 nh 1 > ~ io — OK 4 A cl a Rises i oe & a=) Zz fo) =a oa < Zz < i Ay ~ cal Soe to Cypris virens (Jurine. ) Labrum and both pairs of maxille. Second antenne. First foot. Second foot. Jaws. Caudal stylets. The following figures of this plate are not noticed in the text: Gammarus dubius Herrick. Streptocephalus sealii Ryder. Harpacticus chelifer Mueller. Laoponte mississippiensis Herrick. Canthocamptus mobilensis Herrick. ZOOL. SURVEY OF Minn., II, 1895. Pee AGL Hie Be Xe lave La i Ab come fi Se ee wit ye ae, - He ne ene, ens Ook . Wy : : ee oe ol pty oy , ats a8 7 5 i rat ee Ne a im aes Ruth ee | iy) betel Tg : ut Neen 7 ~ Ns é ‘ (a ical Pres ne aes oan a os ee BP By : R40 >. ’ 7 i ner i one fi a0 ha a ‘“ ha ole ‘i sy “y Behe A aan or Ph Pm ae oes Bar ue a ; a sy vet 7 % a ah Aint eas - 4 a i a0) aS EXPLANATION OF PLATE LXXV. ™) ” Q Sage os he OO Oe ar = © Cypria opthalmica (Jurine). Ventral view. Lateral view. Dorsal view. Cypris. Dorsal view. Cypridopsis vidua. Lateral view. . vidua. Ventral view. Cypria opthalmica. End view. Cypridopsis vidua. Dorsal view. $s vidua. End view. Candona fabeformis. Dorsal view. “ fabeformis. Lateral view. ZooL. SURVEY oF MINN., II, 1893. RIGA TE TEXOX'. eur oe “ ae a By ; ae ? are Week: aia oh Cee “ ay: Mee Pete ue raw ue ee by Pe ae 5; re e Pe oe ya A fe me fit inet Ant K : DA shoe) Sar = ernie My argh pets gi 8 zis ea tae ‘ im > as ee 7” — ’ ae A Leen nie . a Soi ae ue ey ei ay RY me rain ae ana ve r ahi, cae a Lies a Bs we HXPLANATION OF PLATE LXXVI. Cypria opthalmieca. Antenna. Second foot. Abdominal ramus. Cypridopsis vidua. Abdominal ramus. Cypria opthalmica. Mandible, gill missing. Candona fabeformis. Antenna of female. Cypridopsis vidua. Antenna. Candona fabeformis. Abdominal ramus. Cypris fuseata. Muscle sears. Puede 1G x Xavi 1895. ZOOL. SURVEY OF MiInN., II, Pane ; Nit ah oF a Ope ee i sel ae od Sete ae me on em ) Aho > a i as ‘ BC A Pea ) Bai ee ern Loa Hs - or a . oa Bee wie oe oy bee Bi iy ‘Soe a core ‘ _ EXPLANATION OF PLATE LXXVII. t8 Erpetocypris barbatus. Fia. : 1. Lateral view. 2. Antenna. 3. Caudal ramus. This plate is copied from 8. A. Forbes. Zoou. SURVEY oF Minn., IT, 1895. EASIER, lax oe Valle ) are yar aL we oe » ond ay 2 ey “Nein SAP a ee eRe 2 See ~ A rg f ai walt, wb; i _ eo Bean ne ois vm Fyald “i Se oe ae os 2. ee .— a Pr AL * te a) oe ore bie ry, eis -_ ee ae Li fate =? —— Pad i6n RCoRe A - a rt my 4 ee — @ se) f sy noe . ie a - me a ~ hey 2 _ =~ 7 _ ‘ 47 ay 7 : i’ ' ’ — oe a bie - A re on : Ae sh ur a > 1" ; a 7. : : ae ae eal a Pad ie nm 7 a5 7 —_ 7 , * == Ps i eee oy Ve fe itd re a * : 2 ° 7 , et? oes per 48 7 co > ar ; 7 — vie _— my ee ia ie oo Me ries : 7 ta, J iar it Pay we Ae ‘ a ; : rt Paap | Cepe.ar ' an ; a) ; - wa ns 6 wa mh a fy ie th * ; ; eee a ; - wk ee 7 7 ia) - - i , . “ae —_— om 0 - 7 : _ en 7 4. - 7 hn ' Ai on) i 7 7 ; Si Tas -. ty : . > ' low Bone tt, a rode wh AA fe ont ge 7 2 J : ahi ) ie i" oe Pony bss’ : og See Mae ; : A a y c) ei 0 ae me 7 7 — n i =e : ay 7 ' : 7 7 | Ne ae an) . 7 a 7 c a WwW T> i nA - mae 7 _ , ‘ 4 a - . Un) +5 = , . - bE — i fl a ; | mi — ans rh ea =e _ > : ere Ye ; . AD Agia ee EXPLANATION OF PLATE LXXVIII. ny ee et eS eee Cypris albuquerquensis. Lateral view. Dorsal view. First foot. Mandible. Antennule. Antenna. Second foot. The figures on this plate were made by Professor C. L. Herrick. Zoot. SuRVEY oF Miny,, II, 1895. BEATE EX XVIII. 7 i oe ¢ : 7 ie . yy ety Pre, ie ay = AS oe, 0) os "9 nm ‘ Ad 7. : i : , . ‘ : Aen A ee 1 eee - ee oe Gals dacme cae = oe ae - a ae y: ay! 4s! ‘heal in. a yee © - oo ae aa 8 9 ee eee ae” i? 7 i 7 a Vy : ra Pike free ; ‘ » we kod uP c DESY So eee 1s 7 . i _ > » e* 7 a r * ® eT a oF + te in. 7 a Aa. 5 es, . ‘ons ' aff ie i Fil | ee’ ¢ ~ ~ _ ~ Pai» a» a : = a a) re 7 ei ws | A ree FS hr wes 7 aay _ naa : De : a ie ee > _ = Ts. # 4 in: 2 i -_ SS is Py ae Gg n 7 _— " + 7) ‘ rs — > a ‘ ’ = A se 7 7 } : — = _ pay : a 7 L Aa. . 7 a ve 5d a a a . iat : 2° ‘ ye i Dee nh aa nn tt i, ; Te, a i ‘ . 7 : ree : 7 7 : ~~ a - 7 iat 2 (i . 7 i » 7 a ' = ‘ - a 4 2 . > : 7 th pon we - - 7 a - 7 7 Ld - : — eo 8 : : - - eS - 7 at - ay bd - — a i] > -m * - a af 7 - . af om e _ a ae , =- ‘ga ane NS be a 7 iy ] — a M ra s <— > A Bled oy bd e, «= - ? ae - = . - ia 7 ae : == me a | - - = ote - 7 *~ iz) - a a te n can apt Pa whe a ae - : - 7 od a _ & 1¢ 7 = =! ‘ aus a't, A is - tas & a Sn i - Saw Te, Hie 7 7 7 ‘ a> ai. A ys 1 4 ow etie : i -_ m ae! LaLa 6 i - re | -_ — Tie - af c- _. 6 Se 2 EXPLANATION OF PLATE LXXIX. Cyprinotus grandis. Dorsal view. Lateral view. Palp of first maxilla of male. First foot. Second foot. Mandible. First maxilla of male. Abdominal ramus. Antenna. Cypris altissimus. Second foot. Muscle sears. Antenna. Abdominal ramus. ZooL. SURVEY OF MInn., II, 189s. PEAS Hee Te XeX. PN 2 3 ea y a 1 EXPLANATION OF PLATE LXXX. Candona peircei n. sp. Antenna of female. Antennule of female. Antenna of male. Second maxilla of male. Lateral view of male. Ventral view. Second maxilla of male. Lateral view of female. Abdominal ramus of male. Copulative organ of male. Abdominal ramus of male. ZOOL. SURVEY OF Minwn., II, 1895. ACHES EXO Xe 7 és : pares Nw Was oi Ove bt) aaa oes are =H Onl 53 la op BY en ae D ‘ i age is ie vehi zr ie? oa Bat gents oe es aa vo a0 ik . + ad oe a Si sodas Ae : Pica: a x ane th Re Pat bey i a or es cee ie of) a ws q ve : +; ek ee Pee ae ra rae ie ee oh. om he oe Bar ae ie are Ay Laan 7 dye Glia ie is ee > es es ey e ty i A Re i, le es ’ Bo 7 Ld 1 Tee Ree 5 vi ey 9 aro as etd: r o aang ie 7 Aan a big a a al _ ot he es dure : aay. : nen acy as erey Lee Wi, me lg ro es he: 7 ‘cs ree 2) rr es 