i ‘i go! alia nm lind ice CLARENCE LUTHER HERRICK ut} (1858-19044) fg ee 4, MISCELLANEOUS ZOOLOGICAL PaPeRs /+ (exclusive of papers on Mammals, Reotiles, Neurology and Geclogy. Biogravhy and complete bibliography are given in Jour. Comvarative Neurology and Psych- ology, Vol. 14, No. 6, November, 190, and in Bull. Scientific Laboratories Denison University, Vol. 13, pp. 1~33, January, 1905). 1. 18/74 #=OGrmnithological Notes. Geol. Nat. Hist. Survey Minnesota, 5th Ann. Report for 1876, pp. 230-237. es 1667/7. & new Cyciops.. Geol. Nats Hist. survey Minnesota, 5th Ann. Report for 1876, pp. 236-240, figs. 1-2, 4. 18/79. Microscopic Entomostraca. Geol. Nat. Histe Survey Minnesota, 7th Ann. Report for 1873, Appendix B, op.gl- 123, plse 1-el. 4. 1879. Fresh-water Entomostraca. Amer. Neturalist, Vol. 13, po. 620-62), plsel-l. [Photostatic coor] 2 LEE . Papers on the Crustacea of the Fresh Waters of Minnesota. I. Cyclopidae of Minnesota with notes on other Covevoda. TI. Notes on some Minnesota Cledocera. III. On Notodromas and Cambarus. Gecl. Nat. Hist. Survey Minnesota, 10th Ann. Report for 1881, pp.219-254, i-ii, pis. 1~ll. 6. 188e. Habits of Fresh-"etcr Crustacea. Amer. Naturalist, Vol. 15, op. 813-816. {- 1882. A new genus and species of the crusta- cean family o& Lyncodaphninac. Amer. Naturalist, Vol. 15, pp. 1006-1007. a #) eae S. tae 7. 4 Sy Se 10. 13. 14. 16. 7, 1883, 13384, A blind cocepod of the family Her- pacticidae. Amer. Naturalist, Woke his Pe 206. Heterogenesis in the Copepoc Crustacea. Amer, Naturalist, Vol. 17, pp.208-211. Heterogenetic develoonent in Dia Amer, Naturalist,Vol. 17, po. 321-389 499—505. Heterogenetic development in Diaptomus, etc., Corrections. Amer. Naturalist, \; = Vole 17, PPe 794-795. A final reoort on the Crustacea of Minnesota incluced in the orders Cladocera and Copepoda, Geol. Nat. Hist. Survey Minnesota, 12th Ann. Report for 1853, 191 po., pls. A-Y. Editorial Statement. Bull. Denison Univ. Lab, Vole ty! Dds 3-5 The Evening Grosbeak - Hesperiphona vespertina, Bonap. 11, Denison Univ. Lab., Yol. 1, pp. 5-15, pl. l, and Frontsvpiece. Metamorpnosis and Morphology of certain Phyllopod Crustacea. ‘Bull. Denison Univ. Lab., Vol. 1, 00.1624, pls. 5=5, 10. Mud-inhabiting Orustacea. Bull, Denison Univ. Lab., Vol.1,pD.37—-2, pl.9. Notes on American Rotifers. Rull. Denison Univ. Lab., Vol. 1, vo. 43-62, ols. Onl}, 10. ; Contributions to the feuna of the Gulf of Mexico and the South. List of the fresh-water anc marine Crustacea of Alabama, with descriptions of the new species and synoptical keys for identi- fication. Mem. Denison Sci.,Assoc., Voll, No.l, 56 pp., 3 pls. Beem Filed separately. live. Mar.shur Ly he fi ies po «eee rete se * Z es he a sh ' e ; rw { en ae i Loy j ma rat ue ra ~ mat Hoy of fet ins iD > i » Pay sth & i" ii tall j we Pee f ; Pin ae es ob TRL yy i SG + a ¥2 iy Py ey hy Bat DEN TAT ag ' "oy 4 : J t tie ~ ye b a = = af - 4 s “> a A RE WES gd Ba TE NBO PRA Ig RED: BO 8 ae Pack he ag ee ie telintintee tO wis fe Bd teloas: Rak ees a ie he 2 i i Oe ty ae ye me ee ye. Sls ts UB he ee a * HANA. DAE vale PMA iste oe ar “ my a i mie Z vi . - PM. oe) Sh Taek a ea ee ” ; " ae e ee " ; 7 an sia t/a i ai ‘s hy k Pear LO KAT, weet mer lh EM Pe oS ult ; F Pa ow ot al ae ' val oe wee. Re Oe Waar 3. FR “ » - i : i ee ~ Pf, ar 2 TM TS ’ rf a? “id 4 Ee a a \} i ” Batt) %) ¢ i ke *« s hi ia hl ep- ROS Ng Oo \ b Aoi ne ohe A a > aie) Fr pe 7 ° r al ete re) ‘ie oe a oe © _" 2 , q* wet etw Aocy © « iA ee > = 4; wo Sy Ree aia i ® 9x i € : ise we he ; ; ee ee f ( aS Ae a ide Me - sy " eh Meg - 1 A ‘ $ hy Ne batt, my, z 4 mi bh) wm as ¢ y ‘ime | ie ‘ “y i Ants 5 er H t sige det a dt : 0 -_ , ’ Pa )2 Pe ie ; Ay we ie e * . . ee my Wi whet ge ethtaack Seen. OSE = a Amie 9 ae a ie be a a i (dep Ad , Bi € Oa ONY ae Sei dene i re oReafy at? a . ee >a Fan ? y* ThE ie 7 i , > . * wh at 9. Vier, gauge a rg Bb bot thy ae fe ot Uva aN AM, A tad Sa eee te oF ie: 18. 1895. Microcrustacea from New Mexico. Zool. Anz., Vol. 18, pp. 40-47, text fics ° 1-29 ° [ Photostatic copy]. 1895. Synopsis of the Entomostraca of Minnesota. Geol. Nat. Hist. Survey Minnesota, Zool. Ser. ée, 525 pp., pls. 1-81. [With c. H. Turner|. Bound separately. 229 SURVEY OF MINNESOTA. eoer ese sce vere sores es aDUUlsy yoImpursg ‘vOnvB[Ly eove rer "dIBO eeseeeeeee eee Cr Oc i ee i} wewroese ones eaves sere + °° UBIUOIN FT "SYIVWOY PUB 10999/[0D| *UoTyVUIIOy vereverssroccccee x NT BSOLOPUOOL]L, Aur eeoer ee se ees we wee ‘T puvjsy epoyy | sr eeeee*OUl yynoursz10g soneee sevceecuess coe See ‘WOITOg weeese rere ee oe ’ ” Se Af or purvl1equny S88 Sen Cae eveeder ei sRe oie teneny say 107SUBIO Sr ae ae I A “WUE pueLtoqunyg “OIA ‘oyjonbavyy ‘oul USOT “AYTVOO'T \! *SUSTILNEdS JO ‘ON | Se + SNe 8iaig (0 as ieiewien tn avs a's as COTTE JO SUOISSOICWT YIM o4vIS Jo qris ee ee ee ee ** *@AISSBUL YST -U9eIs (8}1URILL) eUBYdg ‘uoT10d UIVU ‘OJITM (O7FLIaUINOM) O71[0Od80gG "S[BISAIO YAP ‘[[VUIS (OFULI[V) O41G}10 vite seen “Ss eeeeeeegartKdoo[vyO Pe Oe **** OI 1TOPId ly ee eere en ee sip) ahs sole apelare sits ee" se OAT TAU EL eoraces SR OLIRID 1 OGY COOL 001 90 1) “BLL sUTUIeIUOD SUOA OTy1IAYdioyg seee"(ATIBOU OFTFVWOVTT) ,OFITOK ,, ‘ouUNy eeer eer ee ee eee ee 4 eeeene sees Case ” PLEL i ” ” sees eeee bt) ” eeereeee ” ” eeoeereere ve ” ” ? veee eee "MB Y YI8d BA fi °§ 9LUBT : “e0ueT M “uey *CUNIVLIQ eeereesoseeerING[Ns OAVN |UOT}IsOdxY [vIUUEZUED|g/9T “AON ereeen Ooee osvquntd é 20d ” 20q M ‘ponunuog—9 LST ‘TE “equasagy 07 Swnasnyyr ay) fo uawradg jor Soposauapye pup 709180,004) ay7 fo ansojn0/) 230 GEOLOGICAL AND NATURAL HISTORY eh | / ORNITHOLOGICAL NOTES. By C. L. Herrick. MINNEAPOLIS, Dec., 1876. Prof. Winchell : The work represented by the following list of birds was, of course, much impeded by the difficulties incident to the season during which it was prosecuted; for not only are there compara- tively few birds, and those of the commonest species to be found during the heated term, but those actually collected are often unfit, on account of the summer moult, for preservation or study. Yet though the field work was over before the fall migration was fairly commenced, a few facts of some interest were noticed. From observations made during the summer it would seem that the Brotherly-Love Vireo (Vireo philadelphicus) is not as rare as until recently supposed, and, indeed, it may be found to be quite as common in this locality as the Vireo giluus. The vireos col- lected were shot without discrimination, yet two were quite typi- cal specimens of philadelphicus. The results obtained from the study of the few shrikes as yet collected at Minneapolis are so unexpected and withal so contra- dictory, that the following remarks are given with some hesitancy, especially as they are at variance with what has been written upon these birds by others who have collected in this State. The Great Northern Shrike, or Collurio borealis, is as yet only ) noted as occurring during Spring and Fall. I have never heard of | the nest in this vicinity. I am led to believe that the bird is some- what rare, even during the migrations, for in the Spring it is very conspicuous from the habit it has of perching on a high tree and uttering at intervals its peculiar metallic cry on its arrival in any woo ge lapel. pod che pea / 870, pitt, /37 ie SURVEY OF MINNESOTA. Po | locality; and thus the comparatively small number of specimens collected is more significant. The smaller shrikes, so abundant here, or many of them, seem to partake of the characteristics of both varieties, viz: ludovicianus and excubitoroides. The three in the museum seem to me to nearly accord with the descriptions of ludovicianus. They all, together with two in my own collection, have the two inner tail feathers black to the bases; but another, which also possesses several other resemblances to excubitoroides, has evident white patches on all the tail quills. Again a number of these birds in the possession of Mr. T. 8. Roberts agree ini disagreeing with every description of either variety. | I draw from these facts the inference that the variety ludovi- cianus predominates over the other, but that the types are mingled and blended so as to baffle any accurate identification. The nesting of these birds may be easily observed in many parts of the suburbs, but the nests are often mistaken for those of the more northern Butcher Bird. Perhaps the Red-bellied Nuthatch may be less rare during mi- gration than supposed, if searched for in suitable localities. The bird-fauna of the State has received one addition in the tern Sterna caspia (Thalassus c. Boie.) This is the largest of the | terns, and is a very beautiful and striking bird. The only speci- men as yet identified from this State, as far as I am aware, was secured at Long Lake by Will Secombe, of Minneapolis, by whom it was presented to the museum. The English House-Sparrow was simultaneously observed by Mr. Roberts and myself during the early part of the winter about the streets of the city, and I learn from that observer that they have survived our severe weather as yet. The fact that birds are often infested by intestinal worms par- ticularly the Tape Worm, (Tenia) has attracted so much notice of late that I mention the collection of a variety of these parasites from the solitary Tattler ; also a quasi-parasitic colony of crusta- ceans found upon a goose. I received from Mr. Roberts several specimens of crustaceans collected from Hutchins’ goose, found deeply imbedded in the feathers near the skin. These proved to | be miniature Sand Fleas (fresh water.) Of course it is hardly to be supposed that this was more than an accident. I cannot account for this except by supposing it to be the result of the pro- clivity of these fleas (so often noticed) to wedge themselves in the thick masses of leaves upon the Bladder-wort and other water plants. “MARSH COLLECTION” Se ee eee a EE eae yo oe —— oo ; 232 GEOLOGICAL AND NATURAL HISTORY mov iS Note. A star (*) signifies male. A dagger (f) denotes the female. 11. 12. TURDIDZ. Harpochynchus rufas. Cab. Brown Thrush. Minneapolis, Aug. 20th, 1876. (69.) Mimus carolinensis. Cab. Cat Bird.* Minneapolis, May 14th, 1875. (26.) SITTIDZ. Sitta carolinensis. Gm. White-Bellied Nuthatch.* Minneapolis, Aug. 12th, 1876. (64.) Sitta carolinensis, Gm. White-Bellied Nuthatch. Minneapolis, July 24th, 1876. (65.) Sitta canadensis, L. Red-Bellied Nuthatch. Minneapolis, Aug. 16th, 1876. (66.) Not common. SYLVICOLIDZ. Mniotilla varia. Vieill. Black and White Creeper.* Minneapolis, Aug. 16th, 1876. (10.) Mniotilla varia. Vieill. Black and White Creeper. Minneapolis, Aug. 18th, 1876. (77.) Dendreea estiva. Bd. Golden Warbler. Minneapolis, May 7th, 1875. (6.) Dendreeea estiva. Bd. Golden Warbler.* Minneapolis, Aug. 16th, 1876. (7.) Dendreea estiva. Bd. Golden Warbler.* Minneapolis, Aug. 14th, 1876. (8.) Dendreeea coronata, Gray. Yellow-Rumped Warbler.¢ Minneapolis, May 15th, 1875. (9.) ’ Mniotilla varia. Vieill. Black and White Creeper. Minneapolis, Aug. 18th, 1876. (76.) 13. 14, 15. 16. 17. 18. 19. 20. 21. 22. 23. 24. 25. 26. 28 28. SURVEY OF MINNESOTA. Zao Seiurus aurocapillus. Sw. Golden-Crowned Thrush.* Minneapolis, Aug. 20th, 1876. (79.) Seiurus aurocapillus. Sw. Golden-Crowned Thrush. Minneapolis, May 15th, 1875. (4.) Seiurus novembraeinsis. Nutt. Water Thrush. Lake Minnetonka, Aug. 14th, 1876. (5.) Setophaga ruticilla. Sw. Red Start.* Minneapolis, Aug. 20th, 1876. (80.) Setophaga ruticilla. Sw. Red Start.* Minneapolis, Aug. 20th, 1876. (81.) . Setophaga ruticilla. Sw. Red Start. Minneapolis, Aug. 15th. (15.) TANAGRIDA. Pyranga rubra. Vieill. Scarlet Tanager.* Minneapolis, July 19th, 1876. (28.) HIRUNDINIDZ. Cotyle riparia. Boie. Bank Swallow.* Minneapolis, Aug. 14th, 1876. (47.) AMPELIDZ. Ampelis cedrorum. Bd. Cedar Bird.* Minneapolis, July, 1876. (25.) VIREODINZ. Vireo olivacea. L. Red-eyed Vireo.* Minneapolis, July 19th, 1876. (11.) . Vireo philidelphica. Cassin. Philidelphia Vireo. Minneapolis, Aug. 1876. (14.) | Vireo philidelphica. Cassin. Philidelphia Vireo. Minneapolis, Aug. 20th, 1876. (78.) Vireo gilva. Cass. Warbling Vireo.* Minneapolis, July 11th, 1876. (12.) Vireo flavifrons. Bd. Yellow-throated Vireo.* Minneapolis, Aug. 16th, 1876. (138.) LANIDZ. Collurio ludivicianus. Bd. Loggerhead Shrike.* Minneapolis, Aug., 1876." “(7.) Collurio ludivicianus. Bd. Loggerhead Shrike.f Minneapolis, July 20th, 1876. (2.) Collurio ludivicianus. Bd. Loggerhead Shrike. Minneapolis, 1875. (3.) 30 - 234 GEOLOGICAL AND NATURAL HISTORY FRINGILLIDA. 30. Chrysomitris tristis. Bon. Yellow Bird.f Minneapolis, Nov. 26th, 1875. (81.) 31. Chrysomitristristis. Bon. Yellow Bird.* Champlin, Minn., June 18th, 1875. (380.) 32. Plectrophanes niralis. Meyer. Snow Bunting.* Minneapolis, Nov. 30th, 1876. (88.) 33. Plectrophanes niralis. Meyer. Snow Bunting.t Minneapolis, Nov. 30th, 1876. (89.) . 34. Pocecetes gramineus. Bd. Grass Finch. Minneapolis, Aug. 16th, 1876. (35.) 35. Pocecetes gramineus. Bd. -Grass Finch. Minneapolis, Aug. 1876. (36.) 36. Spizellasocialis. Bon. Chipping Sparrow.* Minneapolis, Aug. 14th, 1876. (82.) 37. Spizella monticolor. Bd. Tree Sparrow.* Minneapolis, Oct. 9th, 1876. (84.) 38. Spizella pallida. Bon. Clay-Colored Bunting.* Minneapolis, Aug., 1876. (383.) 39. Spizellapallida. Bon. Clay-Colored Bunting.t Minneapolis, May 7th, 1875. (34.) 40. Chondestes grammaca. Bon. Lark Finch. Minneapolis, 1875. (38.) 41. Melospiza melodia. Bd. Song Sparrow.* Minneapolis, Aug. 12th, 1876. (87.) 42. Goniaphealudiviciana. Bowdich. Rose-Breasted Grosbeak.* Minnee apolis, June, 1875. (27.) 43. Coniaphealudiviciana. Bow. Rose-Breasted Grosbeak. Minneapolis, Aug. 18th, 1876. (75.) 44, Cyanospiza cyanea. Bd. Indigo Bird.* Minneapolis, July, 1876. (29.) 45. Pipilo crythrophthalmus. Vieill. Chewink.* Minneapolis, Aug. 4d, 1876. (39.) 46. Junco hyemalis. Sd. Snow Bird.* Minneapolis, Oct. 9th, 1876. (83.) IETERIDZ#. 47. Dolichonyx oryzivorus. Sw. Bobolink.* Minneapolis, July 20th, 1876. — (42.) 48. Agelzeus phoenicus. V. Red-Winged Black Bird.* Minneapolis, Aug. 4th, 1876. (41.) 49. Sturnellamagna. Sw. MeadowLark.* Minneapolis, July 18th, 1876. (40. ) 50. leterus baltimore. Daudin. Baltimore Oriole.* Minneapolis, May 22d, 1875. (21.) 51. Ieterus spurius. Bon. Orchard Oriole.* Minneapolis, 1875. (22.) 52. Ieterus spurius. Bon. Orchard Oriole.* Minneapolis, 1875. Juv. specimine. (23.) 53. &4. 61. 62. 63. SURVEY OF MINNESOTA. 235 Ieterus spurius. Bon. Orchard Oriole.t Minneapolis, July, 1876. (24.) CORVIDZ. Corvus corax. L. Raven.* (Mounted.) Minneapolis, Oct., 1876. (85.) Not common. Presented by N. Herrick, Esq. Cyanurus cristatus. Sw. Blue Jay. Minneapolis, July 20th, 1876. (45.) TYRANNIDZ. Tyrannus carolinensis. Bd. King Bird.* Minneapolis, May 14th, 1875. (20.) Contonops virens. Cab. Wood Pewee.* Minneapolis, Aug. 11th, 1876. (16.) C. virens. Cab. Wood Pewee.* Minneapolis, Aug. 15th, 1876. (17.) C. virens. Cab. Wood Pewee.t Minneapolis, Aug. 15th, 1876. (18.) C. virens. Cab. Wood Pewee. Minneapolis, July, 1876. (19.) CAPRIMULGIDZ&. Chordeiles virginianus. Bon. Night Hawk.* Minneapolis, Aug. 16th, 1876. (44.) CYPSELID 2%. Cotyle pelasgio. Bd. Chimney Swift.* Minneapolis, July 10th, 1876. (43.) ALCEDINIDZ. Cryle alcyon. Boie. Belted Kingfisher. Minneapolis, Aug. Ist, 1876. (46.) PICID 2. Picus pubescens. L. Downy Woodpecker.* Minneapolis, July, 1876. (60.) Picus pubescens. L. Downy Woodpecker.* Minneapolis, Aug. 16th, 1876. (61.) Picus pubescens. L. Downy Woodpecker.* Minneapolis, Aug. 20th, 1876. (73.) Melanerpes erythrocephalus. Sw. Red-headed Woodpecker. July 23d, 1876. (62.) Melanerpes erythrocephalus. Sw. Red-headed Woodpecker.* Minne- apolis, Aug. 28th. (71.) Colaptes auratus. Sw. Golden-winged Woodpecker. Minneapolis, April 29th, 1875. (63.) 236 70. 71. 72. Mise 74. 75. 76. 77. 78. GEOLOGICAL AND NATURAL HISTORY Colaptes auratus. Su. Golden-winged Woodpecker.* Minneapolis, Aug. 28th, 1876. (72.) : STRIGIDZ. Bubo virginianus. Wilk. Great-horned Owl.* Minneapolis, Nov., 1876. (86.) From Collection of C. L. Herrick. FALCONIDA. Falco sparverius. L. Sparrow Hawk. Minneapolis, Aug. 2, 1876. (67.) Falco sparverius. L. Sparrow Hawk. Minneapolis, Aug. 13th, 1875. (68.) Buteo borealis. Vieill. Red-tailed Hawk.* Jav. Minneapolis, July, 1876. (82.) (Mounted.) COLUMBIDZ. Ectopistes migratorius. Sw. Wild Pigeon. Minneapolis, July 11th, 1876. (58.) Ectopistes migratorius. S. Wild Pigeon. Minneapolis, July 11th, 1876. (59.) TETRAONIDZ. Bonasaumbellus. Stephens. Ruffed Grouse. Minneapolis, July, 1876. {48.) \ CHARADRUDZ. ZEgialitis vociferus. Cass. Killdeer Plover.t Minneapolis, July 22d, 1876. (57.) SCOLOPACID. Totanus solitarius. Wilson, Solitary Tattler.* Minneapolis, Aug. 17th, 1876. (55.) Totanus solitarius. Wils. Solitary Tattler.* Minneapolis, Aug. 12th, 1876. (56.) Totanus solitarius. Wils. Solitary Tattler. Minneapolis, Aug. 20th, 1876. (74.) Tringoides macularius. Gray. Spotted Sandpiper. Minneapolis, Aug. 4th, 1876. (53.) Tringoides macularius. Gray. Spotted Sandpiper.* Minneapolis, July 14th, 1876. (54.) Actiturus bartramius. Bon. Upland Plover. Minneapolis, Aug. 6th, 1875. (52.) 86. 87. 88. 89. 90. SURVEY OF MINNESOTA. 237 ARDEIDZ. Botaurus mugitans. Coues. Bittern. Minneapolis, 1875. (49.) RALLIDZE. Porzana carolina. V. Carolina Rail.¢ Minneapolis, Aug. 20th, 1876. (70.) LARIDZ. Sterna caspia. Pall. Caspian Tern. Long Lake, Nov., 1876. (87.) Rare. Collected and presented by Will. Secombe. Hydrochelidon lariformis. Coues. Black Tern. Minneapolis, July. 19th, 1876. (50.) Hydrochelidon lariformis. Coues. Black Tern, young. Minneapolis, July 19th, 1876. (51.) ANATIDZ. Bucephala clangula. Wils. Golden-Eye. Garrot. Minneapolis, Jan. 17th, 1877. Just as this proof is going to press, | have the pleasure of an- nouncing that I had the good fortune to secure for the collection two specimens of Le contes Sparrow, coturniculus lecontei, thus adding this to the very few localities of its occurrence. A more extended notice will doubtless be given hereafter. 238 GEOLOGICAT, AND NATURAL HISTORY XI. A NEW CYCLOPS. By C. L. Herrick. f Cyclops quadricornis has often been used as an object for study by those desirous of becoming familiar with the process of develop- - ment in crustacea. For this it is eminently fitted both on account of its very distinct changes and its abundance in every pond and pool. Fig. 1. There is another member of the same genus which has not, apparently, been described, and I have therefore provisionally | named it C. longicornis from the very long primary antenne. | The appearance of an ordinary individual (F%g. 1.) is not very widely different from the ordinary species. But the first glance of the female with the spherical sac of ova under the abdomen makes the creature seem quite distinct. The general appearance and its movements while swimming briskly about cause it to look like a magnified cladocera, the long SURVEY OF MINNESOTA. 939 spreading antenne increasing the similarity. The glass at once dispels the illusion however. The eggs are larger in proportion than those of guadricornis and are loosely aggregated beneath the abdomen. The cephalothorax is very large and carries the usual-complement of motory appen- dages. The first antenne are long—exceeding the body. The second pair are specialized enough to be called antenne, and the claws are, according to my observation, small though they were indistinctly seen. The abdomen is in proportion smaller than in quadricornis, and the tail similar to that of a young of that species. Of internal structure little was made out, but the red glands are as prominent asin the other. A curious case of malformation of antennez is shown in the figure. The color is transparent white, except the tips of the antenne and the last segments of the abdomen. The process of cephalization is well illustrated by the cyclops, though not as aptly as in the larger crustaceans, the Sand Fleas. A recent observation of a number of diatoms dipped from the bottom of the deeper portion of Lake Calhoun, seems to prove that one species is clothed with cilia throughout, and not simply at the ends as usually described. While watching the motions of a Navicula-like plant propelling itself slowly along it was seen to col- lide with a large mass of vegetable matter, and while thus brought to a stand-still the infinitesimal particles floating near it were seen to traverse its whole length, the diatom and particles beyond reach of its influence remaining motionless in the meantime. This specimen was of sufficient length to preclude the possibility of the cilia at the ends having any influence upon the particles. Other Collections. Besides the Moose mentioned in the report of last year, the fol- lowing mounted mammals are on exhibition: Antileapra Americana. Ord. Pronghorn Antelope. 2 male and 2 female. Custer Expedition to the Black Hills. 1874. 240 GEOLOGICAL AND NATURAL HISTORY Corvus Canadensis. Exl. American Elk. Custer Expedition to the Black Hills. 1874. Badger. Custer Expedition to the Black Hills. 1874. Ursus horribilis. Ord. Grizzly Bear, female. Custer Expedition to the Black Hills. 1874. Corvus lencurus. Doug. White-Tailed Deer; 1 male, 2 females: Cus. | Ex. Blk. Hills. 1874. Rangifer Caribou. And. and Bach. Woodland Caribou (unmounted. ) Presented Dec., 1875, by Nathan Butler. Seiurus hudsonius. Pall. Red Squirrel. Three specimens. Tamius striatus. Bd. Chipmunk. Spermophilus tridecemlineatus. Mitch. Striped Gopher. Hesperomys michiganensis. Wag. Michigan Mouse. Procyon lotot. Ston. Common Raccoon. Reptiles. Pana catesbiana. Shaw. Bull Frog. Amblystoma tigrinum. Bd. (Immature.) Common Salamander. Eutaenia radix. Bd. & Gir. Garter snake. ‘Skeletons Mounted. Podilymbus podiceps. Lawr. Pied-billed Grebe. Botaurus mugitans. Bart. Bittern. rN Ee (S77 APPENDIX B. ; MICROSCOPIC ENTOMOSTRACA, - BY C. L. HERRICK, Laboratory Assistant. New Haven, JANuARY 8, 1879. Prof. N. H. Winchell: Dear Sir: I have examined the chapter by Mr. Herrick, which you placed in my hands, and think it a valuable contribution to science. It will make a very appropriate addition, it appears to me, to the Minnesota State Report, because of its illustrating with well-drawn figures and good descriptions the life of the fresh water of the State. The species are among the most interesting of the minuter animals of the waters, and have a wide distribution over the globe. Yours truly, JAMES D. DANA. MINNEAPOLIS, Minn., JANuARY 14, 1879. Gen. H. H. Sibley, President of the Board of Regents: I herewith communicate to the Regents an illustrated memoir on the micro- scopic crustaceans of fresh waters of Minnesota, as a contribution on the Natural History of the State, in accordance with law. This valuable paper, by Mr. C. L. Herrick, my laboratory assistant, has cost the Survey nothing more than the use of its rooms and apparatus, and has been submitted to the approval of Prof. J. D, Dana of New Haven, who indorses it as a valuable contribution to science, and recommends its publication. Very respectfully, N. H. WINCHELL. PREFACE. It is with the hope that the following paper may be of service to some who, like myself, were interested in the many and varied forms found in every stag- nant pool as well as in the lakes and ponds of our country, but who were unable to find any connected account of them, that it is offered to such, as a contribution toward a better understanding of a little known order of the natural kingdoms. The lakes within a radius of ten miles of Minneapolis have furnished all the material examined, and the supply is not exhausted by any means. It is only hoped to so outline the extent and limits of this division of animal life that it will be less difficult to place the forms found from time to time, in approximately their true position. With very few exceptions, as far as has been ascertained, no one has devoted any attention to the fresh water Entomostraca of America, and it is necessary for some one to act as a pioneer, to learn whether any of the forms described in Europe appear here, and to discover, if possible, if there be a general similarity between these widely separated faunz. This has been the ambition of the pres- ent writer; and if only an intelligent attention be directed to this field, he will feel abundantly repaid for the attempt. The works consulted were Dana’s ‘‘ Report of the Crustaceans collected during the Wilkes Exploring Expedition to the Pacific Ocean’’, Dr. W. Baird’s ‘‘ Brit- ish Entomostraca,”’ ‘‘ Report of U.S. Fish Commission,’’ papers in ‘‘ Hayden’s Survey of the Territories’’, and papers in the American Naturalist and other peri- odicals. Many thanks are due to Prof. N. H. Winchell, director of the State Geological Survey, for assistance and advice in many ways; to President W. W. Folwell, and Dr. P. L. Hatch, for assistance and intelligent sympathy, and to fellow members of the ‘‘ Naturalist’s Club.”’ That there will be found mistakes in the work is to be expected, butit is hoped that the information will be reliable in the main. It is not without hesitation that, as a novice in scientific investigation, names are suggested for the new species found, but the purpose of this paper will be best served by defining as well as possible these forms, and submitting them to the test of further study; and if in the future more experience and greater research can be brought to bear upon this domain, these preliminary notes will perhaps not be without their value. The drawings were all made by the writer, in most cases from life, though some details have been introduced from the works con- sulted, and the plate of Phyllopoda was collected from the government reports ‘and elsewhere. Clearness in outline and detail rather than beauty in execution was the desideratum. C. L. HERRICK. §4 ANNUAL REPORT. INTRODUCTION. ENTOMOSTRACA. The name was derived from two Greek words meaning insect and shell, by Otho F. Muller, and applied by him in his ‘‘ Entomostraca’’ (1785) to the animals which had hitherto been all comprised in Jinnzeus’ genus Monoculus, named from the supposition that they all possessed but one eye. The name ‘* Branchi- podes’’ was also proposed, «nd would have been appropriate enough, but Muller supposed that the branchial appendages which suggested the name, were want- ing in Cythere, etc. Muller, aside from naming the group, was the first to. arrange these animals in anything like a systematic classification, and collected a. great deal of interesting information. Since his time several authors have writ- ten upon these interesting animals in Europe, but with a few exceptions no sys- tematic work on Entomostraca has appeared in English. Dr. W. Baird published in 1850 a superb work on the Entomostraca of Great Britain. which is still the best thing in the English language. But since this work was published, many additions have been made to our knowledge. In Prof. J. D. Dana’s magnificent work on the Crustacea foundin the ‘‘ Wilkes Exploring Expedition’’, many new species are described, and a revised classifica- tion tor the whole order is proposed. In this work every known genus was char- acterized. Since then additions of new species have been published by various authors, and are scattered through the reports of various societies. Moreover, recent studies in Embryology have thrown new light on the classification of all the lower animals, and many changes are necessary, but it is not possible at this stage of the study to attempt a SYSTEMATIC ARRANGEMENT of this order. We shall follow quite closely Dana’s system as being most com- plete. The following changes, which will not affect essentially the nomenclature used must be indicated as the necessary result of modern research: 1. The Merostomata, or King Crab group, which contains the modern genus Limulus (Horseshoe Crab) and the ancient Eurypteride, etc., which was con- sidered by Dana a sub-order of Entomostraca has by recent writers been regarded as a distinct order intermediate between the TJvilobita (which Dana included with the sub-classes Chorestopoda and Entromostraca in the class Edriophthalmia or Tetradecapoda) and the Hntomostraca. Trilobita now stands at the foot of the sub-kingdom, its inferiority in rank being assumed from the inferiority in point of time. The Cormostomata (including Pecilopoda or Epizoa) has been united with Copepoda (Cyclopacea) thus doing away with the sub-orders in Entomostraca. STATE GEOLOGIST. 85 The Pectostraca (including Phizocephala and cirripeda (barnacles) have been assigned a place among the Entomostraca from facts learned regarding their development. These crustaceans have been tossed from one division to another till they ought, it would seem, to find a permanent resting place. First consid- ered mollusks, they have now taken their position among the lower crustaceans. These creatures, which are at maturity firmly cemented to foreign bodies, and are inclosed in a hard shell-like test have, in their earlier stages, forms resembling the ‘‘Nauplis’’ stage of Cylops (see plate III,) and also a stage resembling the mature Cypris. It is now known that, as Huxley expresses it, ‘‘ the barnacle is a crustacean fixed by its head and kicking its food into its mouth.” The attachment of the head finds a »varallel in the genus Sida (see beyond), which contains animals that can attach themselves at will to bodies by a sucker-like disk on the head, corres- ponding to the pedicle of the barnacles. As the barnacles and epizoa have not been observed no further mention will be made of them in this connection. The following table from Huxley’s Anatomy of Invertebrates will perhaps be useful for reference. (Articulates or) ARTHROPODA, i A Without manducatory appendages (Gnathites) Trilobata. Tardigrada ( ?) Pentastomida( ?) Iie With pediform gnathites. Merostomata. Arachnida. Peripatidea. III. With maxilliform gnathites. Entomostraca. Myriapoda. Malacostraca. Insecta. EE US ———_- Water-breathers. Air-breathers. \ dl For the most part. The extent of the Entomostraca has been outlined above, and the Malacostraca includes the remainder of the crustaceans, viz: those included by Dana under Podophthalmia and the order Choristopoda of Edriophthalmia, thus embracing crabs, shrimps and all the higher crustaceans, whose body consists (almost always) of twenty segments (somnites) of which six constitute the head, and bear, respect- ively, the eyes, superior antenne, inferior antenne, mandibles, and two pair of maxille. Of the remaining somnites eight pertain to the thorax, and carry the foot jaws and walking limbs, while six are abdominal and bear swimming limbs. These higher forms do not go through the Nauplius stage in their development, as do the Entomostraca. 86 ANNUAL REPORT. GENERA CHARACTERS OF ENTOMOSTRACA. The Crustaceans of this order are quite various in form, habits and internal structure. They possess specialized jaws, but there are never more than three pairs of qualities, while in the higher orders there are often six. The somnites of the abdomen (that portion of the body posterior to the wonitale aperture) are devoid of appendages. Though the study of these animals is very fascinating and instructive the task is a difficult one, both on account of the minute size of most of them and the great difficulty of ascertaming with what organs of the higher forms some of the novel instruments seen are homologous. The curious misapprehensions and inaccuracies into which authors have fallen still further complicates the matter. The descriptions of these organs, and their functions, must be taken up under the divisions of the order and treated separately. The process of reproductien is particularly interesting in this group, for we have numerous instances of agamogenesis and the Pectostraca are hermaphrodites peculiarly modified Al- ternate generation will be spoken of more particularly under the Daphnioidea. The species described have all been collected and compared with descriptions of previous authors, the new species, it is hoped, will be found sufficiently well defined in connection with the figures given to permit of a ready identification. . The following table of the families of the order will be useful for reference, while the characters upon which they are founded, and synonyms, will be found in their appropriate places. TABULAR VIEW OF ENTOMOSTRACA. ORDER ENTOMOSTRACA. LEGION I. LOPHYROPODA. TRIBE I. CYCLOPOIDEA (here used as equal to Copepoda with the Pecilopoda among he Cormostomata (or E’pizoa.) Family 1. Calanide. Family 2. Cyclopide. Family 3. Corycaide. Epizoa? TRIBE II. DAPHNIOID&. (Cladocera.) Family 1. Penilide. Family 2. Daphnide. Family 3. Bosminide. Family 4. Polyphemide. TRIBE III. CYPRIDA. Family 1. Cypride. Sub-family a. Cyprine. (Cypride Bd.) Sub-family b. Cythrine. (Cythride Bd.) Family 2. Halocypride. Sub-family a. Cypridinine. (Cypridinade Bd.) Sub-family b. Halocyprine. STATE GEOLOGIST. 87 LEGION II. PHYLLOPODA. TRIBE I. ARTEMIOIDEBA. Family 1. Artemiade. (Branchipodide.) Family 2. Nebaliode. TRIBE II. APODIDA. Family 1. Apodide. TRIBE III. are nie Family 1. Limnadide. Note—Other genera have been added to those given by Dana, and changes made. The family Estheriade seems, however, to be equivalent to Limnadide. LEGION I. LOPHYROPODA. Bibliography.—Lophyropa, Latreille, Cuv. Regne An., 1677; Lophyropoda (in part), Leach, Dict. Sci. Nat., XIV., 554. —_—— ——— Gray, Cat. Brit. Crust. Brit. Mus.,. 1850, } 100. * : ———— Baird Brit, Entomost., 138. Cranchiopodes franges (in part), Lamark, Hist. Ans. Vert. Characters.—Feet normal and not greatly multiplied in number. TRIBE I. CYCLOPOIDEA. Bibliography .—Carcinoida (in part), Latreille. Copepodes, Edwards, Crust., iii., 411. Copepoda, Baird, Trans. Berw. Club, ii., 1875. — Baird, Brit. Entomost., 182. Cophyropoda, Burmeister, Organiz. of Trilobites. Copepodita, Gray, Cat. Brit. Crust. Brit. Mus., 1850. Crustacea copepoda (Cyclopacea), Dana, Proc. Ardes. Acad. Sci. and Art., 1847. Cyclopoidea, Dana, Rep. Wilkes’ Exp. Ex., p. 1020. Characters.—Body elongate, straight, never incurved. Cephalothorax and abdomen with few joints. Feet and jaws 16 to 18. The 6-10 posterior thoracic feet are double, foliacecus, with the last often prehensile. This is a very extensive and widely distributed division, and there is a greater unity of plan seen in the structure of the animals comprised in it than in other divisions of similar importance. These creatures are distributed over the world, in both fresh and salt water, and the numbers may doubtless be reckoned by thousands, but little attention has been devoted to the subject, and our knowl- edge is quite meagre. | 88 ANNUAL REPORT. The Cyclopoidea are considered the highest group in the order, approaching the Macroural Crustaceans. The body is not covered by a carapace, as in the following tribes, and the abdomen is extended in the same line as the body, and not incurved as in Daphnioidea, etc. The abdomen is terminated by two stylets which bear several sete. If the Epizoa are to be admitted into this tribe, certain modifications would be necessary, which we need not discuss. The cephalothorax is composed of from four to seven segments. In those spe- cies having four segments, the first bears the first and second antenne, mandi- bles, maxille, maxillipods, first feet and one pair of natatorial feet, while the — following three carry the remaining pairs of natatores. Eyes of the three kinds: 1. A pair of simple internal eyes with spherical lenses, which are the ordinary kind. These are usually united near the front in a single very small spot, though they are sometimes remote. 2. A pair in an elevation on the under side of the head between the antenne. The pigment is often like a piece of solid indigo. 3. >, PLATE II. Diaptomus pallidus, Herrick.—Back view of female. (In this plate the antenne are represented far too short.) @, maxilliped. 8, fifth pair of feet. c,. extremity of male antenne. a, extremity of female antenne. : . The Geological and Natural History Survey of Minnesota. MICROSCOPIC ENTOMOSTRACA. SS Sess SSS 19 6 = = ae SS Bp On ; i, \\ \ N i ———S = => ==> , sania! = = eT yore Ene. Co NY, C.L HERRICK. Del, Plate II. USe eees ee a eee PLATE III. Cyclops quadricornis, Linn.—1, mature female with egg sacks containing ova. a, egg. 6b, young just born. c, young eight days old. d, young fifteen days old. c, young seventeen days old. a’, mandible. 0’, first pair of foot jaws. 2, side view of mature cyclops. ge : i The Geological and Natural History Survey ta. \ nneso CLHERRICK Lal. of Mi q q “A 3 wy \ / M 7 (©) MY f 0 =| AY pn 3 lee if a | N A — 6) N i 2 EH ) as: fe) at Oo mM (@) 04 ; Paoro Eve. CoN PLATE IV. ~ eas — Cyclops quadricornis, Var ?—a, last pair of BP ae antenne. 5 3 { . > ° % : } . f b ’ i , % : CLMesKich, Det — Se IW \\ Bests 23 CA := Zz ; SY SS Plate IV. aS | aaa a eee ee ene a ——— ——— - ; * : The Geological and Natural History Survey of Minnesota. o MICROSCOPIC ENTOMOSTRACA TE — LT $e PLATE V. a, Canthocumptus minutus, var. occidentalis, Herrick, male. b, do., side view. ec, young, or Nauplius. d, underview of head of male. e. external ovary and appendage of female. Jf, antenna of male. g, antenne of female. i, foot of first pair. k, appendage to abdomen of female. (Fifth pair of feet.) h, foot of second pair. The Geological and Natural History Survey of Minnesota. MICROSCOPIC ENTOMOSTRACA. 7 OL Herrick Dev. PLATE VI. Sida crystallina, Straus. a,b, ¢, feet of first, second and e, extremity of abdomen. /, superior antenne. ee, 1 iz ie ’ The Geological and Natural History Survey of Minnesota. MICROSCOPIC ENTOMOSTRACA. LAA \ Wl ) \ | Wy = = FPuora Ene..Co NY Plate; VI; CLvereicx: Del, 1, Daphnia reticulata. a, superior antenne, , heart. ; fi 2. Sida erystallina. a, head. Ci ea The Geological and Natural History Survey of Minnesota. MICROSCOPIC ENTOMOSTRACA. Ys = YO! y ee (i li i {i ah J Yj Z SESW SS © —- ~—— \ SR : aX \ / CL Sernick, Del Plate VII. — Nh sey ie Sesh = pees of Minnesota. H | | The Geological and Natural History Survey AGin long. \\ MICROSCOPIC ENTOMOSTRACA. S\N \ WW \ C.L HERRICK Del: DA i wy \. \ AyZ LA (Ye yV/ \ 4 ; | $2 ; Va si WETS Lis YiieZ Mf JZ es ENC ff, CE ZZ RY SNS SN WY es ae a AS . Sian SINE, 2S fo PoP ETE g Lew Ny é \ : WAV jy Leh bhi, My Zwiy Pee ? x y ani } LESS Y ON Hy es : FANNIN UN Z NOD y ZZ => —— a ETS IE z - 4 : rea eases “ = ~ - oa — FPuorto Enc. Ca MY Mates VIP. ga b } | : e * : at, : ~ res : F ps > * ‘ oe , e z “A E i a] -, ee o s . s is : es ge = 7 ete ee s . Se - : ny t fe eet 4 3 + ‘ee. PLATE IX. Fig. 1. Head of Daphnia Scheefferi showing alimentary apparatus etc., antenne removed. a, heart. b, stomach. c, ceecum. 4d, superior antenne- e, eye. f, labrum. g, jaw. A, B, C, D, E, one of each pair of feet. Fig. 2. Superior antennz. Fig. 3. Posterior portion of body. _ The Geological and Natural History Survey of Minnesota MICROSCOPIC ENTOMOSTRACA. ““ , ly Ye ij i} ~ Hl re ( (((i il | Fuoro Eve. lo MY CLAERRICKDEDL. Plate: TX. PLATE X. Daphnia vetula.—1, under view. 2, side view. 3, young extracted from egg. a, one of the set from the antenne. 0b, jaw. of the superior antenne. d, end of abdomen. c, base of the two rami The Geological and Natural History Survey of Minnesota. | MICROSCOPIC ENTOMOSTRACA. y) yO —_ SSS \? X | fy070 ENG. Co NY. CL HeRNICK oF, Plate X. es a. ‘4. _ The Geological and Natural History Survey of Minnesota. MICROSCOPIC ENTOMOSTRACA. SSS SS Si SSS jes ERI NN SSN nT SASS : oe S ”~ a {a 1 oe a i \ iM ee he Vt iy 7 . | ey i", | Ses | 7 Ve i Ag ‘z i Y 1a va a Hat) > } me , 3 “ EN ‘ . i. é j Ny i bt ) Macrothrix agilis, Herrick. Two views. a, tail spine, ) PLATE XIV. The Geological and Natural History Survey of Minnesota. MICROSCOPIC ENTOMOSTRACA. { i L Ax070 Lug Co NY CL HERRICK Del, ee late 6 TY. _ PLATE XV. 1, Lynceus macrourus, Muller. a, abdomen. 2, Lynceus quadrangularis, Muller. ; a, beak. 6, jaws. c, end of antenne. 1 hd t .» i , . ‘ \ ey : A > é « f F * %, F 3 E Baa ., «A a in r EGA 1, "a The Geological and Natural History Survey of Minnesota. | MICROSCOPIC ENTOMOSTRACA. ERR SOROS PERSE AY Ne CSE 6 gi eda = LE AV 40 G75 y YG, p> A ni y A ] CZ RERRICK Det; Plato ON. PLATE XVL 1, Bosmina longirostris. a, portion of shell 4 superior ai 2, Lynceus sp.2 — es le THR RSS oS . SELES Ss i sy : PR $ Uy << SL . ih ISG YW SSH : J ~~ SY Lye A> = SS 3 TA — LL ees Plate XVI. The Geological and Natural History Survey of Minnesota. — MICROSCOPIC ENTOMOSTRACA. CL HERRICK Del, fF Se re ees wag ee _ PLATE XVII. 1. Cypris vidua, Muller. oe —— top view. 2. .Cypris neglecta, Herrick. a, testicle. b, maxilla. MICROSCOPIC ENTOMOSTRACA. ) Sa j i SN a age Sra Lo Gaz er ZZ az 2 CL HERRICK, Bel, Plate XVII. PLATE XVII. Chirocephalus diaphanus. a, head of female, b, head of removed. c, head of male. d, appendage of claspers. and Natural History Survey of Minnesota. MICROSCOPIC ENTOMOSTRACA. The Geological SEB ae YB => tae Uhh EE L WNITIEF fazors 24h ye FE /kgizrs: WU, AY “1, ET LLL Lp LE 2 Un « : SN AA = Ey B Be hs Hi \\ SS So Sau Y} Se _ | S\N Saw SS CERT XK AW GG \ = CLMERRICK Le, a | Of ae z Deere £w6.Co NY . Plate XVIII fee petite Se ees OS tit PLATE XIX. rs x 4 A . \ | | | Streptocephalus, Artemia, Apus, Estheria and ta UnNeSsO ‘ of M | Histor d Natura Geolog y Survey MICROSCOPIC ENTOMOSTRACA. ical an OLAERRICK Del» SS & Plate XIX. tigies PLATE XX. Candona elongata. 2a, testicle? 2 The Geological and Natural History Survey of Minnesota. Wp Linn if A, af, LUT ppp —§$<— Lye y), tp —— oe CL.HeERRICK. Del Plate XX. ¥ > i, “*) a, VF me: x PLATE XX: . 3 1. Daphnella Winchelli. 1a Embryo. 2. Side view of same. f 3. Polyphemus occidentalis. 3a, 1st pair of feet. 3b, 3d pair. 4. Eurycercus lemellatus? 4a. foot. 4b. jaw. , ¥ : ' , ' 7 . * . j * , " 4 . ae ’ F , . b - # Ki c ' \ c /. s ? ; . - s é. + ‘ s . . ri j ' p “hy ¥ i oe } i? > ‘ } i * 7 I 4 \ § Ay 4 4 / > ee ’ ( ‘ ak Hig [2 | ae, ina ~ S The Geological and Natural History Survey of Minnesota, - : MICROSCOPIC ENTOMOSTRACA. [ Pes if = p 4 - ) ; id} AVS \ ‘ i k f : / \ Hf / Vi iy, v4, 1 YH, 7 : Plate x * INDEX TO THE GEOLOGICAL REPORT. | PAGE been ERSTE HRC RIG CI 4a oie «/c.0i6 aie (ste) © Severn 6s selevais sie de a fo oe abs ae 4 leet 5 IE EER RT OR TE OIMOS UE ACA cai) 5) 65 eo 921s) ciate «! ef wi sn/eis.olo 4 = Hs daiwa o's se a'e so eco oe 121 ‘Agricultural value of Northeastern Minnesota. ...........-.0.ee eee e acces 25 SMM RMRT PEP ARTRGEY OLE loli stcie arclade sire dis ava vio <'ole' a Sie aiejoie a's 6 40'S dw a cleie y acai 22, 28 RUM OLET OCS Se i alae oct oe! «ix chay So the via 'v als. c c'biein. léieleln'se, 54,6 00a os Sea dle’ 33 RINE NELUCITNITOE 1 aslo aS neni iee) cis w o>: ae, eia' s/o) sie visio sive @ 5 BRAG h 6 sb 8 seo 19 Appeddix A. Instructions of Executrve Committee...................... 79 eerie ty-4, Microscopic Hntomostraca. -. 2 = . 6... sek aie cae ceen ce eeednes 81 PE PANTER OSES TOTITIARION nia 0, 12) ia s) 4)5 Avie e's 2's dic a's eases a'e sean h feman se 5 14 Bee macrattia ne red SulOCATON:. «1626 <0. 50nc cece ceseas Gener cc belne eed eee. 16 i Botany; report.of Mr. B. Juni......... EL AIE SEU y Btip = CC SOA rE 30 eamremariOn Wr ko Wy, Match «2+ 0% 0 icc sss 0s.e ese cece aaieniede eaae ee as 34 PLE GLP TRB ines, AR Be enc a oe ee 30 Maimorie OF SPECIMENS TEZISLETED.- 2... 620 cedecscce case ceeds cece cuscens 49 PEemeny LCDOLL OF Eror, Peckham: 2... sce oie «00's sae eiea's else cic csia ee we a2 Seema) Ey ClOVALIONS Dis c< cist esc oS ose lielsg 4 os a acne acne ae 30 RPE SIT ONE TSEASON OL OIG: <<< -'s 5 = less am «ia ats reise wees dimes ein wlniee'e es AT OS PI Serene ca Sin tat cvs Tal ch « wso, orci = 5:0, « retoNe 4) eo eth 32 Pime, wanton destruction Of... 0.00. seis seo sone cee ss sian geen 24 Plants, list of on the north shore of Lake Superior..... ..-..-eeseeeeeeees 36 Plants, species identified néar the University............... +. «epee ~ 45 Ouarizose cConmlomerate ces. \/ group but is a very divergent member of it, worthy, probably, of form- ing a distinct section or sub-family. The most remarkable feature is one which appears in a comparatively early embryonic period and, in __ some Gases, nearly disappears in later life This is the development of — along spine from the dorsal, posterior end of the shell. Thisisthe real diagnostic test and has not yet been incorporated into the defini- | tion of the genus The occurrence of a crista is more variable ap- parently, but may be of some importance. The following is suggested as a revision of the diagnosis: Shell more or less oval or sub-quadrate and reticulate; head rounded anteriorly, but sometimes with a crest, prolonged below into a beak which is truncate posteriorly and bears the antenne near the apex; upper dorsal corner of shell in young of both sexes and mature males prolonged into a long spine; the macula nigra is present but not always pigmented; the post-abdomen spined behind; opening of rectum at the end. The female with two age-forms (heterogenetic and dimorphic); the second form frequently scarcely spined; antenne small, not movable,. furnished with sense-hairs; ephippium with two ova, separable from remainder of shell along the latero-median suture; the brood-cavity closed by more than two unequal processes of the abdomen. Male with long movable (almost two-joimted) antenne furnished with prehensile stylus; first foot bearing a curved claw; swimming an- tenn very long; vas deferens opening at the end of post-abdomen. Embryo with second antennz palpate; a curved appendage to shell which becomes the spine of adult. DAPHNIA PULEX. This species is mentioned here simply to remark concerning D. pulex, var denticulata of Birge, (Notes on Cladocera, p. 11, plate I, fig. 11,) that the European as well as all the American specimens of D. pulex, have a fine series of spines on the claws of the post-abdomen. A glance at Tafel XII, fig. 39, of the Zeitschrift fiir Wiss. Zool. Bd: XXXIII, with Weismann’s plate of the end of the abdomen of this species, is sufficient evidence of this fact, though as the animal is a male and quite young, the spines are less evident; moreover the number of caudal teeth is known to be variable with age. Some other peculiarity must be found to give this varietal distinction validity. STATE GEOLOGIST. 