7 a 2 hs ay i ae : he té ee? . Fits 2h a Rie?) j EXPLANATION OF PLATE LXXXI. i?) Nw Fa Darwinula improvisa n. sp. Antennule of male. Tip of second foot of male. Antenna of female. Candona crogmani. Palp of second maxilla of male. Palp of second maxilla of male. Cypria mons Chambers. Dorsal view. Lateral view. Antenna. Tip of first foot. Lucid spots. Second foot. Abdominal ramus. Darwinula inopina. Tip of first foot. Figures 6 to 12 are copied from Chambers. Zoot. SuRVEY oF Miunn., II, 1895. we of / PASTE ly ox XaTe Oy ae a oN Peat a ure rite Sg ‘ + \ An Ls Wy - Hae ae re, ep eees ag Y pee a i € at gig if a pat Berths ; ees} sei ral ioe al Pay ee aed sh a Mh Ane it ae we rae eT et St ara ney i opal en al se 8 mee Bs Fo iv} Pe «5! ih bres i Sens y ‘@ AP Oe 7 ah a my! ei ™ oe r ee 7 na i= J ne a cee i ee) ; a gs? ae he i pf ee iy ba hie, Lah AC ite ae 5 ¥ Fe iw het Thay iF a eG ar ie iy vi, cy AO Abs fa ee? X “ea i wo ie fal 4 ny : , mii eae ae i Aleta id z oe ms i. fd “ so a > & : iA. nati ' ~~ oe mn oe fee Veep oe ik Thy ah aS ar 7 AS ; aie Pe . men A hes » ba fe) race mn 44) i /\ | Ug a ean et “i Z| AM: ee ee. Set Gy? ee A 4A am Vv v ang a A ot oh ¥ v ne ve fice es. be + ae jt Deyo so be i, , a is ee a et - +h : 7 Wi Nog . ifs [ye ac wai i rata a ae baie tt Rn mes! ey . Ad Wash ae 2, INDEX ae) Ps Agty Py. ieee INDEX. The figures in boldface refer to the page on which is found the description or “‘key’’ of the species or group. The figures within parentheses refer to the plates. The author’s ‘‘Alphabetical Index of Species of Cyclops’’ (a list of synonyms) has been incorporated with the index. The table of contents (page iii) shows the families and other groups considered in the report arranged under their respective orders. Pane MANOEL CUS LIGICAUS Js +2000 setavecests Meccdschecetstevedtscancasves seueteroe releccnet saoaeanee 218 BONQUQUS sc c.cocrasvess snes tsdese suse suacernodtveeces res “PSOE CEKIOOL CONUOIOOGO CES CoD CaCOUEEOOs Gecwb 2608 220 Acantholeberis.................... sdalvedteactentrowsae cece citesssdentehisien ate 218; 143; 211,273 CUMVLTOSULIS Tasos one clecatenietacatsosumoee te soaae se ae cmectie sere cerbaeetn toatl enateees 218 (46), 273 GIGTIU RUE ood codon BpbaGac JeC den pacoB an CoSoE Coe Edn: bon scoUaHosebaden od lock eeoUe Bor, sdocid ddenadauBodosbedac 217 MIU Meese cdsesoccivnsccosoases pon Poo 80 d00CRD0LS.6 ce Aoom Gases uoERmoRagoOgIoOAAADOAOLENOG Odacapobsoddnee 218 TIGL) AACE epnced SARE RACE CocHROO-AICO CCR. OO doc: Conon cee Seo aceb bare cdaccboontoneadesbes cee staan: 218 PRETO PRC TUS se occscscns ceases csece eee Pes waecieseaces meceeastes 227 (sp.? 65), 226, 231, 233, 237 PUTIONUI OS en ay ccinccssuauonadfecasdcationge teach tesess cach ot Una ta tewieiedas4)e nape smentcer sesame 228 JID SRE) Biss Gass aera guesea eesee eee ae eerie aoe “Sheri sane 3. eecseh ace. ee: 228 (62) CAMPOS LUIS cet doacsscsa ce senesececsecerceaderscriccnenseincss-smcansden concn sates soca se seea scar merce 228 MALE) «-.--..eccaee eancereecssabon Pphoco sth aackboane --tada esses aco Sdoane soc BAS Me tect ante 227 AMG LEG UU Scamactaseaase ss se covseisscceeecnssancasectaccces er aavectabercsttsdeerisen ena ececseeeecne 231 PEMCOCEPNALUS!.\csatecatsstarecgs-doecen-caveciscceMvssssssaiatneccdtoccteteuces 227 (61, 62), 233 RUT ART lena ddseeicto sec Ce BeEO ROU BAB ROUE aoc OaEC Be BEB BOB GE NG ahora Adsaciescdadcodussucocnpucsoucdecccocaos 227 SEEMS V AULCUNS cscenspeese recess demssentsatecs see reccess'ee/ aa Sesh as ecme den stinckess seen tasc/eeeeet 228 PRM ICMEDSA PRUs: (Sees jooncs 241, 240, 251 OVALA etches ti vesccdcetoacos deeds deskedoclestematcnietiee ojsale sadness atisinamisce sistas hates ets aerate 248 PANVULG si coscssesacios sadegesmeataane Eis sictnbite Sie Hpac ar Genes ceeees eaxtetee Kees 248, 242, 244, 249 parvula war. tuberculata cd. :s. 500 ccteds cscs ces aeet cones sacaeis sc see ceen eee rete aeneen ane 243 PODTE CHA os saeco ss sa'sedeescedasicaessceasjeh nccenb. de aeeedoateaaeinas oscilnons daleapt testes sees 246, 275 PUI CH TAs sos cee voce sesesais sigccis as cdi Sess oetioneseancaccdecislelsTosstasaes culstesseenaieeettase 2415, 247, 249 POY INGO BI alge cs eins oe ope cis ae oe c's sls'e lossls deteloe sina erdaloiclois ~'oleeis/n(ele cleaiclelte cine icles ele taste = aetna 249 Quadran cul arisy 4..cdescerointohets tev ast vtsaswaieenacses 240 (61), 234, 237, 246, 249, 274 TECHAN PULA. 5 acc si00oces 0 ces cvigsmsiee emeieiods asain calelsle Celera celseafsee came sce apis Cee eee mma 245 TOCHANPULATIG......26s5c. cola sosseae ce secedesowa cts ceuedacMessueeecanesicces se Gees deaaeemeee aes 249 VOCUCULAT ALK: on saineccescadacemevasaceesensiuceetsnaeersisesscesecemonsaestek oleate seen s ammees 236, 249 TOSHLA GAL a .a0a ves asiiccis venassevssiiccrudecsecceuule oes Dedpudeee ete ca tee ats =e aan 249, 250 BAN OUND, .. .vcdcnesiseeteicseadaecceneocedsciatecttascesmedaeeasndence: aa ceo esi tent te amene 239 (62) BOCOTS! sieqsecics esos an) scincasiectasieacnvisanestas vel: asian iesianinenite eae citovaslesis sr See tiala sls aint at aman 249 SPIMULELA. cois2. sca cevensdhcesecssscoencopncnetelenstsetenaaecsessnecieas tts coe: dul eeement tenet 241, 249 SUALMIALIS..-2-)-22 si00sosalsionnceesne det siclenctniiendes vente couriedssicncee tad este: teste ici stse ttt nema 246 AMAT AL as cca selecccvaees'soe ace site te slesaiccn codeee@eis tdesicc ste scicicns tetas stent: stem ettaaa 249 SUI CAGH Koco scescccevccedesnecdages seuss celsas simu dod Metab ttele Soest nctitae ce htieie i aman 240, 249 TENMICAICIS’, ssincscece osc coke hes avople shina sonbesaeebe comtiannlineacce ancisomaeiaee 242 (62), 246, 248 TESCUMINATIAS 600000000. 000s vcsskentwes tase veedeadsleNeinneive cme teusle Uesici ceiaee stake Memeces maa 235, 249 UPATISV OTSA. occ. 5 ccbivcads oss savecsdeeudadle destees doves sulduevedregueneceECepe eset teeaeemans 249, 253 tuberculatac)./. cc ascecs cussastecwdectiessoveccammenmeesnes Usa ta dseinelves coat pace eeeareee 243, 244, 249 VOVTUGCOSA. cisie se chisacuaccessousccenscdecdeabsaede ceslgemsaetaniae itaa dec alen ie adsense mene 243, 249 Alonella............ wade Sos de'ndaev tuoi dosha usa vse cae one tube cas eens Meant ee 249, 235-233, 248, 249 PX CISH te cake oe sk cceaviaavs devevivcesnaceedsns tAveeee eee eee Rta 251 (22, 61, 63), 248-250, 259 OXIQUAL S .scccesncbasce tu encakareiavaass ssneetseh tapas camtae renee 252, 218-251, 253, 259, 260 QTISCD . ccicdevsircccosccevesccedsntacesdetdisenecdenvacededaevoce et aoe cotoate cette eetaet natnane 252, 248 PULCHE ain. ..i0., cisvecncevscevieceis ee dvwnss vedacs vevecuowsate ce scene as eenamees ateaeaman 250 (13) DY PNA. sine siacsateccedenvasescasccecoesstletdccntes Steet mceemetentemant 258 (60), 248-250, 259 TOSELAGA; 65065. ceee se vac oss coin sd dbeae s¥nd Suess epee ctecdia eer seemeenaeee eaten annams 250, 249 BEYIMtAr, 6.00’ dvevcocsdes vadeccsaedee'iecs svccdedetociesibaee de ceeeele ee ene nEn cinaenee 258, 249, 259 INDEX. 509 Alonopsis............ sisdle eave darnguennide Vile aad tuoatleaae tai He ek Qh Sesicesy oeanert 231, 143, 237, 248 SLO LOR SOU DRS. aah Nt aca ee es Ee er AA Rae MO al 231, 248 NALISSIMNI A esceoseee ese tose ets RSSoAnCouiOnBLT ocd cenSocsre porch tic Meera ae 232 (61, 63), 233, 248 PADISSIMNA) VATS INEM Ase. caress ony ee a dass at ecteicet ek eh oie ee ee 232 (61) Anchistropus........ alasaloas sles ein ve? seleeis denise oldaeite tect ecmiee te hecee cl eaceo: aetna 264, 257 CHUAT EIN AUUG. cee scene uevert sn tebec te stdte cen EMIS see oD FCO heater eters Oe ae 264 BRUPERDSTECO ISOMER IL. one Pncs eo ccet core oL eC Lee ee ecg te wh Ee ate 145, 146. Ih LILELIY EQ) LG VARS GE POR ATE MRENR naa a et HEN stanetecienattenenceoteg cates metas 136 EEMEGRUDY, sciretss cosas vsbturs'stuealeredes tovuasanste eran. ee eee les scta ees eee 135, 136 BPUMOSA Recess cnc caes seie'seses costisacte od eleas's celeieifctnan cde eitnoecstslecesscmisch anes sh seen ences odue naseeeee 136. LES DILTIIG |S 2 OE NB en dat RARDIN Uae FY. St be NR LET OA AR ob 294 MUONS ORANG cn: «53036. siissoleceguatseatet Wedletc case eee ne es a 9, 280 Patremice Meds Drasilieniaie'.5...0:.j02< eee oc sedess yo ees aces tke ee (11) BRMUCEUL ALA. 955, dwidan oi si gtetestenchacns ashy mnebeate eee aaa tack dee Sere ( (itil) MER OR MER ETVEGA Fe soci asco Sons bao duons cultecenasttncosteratee ners 2C6 (sp.? 45), 143, 214, 215, 272 MURBTEACTINISS«..5.2,-c'ccash tues s dosscaete amar eeceeee ert eae tee cna tack oe Sea oee ae Roe 209, 273. IG BTENCH i «0.0. cc's cee dole salve dev uatewadeoumiee dae tou teak ee eae coonew easel ees tk RE 208 RRC MICOLILIAS Ss tus sot, 0d< « enisi-juanechudedemaades arse tanh vokek cab eaaae here ee 207 DI MCOSET IS c3 o 60's sede scueaceteecsba ane Senet careetnen hie essen ae ote ease eee 208, 207, 209 PEMA Bees os 2a veasis.o dassedaatecen saceccesasSsbiaes nettws aeeuneseseend see te aay Sate eee ee ee 209 COVMIUGA aise. ese.asss's atcvian staaneboncene tent attack Souci occ er me nadeecshatte meee 207 (65), 209, 272 PUL VITOSELIG Ss. 02S aBss ancenn'seceae conn dae duanteeseances costs Soccbao ied wiionnt aac ee ee Eee 209 CEVATPIATIG:} <5 ewsinontonsistas casi face~decicces dobort osacenstessracst.cseen sae ande cedettes: nae 208 BEUDOUA ture c.Gss soon ndicaveoeos rap accasae age deine catioghten nel oles Tecan cane ee ee ee 209 TACUSELISY, «teseongsasesieesece se :liencile opiolseseletcss seaicen selec cesar cinesach darter ca Ae eae eo eee 209 MBEAN sce Scvegactanscrrdadact: baka scupsescederectes cuir seta Gissesatnn ti tee rset ere cae ae 209 POUNCE WOT Tea.te cascada ceases ses ccsesave seuss sat ane tere se vcs deqies eck eseotedeeeae cee 208 (45), 209 MIMSHLOHSIS 26.550) ciodsicaaceton ces ndoshadcdeatinessiesesadevoanedgs soe te cascace nae ai tate tein ene 209 BUTT UCOTNIG.S/..csdssss'celesn sehen whtee sag seivenlesoaepass au caveetioe’ cea uncens sataaow ase eee eateas 207 longirostris........... Woeseetseshcre arsaie classes daeetae dese ene ecnceeen seers 207 (45, 65), 209: MIACTONM YI CHAsersnecoscccodsecs secret ttsesre RIDEROSRRPRBCO UAB aco neaceE ononatHde ceauboadadcdotocdons: 209 MVATELUINIA bs de codon vase dee acdavoa ctaslecnccer ans vc cescd coanasnicnesacdece eee mtonte neon ten aan 208 RMU cence dedcesids > snasnsceapdosetennmtereckeueeceene: ave sdedansoe codecs eevanmer scckrcemen cena 208 MUV BLO Brcnbe cosctie'sssssesciles.aceisbaics sees decelsloasctbbayele snaicteice Rave salstjaciaupesatette coe Greene 209: OIDUMSITOSELIS: sc cnice d vccicigs se bas covasiincce apes Cais baisce eu elewees snes sealsclelieceasets decks dat ouseaeee eae 209 MOUMMG Aeereecbastec sas codecs sodececaccce decodes socnsbaevecutecnesteeneeee tere ant eee 209: SUI A er menca etek Fi « octane oeiscouiictinoctstense Coseaetc ane oeeceeaeeaeect acc ieee cere eee 209 (65) MPS OP SIU UTN CL AS een nc cs s0s tea aecbscesderarsietatscnscter eeveeees 206, 142, 146, 160, 161, 210, 272 ESWRERODOV SE ou lore che Cate. oa sss eto eset aes se cocetnck esc venue teocckoodenshteedoceaes nike skatoc erate Ss 124 MIMI CO dececemeivesentccsesecectiecincee eset rotesssecane cave sigceteacetearest Lassasesentacoddeceeseaee 136 ReReeEN COANE TOOL Ms 6 ccc ots Gree ces dase tact haav dese ede