239 DAPHNIA sp? (Plate X, figs. 15-16). _ From acold marsh a gathering in June, 1882, contained several fe_ males like that represented by fig. 16. They were far from being abundant, however, and the pool contained no other Daphnia showing that it was unfavorable to the growth of these animals. These females differ from D. pulex chiefly in their small size, (1% em.) | being the smallest Daphnia seen with an evidently mature appearance. The caudal spine is sickle-shaped; post-abdomen as in pulex; antenne short; the animal beautifully clear and varigated by the brilliant con- tents of ovary, eggs and intestine. I hesitate to regard it as a destinct species. Figure 15 represents a single specimen of Daphnia found with the above which was somewhat injured during its moult. This resembles D. apicata, Kurz, and D. pellucida, Miiller, and is perhaps the male of the species represented by fig. 16. Our knowledge of the variations induced by environment is yet too meager to draw up definitions of _ species with certainty from a single gathering, but these forms are pe- | culiarly interesting. _ See also the accompanying figure, (fig. +,). These forms merit closer study. : % \\ < Wa N SS SEs BA YS 4) N \N y \Y 1) ) I W999). Nn LT) DSSS Fig. 4. Daphnia longispina (numbered 1) ete. os No riage eal ie t STATE GEOLOGIST. —s- pee 2 SCAPHOLEBERIS, Schédler. be na former paper S. mucronata was reported from this locality with mark that only the unhorned variety seems to occur here. A diligent search has failed to find var. fronte cornuto, though our —\ y Ny | \ SS & sey 3} Ah SSS \\\\ WSS —Seeaehey i ae : \= a CL. NerReice Del) | Provo Eng.Ca. W.¥. Fig. 5. .Scapholeberis mucronata. | BovAg STATE GEOLOGIST. 243 A second variety or species has been found which differs somewhat | from typical mucronata, but does not appear to be nasuta of Birge. Is : not the latter a variety simply ? SCAPHOLEBERIS ARMATA vVar.? nov. ;.. Length 575-735 cm.; much as §. mucronata in form; but the spines are _ greatly elongated in old as well as young individuals; and in individuals having winter as well as summer eggs, though the winter form seems _ to have longer spines which are nearly equal in some cases to the hight. Antenne are short and transparent. The head is separated from the body by a marked depression; but is curved forward so that ! the beak lies generally between the valves. The antennules are of medium size. Nowhere reticulate (?) nor tuberculate. The shell is marked by impressed lines, especially anteriorly and below. The lower _ margin is straight and beaded anteriorly, but toward the base of the _ mucro are several long bristles which stop abruptly and are followed by a few very weak hairs. The post-abdomen has three teeth at the base _of the claws, which are smooth. _ This variety is much like S. nasuta of Birge, noche but differs per- ceptably in several points. Most conspicuous are the greatly elongated spines and the short antenne. This variety is about as large as mucronata but less than nasuta. BOSMINIDZ:. Genus BOSMINA. First antennez many-jointed; intestine straight. Sole genus of the _ family, and one which Kurz characterizes as “‘ one of the most difficult of the genera of Cladocera.”’ There are three species known in the United States, two of which are found from the Eastern States to the Mississippi and westward, and are*identical with European forms. The third may not prove distinct. BOSMINA LONGIROSTRIS. (Plate X, fig. 2.) Differs from the following in having the terminal claws not toothed, and from B. striata in the shorter antenne and reticulate shell. 244 TENTH ANNUAL REPORT BOSMINA CORNUTA. (Plate IX, figs. 8-5.). 35) em. long; shell reticulate with hexagonal meshes; antennz curved backward and outward at the tip; claws with several teeth near the base. In embryonic specimens the antenne are straight, 4 BOSMINA STRIATA, Sp. n. (Plate IX, fig. 1). 1359 em. long; shell marked with anastomosing longitudinal strie; antenne very long; frontal seta about midway between eye and the sense-hairs of the antenne: posterior inferior angle of shell spined as in the previous species. The species resembles B. maritima greatly. The members of this genus have been little studied owing to their small size and compara- tive rarity, and it is even possible that some of the species will prove invalid- Be All three of the above species were found in one gathering from Lake Minnetonka. Only one eee (for B. longirostris) is known to me in this State. LYNCODAPHNIDZ. Genus MACROTHRIX. Aside from M. roseus and M. tenuicornis (to which, perhaps, M. agilis of a previous report may be referred) a single species of macrothroid | crustacean was collected at Lake Minnetonka, which is very remarka- ble. The specimen was apparently somewhat injured in moulting, and it is not possible to tell how much of its peculiar shape may be due to this. fact, but some of its characters are sufficient evidence that it consti- tutes at least a new species. It resembles in outline Simocephalus vetulus; the antenne are very narrow and curved in a lateral as well as posterior direction; the second or swimming-antenne are long as in other members of the genus; macula nigra present but small; eye small; post-abdomen short, triangular; claws pectinate; a dorsal sucking-dise is present; STATE GEOLOGIST. 945 Tength em. For this species the name MACROTHRIX PAUPER is pro yisionally offered. (Plate VIII, fig. 1.) MACROTHRIX TENUICORNIS, Kurz. (Fie. 6.) _ The description given by Kurz is very full and agrees very well. The _ peculiar arrangement of the movable spines at the margin of the valves is characteristic. I have observed that this species forms an ephippium. Miiller says destinctly of the series of genera including ie Macrothriz, Drepanothrix, Lathonura, Bosmina, Acantholebris and Iliocryptus, ‘‘ Testae abjecte corporis, nullo ephippio, ova hiberna obtegunt.”’ Bosmina is little related to the Lyncodaphnide and, however it may | 4 be with regard to other species, in M. tenuicornis an evident ephippium _ is formed in much the same way as in Ceriodaphnia. In Daphnia this - egg-cover is produced by an alteration of part of the inner layer of the shell which becomes turgid and secretes a thick coating. The _ ephippium simply extends over the brood-cavity, being marked off ' from the rest of the shell by the median suture of the valves. In | other Daphnide and in Macrothriz nearly the whole of the valves are - thus modified. The shell of M. tenuicornis is normally smooth, but in the ephippia] female, that portion of the inner layer of the shell 246 TENTH ANNUAL REPORT bordering the egg-cavity and a little beyond, is composed of large and very deep cells; the space between the outer and inner layers is much — greater than in Daphnia. Genus LATHONURA. Although no species of this genus has been found in Minnesota, it is to be expected that it will eventually be discovered that the | cosmopolite L. rectirostris, Mill. occurs in our limits. It occurs in Mass. according to Birge. The figures (Plate VIII, figs. 11-12) - were drawn from specimens found in Leipzig, Saxony, illustrating a — tendency, especially common in the Lyncodaphinde, to abnormal — growth of the spinous appendages—in this case the anal sete. ! Genus ILIOCRYPTUS. A genus represented by a single European species. Our form may differ somewhat in some respects from the generic diagnosis, but certainly belongs here. There are no anterior cceca (as indeed there are probably not in the European J. sordidus though so stated by Miiller,) and no permanent ccecum or dilation of the intestine before the rectum. The marginal spines are straight, long and movable with- out branches. ILIOCRYPTUS SPINIFER sp. noy. § (Plate VIII, figs. 2-6.) Short; depth nearly equaling length of body excluding head; rounded behind; free edges of valves beset with slender ciliate spines which are | not branched; antenne exactly as those of J. sordidus, as is the post- | abdomen, save that the anus seems to be situated higher; ova three or more. | This species occurs in Silver lake, east of Minneapolis. It swims | quite well, while of the European species it is said this is not the case. _ It does, however, frequently load itself with filth so as to be too heavy — to swim freely. : STATE GEOLOGIST. Q47 LYNCODAPHNIA, Gen. n. (Plate IX, figs. 1-3.) Form much as is species of Alonella, etc., truncate behind; superior antenne like Macrothrix, attached movably to the end of a blunt prominence beneath the head; second or swimming antenne slender; four-jointed ramus with three long setze at the end of terminal joint where is also a stout spine; joint following the basal joint also with a spine above; middle joint unarmed (?); three-jointed ramus as in Ma- crothrix; the basal segment armed with a much elongated seta; eye rel- atively small; pigment fleck present; intestine twice-convoluted, ex- panded in front of colon, opening in the ‘‘heel’’ of the post-abdomen , post-abdomen slender, sub-triangular, margined behind with a double series of spines; terminal claws large, straightish and furnished with a long and short spine near the’ base, also very minutely feathered be- hind; shell marked alone by the so-called ‘‘stuzbalkein ;’’ lower margin with movable spines. ; Few more interesting forms have been noticed than this, since it combines the characters which have hitherto been considered as very clearly forming the boundaries of distinct familes. Kurz says, (Dodekas neuer Cladoceren nebst einer kurzen Uebersicht der Cladocerenfauna Bohmens, p. 30:) “Keine Cladocerenfamilie bildet eine so streng in sich abgegrenztes natiirliches ganze, wie eben die Lyn- ceiden,” and this even after recognizing the relationship of Macrothrix and Lithonura to the Lynceids by placing them in the sub-family Lyn- codaphnie. The form for which I propose the name Lyncodaphnia is quite as much like such forms as Alona: and related Lynceids, as any species of the Lyncodaphnine, while at the same time the characters of antenne and head are almost identical with Macrothrix. This furnishes but another example of the fact that possibility of distinguishing families and genera lies alone in the meagerness of our knowledge. | LYNCODAPHNIA MACROTHROIDES, Sp. Nl. 9° Form sub-rectangular, greatly elongated; length 12, em., hight 1°) em. or less; first antenne long and slightly curved, bordered be- hind by about ten spines and terminating in two unequal sword-shaped spines and several sense-hairs, about ;}7, cm. long; swimming an- tenne very slender as in Macrothria, ,}) m. long; head not marked off by a depression from the body, small and extending below into a blunt elevation for attachment of antenne; labrum rather large; eye 248 TENTH ANNUAL REPORT small; macula nigra conspicuous but not large; anterior feet strongly armed with curved spines. The intestine anteriorly is furnished with © ceca, is twice convoluted, broadened before entering the rectum and — opens a little distance beyond the oval seta in the heel of the post-ab- domen; post-abdomen rather slender, toothed behind with a double series of about twelve prominences, becoming distally sharp, strong | teeth; terminal claws curved at the end only, pectinate and bearing two unequal but large PrOpeSscs RUBE the base; eggs much like those of Macrothrix. Occurs in Lake Minnetonka, Hennepin Co., Minnesota, rare. LYNCHIDA. But few of this large family, furnishing the majority of the Clado- _ cera fauna of any locality and at any time of year, have been carefully studied here. The following are mentioned as of particular interest: SUB-FAMILY EURYCERCINA. The single species Eurycercus lamellatus which constitutes this sub- family has been mentioned and figured in a previous paper. It is quite abundant and constant. Eurycercus is connected with the true Lynceids by the following — genus which has quite as many affinities with Hurycercus as any Lyn- ceid. Schddler seems to be the only writer who has laid sufficient stress upon this similarity, though it may not be best to unite the two forms as he did. Genus LEypie1a, Kurz. LEYDIGIA QUADRANGULARIS, Leydig. (Plate VIII, 7-8.) The Minnesota species is referred to L. quadrangularis under the be- lief that there is no specific distinction between that Spe and L. acanthoceroides, Fischer. Our form does not agree in every particular with the very minute * - STATE GEOLOGIST. 249 description of Kurz and does agree very well w th what is said of JZ. _ acanthocercoides. However, Kurz says of the latter species, ‘‘Diese Art is von der vorangehenden (L. acanthocercoides) im weiblichen Gesch- lecht schwierig zu unterscheiden,” and itnmediately adds that the male is unknown to him. In P. HE. Miiller’s time both males were unknown. Miller says of acanthocercoides, ‘“‘ungues caudales inermes,’’ of guadrangularis, ‘‘ungues caudales dente minuto.’’ Kurz on the other hand says of the former, ‘‘der Basaldorn ist kurz,” of the latter ‘‘die Endklauen haben keinen Basaldorn.”’ Our species has no spine on the claws, and has a small spine on an eminence on the dorsal part of the abdomen, as well as two ciliated _ prominences between it and the oval sete; length ,°, cm.; color red. Silver Lake, east of Minneapolis. CAMPTOCERCUS MACROURUS. (Plate X, fig. 9.) This large species occurs rather sparingly at Lake Minnetonka. It is probably widely distributed in America as well as Europe. It is known in Cambridge, Mass. and Madison, Wis. (Birge). CAMPTOCERCUS ROTUNDUS, sp. nov. (Plate VIII, figs. 9-10.) Short, quadrangular, dorsally nearly uniformly arched; antenne of first pair long, curved outward, with long terminal bristles; abdomen long, nearly uniform in width; teeth of post-abdomen few, inconspicu- ous; terminal claw nearly straight; basal spine large; the claw also has _aseries of spines beginning a little beyond the middle and shortening proximally; length ,7, cm, This resembles C. rectirostris, Schédler, a little in outline of body but the head is like C. macrourus, except that - there is a slight beak directed anteriorly (not shown in the figure); the -post-abdomen is much as in C. macrourus, but is less heavily spined. In size it is somewhat less than C. lilljeborgii, and the shortest species known to me. ACROPERUS sp ? (Plate X, fig. 10.) Resembles Camptocercus macrourus greatly. Are these two genera really distinct ? 250 . TENTH ANNUAL REPORT PLEUROXIS PROCURVUS, Birge. (Plate X, fig. 6 ) Very characteristic. Found in Shady Oak lake, and elsewhere abundant. | PLEUROXIS UNIDENS, Birge. A species which agrees best with this is quite abundant. It is, how- ever, always of a deep brownish color, and the beak is long and curved - inward; it may be distinct. j A third form of Pleuroxis, probably P. denticulatus, Birge, is abund- ant also. | GRAPTOLEBRIS INERMIS, Birge. (Plate X, figs. 8, 11-12.) Resembles Alona testudinaria very closely; the antenne are peculiar; | each joint has a median circlet of fine bristles; the upper ramus is ter- i minated by two long sete, one shorter seta and a stout spine; the joint preceding the terminal one has a stout seta. The description given . by Birge is otherwise complete. Lake Minnetonka. ; CREPIDOCERCUS SETIGER, Birge. This is exceedingly rare, and by reason of its small size, difficult to distinguish. It has been encountered but once in Minnesota. This species is easily recognized when found, and though our specimens differ a little from the figure given by Birge, they are doubtless the © same. ALONA OBLONGA, P. EH. Miiller. The specimens examined differ somewhat from Miiller’s description. The caudal claw is pectinate; the spine at its base is large and covered — with a tuft of hairs; the teeth of post-abdomen are large, emarginate _ and hairy; otherwise the agreement is very close; length .0T em, Found in Grass Lake, Richfield. ‘ a ne STATE GEOLOGIST. . 251 TRIBE II] oNYCHOPODA. POLY PHEMID/4. POLYPHEMUS PEDICULUS. (Plate IX, figs. 4-6.) Bibliography. -Monoculus pediculus, Linneus, 1746. Gmelin, Linn. Syst. Nat. Fabricius, Ent. Syst., etc. Sulzer, Insecten. Manvel Eneyclop. Meth. Monoculus podidulas ramosus, De Geer, Mem. pour serv. 4. V’ Hist. des Ins. Polyphemus oculus, Miiller, Zod], Dan. Prod, et Entomost. Cuvier, Tab. élément. Latreille, Hist. Nat. Crust, etc. Leach, Kdin. Encye. Polyphemus stagnorum, Leach, Dict. Se. Nat. Latreille, Cuv. Rig. An. Demarest, Cons. Gén. Crust. Polyphemus pediculus, Straus, Mém. Mus. d’Hist. Nat., 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. Scalicerus 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. ee lect pediculus, Lilljeborg, De Crust. ex ord, trib. Polyphemus oculus, Leydig, Naturg. d. Daph. Polyphemus pediculus, Schédler, Neue Beitr. zur Naturg. d.Cladoceren Polyphemus kochii, a ry ‘ ie Polyphemus oculus, i . i 7 Poly phemus pediculus, P. #. Miller, Danmark’s Cladocera. Kurz, Dodekas neuer Cladoceren. Weismann, Beitr. z. Naturg, d. Daphnoiden. Birge, Notes on Cladocera. 252 _. TENTH ANNUAL REPORT ~“ I have colkected from various sources what I could of the extensive bibliography of this, the sole species of the genus. One of the most characteristic and pleasing figures given is that of Weismanu in his — article on the ‘‘Schmuckfarben der Daphnoiden,”’ though we believe that author in the wrong in the deductions made. Ourspecimens rarely — approach the brilliancy of the plate, and there seems to be a more le- gitimate way of explaining these secondary colors than by sexual selection. This species is never abuudant, nor is it very rare; found in Lake Minnetonka, and the larger lakes with their outlets. | III On Notadromas and Cambarus. CYPRIDA. | This group is one of the most difficult and perhaps least studied. A — number of species some of which, perhaps most, are new, occur in Min- | nesota, and among them is a Cypris which exceeds any described form in size. [only mention one genus which is cosmopolitan. NOTADROMAS, Lilljeborg. Carapace differing in male and female; eyes two; antenne similar to those of Cypris, the superior having seven and the inferior six joints; sete of inferior antenne reaching beyond the apex of the terminal claws; second pair of jaws without a branched appendage, in the male pediform; abdominal rami rather long. NOTADROMAS MONACHUS, Miller. Bibliography. Cypris monacha, Muller, Latreille, Bosc, Demorest, Baird. Edwards. Monoculus monachus, Gmelin, Manuel. Fabricius, Rees, Jurine. Notodromas monachus, Lilljeborg, De Crust. ex ord. trib. Brady, British Ostracoda. | Females of this widely distributed species were collected near Min. © neapolis, presenting in as far as could be seen no material points of dis: tinction from English types. Ne ee STATE GEOLOGIST. 253 DECAPODA. But two species of Cambarus, C. virilis. Hagen, and C. signifer, occur in Hennepin county, except, perhaps, in the Mississippi. The following localities for the former species are known in the State: Mississippi river, Minnehaha creek, Bassett’s creek, Cedar lake, Lake “Minnetonka, Lake Independence, Lake Superior. It is possible to recognize three age-forms in the males of this species. A. The immature male (II Form, Hagen). Reaching two to three inches in length, this stage has the chele proportionally smaller, and _ the spinous armature less developed: the first abdominal foot is simply bifid at the end. } B. (Form I of Hagen,) usually over two and one-half inches long; chele larger; branches of abdominal foot destinct; inner branch | grooved but lance-linear. C. Very large (four inches); inner branch of abdominal foot spatu" “Jate at end; the two rows of tubercles on the inner margin of the ‘hand’’ with six or seven in a row instead of five. Male of Form II, A stage, 23 in. long, Chela. 7 in., thumb .49 in. os « JT, B stage, 23 in. long, COSA er Or a .6 in. - «© TT, © stage, 4 in. long, es Se Tne eS Geet Sir ae si if A stage, 3 in, long, Neon 4 Or ie. It will be seen from the above that size does not govern the transi- tion from the first to the second form entirely. This differs either in different localities or at different seasons of the year. A large gather- ing from Cedar lake showed no specimens of the form I, while a similar gathering at Lake Independence contained but one of the form II. A male from Minnehaha creek had rudiments of a third tooth on the carpus of the left claw, thus indicating an approach to Hagen’s War. A.. CAMBARUS SIGNIFER sp. Nov. (Fia. 7.) A slender, graceful species of rather marked colors, belonging to the section haying a hook on the third pair of legs but not on the fourth. The rostrum is not carinated nor toothed at the apex; acumen moder- ate, lateral borders curved, moderately excavated. Cephalothorax arched and not depressed above, densely punctate; areola linear; chelae slender, straight; thumb deeply .excavated on the inner margin for the proximal one-third: opposite finger with an impressed groove on the inner but not on the outer margin. 254 TENTH ANNUAL REPORT Male, I Form. Color reddish-(crimson) brown, not obviously fig- — ured; tail lighter; fin chestnut, marked with gray: chele bright crim” ; son below there are green markings on the body and legs, and some 7 yellow below. | The hands are rather narrow and straight, while the thumb” i 1s deeply excavated for one-third its length, and the notch thus formed is armed with three or four teeth; the finger opposite has a tooth half — way from the apex, and others near the base; the ange at base of thumb ‘ is densely hairy. The penultimate and previous joint of second foot 2 bears a very dense and thick tuft of hairs on the inner margin which it ~ particularly noticeable in living specimens. The antenne are short about as long as the thorax when reflexed. The first pair of abdominal feet resemble those of C. virilis some- i what, but are stouter and less divided. They are more strongly curved than in C. propinquus. The lamine of antenne are much as in C. troglodyles but wider at i the base. a The second form has the two branches of the abdominal foot united almost to the end. The young males have the chele greenish-blue and mottled, while the coloration of the body is like the females. | The females have shorter chele, and broader abdomen marked with chestnut bars on each segment above. : A male 3.3 in. long was still in form II, while another 3.2 in, long — was in the form I. Found by hundreds in a shallow pool known as ~ Grass Lake, in Richfield, Hen. Co. Fig. 1. Cambarus signifer. | a chela. 6 lamina of antenna. c rostrum. 4d abdominal foot of | form II. e¢ abdominal foot of form I. INDEX OF GENERA AND SPECIES. i Page 0 249 PUETUELUB ra. Soa) dia a bon ee DPR are fa a's > 5 2.9 ides 249 TUOOUB). Win oo si asus sib) ny vi ei8\ ye ninls | Alona testudinarid........+.eeceees 250 DETOUS ork wi rlasek we datas WIOROG...- 2s ese ccs canes 250 TEES PURO IES A SCRA oie BENOMOPODA cass cess seen none ses 25 pulchellus OS) ore aetna are MUMEMINNIN DR ceria csc eee ss Ooi d etal eral 243 SEPIULATUS oc Ce se ces LO LOR RS a Sie 244 PGNMCUIS A nade: th ae Z POROUPOSTIS 2... oe ees woes 243 SPUVULOSUS., 6 oo aw wate ect shes \% EMO R e iniL8 5's ges e)sdle > « 244. LENTECOPIIS Si oe veces se nes MOS MINID Ane os... es eeeeee Ae Oy PRIDE re be Pe ‘Cc ALANIDA...