ve no acasesocnsaeersnereceitetal tepceemeRaeem 293 MO MINSEARULISUUS coer ahistcnrotacWaaterceatevsesusqctweesosabdecote ccs cca etusaccrnesiptls pba nct aaa 141 ESE OL GOS tects cise ota tat snarcenccoccceatle se tectonic cence. vase sesde abs steh bce esue cae nee eee 80 HLeUTE Lar mmacngta eto tors sae e nose Suites Canteen tvicis sucainee ess elderto'e saclec toe tn eee neato can ee 80 (10) ES MiG MO ULE DILGSscyrtccccosgccssatl costtncntonte reso deme aaccie tees cactice cesta cess atc Ses ae 267 REGGISUOMM eis. tarscsscccsoss Stee coses cre eoe er senectle dessa Newuesnselsionsccea tee atee cane RSS 267 MGSITERUENLAN Stacie testes ceuctoaiscces tance sccech oc ewe aye sdsisGo aves soteebete ce seh essences 267 (27) UNAM ace esse. o Wee cc iventecsttsecadeedseuvtecsotosnouse ta obee sas het eothedstonds 46, 48, 87 510 INDEX. CAM PCOCEK CUS! oars voces cases ode csereeteeetdovees cOoaes 22'7, 228, 143, 232, 235, 237, 274 DISCUTARNIS ct coco cece cw usecantaccsoamess tenes oaeenesaans cathe Sedeaueessasaensdy amas eoeme 229 (62) TE yin is) lt: peep ede d baceectcr-cocchiodar coy sadasisenes uabscasiidacunonanacss EBA AARON EL A 230 (62) PSuCOcophialws.c: se. ..0 hisicoss cavsususis cba oegpeseanceeeqee ods cone cant sis ane ee nse aaa eee (22) TUM OHON Ice, caves csc cc cosenx tes naocdbau runes? entity teacermenateee rete neesnad= alee meeeeee 230 (62) TMVACTUTUSin sce ckiscvcse tosses aduatpsescebast sates lncceecssckphanenuseeleses 229 (61), 230, 231, 274 TOCUTOSETIS. 0.2505 swab aliases e's sa enone’ op se sodas Ohencestetidascaee tes ae eeeutean sana 230 (62), 253 TOCUNGUSHs..\. 5. .oedsscacccddcce wcseessacacetstestoseaces seeceensuce seledscecnsaiens cease Rene EeEEn 230 AG AINE OWA iais 3. s00s05.c2anvnsnnystecesos cosuhpoertosquh evs saceusensstoeaee suibes teat OhstcegNteenmaeatneme 298 ACHINVIBALAL docs se coves Geavdesadsueeseensetnbacseecemmontees cab cosnpeen reas ateemateastmmaE 299 (71) GANCIG RY. iiss cacecinns pisces sa siensceiunn sesiee's de seseneeeluatet ce ns seen saiecse et sede tesa eee ate aeae ae 300 CYOPSMANDI......12.-.000% seas beotute laces cena oseniaenenctestmeme etme cioaustcien saincee eames 300 (71, 81) CLOPMANIBUA, senescence ccinsasstislederaces de etecciedemsacca cee ce senlccs aster ae stest see ee eee 300 COLMWATCUSIS s:ipse5-.ccket~ eos -paere neers es ssecesemeiics sete sence aber stes lane erat nee meeenee 308 (71) DEW SATE T EY Seg anaacopsocogcL0nde Ha sSbouBBooObdoRcodod ba soodaosbooanpenodadonsbasdoDSLéSoaDea09 aNAS4o0s 299 HADESLOVINIS 3 24ae sciens qncule se couse pons welak ooee acne ctes he eeeninvces Wabreee eaten 299 (75, 76) PRIS DUGG fc Se ccic onnsncedevacs thes «dcche denna ciinaisleue sates sees sees deiek os cataemeanite ten ae nena 320 OND ALAAeccccniesacicaesciicdaciicck > seccwnssveessclescapbancines cess essere ae temeett cee tae enee neers 316, 319 WIGIE COL pose ak cere « fc0eie se spinor oseshs cece cen tatestebisucdvanscndgants sa.Nh, Stee ere akan enmeeeEe 301 (80) PEL INL OCATIUID CLINGS. 5.0 cns cee cedsnradedecse stance sseceos nes desecniteascsescaetene eee aeneaanm 125 GUAT EN OCAMA PES... ois cccdepcec con danae ded sco Meuldhs dais inna Cet gemomten tere 125, 128, 121, 136 DONCHOTGID PT cscsccs soncecshnstaececneseessnoecens sect slsts secs shesas Ghetea sean ccaeesue smenaeane 134 NOVA POSzs cosas scetiset oosssice skccerseaseSeints soucdcesens onersisascnanas odes dee chedsseeepedet teen eeeem 130 CTASSUS satos osesetencswaaaisectwsdces cae teecn atceesie ster ccesesen te sealeegacceccinecmace tee eee teen 130 ClOMAMTULMSH roseseecsoscestrsccecpciteerinasncsnesinoes enieosones> spitsmeeeaetts eer eae eect meaeme 129 PTACHISS cece e oc ace waves cas cco c/asacatinncaecuivawnsateradlstess em dceaasaatesnal eee eeeeenees ee aaneeem 129 HUD CUDACHS.iscacsncesdasccaseere daananletesmcowtoile renkecsatsipidnus velaaun iat nee antennae 134 (50) MLOVDUGUS ices tot asekncle,slocioeeea siesta ciiesoes ciepels esiossieetiaseesiailsseensitsa st steeca nt aaseeaee ieee 129 MII OISCDSIS\ sr; owe dedssdacciacdcsamevdiarsosectavecsscaicnnceosconsen peace stems hasncey ise Emeee acemmed 129 MINNESOLENSIS f5 5.2505 baeoa shi salen ne ceceteses seas@ocectneome aces ccemecceoimcseeen seat 135 (22) MUU GUS recs vsorene sate ccc ences eos telscncevacteds anes sadanes 131 (47, 50), 129, 130, 134, 135 MINMLUS) VAT. OCCICENUALIS, «<5 oc csesessnce orcs sc cteasoee densiecinetisercw ens s ints = scimemtent act teatime 131 NOLOHUMPLICUS: «:s oo osie heath cece ns de voecoce costes cccseereces . clas Ree een Meee ten See wehan eat onic dosias nays dell ewaceesteecestpie 98, 97 Oithonoides var. byalina..........cceee ccceecsneeeeeecerseeeessesenesae weasereeceeeeeeeessseneeas 97 orientalis Uljanin (—varicams)...........-.seeee SRE REEDS CROCE COCE Jaca, Seo nocd Bubobsq0 ce 116 ornatus Poggenpol—?; of Rehberg—clausii. paradyi Daday (—Strenuus.)........cceccceeeeeeeeeeecuneeeeeserecanenaecsseeeeseescensnaaaue ns 100 PUABCHSB Cod sans sods dtcsesu'esessens Mane acisctee ceases 98 (20, 21, 23, 34), 90, 95-97, 99, 118 pauper Fric (—fimbriatus).............seepeseeeseseseeencceserseneeeeeeeesesenaeeseausaueeeees 12H pectinatus Daday (—leuckarti; of Herrick— bicuspidatus)............ AOR HANI 96, 101 POCHIMIFET............ccceeesceeeeceeecerseceneeseenseeeeese eenceneeesseesnseecaneessescseunn ees 111, 113 pennatus Claus—signatus var. tenuicornis. pentagonus Vosseler (==praSinus)............11+sessereeesereeeereeeseneeeeneseeueeeees 113, 115 pentagonus var. vichyensis Richard (=prasinus).......++....++ soba scisiseysncceuenedes 113 514 INDEX. Cyclops perarmatus Cragin (==phaleratus) ........-.csaisecesssccksencheansnaersanasrmceeste Dene eee 120 PUinleratUey ss ssactacwcescsvcecenccenesasccinaciea dousete cuechtens 120 (17, 18, 19, 21), 117, 118 poppet Rehberg (——fimbriatus)s..2... sve cade. seneonasetentpdelasesaceiieabee Wasanes see canae sees 121 MIVASINNUS ce ecescentccincss vscosssenccuieciecccgsascsesosvensicenemecnacenese@uacnall tenth ree eeenaneas 113 pulchellus Brady (—strenuus)..........ccseeseeeeee 101 (27, 28) 93, 99, 100, 103, 111 Pulchellus Vary MAVU s.c2.2 cy c.seceber ses ocnedosieccee slnccen ene ceeeme ns eeee eee faa 102 pygmzeus- Rehberg (—affinis)) +. ....c.c.+ secede susescesesatien ss cee sete dssearmascete eran eameren 117 quadricornis Koch (of Lilljeborg, and of Miller—unidentified; of Sostaric ==SEPONUUS) si scescodssscvloccesdesssdvesrecqeesblsas encloses ee teeyenarase tulctase teeec nana 99, 100 quadricornis; var: b’and “var. .C... > sisesesecccesece cage ssnae yaseeclest sor sa-yeeie et mereen Ete 105 MODOSUUSN.)-ccdesesotsavdecccsecedecstesteardes ssscccaeesa case smteaecnmciecsies ote Sannenttee amis Ligne roseus Daday—bicuspidatus? rubens Muller—Diaptomus. sconrmeldi Brady (—strenuus)*....2....5sseck~scessepadescecem »-pdecets: spasetatanenees 98, 96 ACUEIFer Sars: (—StreNnUUS). 0625.0. evo.soens crevesconnsastsnesene> bicscnsesansussemane sages 99, 101 serratus: Forbes \(—forbesi! Herrick) \...5c.csestsces st cecenebecsasearate ance semen nes 104, 122 BORGULAUISS-.sccareserhesssscasccesAscocceensecemmeetctomecoseeccs 111 (15, 19, 26, 29), 113, 123 serrulatus var, eClepans, .4.'5.2 s sateen naman 296 CVE OQIGD.... ice dacs svccescocciccsinstovencaabamsesenh tae aleoantalccue ge ereadsaye tenes a———mrCr 294 DACCYIOPUS BtrOMITl .......5. .cccccccscocesedes saat cateshesces socedeessneitenente ethane eeeeanmees tee 129 Daphne crystallina... ...0:0..cc.secvsessarvoatsces ysedecesaep sposusstaneceng: sates titan ane 147 MANTA OVALS. so.2 sco oc ce occeed vosceeccBesaesceedee eateries 148, 142, 143, 149-151, 160, 161 rach yrar .f. 0 2ie cesescecscecesaceeeceleschodeeodarecimmetedtess sumeuneatesessth aaeme 148 (26), 149 PVANAGANA «.: sc..025.0scccoverascdescsccccoesccceeese atestsmencelewareede rte connote 149 (37), 148 OXCISH coos cts cwenseecadacceev ce sdedegsiesccistcersiccmddetega ese sesetet ens ¢/eme kel eeeant a aaa 149 OXSPINOSA....crveeicasccsesacevesdecensséccsceoscecenzeceeqdvetslemeds tetas: tees en ct aman eeRemnas Ro aan 149 WAMCHELD . poe) ccc scacsecceccescvecsaasopeaseeeucedescauute ot ta densesiet se sahte ames sas amma 149 WANG... 50iscencnesscissinsedas veveseeceseencdeccsica deevandoseu cme toens dine santas att eet saea mama 148 Daphnia......... 181, 185, 141-143, 161, 162, 166, 167, 176-178, 180, 219, 260, 272 Development of, 182; Parasitic worm it. .ssccsccconpeperbccanccaseatedsccceeentaneee CURE ORE REaEEe 194 pulexivar, longispina.:s........c<.ceetcsoeajmecrseseneadn eevee ena aucn ae veseuoancenen 199 Dulexsyar. Nasutus.:.)..:..asceccacsssstescevecetstseemetect ss MMe ueTte ene ene eae 194 (35) pulex Vari PULICATIA:..;.:3.c.2 ccs sees ts crascvotecs otame Cheoue core eee eee Sines toneveceeracnene 194 GUAGTAN UNA | voc. 0000s ccwcassussnasasatbipneutelsenshsSnetnenen terete batcteteEceete eee =aeaannnneEm 172 FOGHIPOSEIIS off aos eae os, cusoe's ys dcsiuniesnouventes denseces tntusbocsinas sesdedlans soeRD cin tee nen aaa 163 PE GUCTULETE i ssiecis conse nen asco caves’ st enaseteauasioastopeeneeceece steady eaeEE eee 170, 172, 206 MELTOCUDV As «sstanc sas qosscosteescdenctotacecosetenmnen niviag oqare eves lee vestee Saas cuuceresp onstage 203, 204 MOSOD ss dectes cokes ops cahenwesveneseeettoose ws sales segeserss cbosacoreeucsccemesees 200, 199, 201, 214 MOUTIMG As 0vcesesicaretenvncedens sueebis senctadensssiereded des cecivasnsicensensetaeh aaaeaeaen ante 169 POUT AGA. |... oaks. n ok sevcestincsansaddenvesancitevhs coavenceue dapuers annveae? uakateeaammeee -aaeaneee 173 BUGS jos 0leoccsechsns cn sssajecebaseesonnonihsdacgeshGnastess’ses bas cone cestee ees Nee eeee een Rae mananE 205 BREST fades) coxa cviese re’ des ns sas nleSmne aenanettesee totivesnaeescesehavher suche niente eee ane 198 BEN POD ss ee see ses gncinpal deleaion os ober eee ee eee 187 (51), 182, 183, 191, 204-206 BCHOOR MORE Jo. ois 55204 doo dons ancte cesee sa cdagenesurdesves Seas este ese teu Een eee rne ee ee 193 ROLVUAbay.crt.s cc shsches desea: secoecwsaeseeces sc cove eccede toe telete ae Suen aeeee heeeee eeeeneee 179, 192 SUING iecavasceractsassncssceescecechdascseanseceeetions savivgendciive redder: teeth ecmtoese tans cemean snes 144, 178 BRUTE cecch shkas ovin a «iva c0ds snc ceanune s Soknme casachas saan ke Retag tse een meee 204 (35, 51), 205 MBOLQGA:) oaks 68 55.0 sorbose cons vs vaasionnehns oan do haphpehatsbadees cua. sea cuns FaeUaE eee een 197 METIULICOSG, wi dis vensty Saswed ansspieaszsapeerechtenancantecke: Uaanaa cha tteeeaeee pose seuslesccesk sete 195 VOUIIB 5 ocascccos poatensaocsecaseds.ntrackdaasedconssse ses aptebecedsdertocptedecah sete ti: aeeeeemmmname 178 WLEROR: tla daen aoyscchs qndoosiaanssadgsation eguenashits haccoddesd waves ane tens (35), 196, 203, 204, 206 RANT oie ese skeen achoocnees 152, 142, 146, 160, 161, 210, 215, 216, 218, 224, 271 Circulatory system’ Of:.:...553.c.csccsssestees cscs ta ceesert canes tedecenaccuenes 152--160 (51) WIAPUWMOIGG ...5.cccccececsscrccscotectceace cuosasee vey caccecuk cbse eemeedeeel Tekc es eetee anna 142 WOT WU A 052d Tecan esndsccassdh scodeasthaced opaces sented eee taseeee aan te ae aan 336 LIA PVOVISA <54042:4sn0ssc0cesanseesnsnnduses suvtecees tastsss ten sant teletne cammCen Gren Tate aaEam 336 (81) BUC VOTBOML ce $025 .nisisni's a as ale soe vie veles sin Verto duucla seven sons apeetet tee dtance test ees eat Geeta enema 337 PAP PAT GO. |i... asccdinssc.cdsisacnsar ches cocvupeckveneumucsl eeteevie ie eceea name 335, 294 Development of Cyclops, 122; of Cypris herricki, 326; ot Daphnia............ 