-.-.6- eee PAVILION a area te aa DIV OATUS: coc. et cee be eee Wa ieciraitay eta teva rs 253 NE OTIECIL DRE Shs De ee OP TET ss A a ae Aeaey 373) PD TNIME Ae eis gc gee ain iara eevee v0 %e woes | WEG he ass se wns 2a 's see 200 EFYMALUIUAS: «soc cab cane « he Camptocercus Sete sp aee sees estes xo DROME Ayes ods os cces alte s «sce es | WEUCTOUPUB 6s. sc awe'a 249 DrAChYUTA. 06. cece vee eens : lilljeborgt..++.+0++5-- 249 brandtianad.... 66... cece. TECLITOBLTIS «5/0 63\s 60 30 » 249 CUDINOM ceeds cic cs Oe ; TALUNAUS...+.+00+ sees 249 winchelli..... .. Bee Ne Centrophages Pee Nie carat e levis iata)m xi) visi aces 224 WOU De aa, ota fait imis im acelin v miele 6 MMETIGCCCETCUS.. 026-0500 ene e cesses 2S CU SAD EXACTS aie ee a ER ae a SLEEP (orice. < eptire nie os 250 oy EMMA a siete cae ai vsa eee PEON. ee hice niele oie eee 5 + 235 TROND SR a Git oie 3 es SYCLOPID.......... Oot 225 rit SSSR are etn aN eA mara Byclopina..........-- -..262-6+s-- 225 CHIOCLT ANE SP REA BVCIOPS. 0. oo eee eee cece eee 227 DUET POU Bee ae «lntaelss ues . AGIOSLONS os sess sv edlaene 231 PR YRUAIUETUL sce oirecsin wo apaiare cae 1 EE EE SENS ae eco 228 A EL IN LID AEG sais a olnisie pew ue DLEVICOTNIB . 6. ce ccrsceveces 228 GDECHBOGDGD og sins v0qyaia wale oe BAFONGIUB sas bb cas oe ea ees 227 | Diaphanosoma brandiianum....... CHUSSICOV IIS... eevee vees 22" | Pa phOURUS : o's «=i eatiel are ss 2 vee y PEA, ocd vohis so be oe 231 I aR MINE ey GOR a CU 228 MOGUBGOWL. sca vaesceuitss cn ACRE oieia = ocilin eis see 55 5 228 MDOTIUB Solilan epee ss MLACTOUTUB. 0.065 evs ec case 230 AYMALUB.... ee ces AAR OaS Rea MAYNACEPS. +s eereererrees 232 | EURYCERCINAS.....00+ wees soles § Pag 230 229 229 232 229 230 227 230 227 252 252 252 235, 235 236 236 236 236 236 236 237 238 238 239 239 239 235 237 253 236 221 221 221 222 223 248 re PAP COCs Nh. spies wee eae oars 248 CEPIDELLGINE.. oie: de inteltan sn nsiers 248 Graptolebrise. 0.5 Ges sea eet See DO : RNETHEES S553 la ws oe ea 250 Ichthyophorbia... . <5.) eetiises 224 Aipery Ptuss ik sacha ee et 246 STUB CF Cc EE is 5 246 SOPUROES vere ase oka ee 246 Lathonura FES eae eee whee on ratios 246 rectirostri8.............. 246 Treydisig..'.. sco canteen eae ake 248 QCOILOCET COTTE ion a oly sk on ws 248 QUAATANGUIATIS. ..0.. wee eee 248 Lephophorien: 700.060 acca ee 225 1 VOINC ELD Ab seosscscueae pees 248 TiyReodnphwis 5.5 nsdn nee ene a eee 247 macrothroides ......4. 247 LYNCODAPHNIDZAL...... 244 NIB GR ORIEN 351. nin city Us So eee SA en 244 GCLOB c.0/cs es ohne Ris Vit ae 244 DOALDON os anise wie a's.» sie, woe =245 TOSOUR SS wna 'a gis iaie ae ech le 244 TENUICOTNIS . peccacerssse's 245 IMIBOPRTVA .'s. 8% needa wanes oer Eee 225 GU aera oss kk See eee anced Pe 237 INDEX OF GENERA AND SPECIES. ’ : Orachtiata oo. cee Notadromas.s.:. 6. oss + cee eet PrOCuruus .-. < «ss is pee UNIAENS 0 inns ounce POLY PHEMIDJE.... .«... wt Polyphemus. ... .. «.<= = sss SLAGNOTUM . cases weeee- Potomoichetor...... s.sssses50nme Pseudocyclops...... RN ~ gs “Wy } fae hab RE ay te Chil e's - f ar sh Zz PE era | on GN Gt Ne A 1 y 4 5 ‘ oe it ay ; ‘ % " f 5) f ‘ea ~ ¥ _ ; ot Rae a iy if a ] 7 op’ west ae Py = PLATE Tv.) Ge Cyclops ingens. | . Stylets of mature First segment of abdomen of female. 5. Antenna. he 6. ‘SO Fifth foot. 7. Maxilliped. aa Antenna of young male. 8. “Mandible, (= ° 9. Cyclops crassicornis, Female. oe Antenna. 13. Second antenna. — Terminal portion of abdomen. 14.. Naupliusform. Female fifth foot. ye" Oe. MINNESOTA, CRUSTACEA. (Te. Nat. Hist. Sur. Jy & Geol. PLATE. IV. MW Annuat Report SY ——2 SSS PS S \ SES = ‘Stylet of ordinary form. He: a i ) iL ae | fie ~~ } | hats A ne i lt Ane aXe 4 o ; ps Tree tress ce ‘ (hens ei Nes PLATE. .¥: Female. : 4. Antenna of very Antenna of elongated form. 6. Cyclops navus, antenna. Furca. — te Abdomen of young. 12. Antenna of yt Abdomen of male. 13. “ Opening of spermatophore. \ C. * signatus,’’ maxilliped. C. navus, swimming foot of first pair. AEE “second pair. Maxillipeds. = Fifth foot. 5. Stylet of elonga | MINNESOTA CRUSTACEA. PLATE V. £ LO“ Annual Report Geol. & Nat. Hist. Sur. Minn. a it laa ts 5 is oe q Female. Mandible Maxille. Stylet. Abdomen. Antenna. Abdomen. Antenna Fifth foot. Opening of spermatophore. Abdomen. Foot. Female antenna. - ty ti. t ae { we Fs ” oe 2% } * x q ‘ = ey ls a Pine ee or ¥? cleat a yy a ee fee hg SIN 3 Pei 43 Pie ny b : ¥ et | wa ys { i \ y 2 Neen } , { } j ay i PLATE VI. Cyclops lenwicor nis. 5. Fifth foot. we 6. Maxillipeds 7. Antennule. C. ** signatus. ” 10, Frith foot; Cyclops parcus. Cyclops adolescens. 19. Eye. 20. Male antenna i 5 21. End of artenna of a fe Pen ere MINNESOTA CRUSTACEA PEATE Vi. Geol & Nat. llist. Sur. Mlin-. = ee. 24 SEE 1-9 Antenna of young. 4. Abdomenof young. 10. Ye 14. End of male ab Daphnella brachyura, female. cc Pi ae male. Part of edge of valves. — PEATE Vip.’ 1 . Cyclops fluvialitis. 15. End of female oO es Geol & Nat. Hist: Sur. Men PLATE VIL MINNESOTA CRUSTACEA. \ : ig | » \ Was z ed eicieeett a OR) as Nae vi Wr LYONS ag ace et ae 40% Annual Report + ae Ff 5 > 2 2 a a ey * + , - ie pda. i matined uly ’ Rios baie i Aoki ayy, = % + wR tt Mee Pe SF oem ee a Fomine Srey =n ~~ any, , ao ae | Macrothrizx pauper, 2-6. Iliocryptus spinifer, 7-8. Leydigia quadrangularis. ‘ 7 PLATE VIII. 9-10. Camptocercus re yt 4 nA ees Lathonura re Ah Geol. & Nat. Hist. Sur, Minn. PLATE - Vill: ) 4. i MINNESOTA CRUSTACEA. 10% Annual Report 1 a “ Crt \ ' =! ; A) : 5) ‘ ma) a . =i ») qe ‘ 2 » Nee . / ) ‘ - My ie , i 4 ‘ ; i +a ways hlaancaney | 1-3. Lyneodaphnia macrothroides. 4-6. Pol : y ‘ a - ° . . ' ; - ’ a - 4, . - ' ‘ . ‘ . d . : ‘ we . « i ‘ ‘ * * ‘ ' > ‘ - ? a f MINNESOTA CRUSTACEA. Be 9% Annual Report PLATE 1X. Geol & Nat. Hist. Sur: Minn. PLATE X. ~ ‘ he 1. Bosmina striata. 8. Graptolebris 2, longirostris. 10. = Acroperus sp? 3-5. ‘ cornuta. 11-12. Graptolebris ine 6-7. Pleuroxis procurvatus. | * “ - . . - . ‘ . . Fe . - s rae z ‘ > 4 . f . iad a * by ‘ ra ) fi MINNESOTA CRUSTACEA. Ceol. & Nat.Hist. Sur. Minn PLATE XX. 49 Annual Report (ti \\ beh it v - PLATE xi . Limnetes sp? male. . First foot of male. Antenna. Mandible. Maxilla. Mandibler teeth. bo ho coma a . Head, labrum etc., of female. Caudal appendages of female. Haast ¢ = MY A aay .. < ; ey i SOP ba ne myst wry ‘ oy # WY | 4 i + ‘3 \ 9. Antenna (2d) of fe 10. Foct of female. — 11. Exterior of whole 12. Modified (sexually) 13. End of process of 14. Magnified spines of 15. Daphnisp.? 16. Daphni sp. ? * € ed money MINNESOTA CRUSTACEA. 10% Annual Report PLATE XI. Ceol.& Nat. Hist. Sur. Minre. Se re ere cee TT HOUT ey ate tod gt { Sa GY iy} j ATIVE — (aa. Ss N =A NSS WAN WL ee ad — QQY WN WN eZ: SS SQ 7 ws nn ee ett RPE GR Zovlogy, : 813 nae x on i » 2 % & (From the American Naturalist, October, 1882.) ZOOLOGY. i Hapits OF FRESH-WATER CrusTAcEA—No one branch of bio- logical study is now bringing forth more interesting and every __way useful results than embryology. Throwing hght as it does, _ not only on questions of classification and theoretical biology, _ but also on the application of such theories to practical life, | this new science may be termed at once the root and most typical fruit of a revolutionized biology. No other science fur- nishes a better illustration of the value of minute, accurate study iy of the most common and apparently insignificant facts. Sets of ‘ isolated facts evolved by conscientious study of different men spring suddenly into line when once the clue is found, and the result may be a new law which renders all these facts eloquent. To the systematist the merely external study of life histories is of greatest value as a check against redundancy in classification, and furnishes the only reliable method, among lower forms at least, of setting the bounds of species. Many eminent.monographers have been obliged to considera- bly augment the nomenclature of their specialty with names which, later, have proved to apply simply to larval or immature forms, on account of the impossibility of following the whole life history of each individual. | To confine ourselves to the class Crustacea, many instances of oe? te. yee ey ay edhe, _ ro eli bad this sort could be recounted. The best known is perhaps that of _ the common Cyciops which in the earlier days of carcinology » enjoyed as many as three names between its exclusion from the egg and maturity. The discovery of the earlier stages in the life _ of Cyclops opened a new vista in the whole subject, and now we ‘) recognize a “ Nauphus stage” in the life-history of nearly every crustacean. ' It has been more recently discovered that similar opportunities _ for error are afforded by the difficulty of distinguishing the ulti- ' mate stage in an animal’s life. It has been shown that the func- _ tions of reproduction are anomalous in the lower animals. Espe- eItson affords no sufficient ees that the Roane mS | in its historically perfect form. The enthusiasm elicited b reproduce during a larval stage, was almost ne b believe it demonstrable that, not only species, but families : lower Crustacea are normally ‘sexually mature in a stage Bis Bp ; _ ing actual maturity. if . We most naturally turn to the order Branchiopoda for a test, _ since the most remarkable cases on record of heterogeneous repro-— 2 duction have recently been read in their history. We need ae ia mention the parthenogenetic summer brood of Daphnia,’ and the — 4 Bis case of heterogenesis discovered by G. O. Sars in Leptodora,2in ee which Sars concludes that L. Aya/zna has both “ dimorphous de- — ae velopment and alternation: of genérations.” Nor are we disap- — Oona pointed in looking among the Cladocera for examples of hetero- — , genesis. During the winter semester of 1881-82, at Leipzig — i University, we-had the opportunity of studying the development of.” ae, - Daphnia magna (=schaffert), and among other interesting facts . the following were elicited : > Siaeane | The development proceeds in very much the way described ae é Moina by Grobben? The secondary or swimming antennz have an evident palpus in the nauplius stage, however, which makes E the parallel consplete between Copepod and Branchipod Crusta- — ° i cea. The heart and circulatory system apparently is formed dif- @.. ferently from the method given by Grobben. I may be permitted : to say in this connection, that the circulatory system is much - “ more comphcated than hitherto described, and seems to originate about a mass of deutoplasm which surrounds the intestinal canal in the embryo, and which is a remainder of the food-yolk, j 4 ‘ Nahrungsdotter,”’ of the egg. The embryo, in a comparatively ~ early age, begins to differentiate the walls of the valves, which first appear as a fold over the maxillary region near the position | occupied by the heart, and extends gradually backwards in a — Bears thick fold of turgid cells between which fluid flows. Quite Bie.) remarkable is it that from the dorsal region a process extends, : growing much more rapidly than the lateral portion till it me yeury reaches the membrane of the egg, when it curves downward Rh and forwards till it reaches a position nearly half way from the Osea extremity of the abdomen to the maxilia. The method of © growth of this tail-like appendage of the shell is obscure, but it seems to stand in close relation to the formation. of the brood- 1 See J. Lubbock; Phil. Trans., Vol. 147, p. 98. ae Cfr. R. Leuckart: Archiv, f. Naturg., xxxI, and ' pect: ee . v. Siebold: Wahre Parthenogenesis bei Schmetterlingen und Bienen...) oe , 3 2G. O. Sars: Om en dimorph Udvikling samt Generations vexel hos Leptst ; LO ae 1873. 1879. Zoology. ; 8 5 cavity, and is he result of a secondary folding of the common ‘ shell envelop. At the close of the development in the eve, this On) “tail” lies between the valves of the shell, curved beneath like the tail of a frightened dog, although the frequent motions of the — ~ post-abdomen are not a little hindered thereby. : _ On its escape from the egg, the animal swims freely, and soon kicks this pliant appendage backward and upward till it assumes a direction parallel to the long axis of the body, and then very soon its unequal growth causes this tail to be somewhat elevated. The appendage probably serves as a support for the cast off skin in the molt, so that it cannot fall down upon the post-abdomen and then be broken off before that portion cf the shell forming the inner covering of the brood cavity can be successfully molted —a danger especially incident to long forms with narrow brood cavities, and to young animals in which the shell is tender. (It may be for this reason that males, in which the part correspond- ing to the brood cavity is very narrow, and young females, have this spine, while adult females do not, for, as is well known, the males of all this section of the genus are spined through life.) Successive moltings increase the size of the animal, but the spine remains and increases correspondingly, giving the animal a very different appearance from the parent, which was not only of an entirely different form but totally without the spine. Finally the young female produces eggs parthenogenetically, and is, therefore, according to our customary notions, an adult. We have here, therefore, a case of heterogenesis. Under circum- stances where food is not sufficiently abundant, it seems certain that the above-mentioned state is the final one, and that the ani- mal does not reach that condition which we name Daphnia magna, but remains in a stage which has received a different specific name. : The same process has since been observed in the case of Daph- mia pulex, in Minnesota. Some of the so-called varieties are but age- forms. There is in each species what may be called a post-zmago form, which is only assumed under favoring conditions. With-_ out going into the synonymy of this genus, which will beara revision in view of this and similar facts, we may safely say that in the Daphnidz we find heterogenesis almost a rule, at least in the genus Daphnia.’ We may add that every possible provision for the reproduction of these animals seems to be provided. (1) They are very prolific ; (2) reproduce both sexually and par- thenogenetically ; (3) resist great extremes of temperature ; (4) accommodate themselves to great alterations in the purity of the water ; (5) the winter eggs are provided with a horny covering or gphippinm, which permits them to be dried in a mass of mud or frozen in a cake of ice without destroying their vitality ; (6) 816 : General Notes. chm [Octobe during mild winters both summer and winter eggs are predate ty and the successive broods of young after producing agamic 5: young, throw off an ephippium so that the pool is filled with eggs which are calculated to stand any vicissitude. Thus it happens that after a pond has been dried for a long time the first warm shower quickens in it swarming life. The above facts are more : significant when we remember that the Cladocera are above ail others among Crustacea, the most useful as purifying agencies. The greater number subsist entirely upon vegetable matter, and the only means they have of collecting it is by causing a current of water containing such minute particles as may exist in it to pass between the rotating jaws, though, perhaps, in some cases the labrum is sufficiently prehensile to grasp somewhat larger food, Certain it is, however, that these same minute animals form an indispensable agent in the economy of nature, purifying all our b stagnant pools of the decaying vegetation floating therein. One F | who had given no attention to the number of these creatures ; would undoubtedly be surprised on carefully examining a given quantity of water from the nearest lake. Here are some figures. In a quart of water taken by dipping from a lake near Minne- apolis, the following were counted: FH TIGA MNOD Se Siheai awake vol sess Re swe kine ooh wipia ofa eae lesa 1400 ey ROATITINEL S geveath wide <0 id din Sr pWe Mivcmisl be oe Ope a ye ook ieee 9 \j SEGRE PMAINS, cin \oio0 ciate wine nice cc ech sus sine sis 48 ties bs 0c nies n 56 Ae oyitde is weet She Seo han ss 4, Wee eg ale oe & eels athe eee eee re RV OUS ss) k sa ahinlie’s t. s'a:a og aie sis whely aix’'n's o's ¥ wig aft She he 28 ie Amphipods (chiefly young)...... ibs th lage Sinks ini hs ee ae os eee 120 Lis DWVGEIOS Be Vo cs os edhec a ea piv m pamela s.|| wen tie imu pt ete tren 35 f WREMAICR ia} 5 uk leis Voa's o> b vw iwid y Bis bias e wince uo eud'ee wpie renee Onn 22 my POS EECA VEE) ia 5 sein bie o's ois o 0S bnlp boa $:6'5 bla lean’ vein a ielg lel oa 100 L PATATIVCIY v0 cw elie bbie.cwsepaen's one 6 o/s ei.a/sinilee es 6 it en 9 etc., all visible to the unassisted tee L. Herrick. : | | . Ba | oe General Notes. | December, (From the American Naturalist, December, 1882.) ZOOLOGY. A NEW GENUS AND SPECIES OF THE CRUSTACEAN FAMILY Lynco- DAPHNINE.’—Lyucodaphnia, gen. n. (Plate xvi, Fig. 1-4). Form much as in species of Alonella, etc., truncate behind; superior antennz like Macrothrix, attached movably to the end of a blunt prominence beneath the head; second or swimming antennz slender, four-jointed ramus with three long setz and a stout thorn at the end of distal segment, the joint following the short basal one with a thorn above, the following joint unarmed (!); three-jointed ramus as in Macrothrix, the basal segment armed with a much elongated seta; eye relatively small, pigment fleck (macula nigra) present ; zutestine twice convoluted, expanded in front of the rec- "tum, opening in the “ heel” of the post-abdomen; post-abdomen slender, sub-triangular, margined behind with a double series of spines ; terminal claws large, and furnished with a long and short spine near the base; shell margined below by stout movable spines. Few more interesting forms than the one forming the type of this very peculiar genus have been found, since it combines in a curious manner those characteristics hitherto regarded as distinc- tive of the families Daphnidz and Lynceidz. Kurz says :* “Keine cladocerenfamilie bildet eine so streng in sich abgegrenztes natur- liches Ganze, wie eben die Lynceiden,” and this after recognizing the relationship of Macrothrix and Lathonura to the Lynceids, by placing them in the sub-family Lyncodaphnine. The form above referred to, however, has quite as close affinity to the Lyn- ceidze as to Macrothrix, though it resembles the latter rather more on a superficial examination, indeed if one were to divide the animal back of the heart and examine the two portions inde- pendently, it would be impossible to avoid referring the head to Macrothrix and the body to some Lynceid genus. Thus is fur- nished another of those curious intermediate forms which remind us that the possibility of distinguishing families and genera, lies alone in the meagerness of our knowledge. There can be no doubt that this genus should stand next to Macrothrix, but it will be necessary to modify a little the diagno- sis of the Lyncodaphnidz to receive it, and it then appears that _ it cannot longer remain a sub-family of the Daphnidz, hence I _ have proposed to give it equal rank with that body and the Lyn- ceids as an independent family, Lyncodaphnine, including the _ genera Macrothrix, Lyncodaphnia, Drepanothrix, Lathonura (= Pasithea), Ilyocryptus. As thus limited.a very natural group is formed, in size and isolation corresponding well with the other related families. ‘Series secunda generum (Daphnide), P. E. Miiller, Danmark’s Cladocera, p. 134; _ sub-family Lyncodaphnineg, Kurz. Dodekas neuer Cladoceren, p. 24. 2Kurz. Dodekas neuer Claduceren nebst einem kurzen Ubersicht der Cladoceren fauna Bohmens, p. 30. COLLECTION 1882. | ; — Loology. 1007 — Lyncodaphnuia macrothroides, sp. n.— Form. sub-rectangular, greatly elongated ; length 4°"; height ,{.°™ or less ; first antennz long and slightly curved, pordcicn Behind’ by about ten spines, and terminating in two or se sword-shaped unequal spines and several sense-hairs, about 4°" long; swimming antennz very slender, as in Macrothrix, io long ; head not marked off by a depression from the body, small and extending below into a blunt elevation for attachment of antenne; labrum rather large; eye small; macula nigra conspicuous but not large; anterior feet strongly armed with curved spines; intestine anteriorly is fur- nished with coeca, is twice convoluted, broadened before entering the rectum, and opens some distance beyond the anal sete in the heel of the post-abdomen ; post-abdomen rather slender, toothed behind with a double series of about twelve prominences, ciliated near the anus but distally becoming strong, sharp teeth; ters . minal claws large, curved only at the end, pectinate and bearing near the base a small and large tooth; eggs much like those of Macrothrix. Male not seen. Occurs in Lake Minnetonka, Hennepin county, Minnesota ; rare—C. L. Herrick. | PUBLISHED December 1[2, 1882. 206 General Notes, [February, (From the American Naturalist, February, 1883.) _z\ BLinD CopEpoD OF THE FAmILy Harpacticip#®.—The interest now centering upon these animals, which through peculiarities in their habitat have dispensed with important organs, may warrant the mention of a case-of the disappearance of the eyes in an order of Crustacea in which it has not been hitherto noticed so far as I know. _ While collecting marine Copepoda in the Gulf of Mexico a gathering was taken from a very slightly saline marsh, a ditch ‘passing through the marsh affording the only water of sufficient depth in which to use the net. This ditch is about eighteen inches in breadth, but of moderate depth, and extends continuously for some distance; it is so shaded by high salt sedge grass as not to be found save by accident. The gathering here secured proved to contain a new species of the sub-family Longipediinz and closely allied to the genus Bradya established by Boeck in 1872 ee for a marine Copepod dredged in rather deep waters about North Europe. The American species, which has been named Brady limicola in allusion to its muddy habitat, was found to lack in both sexes the pigmented eyes which in other Harpacticidze are so con- spicuous in the cénter of the forehead or on either side. It is to be regretted that lack of opportunity to repeatedly collect this interesting species, and to endeavor to ascertain if truly pelagic species also inhabit our waters, robs this discovery of much of its interest —C. L. Herrick. 208 General Notes. | February, * e 1 (From the American Naturalist, February, 1883.) | HETEROGENESIS IN THE COPEPOD CrusTACEA.