182 Diaphanosoma, brandtianum, .......002c.0cssacss>s0sssesaacces cabentcas sue eaeneey nee eea enna 148 AAAS 750.005 oo o00seosainucebin dss vvn gn cuqenatencimrode teens aatee oiete mean Leandassermecicenar 149 REA TVCOVMUSE ss. n55. cehsca sche sstctdevcte. serach meee dasedaneewensenctaebet ierers 54, 47, 53, 86 PMNS cs saeycodececnsasqeecelucdecsngess ics caste acbancanantdevanexcdaener stent ts nete en aa=amnm 7'7 (10) albuquerquensis.......... daesed ctvncecscat Coactersrseasbeeencene ace Ge eRe teerer ere 67 (6, 7), 70 AMDUVOGON se) 5.2.50 .cose cvusensercavove sbassueanens aeuesdeuuant aby seck ttantantalalie inna 78 (9) ALIMAGUG, 0. Sinacacesseecclensccecenecngdade caoievies siedewoscecsskaoesnatens thie CROs et eteaa mma 72 QSL ANG. «50.5, svn -cse0ncocecdaevedinssisaueee cas acssns seeesenspone) pues cnaveeshen teeeannnmnnnnn 60 (6 ABUAULCTIS, «010 soneveducctnbascsconscscevucsigeaeespassocssdentess tivesdstalrent atin nn 56 (10) DACCU OR is os ce sveascesensstsatent anes» nnussdeechert «aces desenseheunusdes ish iennnat san manne 61 (10) DIT ZON vo ncvavvgsesesvarscecesessovasahussnegudvacy dedadudienvackucbessscuiersssaiiyelnanen amma 79 (47) DIAMCHALGL 23.2.2 ..0<5.sssceedondeSoctiveccnsecd acavdvecscn vet Mecesvede siete seen ten aaa =ennnmnnnEEm 59 DOTMANOWL...... .cacesacs’'nesuawand sannasonpnbavececs teveseedesuuites salieh Eh ie (atta 78 DOTOALIG.... 020005 sen scese sdscessstpcoesuccsnccsed esedees scatecansel eaeeee see arene tn tenn (10) CUTO] Ls, 0 con. dc-caocstinns doncooaccocece tev ecuctes sansa cst ccqnmntes tateeetts cs ane init enme 226 MOAPYCOMIOLA 5.00 05c000vcoe sees esvcetaceeccns nouaeedanaasaveeesdpnsaninasestsoocpescetu¢nssiaemmamanal 49 ATL INIG toe ce de coo tcs ae aac a tenes eee sets saucece ste cease stenered ces Situs cane ataeazes 51 (1, 60), 50 FUIDUTGO) va ccosccnssecdscce css scvccsatewenecsacedecunclscsence tens scan denims ncmsmada << cael e pape ec Une 51 LACHSULIS sods dene vcesleevese dec tai stdodecysaveseecdeWnd eee ov nes «1s edalies cams tines scat ite tia es may 50 MV ELOM hates iio a ha anmey teeanee 235 VADICTUL AGA sevcseencasdeacuscoccccccescesdocdcosslsel dus 0seedee Colnasvaneea sassy neta Wnemhemes 236, 249 TORT OLTISTIE S550. cctsd ancda es dus tecen@uckon te vp daaniseccatees suena Nt re Dtee meneame ds 235 (65), 249 teBtUdinaTiA VAL. INETIVIS, ...0.scorecssecroccceccneccccsscccancscsacsceteccebeas, cesadseuswaened (65) GYMBOMETA ........s ccc escvccscnncccnsorcaesssconcescosccsssnanveetes cas scenes 145, 266, 141, 146 PRArpactici dae -i.......0c.cccscsccseccccnesnetenccnesavedseps sacssscceeesecesensuassrennands 46, 124 PEA POE GNGIUUS.. 255 81) .i: acces sasectcadevoeonane sa Aguada tN ahie dp ibe ee cbtad cere 237, 260 FALC AES cs uwscdeascchscedacs ce Osasvepvadeosdeestiavdaancsnstsnandeccineses cutese tiene scuasuemen 244, 260 INDEX, 521 ESC RC ONG eepeta soc cg tas ects Levee masonite ss oh Oks 66 Os 0s Vere dus vasll eoea a Roads 80, 81, 47, 59 UT Ae menu celseial Ces ne Cote pee e cn re ni Mart a rlscebis nad ocnausasulevaecedinucesgeestomeaaee 81 MUDSUGICULATA stig or rave cen eahie Chat sa eoesrabe rete cbues te dente sbetuens wv scgectioecdides 81 (11) PRIM OCDES ye, waic erste Sar votive Recta dele cles ee ede mtaaas Oath 9a1ee cee c aes besos cecian ac udSeeenatemboes 81 (10) OSMUDIL AM vars a Aeinle sadarcontete tenet acasatsine testis setae cess eek Serawiatasisis cceinclelscisaeis ciate iceamien eemaaton Pescoed: PAUL OTISE clon uiucls pburverts Uauithe riateideavels q/souontuganidmacNe nda bastions eee ue aslsedees cee chine: 81 (10) Pie COLOLECRESIS: IN Cyclops stick series tecedec stack euecanidete eseds ledadosceaal evebeaessocbor 122 PR EMUD ED COLOR OTe oss e550 cueG china SeaseRelasnde s Suds seaeetBesd puaasedeee «.adasee veloadece 151, 143, 146 PERVEO PCRLURUMER ¢ 2220 ccs doce os -3seg,b samedi ensue deuczknccn dc Caden de tas toesdguassacnoouloorcevens 151, 161 FUP OSL ese cite 8s osc. a ncedebiceseclldalieeaeumereas neskOrascaterehcceeesntasecavenn denen reeh 151 (35) RE RMIGRTIVICD ES EMD ELD MNE 0 535 So sss oodles Gs co sewer ot cen tREas avenseed jackdob ett ncktoden opel oes seoeeubeeree 86 MEV OGUYRUUS: .0 35.0 6cdecc seecs cede dasceeces 220, 143, 210, 211, 224, 233, 237, 265, 266, 273 ACTRURMITO MS ies istsjce's tn sauce cist. attens Meceeteren dacs Cag siesseeWee eae se oene ee ke 223 (55), 221, 222 DMN Stese cok eae Feiciettiosicus secs age eats dntuorae aains see enes Rea semnee cauisocs nate eowareer Ades (55), 221, 222 OTA DAME TU isi ofsestertr So alae Hetiawse vcd ve cai eutse tole clan tatielaettes ace ea se ottede ease e terete aoe 2238 (55), 273 ROUAUGMIS sect aicce cass Setiecctelec's costattethns -eodesmemeateccies 220 (55, 56), 210, 221-223, 273 SPUN Sheaves sass tes. oeieasias sale seanasstcstanees da 221 (55, 56), 210, 220, 222, 223, 273 Larva of Chirocephalus, (48); of Limnetes.............c0c0.cceeeessceseeeeees Sav eenuete oss (48) forrval historyiot Cy pris Merrick 't..:.. :ccvcstenssdacs dlinececspaedensctmecsevesesce cateeisameaae 326 MAINO TUTE Ge oo cece Ycavs see onto cdebesccces decdedsndsiduss efcwsd dace dass 215, 143, 210, 211, 213 RECEITOSLNIS ses. socharcee ke sincoaesnesear sie renempicencaene tices des Saeeseseeeue ss, oeeteeere en: 216 (57) PIMOS Aes. Sassccs steer estas ceacnetsdogss dcpesiiew Nees basadeedveretaecacacsoniacnc es sne stone cacas eens 216 LLL CLAS eee oiea LOCATE ak Ma ae ae ane ee a 150, 143, 148, 151, 161 BST CL AE tec suis fo clas aataters«clcietetaebotaetcls soticiafurta.ctomoaten seat netetg as ete cepelacecdemeccaenis cee cee emas 150 (35) PT EOE OP SUSisescossccttives ance calcd deo vactes seeitcesaitesmeses cS e caseceseets ened estiuaceseteceeteeton 150 ISUNAIIS cata «each cence memelsct cp tiaansetamalsnstenesee se reanc tances tea teeuiccinavieneseenade tees erento 151 OCCICENtALIS? .5.s.de A igcasce te aust bec casedmeastace trccahe toedtaanuaconeacainieestes 150 (38) SAS RED CLAP Maem VALU As) eistie aes eBvatr Sets betes Seed tise rad coiebhedtiesstvcepadcces toecar teeeat 268 (35) PERL CL UBIO ss, hvac ssc accacss) sate iguclaas dtire sche taahseeUesacdaguwenstantehacaas sasheccke 268, 146 MES PF CSE PN MME RNUES (802.015. 2 coo). mace tenses sihe~ anaes veuack sbidh Soe nbs ssemerenbresenel ase 238, 248, 260 Hell CALUSMMPER A cc ccce sossisedtatioscee Poe tancat ete esc ser ewecsbicecceslearasimenesatenstts 260 (62), 248 RE ESEA GTS OO GN A EPEPOE ani. Ghls «icv apa ssivemak eel each v'esce ge veoomre aa cuesdtind cae’ as oeppme aeten eect teetes 294 OEE N A eet a ceo cass etd on osanp cides ugaksodensavtespetgaseaeoas 2338, 143, 210, 237, 248, 274 ACATLUNOCELCONG CSiesrracs ssnbiswccise tneeceantcs emer ses eosicsel Oaueaasecietioatsnanadace cma vt 234, 235 UNLV ATS Spemere vers elec o dhiuvcetuiare fs sbecesinccias ve omobeesneCsaeietamnsecielsencts cedensenace 235 (66) SIAC RAD OMEMIS chats cncslocenccecses aisuge oesaavcontvaicndene ets cea tes Sdvean 234 (59, 60), 274 MOOTININE CESS oe cee sores nae oo cota t cae ooennsehc erwin sinedoe sscineslsnese ncegessé sriseastcnee sen coeenarecees (48) PORN ITO COVAINUISS. sets cevecsstes castes dactote ae ces sbna see ices codlsseccccteosemecse reset aeeerorme 48, 47 TE CO TINTS octece cto ideaden i666 nabc6sbde 5300! 00 ac gpee ac uaadiedese ne anns secpaSrcocubaditasqAsus: 49 (1) MIAO HUTS cV AT AU CUUSi sain ss vets cslewieiace Mote clacton cteis vditeltiecinclse daisies vis ecwea eines sa saasesianeeleaeeeleceee 49 GITGTIRTE re nanoed. caHSHoBnQCaROBOdeDaCOnDOEEEE yR.Goe nDDDoC aco deHoerinT Mnaim acne PCuBRricis Sereace SARC Nnicc 49 MU MEMEMU ASTRA SE Soe Most e cca nk SAeM cena soS cake ofan teeta t ase clasaccsuae sittechesew ac sdecy 148, 143, 161 MORUDOSHN ERS eays Sots Gas eee vere NG ona Sete Tee ce dislgsbinaan sell sore ste bantehtoeesees Gee 148 (35) Lophophorus........... Eee Ce urdincadieetecss cael sec tecsdecensda se sash thers oanse} Seamceicndees 7 OREM IDE OCL ee Useec eer ce a cae tes on tteusctnaccteo ssh caseceanilee sesives eeanceuanine saat ee siere dees 293 1 Ni 6fS) (1 (2: ee 224, 141-143, 146, 161, 210, 211, 215, 218-220, 225, 226 238, 264, 266, 274 MO MRAMEN Romer Cerae soos ote eich each etctenstedscstadvesds tava ccsediests ap cenaticesuegccaonee 226, 274 EES AUER EOIN cine fc oucosr siceden acs Gowpciass ahs diches {a laeccassdsasnedads oot 237, 143, 224, 238 EMIT OCELCOLULE Sade cee see scectaeatietcue ned. Saweas (acts cerunotoss squat tse sacietheyegecevenaiader same 234 522 INDEX. Lynceus VIN BHA: scsncs ses dcaie'se ‘calysecnscn cds ayss cqeeosseemerse tags yalsise Vasunntapeesunsapaath tne css ewe 259 OKCISUS cae tueds aediccueccsee tacetecevemsueseae coacstmessedstesematen ne aetna classe siitceay tices cots tet team 251 OXIQUUG............ceeserccceesvensccsceseseecscten sanseseensveverseecssees cavecuscnssonesuecensonens 252 BULtAtUS .......ccsescevecescescoerevenserscncresaseen seeeecesesessessecsecesssenescseseancnesasascwees 243 VAMIGUIAUUS score seocsccee Gee sesneeres seeps costes teapeciretesaees «cusses se Seibie.oleide oo OOM IOE Haein de Pele 226 lemcocephalus ............cscscsersessonsertesscnserecesessecssceusnenseeesssenecccesesnens sasseases 227 MACEURUS Ses csivsncleceasssiedseneiestelccade bea cvenathanrancstovendccdas seadeunedestoaihelawname 229, 231 MVATVUIS Ses eoee sco sone ea kencciotecencs tis con aeineecsceeoasienacy va teneceesleceentie seemeceten sa aaa nea 253 PETSONALUS.......0cesececee cereeeeeevecnsenes seseeecensenses sennenesseaeeesees eas enr sauces seseeseeren 259 Quadrangularis............00-ssscssccecceses vooseeesesscesececcenecnscesecese sebencenronscesseeeeren 234 MERI CWIATUS Padas dere da-iaotsesieOrses «tele sbe cle ncbccecedteasterevonteaterahenssesascedeee seee200, 236 AYO S(SLNE Hote cc poged Anon oabds or eGepadBor BSc BoC CDSTIEOS Jo onoodoognsosnagh dedaoanadacocr duokiadalegeoocts 214 TQS (O77 11) Pee Se cee ueoboe oat ado ee pooor Goccogpdbd iauocioag cud aGocunpeUnpEcAncraabootcwa 10% sudusBegscer 250 SPIriCUS........0..ceseceoesenes cecnsecsccnscansersveees soveseeteceneescssevessesenassaaseeaas senses 261 PENUIVOSELIS este cdodeticsoete ds ovotee so aulsic ds ccosaces soca cactetes cemstia cee ajsacenaiee tee emennmae stem 265 MES UIUOUGATIUS scoot entero cccccisces fests dstaclees soeeenie credence ace tehs rome ateernech cr emanates 235 tLiGONELLUS........0sceseececeecceeeecnsceecteneececseesessunnsecseeee Geeeeesuneeeeneeseenaeesseeeeces 255 TeeLTTT ETT TU 2 Fs peep o ERO SET DSTORE ROLE Cor CDOS RB ORE ICCORa cK Ton ob crise ads codeine ssagsGcomesguonee: 258 AIT CUTI AES oe eb pana cess cteseceeiysesens oe cctcceciesoqsaicaitect.cegaceosteindullniersitas terse deems testa 259 LY MCOGAPDNIA...........00.ccccccesssccceraenccecersssecsensseeces sevses as 143, 210, 211, 220, 224 MMACTOENTOIGES! 202s. sdecscesececeuveccesdoqestscves aasvssenessoupseuesenessitn ysis pvesasas/usheeil 219 Lyncodaphnide......... .. 