—In a former paper we have considered examples of heterogenesis furnished by the Cladocera. Let us now turn our attention to the copepods, the Cyclopoiclea, with the view to discover if similar conditions exist here also. | The standard books upon the non-parasitic - eran of the Cope- poda by Claus! and Brady? enumerate many species, but do not agree entirely in synonymy, nor does it seem probable that, Claus, who alone has done most of the anatomical and embryological work in this section, has followed the life-history of anything like | a large proportion of the species named. i@ It has been long known that the marine forms of Copepoda have a very extended geographical range, many of them seeming to complete the circuit of the earth’s longitude and to extend over several zones of its latitude®. Similar and often identical forms occur in the Mediterranean and North seas, over all Europe and the British Isles. Certain genera, as Calanus and Chetochilus, | seem to extend through all degrees of latitude from the equator to the most northern seas. .f A confirmation of these facts may be sought in the works of 2G. S. Brady : Copepoda of British islands, Roy. Soc. 1878-9. q 1C. Claus : Die Frei Lebenden Copepoden. Teipsig, 1863. ft 3 Claus ; Op. cit., pp. 83-86. 3 ‘ 1883. | | Zoology. | 209 Claus, Dana, Leydig, Jurine, Baird, Fischer, Miller, Lubbock, Boeck, Brady, Heller, Lilljeborg, Sars, Uljanin, etc. As yet, how- ever, it is too soon to say how far this similarity may extend. Confining ourselves, for the present, to fresh-water forms, a recent opportunity for comparison of American with European Copepoda has confirmed our impression that a large number of species will be found identical’. It seems, indeed, somewhat astonishing at first to discover that the isolated pools of the Central United States con- tain species identical in every particular with those of England, Scandinavia or Germany, but such is’certainly the case. In fact the populous genus Cyclops has few new species in America rela- tive to the number identical with transatlantic forms. A Diaptomus, believed to be identical with D. castor in typical as well as several varietal forms, occurs throughout Minnesota from the shores of Lake Superior to near its southern boundary and in Illinois. Another species believed to be nearly allied to a Scandi- navian species is known from Minnesota, Wisconsin and the neigh- borhood of East St. Louis, Illinois. Cylops serrulatus Cls., with similar variations to those noticed by Claus (Op. cit., p. 85) and Brady (Op. cit., vol. 1, plate 22) occurs as our most abundant species. | It may be observed that Brady’s work is so strictly systematic that his figures are frequently little more than schematic, and lack the life-like character of those in the earlier work of Claus. It would seem that some of the species of Cyclops described by Dana? are identical with the above, although details are wanting to identify positively. Without delaying to discuss the question opened as to whether these widely separated forms have all diverged from a primitive geographical center or have arisen independently from original marine prototypes, as suggested to the writer by Professor Leuckart, we may remark that the former theory is rendered pos- sible by the fact that the feathers of water-fowl often form a vehicle for the transportation of even larger crustacea. Amphipods, for example, are transported hundreds. of miles under the feathers of geese. While it is unlikely that these larger crus- taceans or their eggs would survive a long aerial journey, it is quite certain that the eggs of Cyclops would pass many hours or even days without being destroyed. On the other hand, it seems that some entomostraca are in a nascent condition which permits a slight change in the environment to induce remarkable altera- tions in structure which are uniform wherever this change is effected? and if this be not now the case with all, it may have been so at one time with the prototypes of our fresh-water copepods. To return to the question of heterogenesis. Selecting the larger 1 Herrick : Copepoda of Minnesota. Rep. Geol. Surv. Minn. 1881. 2J. D. Dana; Wilke’s Exploring Exp. Crustacea. 3Siebold and Kédlliker, Zeitschrift. 1872, p. 293. Packard; synopsis of Phyllo- poo crust. N. A. U.S. Geol. and Geog. Surv. of Col. 1873. p. 614, etc. 210 General Notes. | February, species of Cyclops, say C. signatus (= C. coronatus Cls.), we find a form not at all rare but less abundant than C. tenuicornis with which it seems to be constantly associated. In our investigations we found Signatus almost constantly larger, 7” the same gathering, than Tenuicornis. The only distinction, among those given by either Claus or Brady, which is constant is the following: in Sig- natus the last joint of the antenne has a longitudinal ridge shaped like a pruning knife-blade extending beyond the end in a hook with the proximal two-thirds of its length strongly toothed. (The only other species which has teeth on the first joint is a species allied to C. parcus Her. found in Alabama, but this has no knife- like ridge.) The two species agree in having the ridge which ex- tends nearly to the base of the antenna; they both have certain series of spines arranged upon definite parts of the antennez; both have the circular series of spines on the basal joint of the fifth foot ; in short there is a complete agreement even to the microscopic de- tails—aside from the teeth above mentioned. Nevertheless it is possible to pick out Signatus from a glass of the other form by its larger size and different color as well as to detect a different relation in proportional length of the caudal sete, etc. Close examination fails to discover an earlier stage of Signatus while Tenuicornis is constantly accompanied by males and smaller forms as well as the larval stages. The curious fact is demonstra- ble that these species of the section of Cyclops with 17-jointed antennz become sexually mature long before they are perfect in form. In this species it is no uncommon thing to see females of less than half the size of the adult with ova sacs. Indeed it is common to meet larve in which the antenne are as yet composed of but few joints in a similar condition. This fact alters our con- ception of a species considerably, inasmuch as it has been thought sufficient to prove the maturity of a specimen to find the egg sacs developed. A glance at the literature of this family will suggest that in more than one case a species has been founded upon a larva which was simply prematurely gravid. In Crlops serullatus the same fact is more easily observed, as the species is so easily recognized: as to be unmistakably at an early stage. The var. Montanus Brady, is not at all a variety due to station as suggested by him but, if our observations are correct, is the last form, in exceptional cases of the common species. It is but a step further to show that as C. é-nuicornis isa more advanced stage of the small Cyclops forms with larval characters, so C. signatus is but a post-imago of the former. In truth not only in this species but in all others which we have had opportunity to examine, there appear at favorable opportunities unusually large and somewhat altered forms. These large, or post-imago stages appear to be dependent upon abundance of food and a shallow, warm. habitat. The species considered identical with Diaptomus castor is abun- 1883. | Zoblogy. : 24 dant and varies in size and particularly in color. So marked are these differences that it would be difficult to believe at first sight that they are not indications of specific distinction but these changes are dependent upon food, light and other similar circumstances. The typical form is found oftenest in rather large pools with no outlet, but which do not actually dry up in summer. In length the female is often ,}°"- sometimes less and not seldom more. In the smaller females the eggs are observed to be usually fewer, but G@ecie same size jy to zy +JRecently, however in a small and very shallow marsh which is frequently entirely dry, but which lies near a less shallow pool swarming with the common Diapto- mus (both being half a mile distant from any other water) we found a new species of dimensions considerably exceeding those given by Brady for var. Westwoodii!. Closer examination showed that _ the size and color were the only marked differences, antennz and first pair of feet being identical, while the fifth pair of feet were but little different and these differences were seemingly but the inten- sifying of the characters of the smaller species to form the larger. Here there were two pools, which within our personal recollection formed but a single body of water and were now separated but by a dozen steps, only differing as to depth and muddiness, in the one of which flourished a// stages of the ordinary form, while in the lat- ter the ove enlarged form alone existed. The conclusion is almost forced upon us that the second pool needed only similar conditions to bring forth this final stage of twice the usual size (but with eggs but little larger—,™). Shortly afterward the more shallow pond dried up entirely so that no more of the larger form could be obtained. It is not necessary to emphasize the fact that just such insignifi- cant variations furnish the data upon which the generalizations of modern science must stand or fall. A most interesting field is open to any one with the opportunity to rear such forms as these under conditions which can be altered at will in order to discover what farther structural changes can be artificially induced. The practical value of the fresh-water copepods can hardly be overstated since they are scavengers and almost entirely feeders upon animal matter. The aggregate amount of putrid flesh which the Cyclops fauna of a quart of water will consume is quite remark- able, as any one may satisfy himself by watching the decay of such a creature as a polliwog in a jar of stagnant water.—C. L. Herrick. MOp. cit. p.'60. atl blvove eit nba f° Ye, aie isy : . ' i MatinatAt, vf] . 1883.] Heterogenetic Development in Diaptomus. 381 ie | almost all their special characters at once, in the White river. __ The Hystricomorpha, whose home is in South America, are un- a known in North America below the Loup Fork or highest Mio- . 4 -cene, where Leidy identified a true porcupine, Hystrix venustus. __ — Many of the extinct genera stand in evident genetic connection with existing forms. The Miocene Castors doubtless include the . ancestor of the modern beaver. The Ischyromys is a primitive ‘type of the Sciuride, and Gymnoptychus connects it directly | _ ‘with the existing forms by the character of its molar teeth. -Eumys is the primitive form of Hesperomys, as Paciculus is of Sigmodon. Entoptychus and Pleurolicus are the near ancestors of the Geomyidz of the Pliocene and present periods. Palzo- lagus, Panolax and Lepus form a direct genetic line. The ancient genera all differ from their modern representatives in the same way ; that is,in the greater constriction of the skull just posterior _ to the orbits and accompanying absence of postorbital processes. _- This relation may be displayed in tabular form, as follows: Skull wider behind orbits. Skull ‘narrower behind orbits, Postorbital No postorbital Postorbital No postorbital processes. processes. processes. processes, |. LSE St ieee CAastommieny Ly Pia. cs ts ceeds s Castor peninsulatus. 7 SPL Se la iid RA oc gc lclaG Reet aE Beda hae |Ischyromys. 6 a ee Hesperomys. inte CBRNE abe ers eis | EMS, Lepus. oye ce eid Br oe De DIS GOCE bie Tere cr ie Paleolagus. None of the species of this fauna are of larger size than their modern representatives. In the cases of the beaver, squirrels and _ rabbits, the ancient species are the smaller.} [0% _ HETEROGENETIC DEVELOPMENT IN DIAPTOMUS. BY C. L. HERRICK. Fe ER ee ee ee ee N a paper in the Report of the Geological and Natural History 4 Survey of Minnesota, the writer suggested that this genus is ' unusually affected by changes in the environment, and an exam- _ ple is given in the case of D. castor. The form called gigantcus a was shown to be probably an enlarged variety of the above. In A a paper in the-NatTuratist this matter was expanded and an he, attempt made to parallelize the two forms with the two S7h akit iat Ute ea ee Ak 7 2 are anh ft _ 1 For these conclusions see Bulletin U. S. Gcolog. Survey Terrs., v1, 1881, 362-3. ou *~ a ee 7 o a 382 Heterogenetic Development in Diaptomus. [ April, stages in adult Cyclopide. I am now able to set the matter at rest with reference to these two forms at least. Having had occasion to collect fresh-water animals through the entire length of the Mississippi valley from Lake Superior to the Gulf of Mex- ico, many hundreds of specimens of Diaptomus have been exam- ined in the most diverse localities. If it were permissible to establish a species upon slight variations in structure, numbers of them might be distinguished. However the following facts debar me from attempting it: At Decatur, Ky., a series of small pools in various stages of stagnation, furnished an opportunity for study- ing the variations due to age and conditions of the water. It is remarkable that in such small bodies of water only one stage may be present in one, while the next, a few feet away, may offer another. In the same localities the various stages of a Phyllopod cont be studied in the same way. The normal D. castor, like Minnesota specimens in its various stages, occurs in some pools, in others, a few steps away, occurred a larger form, at a glance distinguishable from the above by the short antennze and stylets, and the structure of the fifth feet. I was, however, struck by the fact that all these specimens were im- mature (though nearly as large as D. giganteus), and unaccom- panied by the adult stages. Figs. 1, 2, 3 and g, Plate v, show some of the peculiarities of the normal D. castor; 1a and 9 show the effect of senility on fifth feet and antenne. Figs 4, 5, 6 and g show the corresponding parts in the enlarged form. Further study showed me that the difference distinguishing the second from the first forms, saving the compact build of the for- mer, are just those found in young of castor. It then only remained to find the specimens in the process of molting with the combined characters of both (Fig. 8) to convince one that the en- larged form is really identical with cas‘or, but by favorable circum- stances enormously developed. Differentiation takes place before the mature stage is reached, in the same way that tadpoles wintered over are greatly enlarged. I have found the typical D. sanguineus of Forbes in Alabama. This form has some peculiarities to distinguish it from the com- mon var. of D. castor. | In view of the facts now known regarding the development of Diaptonius, we may safely say that 7. staguals Forbes, is an en- — Ca O> ~ epee Opie > Yo ‘eens ns Se ee ee 1883. | Heterogenetic Development in Diaptomus. 383 larged variety or age form of D. sanguincus, but the writer must still express his decided belief that these must all be referred to the European D. castor. It must be admitted that the intensity of coloration does not depend upon season but upon the conditions of the water which may or may not be influenced by the time of year. In the same montli I have found the same species of all colors, from colorless to deep crimson-red or variegated red, yellow and blue or purple. Weissmann seems to have neglected these facts in referring the coloration of many species of Cladocera to sexual selection. I have found in every case where the Diaptomus was intensely red, the species of Cyclops, usually green or bluish, would be more | or less red also. In Swan lake, near Decatur, nearly all the Cladocera were brilliantly marked, szda and stmocephalus (?) be- ing most so; in the neighboring lakes these species were pale i as usual, 3 | With respect to the identity of our species. rst. The armature i of the last segment of thorax is usually obscured by doubling over. Fig. 12, Plate vi of Brady gives the large thorn but omits the lower process. 2d. Fig. 7, Plate v1 of Brady figures the pro- cess on the antenna of male. (Claus gives the best figures.) 3d. Fig. 5, Plate 1 of Cyclopidz of Minn., Herrick shows that the inner branch of the male fifth foot is armed by three spines (as figured by Brady) in Minnesota specimens. It must be remarked that this applies to young forms only, and that the later forms lose them and become shorter. Brady has probably transposed his numbers as regards the female feet of fifth pair. The serrature of the spines differs between different age forms. i 7 If \ Diaptomus pallidus Herrick (Plate vil, Figs. 1-6) is quite rare as compared with the foregoing. The peculiarities mentioned in the original notice suffice to distinguish it from any other known m to me. - LY. siczlis Forbes, seems to sustain the same relation to pallidus that giganteus does to castor. ‘The two-jointed character of the inner branch of female feet in sicz/zs confirms this view. There are several differences however. Char, spec—Extremely slender; head separate from thorax by | | a suture; antenne longer than the caudal sete; sete very long ; fifth foot of female very short, inner branch with only one ter- | minal seta at end; the male fifth feet long; the jaw is like that of | castor. VOL, XVII,—NO, IV. 27 | PERERA + 2 : aS — —————— o j ‘ : \ ‘ } 384 Fleterogenetic Development in Diaptomus. [April, : Diaptomus leptogus has not been recognized in the South. — Fig. 4 of Plate vir in the NATURALIST, July, 1882, represents the process or inner branch of fifth foot reversed, probably by pres-— sure; Fig. 6 of the same plate omits one of the setz on the last joint. Now comparing these figures with others, we see less dif- ference than as given. EPISCHURA FLUVIATILIS, sp. nov. (Figs. 10-20, Plate v). The genus Epischura, which was founded by S. A. Forbes? upon a species of Copepod, £. /acusiris, inhabiting Lake Michigan, is one of the most interesting as well as anomalous of the genera of Calanidz. The typical family likeness is preserved, but there are several peculiarities which have no parallel in Copepoda, if else- where. The animal for which the name Efzschura fluviatilis is proposed, is undoubtedly extremely near the above, but in several respects disagrees with the points in Forbes’ description which he seems to rely upon as of generic importance. It might be assumed that these differences have generic value, and I should be inclined to so regard them except that there seems a possibility that Mr. Forbes has slightly mistaken the homologies of the anomalous organs as indicated below. As no generic characters were given, this second species may warrant an attempt, as follows: ee es ~~ ‘peniys EPIsCcHURA Forbes, 1882. Char. gen.—Cephalothorax slender, 5—6-jointed; abdomen 4-jointed in male. 3- jointed in female; second antennz as in Diaptomus; mandibular palp biramose ; swimming feet all biramose; inner ramus I-jointed; left foot of last pair aborted or obsolete, right foot in female slender, last feet of male greatly modified (right ?), foot biramose, inner ramus short, lamellate, 1-jointed with claw-like setz, outer branch nearly like female, left foot coalesced with the first two joints of abdomen, extremity alone free; setz of caudal stylets three. Forbes says of &. /acustris that the female has a process upon the abdomen and in both sexes the latter is curved and deformed. — In £. fluviatihs the abdomen of the female appeared normal, 3- — jointed, and differs in no way from Diaptomus except as to the — number of setz. It is to be remarked that Epischura offers an ex- — treme example of the tendency noticed in all Copepods, as well as frequently in higher Crustacea, to diminish or abort the inner branch of biramose organs on either side the median line. 1S. A. Forbes. On some Entomostraca of Lake Michigan. AM. NATURALIST, July, 1882. Bi "" ais he Op a 1883.] . Heterogenetic Development in Diaptomus. 385 This may be observed in the abdominal feet of Palemon, the _ mouth parts of Cyclopidze, but extends to the first pair of swim- ming feet in Diaptomus, and in this case involves all of them. The advantage of this arrangement, as well as its cause in the law of adaptation, is evident in the case of such animals as rely much upon a current below the body for food or the aeration of the blood. In Epischura the antennules rotate and create such a cur- rent past the mouth as is seen in other Copepods. Char, spec.—Cephalothorax imperfectly 6-jointed ; antennz 25-jointed, in the male 6-joints follow the hinge, the enlarged portion is not greatly thickened, the antennz reach somewhat beyond the thorax; mandibles with about nine teeth, the first of which is large and divaricate, more or fewer of the following ones are emarginate ; mandibular palp biramose, inner branch 1-jointed, outer branch 3-jointed; maxilli- peds not unlike Diaptomus but shorter and more strongly armed with curved spines; (last feet of female 1-branched with a straight claw terminating the distal segments, or) left foot obsolete and the other 2-branched, each branch 3-jointed, the right male foot of last pair is much more modified, its inner ramus is lamellate and curved in upon itself so as to make a grasping organ of curious form, in this office it is aided by two or more curved movable hooks which may probably be regarded as modified sete , tlie second joint of the abdomen bears on its left side an appendage of two joints, the basal joint being flat and extending into a strong curved claw reaching to the base of the furca, while the second is slender and has two smali sete at the end, thus is formed a powerful hand, I regard this appendage as perhaps the terminal joint of the left of the last pair of feet ; indeed there seems to be some internal connection with the last thoracic segment, although externally none remains, the abdomen is otherwise quite normal and straight. These suggestions with regard to the homologies of the organ are offered with some hesitation, as such a coalescing of a limb with the abdomen has never been described. However I believe the same thing takes place, though to a less degree, in Cyclops. In C. mullert, for example, the fifth foot entirely disappears, leav- ing only two separate spines to indicate its position. It is sug- gested that certain spines adorning the first segment of the abdo- men in most species of Cyclops may be rudiments of the missing second ramus of the fifth foot. By comparing Figs. 11 and 12 of Plate v with 1 and 3, representing the corresponding parts in Diaptomus. it will be seen that the theory advanced places all the parts in the place demanded by the schema of the limbs in Calanidz. Comparing the fifth leg of the female, Figs. 12-13, with the preceding one, Fig. 20, it appears to correspond with one leg only, ’ : a ieaaeadinael ‘ ; " 4 | 386 Feterogenetic Development in Diaptomus. (April, . but both rami are 3-jointed as in the swimming legs of other Calanidze. On the other hand, regarding both legs as present, the “hand” of the male does not homologize with the left limb, and we have besides to account for a supernumerary 2-jointed limb on the second joint of the abdomen.. The present species was found in large numbers in Mulberry creek, Cullman county, Alabama; the color is bluish-green, and the length about ,}) in. EntTozoic PARASITES IN Entomostraca (Fig. 15, Pl. vi). — We have discussed the relation of the minute fresh-water Crus- tacea to sanitary science ini a paragraph in a recent article in the NATURALIST, but it remains to touch upon another phase of the subject. It may be thought unnecessary to trouble ourselves about the pathological conditions prevailing among such lowly animals, but it can be shown that these same causes of disease may not be unimportant in connection with human diseases. It is a fact constantly receiving new exemplification, that the parasites infesting small animals, particularly water animals, are frequently but the immature forms of parasites of animals higher in the scales. These alterating generations are exceedingly diffi- cult to study, so that while all stages may be separately known, only a fortunate combination of circumstances or patient accumu- lation of facts can connect the individual factors into the complete cyclus. Thus, for example, Professor Leuckart has but recently worked out the full life-history of Dustomum hepaticum, although the adult has been a stock example in helminthological study in the laboratory for years. The importance of such parasites, even in a commercial view, needs but a reference to trichinosis to illustrate. I am not aware that endo-parasites are known in Entomostraca except in the case of Cyclops. Embryos of Cucullanus elegans, a nematoid worm, enter the body-cavity of Cyclops and undergo two molts and then are transferred to the intestinal canal of food-fishes.! Taken in connection with the recent discoveries of S. A. Forbes,” showing how dependent our own food-fishes are upon 1Claus. Kleines Lehrbuch d. Zoologie, p. 368. 