209, 142, 143, 146, 160, 161, 210, 219, 224, 225, 273 MacrocypriS minna..............sscscccsrereccsnsesscccanansseeseneesceeuessceces cesecsenssesessens 335 PUT ROBO IIEUR: oko. soc ccceocedievccnseeesaadessces 211, 142, 143, 210, 215, 216, 218, 219, 273 DOYYSUHEMICH..6.2.cre0sers assvesosetvvascavesteqaucsescesndonsesseos oagerocesaeneatae+Senensee 213 (66) HATS GI COLNIS. $2 cecs cogs vcs ces csnsiosccecesclecssde ces sncceapcetincetoetac cantar sitsap= cgstan-sece'ccncceburvocc¥ash ancaseuayy dauats aera 137 (32) MOOG Bi sheng Ciees Sencce lt Cedacinseehossosne ec oniedennobecepesceasnncay ec sng elpee tee atm ann tec mana 53 MEISOPHia...............:ceeccccccceeone senses ceensanatecssesseeneenenenseacesesenesaoseenees sesseeeusees 87 RWRNOT IND 6 anevada sda vice veud6s¥ ap evee 160, 162, 141-143, 146, 161, 165-167, 183, 184, 271 VAOLGA Tk cle hone italashawevo’ Coded acai ouenssaapmmuse omega veneer eres: ein’ ielatner see 165, 164 PANAPVA, oo. o5 sues seawsens aden oacden cnnaenpesedelsemars, ap sense somesysipengess b> achereanemnannaets 166 TACHI AGA: ok Fnac accd casUovavocdesckubs Senecceanscnss Upeasehiones see atwaen sein oheas 162 (39, 43), 163 TIS GEL Eee sibcgkc tebe twas) Mh amonk igo diteusec oscar beeass besee peak taeda ceaeeia etree tnaanam 165, 164 flagellata......csseccssscceeeeces eecceeeeeeeneeeeeeesenseeeseneseesasseeeesees sane senses see ida 165 MACIEAV LL .....6.5 cecseeeeeeeeeneeerceeseceusccrsnteseesseees seen sanneeuueseaaesceesaneasaansunens 166 | PATACOKA, ......cccssecesseececscscoweerseceeseeeneeecees 164 (39, 40, 41), 161, 163, 165, 271 PLOPINGUA.........cceeeeceeeeeceeseeeeesaeaeeees ceseereeeseueneseesseeneeeseaseeeceesseaeaeen seneneens 165 TECUINOSLLIG © tc ccvns cegrstosenateveanehenepsoceasat ovacneedestmtses 168 (39, 41), 161, 165, 271 BALIN Finccckck ve dbceoossiecdtscdeceuoeeseGemnvook, ass chiedsarcs Wate seep vag easnnnt eee mmm 166, 165 WOiMAM APHNIA ......0. cervecorccseccvsseccesceesrsesecsssven qsvcessenesegesasseesaas 166, 162, 165 AIADAINIODGIG!.

daaemmmmamaas 259 MUIPELQUIN See ccs esvanaacwacceteoce ms cltessclcsicenseltes(scphiecle cast asus vce tue sons cube aamaeaee 226, 236, 257 VENUS ES he cats cas can deccaceccegcovsagustecesdecotedeccsesdaeplte scsttar tine encsaceels see entanen Stee 238 AVM GO PI ao Se civend cac'esceage cers ovs badasVarts acs saquaseeepebespsed cay aatp anunye ey. anne ean 294 EON OED eas ssicececete sce. sion eas cee oaces s> vi Daye CM i As noe ie" ms LA Caer : ie? J 4 4 ae . J . : ¥ oa a 7 i] - b 7 y 7 ey W y : y Pd 7 : i _ “eer y a a ae ; 7 : . * . nt a at } _ Pan | ny _ : * : a 7 Po _——- : ae x ; . - : . On ; 7 - y - - 7% 7 , BA i) 7 ; vor. : ; 7 fy ‘ y ’ ; os 1} ’ ; 7 7 ; f : is - - - ‘ - 7 : a a a J , 7 7 7 na 7 . ; : 7 1 a8 7 ni ' y% > : . : a 7 ’ i _ : 7 : 7 7 ' : ' - J ' “we a ; hog wy « : : ! : : , 7 = [ ¥ - ’ . f 7 : r ; ‘ - 7 ms a ; (Yea 4 7 7 a _ ‘ ; | : 7 (* ; my) : ® " mw 7 , \e n |! ° a 7 7 : a] i > ! 7 p ' q "hk ali ; 7 ‘i aa se @ 7 ; eo « a 7 \ at 7 t Aa a 7 » of Z : . ’ 7 oe oe | 7 1G ‘ ' i . ; 7 7 - - A 7 ; Tu u : ‘ : - Ua . 7 Z » 7 : > > _ a 7 m) a i 7 oT ca 7 ¥ ’ ; ‘ i : TV ’ F : vy ih a “a 1 re 7) ; "a q : 7 a as ie > - 7 a oo ‘ | lh - : g¢ 1 ws 2 , : 7s Aa . or ; on : . 7 . - i p ’ | . Ss 1! j i v , y : Waa . : ’ ¥ : 7 , ' nee 7 7 : , yt Pies | 7 . ' a - : is a “ey : , : , 1 a ° ’ ' ' on : EEF : ; - v fi 7 : f oe i Oo | 7 ne ‘| Ai ; p : ‘ : a ; : in = > v4 - ¢ 7 7) A 7 7 Par a. aa re : : _ 1 ’ pal if vs J i vier ~s) ' ‘ _ nm,” : 7 Boy eu ; 7 : 7 : i, 7 7 - a 7 7” " ; ; a : 7 - ' ‘ ” H - - os 7 : Pues - 4 - _J 7 ail a n _ ' a : al - : | 7 i : 7 ef 7 i z a _ = ] oat oe arr @ " f a? r : a i 7 . 7 ms ian y if 7 7 . 7 ; eu i 7+ an > i) 7 Ay ya 7 5 » 7 MT qr ~~ : _ 7 7 J ay ’ OO os DER _ " iw, en > i" ~¢ 7 7 a : : +A 7 - aa a, : Se ih ae Tak Te oan | fy i a3) : : -_ » 7 o : a - : 7 7 me 4 ‘, ' - > 7 i) , ie } n 7 : 7 7 : A a 7 i : - iy es . : is m vt q a Ct : ir = , : | : - ra i fr AL 4) - = 7 y : : 7 BA PS i OL ta : we iN { y 1 rl ° a ‘ i" | 2 a : ’ a] oe io o aa alti Mage | A a i" 7 i} au 7 mi) : - i ni > ‘ J : ! A . Ween @ « : i ; 7 _ wa Walia ys ie , : ie, a 7 i Up, oe , Pats ¢ ' . - iy»: 7 : a as)> 0 8 a i")! en ' > ye oa) We q 4 vil 7 - a : ~ a bie we 7 a Pa ae : = ° - - ; ui i ye i : : q a7 ya J : 7 : ‘ 7 7 I a ’ a i - ; wa AY nm; “4 fi 7 i a j — i es F . he , 7 A > id iu : . e.. y te | 4 } e. , > q ‘4 7 ot, 7 = "i ey ; 7 6, ™ seers Pe yt) ) ; i . a 7 .) - ® ‘i | 7Ai : 7 “- _ 1 : “Weise 4 e a | | : mal “ee - , : : i ss . ; ae 7 7 4 , 7 , 7 7 ia 7 et . : ok Ce ; 7 (oy : : 4 ‘i - 7 y 7 ie , y rs 7 i r¢ _ : \ é ; ; Ac , s ! uy 7 j : a 0G ' {i . : n 7 7 i we : ¥ “1 ae i - - > : as 2 | _ - 7 7 - ~ . ’ 4 iD + 7 ae : ; F] : | ae il 7» / 7 7 7 i ; ; ay al 7 i Phe " F 7 it ’ dt ie g - - a , H af : > ‘ fra | rw 7 7 7 oie .. 7 : : a ’ f : ,° 2 7 Sanat t : ao i : of a ‘ - i °. iy y er) 4 e - My - n 7 F Aes a \ } a a 7 - 1 i] ps 7 4 a ? : nan ; hi i: : , yl " ‘.- : : ‘@ 6 ¥ 7 r “y ; x ‘ i, heer ; - : > e, : 7 D an er <4 - Tv 7 ~~ m= ¢ - 1 : ? inn = 74 . a : i : ry iN ‘ oF : ; ; i 7 ’ i : a my 7 er p hime } vs . - 7 1 Sy - aren i My an Py ry ey : i : oat oe : guy ‘ ne m yy i : ee : _ 7 sh) ic ws aa 7 a - ae : iY ! ¥ ” - : a AL i u . co 7 , oe a aie | , ae f ee PU. 7 ia a th leh axl | iD, | Cee J . (;, — a 7 oo Y -J _ @ f - _ 7 at 7 _* - 7 " a" a i. : pi » i. = - on - i ri 5 _ ' ; . 7 lh SS > , , a) » i; to { a | : \ ® ; nN i. _ “ot 7 ine : : : 4 * a is * 9 il _ ie A a" ‘ 74 ve rn } : 7 3{ Nth A : 7] : - § ' ; t 7 ss 7 D : 4 = F - ~ a = ~ iy EY *| . MAL Vy, Scone i eine ‘i Hi | ay | R tH M i ; “y, ‘wal Mp il ¢ \? = , ? », a t =O er) < SMITHSONIAN INSTITUTION LIBRARIES i