2 Forbes. On some Entomostraca of Lake Michigan, AM. NATURALIST, July, 1882. Cf. Ryder on Food Fishes, Bul. U. S. Fish. Com. Rael : 1883.] Feterogenetic Development in Diaptomus. 387 Entomostraca, the significance of these facts cannot fail to appear. A similar parasite of Cyclops is Filarta medinensis} The Cladocera are generally quite free from parasites, but I have found in several instances young nematoids in the blood sinus in front of the heart in Daphnia magna. These are mouth- less but very active round worms, subsisting upon the nutriment in the blood which constantly bathes the animal. True cysts could not be formed in the cobweb-like tissues of the hosts. This is, so far as I can learn, the first publication of Entozoa | from Cladocera. The animals were from “Schimels Teich,” Leipzig. While collecting Copepods near Tuscaloosa, Ala., I gathered a number of specimens of Cyclops tenuicornis and nearly all were unusally pale and feeble. On examination they proved to be infested with a worm of the sub-order Distomee. This sub-order includes many distressing parasites and forms which are adapted to be widely distributed by a long period of adolescence and the number of stages passed through before maturity is at- tained. } The larve live frequently in Mollusca, and in maturity the ani- mal inhabits the intestine of vertebrates. Upon examination the Cyclops individuals collected were nearly all found affected, some having as many as five parasites of vari- ous sizes about the alimentary canal, in the common vascular cavity which corresponds to the entire arterial and venus system of the more highly organized Calanidz. The Cercarian or tailed stage was not found. Were the life-history known it would prob- ably appear that the larval stage is passed within some young mollusks, and that the adult infests some vertebrate, probably fish, and would thus be perhaps transferred either in food or drink to _ human system. It is worthy of notice that the host was soon destroyed by the parasite, the post-imago or Coronatus form being absent; most of the individuals thus infested possessed abnormally persistent lar- val characters in antenne, etc. EXPLANATION OF PLATE V. Fic. 1. Diaptomus castor (?), fifth pair of legs of adult male. cae gk. a ‘same (older specimen) showing a greater retrograde metamorphosis of inner ramus. 2. sf caudal stylets of adult. 1Fedschenko. Ueber d. Bau. u.d. Entwicklung d. Filaria medinensis, Moscow. * eR o>: _ 7 i . —_— Pletes Ra + VI maissing Bouma in “separa fotdur - 388 F[eterogenetic Development in Diaptomus. [April, Fic. 3. Diaptonius castor (?) fifth legs of adult female. «mone dies ; a A. eo fifth legs of male of exaggerated or siganteus et (immature). waa thee Ee fifth legs of female. wie sii 3 - caudal stylets of same. rene “ margin of last thoracic segment of same, ee x6 leg of immature specimen of ord form just prior to molt. oe “ O. of antenna of male, gzyazteus form (immature). . ago e' es antennz of male, castor adult. pew. ay ses antenna of male, cas‘or, older form. “ 10. Epischura fluviatilis, sp. nov., abdomen and fiith feet of male: ae if 4 right foot of male. a, che i right foot of female. pap “ right foot of female (young). \ Be oF ‘3 mandible. om a labrum, mandibles and palpi, eek hc “s end of maxilliped. | ay. " globular upper part of testis. | cheb xc = end of antennules. , cee 1, Fe antenna of male. ime as swimming foot. + “ 21. Cyclops modestus, sp. nov., fifth foot. . ; mx 52. “< stylets. | Pye ve end of antenna. “ 24. Cyclops tenuissimus, sp. nov., fifth foot. Bin al “fi terminal joint of antenna. “ 26. Schapholeberis angulata, sp. nov. (a), antenna. 27, es first foot. : : aes ai lower angle of shell. “© 29. Simocephalus vetulus, outline of posterior portion of shell i in old females (a) spines. “30. Simocephalus daphnoides. See, . lower angle of shell. EXPLANATION OF PLATE VI. Fic. 1. Daphnia longispina, “é 2 6é ce 3 ce “cc 4. ce “5. Daphnia dubia, ch GE “6 66 7 «ec oc 68 6c 6c 9 ‘ce “ 10. Daphnia longispina. “© 11. Ceriodaphnia alabamensis, sp. nov., end of postabdomen. C.F 2, “ head. i pe (1 es reticulations of sheil. “13. Daphnia dubia. 6 14. ee re ie ae w whl A Soe Ble Tee EES. + 1883. | Hleterogenetic Development in Diaptomus. 499 HETEROGENETIC DEVELOPMENT IN DIAPTOMUS. BY C. L. HERRICK. ( Continued from page 389.) CycLops INGENS Herrick (Cyclofide of Minn., p, 228, Plate Iv, Figs. 1-8). Found in pools near Tuscaloosa, Ala., with Daphnia pulex and Simocephalus daphnoides. The post-imago is somewhat over ;, in. long, z. ¢., not quite as long as C. gigas according to Brady, which is very little different. Our form has longer sty- _ lets and shorter antennze in the ordinary stage, but the mature or post-imago has shorter stylets. In the last stage prior to maturity the stylets are just as figured by Brady for this stage. It is worthy of remark that C. kaufmanni Uljanin, which is certainly founded upon .a prematurely gravid larva (feet being 2-jointed and antennz undifferentiated) corresponds perfectly with larve of C. ingens. Brady himself considers C. hellert the same species, and we have here apparently an older stage with fully oe feet but not yet provided with mature antenne. A variety of C. zngens is found in cold springs at Tuscaloosa and elsewhere in Alabama, much less in size and with the propor- tions of the European C. gigas. The large examples in shallow “prairie pools” were masked by dense alge coating. The form of the fifth foot and stylets dis- tinguishes the above from other members of the genus, and one is tempted to regard these forms as varieties of C. gigas simply. C. parcus (Cyclop. Minn., p. 229) might be considered a var. of C. InNgens. CYCLOPS PECTINATUS, sp. nov. (Plate vil, Figs. 25-28). Related to C. zavus, from which it is chiefly distinguished by a semicircular series of small spines at the base of the greatly elongated caudal stylets. In the post-imago the stylets are nearly half as long as the abdomen; the antenne reach nearly to the base of the third segment. In the ordinary adult the stylets are less elongate. In all forms the lateral setae are one-third from the end and the outer and inner ter- minal setze are short spines; the fifth foot is as in Navus and the operculum valves is a little different. Most characteristic, however, is a circlet of small spines one. fourth from the base of the stylets. Length over 73,5 in. CYCLOPS TENUISSIMUS, sp. nov. (Figs. 24-25, Plate v; Figs. 20-21, Plate vr). Section with 17-jointed antenne. Extremely elongated; antennz reaching a little beyond the first thoracic segment, short jointed, formula —G eo —©¢ w—yvuovyyy vy. the terminal joint rather short, armed with three teeth near the extremity; antennules rather long, last two joints slender ; fifth foot 2-jointed, second joint with two nearly equal sete; cauda stylet, as in C. ¢enuccornis ; opening of spermathzeca elongated. This species is the most slender Cyclops known to me, and may be recognized by the toothed terminal joint of the antenne, _ acharacter otherwise confined to C. temuzcornis, “coronatus stage.’ VOL, XVII.—"NO. V, 35 ' . t : - ; 500 Feterogenetic Development in Diaptomus. [May, The teeth of this species differ from those of “ Coronatus”’ too much to confuse the two. This species is of the mavus and parcus group, but the caudal stylets closely resemble ‘enuicoruts. Near Paducah, Ky. CYCLOPS MODESTUS, sp. nov. Antennz remaining 16-jointed in all individuals seen, very short, formula — + —£ eo—orvve ve UY —u; antennules short jointed; fifth foot three-jointed, with unequal spines; caudal stylets of moderate length, lateral setze about half way to base of stylet, three longest terminal sete subequal. . This isa small species related to the preceding, but differs in many respects, the form of the spermathzca is oval. The egg sacs are slender, elongate oval. Cullman county, Ala. POST-EMBRYONAL DEVELOPMENT OF TWO SPECIES OF DAPHNIA. In a previous paper it was shown that the spine found on the posterior portion of the shell in young and male individuals, in all members of this genus, is a persisting embryonal character, and its possible advantage to the economy of the animal was pointed out. It was indicated that a recognition of the facts brought out, would throw several species into synonymy. It is my wish, in this paper, to illustrate the extent of the variations passed through in the course of later development, by two exam- ples, one of which has been but imperfectly described, while the other is new to America. These two species differ from any known to me, though they may possibly be found among some of Sars’ numerous nominal ‘species, DAPHNIA LONGISPINA Herrick (Microscopic Entomostraca, 1877). This name was applied to the young, and in connection a figure was given of a male with the spine on the head which, in the female at least, was indicative of immaturity. The name is not particularly appropriate, for the mature ‘female is not evidently Spined., This name has been long applied to another form in Europe, but apparently to an immature stage of another species, so that it is really vacant. In a paper (Notes on Cladocera of Minnesota) in the Rep. of Geol. Surv. of Minn. 1881, the post-imago is figured, and a variety of the younger stage (a little distorted in the molt). I am now ~ able to complete the chain from the embryo to the post-imago (see : | | : -1883.] Fleterogenetic Development in Diaptomus. — 5O1 Plate vit). Fig. 3 is the embryo extracted from the brood cavity, showing that the eye is near the extremity of the elongated head even before the two eye spots have united (Fig. 10). Fig. 2 shows the early stage of post-embryonal growth. Fig. I is the adult in the first stage in which all the peculiarities of the species are pronounced. Fig. 4 is the post-imago (see also Plate x1 Figs. 15-16 of Notes on Minnesota Crust., and Fig. 4 in the text). DAPHNIA DUBIA, Sp. nov. ? This species is very nearly related to the preceding, differing, however, in having the eye small and situated nearly in the cen- ter of the head, while the previous one has an eye of usual size and near the straight lower margin. The head is much more acute than in the preceding but not carinated (Fig. 9). Both these species have occasionally a horn in young stages (Fig. 14). The claws are smooth or simply pectinate. The spine in the lat- _ ter species is more elevated. It is remarkable that the same species has both forms of abdominal appendages represented at Figs. 13 and 8. The post-imago of dubia has not been seen. The nearest ap- proach to it had a considerable spine, but the head had already begun to assume the shorter form with a curved lower margin. The only allied species yet described from America, is D. levis _of Birge in which the development is tolerably well completed. By filling up the gaps till all the stages in each case are known, we have advanced one step toward an accurate determination of species, and require then to learn what variations in the process usually obtaining may be occasioned by alterations in the envi- ronment. But in the mean time we are discovering the laws ~ which govern development and the historical affinities of the dif- ferent genera and species. DAPHNIA PULEX. This common species is subject to variations which are per- plexing, but there seems to be no reason for the separation of the var. denticulata, as done by Birge. The differences relied upon are the fine teeth down the claw and the abrupt curvature of the lower margin of the head. Fig. 4 of Plate 1 in P. E. Mueller’s work figures this peculiarity of the claws. Quite typical D. pulex from Tuscaloosa, however, do not have the fine teeth and only 12-15 teeth on the abdomen. i zs — - ae i oe! MaRS 502 Fleterogenetic Development in Diaptomus. | May, SCAPHOLEBERIS ANGULATA, sp. nov. (Figs. 26-28, Plate V). The genus Scapholeberis at present consists of two species, S. _ nasuta Birge, and S. mucronata with its three varieties (a) fronte levi, (6) fronte cornuti of Europe, and (c) armata,; found in Min- nesota, Illinois and Tennessee. With regard to the European varieties it is remarkable that although they are not local varieties, the horn upon the head appears in the larger individuals and not as would be expected from the analogy of Daphnia, in young and small individuals. However, it is to be noticed that the spines of the valves in Scapholeberis are not persisting embryonic characters like the spine in Daphnia, but the young are like Ceriodaphnia. It may be that in like manner the crest upon the head in Scapholeberis is, instead of an embryonic appendage as in Daphnia, a later production. It might then be suggested that Scapholeberis is now undergoing differentiation or, in other words, is a new genus historically, while Daphnia is past the acme of its activity in the direction in which it has differentiated, and now retains its peculiarities by inheritance; and tends to con- tinue them only so far as they are of functional value. The horn which sometimes appears in young of certain species of Daphnia (D. galeata) and seems so capricious in its produc- tion, may be not unlike that of this species. Were it not that S. szucronata is known to be very variable, it might be admissible to create var. avmata a new species. Addi- tional details are given for this variety in Figs. 23-24, Plate v1. Scapholeberis angulata, sp. nov.—Head of medium size; rostrum directed down- ward and backward; eye of moderate size; macula nigra indistinct; formices and basin for antennz well developed; antennules long curved, armed with two lateral sense hairs as well as the terminal olfactory ? filaments; cephalic portion of the basin of antennee marked by longitudinal lines connected at intervals by cross lines, infe- rior portion of the part of the basin on the valves reticulate; “mucro” absent, the inferior posterior corner of shell simply sharply angled; inner wall of shell furnished with a row of small spines below and posteriorly for a part of the height of the shell; caudal teeth 5—7 in adult, being more numerous than in any other known spe- cies; size large. The “mucro” is absent in the smallest individuals seen. Scapholeberis seems to lie between Daphnia and Ceriodaphnia, agreeing with the former in being a divergent member of the fam- ily, but-still with more affinities to the latter. Near Decatur, Ala. 1 Birge. Notes on Cladocera. 2 Herrick. Notes on Crustacea of Minnesota, Geol. Rep. 1881. 3 Kurz. Doclekas neuer Cladoceren, etc., p. 22. 1883.] Heterogenetic Development in Diaptomus. 503 SIMOCEPHALUS DAPHNOIDES, sp. nov. (Figs. 30, 31, Plate V; Fig. 16;-Plate VI), Four nominal speeies of Simocephalus are deseribed: S. vetu- dus Miller, S. expznosus Koch, S. serrulatus Koch, S. americanus Birge. The differences in some cases seem quite trivial, since the form of the macula nigra certainly varies with age along with the shape and armature of head and the general shape of the body. However, the present species is so unmistakable that it is not requisite to. enter upoa a discussion which lack of material makes undesirable. Simocephalus daphnoides, sp. nov.—General shape very like Daphnia; head regu- larly curved and not strongly angled in front, not marked off from the body bya strong depression ; eye of moderate size, macula nigra oval to rhomboidai; antennules long eurved; anterior portion of shell as deep as the posterior; the three curved spines at the lower posterior angle of shell are wanting; abdomen much as in S. vetulus ; claw fringed part way with weak spines. This species is recognized by its oval shape and the Daphnia- like shape of head. In old females the spine is about midway of the depth of the shell, but the upper outline is regularly curved and not keeled as in vetulus (Fig. 29, Plate V). Quite charac- teristic is the absence of the three or four curved. spines on the shell angle (comp. Fig. 31 with 29a). On the whole in this spe- cies an approach to Daphnia may be seen, Near Decatur, Ala., with Scapholeberis angulata, also in all Southern Alabama. CERIODAPHNIA ALABAMENSIS, sp. nov. (Figs. 11-12. Plate VI). Ceriodaphnia is a very perplexing genus, and one in which the effect of age has not been studied. Three species have been mentioned from America, C. cristata Birge, C. consors Birge, and C. reticulata (= dentata Birge), there remaining pulchella, rotunda, punctata, laticauda (?) and quadrangulata, as described in Europe. Quite typical C. retzculata were collected back of Paducah, Ky. The peculiar shape of the fornices figured by P. E. Mueller can be produced by pressure. I have little doubt that this is the Same animal described from Massachusetts and Wisconsin by Birge. The head is not so suddenly angled behind the eye as figured by Birge, but more so than represented by Mueller. C. alabamensis, sp. nov.— The form for which this name is offered, is known froma single gathering at Tuscaloosa, Ala., but it differs from any known species so much as to leave no “ae < ‘RS sh eee yp aay ) ————————————— Eee ee er 504 Heterogenetic Development in Diaptomus. [May> doubt that it isa new species. A complete diagnosis unfortu- nately cannot be given. Head remarkably small and produced downward; eye very small; the head ex- tends into a beak-like prolongation below the eye; the antennules are very long and pendant as in Moina; the body is longer than in veticw/ata, and the reticulations have a double contour line as in C. pulchella , the abdomen is slender and the sides nearly parallel, the claws being short and truncate, the spines of the usual size. Two summer eggs were in the cavity of the animal figured. A fifth species of Ceriodaphnia was found in cold springs near Tuscaloosa, Ala., which is not greatly different from C. reticulata as defined by P. E. Mueller and Kurz. | | CERIODAPHNIA (reticulata var.) PARVA, sp. (vel var.) nov. 7335-1337 in. long, transparent; head not strongly depressed, somewhat abruptly angled in front of antennules; fornices-not very prominent; antennules short, coni- cal, sheli oblong, ending in a sharp angle posteriorly, simply reticulated; abdomen rather short, not narrowed very much, distally rounded at the extremity; claws rather short, smooth, spines short curved. This very small species was found in considerable numbers, but very little variation in size was noticed. C. pulchella Sars, is 0.5-0.6™", but the head is quite different, though the abdomen is similar. Kurz says also, “ Die schalensculptur ist doppel-linig,” which is not the case in our species. C. quadrangula is 0.6™", but several important differences are observable between the two species. In that species the head is said to be “ valde depressum, ante basin antennarum ferme non angulatum;”’ the antennules are large and the abdomen narrow. In general appearance this species is a reduced copy of C. reticulata, but the claws are smooth. Kurz speaks of a small var. of reticulata with smooth claws, but the fornices are then said to be sharp. EXPLANATION OF PLATE VII. Fic. 1. Diaptomus pallidus, female, “ fifth feet of female. eS 2 at 4 fifth feet of male. ro as “ antennules, tee iF mandible. ade co - head. “ 7. Canthocamptus, sp. n.? fifth foot of female. fcr 8 “ fifth foot of male. ME ait fi antennules. RS, EQ, ’ antenna of female. GeO 8 i Ma spermatheca. “72, stylets of female. epaas. rf stylet of male. ae se maxilliped. er PLATE VII. HETEROGENETIC DEVELOPMENT IN DIAPTOMUS. —— ~ a 1883.] Ox the Morphology of Arteries, especially of the Limbs. 505 Fic. 15. Canthocamptus, sp. n., stylets of female. iy. £6. ue antenna. Beat By ee fifth foot of female. “ 18. Diaptomus “ sanguineus,” fifth feet of larva (¢}). LQ). = fifth feet of larva (Q). 20. 5a abdomen of larva (9). oe 21. as fifth foot of adult (). ea 22: ee antenna of adult. «23. Diapiomus “castor,” margin of last segment ((). nt 24. ee margin of last segment (Q). 25-28. Cyclops pectinatus. “29. Diaptomus pallidus, inner ramus of fifth foot (Q.) EO REMARKS ON THE MORPHOLOGY .OF ARTERIES, Per eCrabiy ViOSE, OF THE LIMBS." ‘ BY FRANK BAKER, M.D. T is generally taken for granted that the variability of arteries is such that they are of but little use in morphological studies. Anatomists are usually of the opinion that since the function of the arteries is to nourish the tissues, their course from the heart to their destination is of too slight importance to the race to have become a fixed character, and all search for law is abandoned. But it is questionable whether some biologists have not too hastily come to this conclusion. Morphological laws are always obscure when studied in the adult individual alone. To trace them we must examine the dif- ferent phases of individual development and investigate the anat- omy of related forms. There is a period when the embryo of a vertebrate animal is not provided with a proper vascular system. During the early stages of the segmentation of the ovum, no vessels exist, the young cells receiving the necessary nutriment from an interstitial plasma, as do those of the lowest Protozoa. This stage is of short duration. Throughout the minute disk- shaped object which is hereafter to be a fully developed verte- brate, certain cells appear, of a slightly reddish color, dotting the disk in a peculiar marbled manner. From their appearance and isolation these are known as 0dlood-islands. They touch each other finally as they increase in number, either at some part of 1 Abstract of a paper read hefore the Montreal meeting of the Amer. Assoc. for the Advancement of Science. eae \ 506 Remarks on the Morphology of Arteries, [May, their contour or by means of processes which they throw out, so that there results a net-work, at first indistinct but gradually i in- creasing in clearness and color as the cells enlarge. it Each of these blood-islands then undergoes vacuolation, a por- tion of the protoplasmic contents becoming liquified and leaving a cavity. By a budding process new cells are formed in the in- terior of the ebeiere is and becoming detached float free in the fluid which fills the vacuole. At this period, therefore, the blood- islands present an outside cell-wall with a contained fluid in which float free cells or ie a the whole arranged in a close mesh-work. Next the cell-walls wherever in contact thin away and disap- pear, there resulting a tube the walls of which are the original cell-walls of the blood-islands, the contents a fluid, plasma, in which swim free blood-corpuscles. There is at first no special difference in size among the vessels thus formed, nor is there any structural difference by which we can distinguish arteries from veins. No trunks or branches can as yet be made out, it is in fact a capillary plexus that appears, all vessels lying on the same plane and communicating equally with each other. But a difference soon begins to be manifest. The rapidity of growth varies greatly. Along certain lines the vessels begin to increase in size so that soon there is visible distinction of capil- laries, branches and trunks. This process of capillary and trunk formation extends from without inward, attains the proper body of the embryo, finally reaching the rudimentary vesicle which represents the heart. (Plate VIII.) It should be noted that the development is centripetal. Noth- ing is more natural than to look upon the arteries as a system proceeding centrifugally from the heart outward, | However convenient this may be to the physiologist or tiie surgeon, to the anatomist it embodies a fallacy. The capillaries are the first formed, next the arterioles, then the branches of larger size, finally the trunks. It is owing to the subtle persistence of this fallacy that the study of the arterial system has advanced no farther. I have mentioned that the rapidity of growth is greater along certain lines, thus leading to the formation of trunks. It is con- ceivable that these trunk-lines should be intermediate in direc- tion, but in fact they usually become established in certain definite situations. What can be ascertained as to the causes for this ? 7 / of Bc: : be _. ursula, should not be considered a sufficiently good species. 4 ys Pp a re me x - —_— tlle! 4 1883.] Sy. : Zoology. 793 The entomological papers from the transactions of the Iowa Stite Horticultural Society, for the year 1882, have been pub- lished separately for gratuitous circulation, and contain much in- rtuation of practical value from Hon. J. N. Dixon, Miss Alice % Walton, and Professor Herbert Osborn. The monthly meetings of the Brooklyn Entomological Society will hereafter be held on the last Saturday of each month ia Wright’s business college, corner of Broadway and Fourth Streets. The Stettiner entomologische Zeitung, Vol. 44, 1883, Nos. 7-0, contains beside others of less general interest the following papers: Dr. H. A. ; (lagen’s contributions to a monograph of the Psocide (continued); ‘eemarks upon the influence of change of food upon morphologi- “ii varieties, especially in the species of the genus Eupithecia, ay Dr. A. Speyer; H. B. Moschler’s notice of Fernald’s catalogue of N. A. Tortricidae; and Dr.C. A. Dohrn’s list of Zeller’s en- _tomological papers, published after the appearance of Hagen’s - Bibliotheca. At the fiftieth anniversary meeting of the London Entomological Society, held May 2d of this year, Professor J. O. Westwood was elected by acclamation titular life-president of the society. ZOOLOGY. THE SEA PENS OR PENNATULIDA.'—Professor Milnes Marshall and Mr. W. P. Marshall give an important and interesting account ‘of the Pennatulida collected in the Oban Dredging Excursion of the Birmingham Natural History and Microscopical Society. Funiculina quadrangularis, Pennatula phosphorea: and Virgularia mirabilis were the three forms collected. The very primitive nature of the first of these is indicated by the irregular arrangement of the polyps, their independent inser- tion into the rachis, and in the comparatively slight difference be- tween the polyps and the zooids, as well as by the shortness of the stalk, or part of the colony devoid of polyps. In Pennatula we have the polyps fused into leaves, and there is a considerable difference in the size of their constituent parts, as well as great anatomical differences between the polyps and the zooids ; the Stalk is also relatively much longer. Virgularia is shown to be the most modified by the restriction of the reproductive organs to imperfectly developed polyps, and, in addition to these points, by the presence of the so-called radial vessels which are absent from the other two forms. A very curious discovery has been made with regard to Virgu- laria; with but one exception all the known specimens of Virgu- laria are mutilated, the lower end being generally, and the upper always wanting; as a hypothesis, the author. some time ago sug- _ gested that the tips were probably bitten off by some marine ani- AE 800, Birmingham, 1883, pp. 81 (4 pls.). = 794 General Notes. . [ July, mals, probably fish. Since then they have (through Mr. R. D. Derbyshire) been able to examine the contents of a stomach of a haddock, which consisted of five fragments of V. mzrabilis, and of these, three were “ actual perfect upper ends;” as a possible ex- planation of this mutilation it is suggested that the apparent absence of stinging-cells from this species is not only apparent but real, so that the fish are enabled to bite at them with impu- nity. As the specimens examined were not in a thoroughly sat- isfactory condition for histological study, the question must be examined again with more satisfactory specimens. The evidence afforded by the dredging leads to the supposition already suggested by Richiardi and Kolliker, that /aniculina forbest, the supposed British species, is only the immature form of /. guadrangularis, which is well known from the Mediter- ranean. The most complete example from Oban is only thirty- nine inches long, but at Hamburg there is a stem eighty-nine inches in length. The foregoing notice has been taken from the Journal of the Royal Microscopical Society. Having received from the authors - a copy of the book, we can bear testimony to the excellence of the plates. The authors quote Dalyell’s statement that Virgularia when in captivity “remains contracted during the greater part of the day, and the organs are seldom displayed before five or six in the afternoon;” but the authors with more reason suggest that Pennatula appears to be “ nocturnal” when brought to the sur- face, “simply because the amount of light it receives in broad daylight is vastly in excess of what it receives normally at the sea bottom, and that it is only towards evening that it is placed under what to it are normal conditions as to amount of light.” The authors are strongly in favor of the now generally accepted view that Pennatula lives upright, planted in the sea bottom. As regards the phosphorescence observed in the majority of the Pennatulida, P. phosphorea receiving its name from having this property, the authors say: “ This was well seen in the Oban specimens while living; the more perfect female specimens when suspended in a jar of sea water in the dark, and irritated or ex- cited by gently brushing the leaves, exhibited a fine display of phosphorescence, the different polypes, when touched, showing minute brilliant points of light which appeared to flash over the whole surface of the feather in rapid irregular corruscations.” Panceri’s observations on this subject are adopted, and his views presented at some length. HETEROGENETIC DEVELOPMENT IN D1APToMUS, ETC., CORREC- TIons.—The editors kindly allow me space to make the following emendations to the article entitled Heterogenetic Development in Diaptomus, rendered necessary by an unfortunate loss of proof in the mail. Cyclops pectinatus (p. 499) should have stood “ C. thomast 1883. ] Zoology. 795 Forbes?” It is at least the southern representative of this spe- cies, which consequently is distributed from the Great lakes in Minnesota to the gulf. The similarity to C. décuspidatus Cls., is very close. ; | The description of Epischura (pp. 384-85) was written before the second part of Mr. Forbes’ paper was obtained, and in making up for the press, the generic description given in that place was not referred to. It might be inferred from remarks on p. 384, that in £. /acustris the female has a structural modification of the abdomen, which is obviously not stated by Forbes. Although the writer has since succeeded in rearing one Cope- _ pod (Canthocamptus), and observing the transition from one of the dimorphic conditions to another, and the two stages, in both of which eggs are carried, are strikingly diverse, it should be admitted that perhaps too much confidence was expressed in the _ inferred conclusions upon Diaptomus. ~ It may be that Brady has confused two distinct species in his account of J. castor, inasmuch as his descriptions disagree with those of Sars. It is evident that the same peculiarities of distri- bution maintain in England as here, however explained. Correc- tions and information bearing upon these questions are earnestly solicited. f An opportunity for comparing types of Diaptomus pallidus " with D. siczlis shows that the differences are even less than indi- cated, consisting of the greater robustness of the latter and a { greater elongation of the antennz in the former. There is a dif- i ference of .1™™ in the length of the living adults seen—C. L. Flerrick. et ——THE CoxAL GLANDs oF ARACHNIDA AND Crusracra.—In this journal for September, 1875, we described certain gland-like organs of Limulus, supposed to be renal in their nature, situated : at the base of the legs. We then said that the organ “in its gen- i eral position and relations was probably homologous with the green gland of the Decapod Crustacea, and its homologue in the lower orders of Crustacea, which is supposed also to be renal in its nature. It may also possibly represent the organ of Bojanus in the Mollusca, which is said to be renal in its function. It per- haps represents the glandular portion of the segmented organs in worms.” In the Proceedings of the Royal Society, No. 221, 1882, Pro- fessor Lankester, in a paper “On the coxal glands of Scorpio, hitherto undescribed and corresponding to the brick-red glands _ of Limulus,” revoking his first expressed opinion (Quart. Journ. Mic. Sct., 1881) that these were not “ of a glandular nature at all,” concludes from histological examination that they are glands, and calls them “coxal glands.” He was also unable, as were our- selves, to find any openings into the great veins, or “to detect the Situation of their opening to the exterior.” Lankester then de- 796 General Notes. [July, scribes the coxal glands of Scorpio, and also finds that the coxal glands of Mygale are elongated and lobed as in Limulus. He remarks: “ Possibly such coxal glands are in all cases the modi- fied and isolated representatives of the complete series of tubular glands (Nephrida) found at the base of each leg in the archaic Arthropod Peripatus.” As will be seen in the foregoing note on Peripatus, that animal is provided with a series of paired organs which Moseley and Balfour, with Sedgwick, regarded as Nephrid- ia, homologous with those of Chzetopod worms. It now appears that homologous organs exist in a third type of Arachnida, for not only do the spiders and Pedipalpi possess coxal glands, but also the mites. In his excellent ‘“‘ Observations onthe Anatomy of the Oribatidz,” in the February number of the Journal of the Royal Microscopical Society, Mr. A. D. Michael describes a sac which he believes to be glandular, and which he calls the ‘super-coxal gland.” The organ was first recognized in the mites of this family by Nicholet, who supposed it to be connected with what he and others imagined to be the stigma. When the upper part of the cephalothorax, and the adipose tissue which underlies it, has been removed, “what appears to be the enlarged, blind end of a fine colorless sac, may be seen on each side of the body, the seemingly blind end being nearest to the eye; the sac descending obliquely downward and slightly forward, and being attached close to the acetabulum of the coxa of the second leg; a closer examination shows that this is not the only attachment, but that the lower end is apparently bifurcated, and that the second branch is attached much nearer to the center of the body, and highe;x in level than the coxal branch. On dissect- ing out this sac, and carefully extending it, a matter by no means easy, it will be found that what seemed to be the blind end was not the end at all, but that the whole organ is an elongated sau- sage-Shaped sac, bent upon itself in the middle and taking a sin- gle turn, so that the two halves cross, but for some distance the two limbs of the horseshoe (if 1 may call them so) lie over each other, or are so closely pressed against one another as to appear one; it is only toward the end, that they stand free from each other when zz situ.” Mr, Michael suggests that these glands are analogous to the nephridia (segmental organs) of Vermes, and the green gland of Astacus and other Crustacea, and the coxal glands in scorpions and Limulus. The resemblance to the segmental organs of worms, especially the leech, is very considerable as regards the general form of the organ, and toa lesser extent in the minuter struc- ture, and if the double lines described in Michael’s account be tubules, “they would be analogous to those in the nephridia. The sac (super-coxal gland) would correspond with the gland in the nephridium, and the globular body with the vesicle.” : ooh eae tind, aes AO oe ae or eagle te ane a Te a CRUSTACEA. € L. Herrick. ¢ ‘ } a The th Pn, fej... fo th. hay / 843, JLOGICAL AND NATURAL HISTORY SURVEY OF MINNESOTA. N. H. WINCHELL, STATE GEOLOGIST. Pe, A FINAL REPORT ON THE RUSTACEA OF MINNESOTA INCLUDED IN THE ORDERS _ CLADOCERA AND COPEPODA, ether with a synopsis of the described species in North America, and keys to the known species of the more important genera. By C. L. HERRICK, Assistant in Zoology. MINNEAPOLIS : JOHNSON, SMITH & HARRISON. ‘ 1884, s PREFACE x a” presenting what may be denominated a final report of the work done in this state upon the group of crustacea best repre- sented, 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 exist- ing 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 material. The entomostracean fauna is quite different at different seasons, 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- ceidee, which are the most minute of arthropods. This study has been rewarded with an unexpectedly large number of forms, and a particularly large number of species identical with those of Europe and elsewhere. Prof. 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 hardly yet known in Europe. The remarkable Monospilius is among these. This ani- mal has but a single larval eye in the middle of its forehead, and ‘ } i th a a — ee See Se eee SS - Ee Ss a —hCUr ee 4 TWELFTH ANNUAL REPORT. wears its old covering over the newly-formed shell till the latter is a curious patchwork mass. The attempt has been made to in- corporate 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 same distinctions in their descriptions, and it is necessary to select points sharply distinctive and conspicuous from the often meagre 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 necessary 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 material 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 per- haps somewhat summarily treated. The excuse must be the con- dition of the synonomy. However, most of the combinations made were the result of careful study of large series from different locali- ties. The sketches illustrating this paper are photo-printed from the writer’s own drawings, and, without the elegance of litho- graphs, serve the purpose of explaining points of structure which cannot be communicated verbally. I am indebted to Prof. A. 8. Forbes for very timely aid in bibliography, without which the paper could not have been completed. To Dr. Lindthal, through my friend Mr. Oestlund, I am indebted for a like service. But my obligation is deepest to Prof. Rudolph Leuckart of Leipzig, who kindly afforded access to almost a complete set of works on Kuro- pean entomostraca. Prof..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 en- abling me to observe the great similarity of widely-separated faune. Mr. Lieberg also sent specimens of Diaptomus stagnalis from saline pools in Dakota. STATE GEOLOGIST. 5 INTRODUCTORY. “ Evading e’en the microscopic eye, Full nature swarms with life ; one wondrous mass Waiting the vital breath, when Parent Heaven Shall bid the spirit blow. The hoary fen, _In putrid streams, emits the living cloud Of pestilence. Through subterranean cells, Where searching sunbeams scarce can find a way, Earth animated heaves. The flowery leaf ‘Wants not its soft inhabitants. Secure ‘Within its winding citadel, the stone Holds multitudes. * * where the pool Stands mantled o’er with green, invisible Amid the floating verdure, millions stray. * * Nor is the stream Of purest crystal, nor the lucid air, Though one transparent vacancy it seems, Void of their unseen people.’’—Cowper. To the poet only, and the man of science, is it given to meet these ‘unseen people” on those familiar terms which warrants the use of the word intimacy; yet may not we who, like Sam Weller, find our “vision limited,’’ because we have only eyes, avail our- selves of the kind introduction these people give us, and shake hands, as it were, though perhaps a little stiffly, with our neigh- bors, the unseen people. Whether we like it or not—Cowper intimates we shall not— these people, in one way or another, touch us constantly, and like diminutive sprites are ever active in hatching mischief or doing their little favors to humanity. Happily most of these are amiable goblins, and are tireless in endeavors to secure us against our ‘Isidious enemies of their own ilk. With your permission we will draw the curtain which separates us from the naiades of our pools and streams. The numbers of living forms to be found in any pool is a con- stant surprise even to the student of this subject, and the variety _ and unique character of the animals, particularly, cause a constant flow of wonder and admiration. Confining ourselves to the crus- — = SESS 6 TWELFTH ANNUAL REPORT. tacean forms which are, perhaps, most typical, abundant and interesting of the smaller animals of fresh waters, it is to be re- marked that they are of a practical value to an extent which can hardly be correlated with their seeming insignificance. To understand this fact it is first necessary to recollect that water in some form is an indispensable vehicle for the nidus of disease germs as well as of all life; desiccation means death. The abundantly-watered portion of our country must become per- meated with the pestilential hordes ingendered in its fens did not this army of devouring animalcule destroy the decaying matters accumulating in the waters. Their importance depends largely on their minute size and un- paralleled numbers. The majority of non-carnivorous crustaceans are so constituted that their diet is nearly confined to such floating particles of matter as are present in the water, in a state of more or less fine comminution; for, nearly without prehensile organs, these animals, by means of a valvular or, at most, ladle-like labrum. dip from the current of water kept flowing by the constant motion of the branchial feet, such fragments as the snail and scavenger-fish have disdained. All is fish which enters the net. Think of it, poor dyspeptic, a constant supply of food of every variety and no question asked for stomach’s sake! Bits of decay- ing alge or the broken fragments of a disintegrated mosquito, all alike acceptable and unhesitatingly assimilated. Nor is the sanitary aspect the only one in which the entomost- raca, as our minute crustacea are collectively called, command attention; they are valuable also as a food supply. Now, does some one jump at the conclusion that the water we drink is filled with aliment in such pleasant form as that repre- sented above—that Dr. Tanner after all lived on a watery solution of entomostraca? Too fast, my friend—food for fishes, but not therefore an insignificant element in our cuisine economy; for it has recently been shown by Prof. Forbes of Illinois, that some of our best fresh-water food fishes are almost dependent on some one or more species of entomostraca. Darwin shows that cats regulate the clover crop of England via field-mice and humble-bees, but it is not half as far from our “bugs” to the price of trout and white- fish. Still we are not prepared to be surprised at this, for have we not long understood that whales go fishing, with their whalebone nets, for little mollusks not big enough to excite the cupidity of the catorial small boy ? STATE GEOLOGIST. 7 The fact is, that the principle laid down by the Deacon (of venerable memory) that “the weakest pint must stand the strain,” maintains in nature aside from the nature of “‘shays.” The minutest forms are in some sense the most important, for they are the links which stand nearest the rock, and if they be loosened the depen- dent series falls. The animals of the above group are, it is likely, the best criteria by which to judge of the purity of natural waters if their distribu- tion were correctly understood. The presence of some species in great numbers is sufficient evidence of organic impurity. A criti- cal study of the contents of samples of such waters will enable us to determine their character almost as well as by analysis. The following list of the animal life visible in a quart of filthy pond- water, taken by simple dipping, will perhaps be suggestive on this point: Daphnia pulex ......206 b sridida she, Sabhd8 1300 54 CRRA Se ee Ose ie ee Pe oe ere 6 GETIODUDANIG 6 civiore ain oie: a0 nein ns de asesee sens epee ie oie ine win niaim + wl aid a/a)h a a:ain'ai in 1400 Simocephalus..........- aversivte's Rfeete ates I raTaleie tie Sls a eine siciale cists oie wicie eraiaiote cia 56 SHDTUS Has ok coke eawies sion ve Panta en open ise: aie slotaciannicde eisai ab acl ese ce wie 50 TREIEE e S eee ee a ee Te 30 OR Dist PE eg SSeS SS Se See pee en a 120 lie Gath nv ) Se a oo ee a a 1662 IMFASOTIAZ 0. ss ce eces PRD Ne Bie Geeta ale halal SiGe eiwc\ ie elu iniciorees' Sinro¢ephalus 1 / 7 a a ae --MO i NA--~--Ceriodaphnia on “Daphnia > ? 1 BS, a ne - Me eee ralaherts Le { = nN } Me thes 7 ¢ "al acro. %, : Bosipi Streblocercus 4: ‘ S\_ Lyncodaphnia e t 4 at ales Lathonura Drepanothrix BES c 7 /Tiocryptuy N N ~ Acantholeberis SAS Camptocercus_ Loken ats ea Alonopsis--~"— 6 ee ih “(Alona)” a ; LL ieand Graptolebris Chydoris “e ‘\Monospilus FIG. 1.—TABLE ILLUSTRATING THE RELATIONS OF THE CLADOCERA CALYPTOMERA. *NOTE.—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 pivetal group, Moina, is uncertain. The author must confess that his inclination is toward a belief that the line culminating in the Daph- nide diverged from a group of organisms resembling Phyllopoda, more definitely, resembling Limnetes. There is a very 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 Phyllopoda in their present form may be well admitted. 1 Entomostraca, seu Insecta testacea, que in aquis Danie et Nerwegix reperit - deseripsit, ete. Otho Friedric Mueller, 1785. 2 Monoce. qui se trouvent aux Envir. de Geneve. 16 TWELFTH ANNUAL REPORT. The Cladocera or Daphnoidea are characterized by the more or less leaf-like feet, and the lamina of thin chitine which encloses the greater 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 maxil- lary segment and is the most conspicuous and variously formed, while really least important, 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 history of the animal. Although figures and brief descriptions of animals belonging to this group are to be found in the works of Swammerdam, Leewen- hoek, Trembley and other 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,? an eminent Swiss natur- alist, was the next to contribute important discoveries relating to these interesting animals, though Ramdohr had given anatomical details of several species. Gruisthuisen, a little later gives farther details of Daphnia sima (Simocephalus). The work of Milne Edwards gives a resume of what was known regarding these ani- — mals 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 Scandinavian peninsula being the birth-place 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. Koch, C. L., Deutchlands Crustaceen, etc. Schoedler, J. E., Ueber Acanthocercus rigidus, etc. Dana, J. D., Crustacea of the Wilkes’ Exploring Expedition. Lievin, Die Branchiopoden der Danziger-Gegend. Fischer, Leb., Ueber die in der Umgegend von St. Petersburg vorkommenden Crus- taceen, etc., 1851. Lilljeborg, W., De Crustaceis ex ordinibus tribus, (or) Om de inom Skane forekom- mande Crustaceer af ordningarne Cladocera, Ostracoda och Cope- poda. STATE GEOLOGIST. 17 This valua’ le work is particularly good on the Cladocera, but is unfortunately 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, Schoedler, J. H., Die Branchipoden der Umgegend von Berlin, 1858. Smitt, F. A., Sur les Ephippes des Daphnes. Lubbock, J., An account of the two methods of reproduction in pepe, ete. Leydig, Fr., Naturgeschichte der Daphniden. The most magnificent work published. _ Lilljeborg, W., Leptodora hyalina, 1861. Sars, 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. H., Neue Beitrage zur Naturgeschicte der Cladoceren, 1863. One of the most important works on the Lynceide. The author is rather too credulous and inclined to form new species. Klunzinger, Einiges zur Anatomie der Daphniden nebst kurzen Bemerkungen ueber die Susswasserfauna der Umgegend Cairo’s. Sars, G. O., Norges Ferskvandskrebsdyr Cladocera ctenopoda, 1865. The best work on the Sidide, ete. Mueller, P. E., Danmark’s Cladocera. One of the most useful books on the subject. Especially good on Lynceide and Bosminide. Plateau, Felix, Recherches sur les Crustaces d’eau douce, etc., 1867-69. Mueller, P. H., Note sur les Cladoceres des Grands Lacs de la Suisse. Weismann, A., Bau und Lebenserscheinungen Leptodora hyalina. Sars, G. O.,Om en dimorph Udvikling Samt Generationsvexel hos Leptodora, 1873. Claus, C., Zur kennt. d Organ. u. d. feineren Baues der Daphniden. Claus, C., Zur kennt. des Baues, ete., der Polyphemiden. Gruber and Weismann, Ueber einige neue oder unvollkomen gekannte Daphniden. Weismann, Thierleben im Bodensee, 1877. Luiz, A., Untersuchungen ueber Cladoceren der umgebung von Bern. _ Claus, C., Die Schalendruse der Daphniden, 1874. Spangenberg, Fr., Ueber Bau und Entwicklung der*Daphniden. Lilljeborg, W., Crust, Suececorum Ordin. Branchiop. et Subord. Phyllop., 1877. Pavesi, P., Nuova Serei di recherche delia fauna pelagica nei laghi Italiani, 1877-1879. Grobben, C., Zur Entwicklungsgeschicte d. Moina rectirostris, 1789. Weismann, Beitrage zur Naturgsch. der Daphnoiden, Leipzig, 1876-79. (Valuable on the physiology). The American literature may be catalogued in a few lines. The first descriptions and figures with which I am familiar are those in the Rep. of the U. S. Fish Commission, 1874, where 8, I. Smith notes Daphnia galeata, D. pellucida and D. pulex; also a species of Bos- mina, Kurycercus lamellatus and Leptodora hyalina. A. E. Birge was the first to systematically study Cladocera in America, and his “ Notes on Cladocera” furnished a basis upon 2 18 TWELFTH ANNUAL REPORT. which to build. A few notes were published by the writer a little later. A few additional notes and descriptions of new species were published in the eleventh annual report of the Minnesota geol. and nat. hist. survey. Prof. Birge published other notes in the Medical Tourer and Examiner of Chicago, which I have not seen. Prof. Forbes of Normal, Ill., in an article in the American Naturals ist, July, 1882, adds a number of facts and one new species. In addition to the abate, a figure of Sida was printed in one of Hayden’s Survey Reports, and some account of the Cladocera of lake Michigan was given by B. W. Thomas, I believe, in one of the official reports of the Chicago Water Commission. CLASSIFICATION OF THE CLADOCERA. SUB-ORDER I,—CALYPTOMERA (membrane-clothed). Body enclosed in a bivalve shell. Mandibles truncate below. Maxilleze feo spiny. Thoracic ganglia discrete. TrisE I.—CTENOPODA. Feet six, similar, foliaceous, all distinctly branchiate. Fam. 1.—SIDIDE. Swimming antenne with two unequal rami, intestine simple. Fam. 2.—HoOLOPEDIDA. Swimming antenne& simple, elongate cylindrical (in the male prehensile), intestine with two lateral dilations. Trise I].—ANomopopDa. Feet five (or six) pairs, the anterior pair more or less prehensile and destitute of branchiz. Fam. 1.—DapuHnip#. Rami of antenne three and four-jointed, five pairs of feet, the last with a curved appendage guarding branchial sac; antennules of female short, one-jointed. Fam. 2.—BosMINID&. Six pairs of feet, antennules elongated, many-jointed. Fam. 3.—LYNCODAPHNIDA. Antennules of female elongated, but one-jointed; intestine simple or convolute. Fam. 4.--LyYNcEID2. as Antenne with both rami three-jointed, intestine convolute, with ab- dominal but no anterior ceca. SUB-ORDER II.—GYMNOMERA (destitute of covering). Body without or nearly destitute of bivalve shell; feet not branchiate, spiny. An- terior thoracic ganglia in one mass. STATE GEOLOGIST. 19 Fam. 1.—-PoLyPHEMID 2. Abdomen curved, terminating in two long stylets. Fam. 2.—LEPTODORID&. Abdomen straight, ending in short claws. FAMILY SIDIDA, Head separated from the body by a depression, without promin- ent fornices (or spreading shields) over the base of the antenne. First pair of antenne, or antennules, as we shall uniformly call them, one-jointed, usually rather small in the female, but extend- ing into a very strong flagellum in the male. Antenne long, biramose, with unequal branches. Mandibles truncate at the end. Maxille armed with large spines. The form is usually elongate, and the abdomen often extends beyond the edge of the shell behind. The male openings are usually in the end of long ap- pendages which depend from the base of the post-abdomen. This interesting family is represented in America so far by four species, one of which constitutes a new genus. Others will undoubtedly be found upon a careful study of the fauna of the great lakes Most of the species prefer the clearer and colder water of large lakes. The processes of development, as traced by the writer, vary very little from the method exhibited by Moina. The ephippial condition, however, is not found in these animals which are less subject to destructive influences of the climate. They do, how- ever, produce so-called winter eggs which are laid in October and are distinguished from the summer eggs, which hatch in the brood cavity, by a brown color and the presence of fatty spheres. These eggs are produced in large numbers in distinction from most other Cladocera in which the winter eggs are very few. These eggs are permitted to settle to the bottom and there develop at the proper time. Sida crystallina is often found in immense numbers in large lakes which contain abundant plant growth. The size, and especi- ally the reproduction activity, is very dependent on the environ- ment, and hence little success is obtained in preservation in aquaria. Some of the genera are nocturnal and should be sought at the surface on quiet evenings. I.—GENUS SIDA. Straus. (Plate N. Figs. 12-14.) Body elongate, hyaline. Head small, quadrate. Fornices ab- sent. Antennules of female small, truncate; of male, with a long 20 TWELFTH ANNUAL REPORT. flagellum. Second antennze with the rami two and three-jointed. Male with the sexual openings just behind the last pair of feet. It is the upper or longer branch of the antenne which in Sida is three-jointed, while the reverse is the case in the next genus. The only species, according to P. E. Mueller, is the ubiquitous S. crystallina. The S. elongata of Sars is distinguished by the smaller head and its concave lower margin and more elongate shell. The terminal joint of the longer ramus has one less seta than S. erystallina, while the post-abdomen has more numerous spines. We incline to believe it a valid variety at least. The bibliography below is extracted from a previous report: Daphne crystallina, MUELLER. Daphnia crystallina, LATREILLE, BOSC. Sida crystallina, STRAUS, Mem. Mus. Hist. Nat. Sida crystallina, M. EDWARDS, Hist. Nat. Crust. Monoculus crystallinus, GMELIN, MANUEL, FABRICIUS.’ Monoculus elongatus, DE GEER, Mem. servir. Hist. Ins. Sida crystallina, LIEVIN, Branch. d, Danziger Geg. BAIRD, Brit. Entom. LILLJEBORG, De crust. ex ord. trib. FISCHER. SCHOEDLER, Die Branch. d. Umg. v. Berlin. Neue. Beitr. LEypiG, Naturg, d. Daph. SARS, Norges Ferskv—Krebsdyr. Sida elongata, SARS, ‘“ Be - Sida erystallina, P. E. MUELLER, Danmark’s Cladocera. Kukz, Dodekas Neuer Cladoceren. BIRGE, Notes on Cladocera. HERRICK, Microse. Entom. Lutz, Untersuch, u. d. Cladoceren d. Umg. y. Bern., 1878. WEISMANN, GROBBEN, Entwicklung. Moina. HERRICK, Crustacea of Minnesota. 11.—GzENus Pszupo-stipa. Herrick. (Genus n.) Similar to Sida. Antennules of the female, with a long flagel- lum, like that of the male of Sida, sensory set lateral. Body elongate, head short, extending into a sharp beak. The post- abdomen is armed with groups of sharp spines or bristles. Most characteristic, however, is the fact that the antennary joint, which in Sida is. two-jointed, in this species is tri-articulate, and the two- jointed ramus has a great number of sete (16-17). Sp. 1. Pseudo-sida bidentata, Herrick. (Sp. n.) (Plate KK. ° Pies.) Posteabdomen armed with 12-14 clusters of spinules in a trans- verse row; the terminal claw armed with two long basal spines, and with numbers of fine teeth on the inside. The two-jointed STATE GEOLOGIST. 21 ramus of the antenne has six sete on the basal, and ten or eleven on the terminal joint, while the three-jointed ramus has a short terminal joint bearing three spines. The valves are marked with sparse spines on the lower margin. In most respects this species is like Sida, which it resembles in size. In the form of the female antenne it is like Latona which it also somewhat resembles in the number of joints of the antenne and the numerous sete they bear. It is certainly an interesting transition form. Found only in swamps bordering Mobile bay, Ala., but whether in brackish or fresh water my notes do not inform me. Sida erystallina lives far out im the bay, and Daphnella is found in pools along shore. u1.—GENus LImMNosIDA. Sars. (Plate N. Fig. 9.) _ Head crested; eye in a conical prominence. Shell elongated, produced above in an acute angle. Antennules small, truncate in the female; in the male of enormous size; antenneze very long. Post-abdomen smooth; terminal claw spiny. The one species, L. frontosa, Sars, is not yet known in America. Iv.—GENUS DAPHNELLA. Baird. Neither beak nor fornices present. Antennules of female small, truncate; those of male long, flagellate. Antenne with two-and three-jointed rami. Male with a hook on the first foot, and large ¢opulatory organs attached to the base of the post-abdomen. Sp. 1. Daphnella brachyura, Lievin. Sida brachyura, LIEVIN, Branch. d Danziger Geg. Daphnella wingii, BAIRD, Brit. Entom. Sida brachyura, LILLJEBORG, De crust. ex ord. trib. Diaphanosoma brandtianum, FISCHER. Erganzig. Berichtig. Daphnella brandtiana, SARS, Norges Ferskv.—Krebsdyr. Daphnella brachyura, P. E. MUELLER, Danmark’s Cladocera. Daphnella brachyura, Lutz, Untersuchung u. die Cladoceren d. Umg. v. Bern. Sida brachyura, PAVESTI, Nuova serie di recerche della fauna pelagica nei laghi Italiani (L. Trasimene). Daphnella brachyura, HERRICK, Notes on Crustacea of Minnesota. {Compare also D. expinosa, BIRGE, Notes on Cladocera p. 3.) The species of Daphnella found about Minneapolis, occasionally abundant, seems not to differ in any important character from EKuropean types of D. brachyura, although I formerly regarded it _ as distinct (D. winchelli, Microscopic Entom., Addenda). Head less than 4 the body (about .27 mm., while the body is .6 mm. long); eye about + head; antennz when reflexed extend a little beyond 2 the length of body. Male, .7 mm. long; antennz a es ote _ 22, TWELFTH ANNUAL REPORT. reflexed, reaching base of shell; anterior antenne extremely long; copulating organs reaching nearly to end of claws. Having care- fully compared our specimens with the descriptions and figures given by Birge for his D. expinosa, the evidence seems to indicate not only that they are identical, but both are really D. brachyura. The distinctive characters of D. expinosa are a greater indentation between head and body, absence of caudal teeth, greater length of male appendages, and the opening of the vasa deferentia below the “instep ’’ of these appendages. The absence of teeth upon the post-abdomen is of even generic importance according to Sars, who gives it in his synopsis of genera as typical for Daphnella, In our specimens the claws are at least pectinate if not serrate, while the appendages of the male reach generally nearly to the middle of the claws. The relative Jength of these appendages and the antennez of the male is variable. Sp. 2. Daphnella brandtiana, Fischer. Head as long as half the body, antennze when reflexed reaching beyond the posterior margin of the valves. Length 0.8 mm. . Of the validity of this species we can form no conclusion. It is usually considered a variety or phase of the above. v.—Genus Latona, Straus. (Plate N. Fig. 8.) Body elongate, broad; head large and square, appendaged below with triangular laminze; fornices present. Antennules rather large. The larger ramus of the antenne is two-jointed and has an expanded process at the base. The lower posterior angle of the shell has a peculiar diverging set of sete. The shell is often orna- mented with numerous flecks of bright color. There is a copula- tory apparatus in the male. Latona setifera, Mueller, Is the only species, and is not yet recognized in Minnesota, but was found by Prof. Birge in lake Michigan. FAMILY HOLOPEDIDA. Genus Hotopeprium, Zaddach. (Plate N. Fig. 11.) The peculiar animal bearing the name Holopedium gibberum has the brood cavity greatly elevated, and the whole upper part of STATE GEOLOGIST. 93 the animal is covered by a jelly-like mass secreted as a protection er float. The antennz are simple in the female and extend through a slit in.this covering. In the male they are prehensile and have rudimentary inner rami. It would be difficult to recog- nize the affinity of the female with its monstrous form were it not for the male and particularly the development history. Found in this state probably only in lake Superior. Forbes mentions it from lake Michigan. FAMILY DAPHNIDA. The family Daphnide contains the genera Moina, Ceriodaphnia, Scapholeberis, Simocephalus and Daphnia, which include the com- monest, as well as some of the largest, Cladocera. The genera may _ be distinguished by the following table: I. Head rounded, not beaked; antennules long in both sexes, shell not covering the end of the abdomen.................--..e0800- Moina. II. Head rounded; antennules rather short; shell enclosing whole ey ee tats Pa ea 82 ici ER tH ee CheNY "nhc idinlela w'3 6 Ga Ss bAis= Se Ceriodaphnia. III. Head somewhat beaked below, shell angled below or extending in long spines from the lower angie, pigment fieck roundish...Scapholeberis. IV. Head beaked’ below; shell rounded below, with a blunt spine above : pigment fleck elongate............. + Be SEC Ae tes Ae meres Simocephatlus . V. Head beaked below ; shell extending ina sharp spine atthe upper posterior angle’; pizment fleck small... 25 2.52 6c. cee ceecuecee Daphnia. THE CIRCULATORY SYSTEM OF THE DAPHNIDZ. In the Daphnide, and, indeed, the Cladocera in general, we meet an instance of great development of surfaces at the expense of solidity of form and compactness of organs. The whole body is composed of an aggregate of lamine, and the appendages all ap- proximate more or less toward this fundamental modification, Thus, for example, the head is a leaf-like body with a laminate shield above and a pair of flat organs beneath. Theabdomen terminates in a knife-like post-abdomen, while the thorax, with its narrow form, foliaceous feet and, far more, the enormous development of the outer wall to enclose, more or less fully, the entire body, is the typical illustration of this fact. Necessarily this structural modi- fication exerts a formative influence on the internal organs which are all more or less influenced by it} and this is peculiarly the case with the more external and, in general, the paired organs. Thus the “shell glands,” so called, which in Copepoda are generally coiled tubes, become here greatly flattened organs closely united with the shell. The physiological result of this modification is the 24 TWELFTH ANNUAL REPORT. sensitiveness to changes in the environment, which is universal among the Daphnide. The compact Copepoda survive the vicissi- tudes of confinement with comparative immuity, but the first taint in the water destroys the delicate organism of Daphnia. The cause for this may be found in the exposure of the most vital and delicate parts of the organism to the influences of the surrounding aqueous medium. In particular the circulatory and respiratory systems, which here are not easily to be distinguished one from the other, constitute a relatively very large area of close contact with the water. It thus happens that the central organs are influenced in a very short time by whatever deleterious substances may be dis- seminated in the water. Notwithstanding this lack of centralization, the structure of these animals is of a very considerable degree of complexity and, presenting so many instructive modifications under circumstances so favorable for study, has been very thoroughly investigated. The © very transparency which has made it possible to clear up many questionable points in crustaceology from the lessons learned in Daphnia, has rendered the investigation of certain sets of organs extremely difficult, and among these may be mentioned the circula- tory system. The circulation of the nutritive fluid and the gen- eral facts connected with the heart were indeed early understood; but there remains many a detail and some important relations which are as yet either imperfectly known or entirely misunder- stood. The following notes are offered as a contribution to the, as yet incomplete, knowledge of the circulatory apparatus. The observations were confined for the most part to Daphnia scheffert and Simocephalus vetulus, with occasional comparisons with Hurycercus, Pleuroxis, Pasithea and others. It is greatly to be desired that the study might be carried to the Sidide, in which the larger size and superior transparency would doubt- less reward the search with several, as yet doubtful details. The circulation of the nutritive fluid in the Daphnide, then, is somewhat complicated, but may be divided into a superficial and a deep system. It must be remarked that this distinction is arbitrary and only used for its convenience. The one extends over the entire inner surface of the carapace, while the latter is in close relation with the vegetative organs, and extends into the branchial vessels of the feet. The nutritive fluid which is normally colorless and ‘supplied with corpuscles of organized nutriment, (it seems doubt- ful if they should be called blood corpuscles) is confined for the — most, if not its entire, course within membranous walls of connec- STATE GEOLOGIST. | 25 tive tissue which, however, instead of assuming a definite form as “blood vessels,” for the most part conform to the contour furnished by the firmer organs. This membrane which is frequently folded upon itself and invests the body walls and the inner organs, isin some places free, and may be seen as a pulsating, swinging film, or, more frequently, it can only be detected as a swaying line (seen in optical sections), thus giving rise to the misapprehension that one is dealing with a thread, or as moving grains, in which case the film isitself invisible but its presence is indicated by the attached grains of protoplasm. About the heart the free swaying portions of this membranous layer are so numerous as to render it almost impossible to distinguish the essential from the accidental appearances. This membrane must serve the most various purposes; eae from the mere retention and direction of the blood currents, it is often transformed into a branchial surface. At definite points it becomes the bearer of the cells which were above mentioned as grains of protoplasm. These are most numerous in young and well-fed ani- mals, and in particular in gravid females, while, on the. contrary, mature males and females after the escape of the young, are nearly devoid of such bodies. ‘These are most numerous in angles of the membrane, particularly about the heart, shell glands, ovaries, intestine and the branchial spaces in the feet. _ These cells vary in size from that of the blood corpuscles to larger cells with nuclei of comparatively very large size. It would be too much to say that such cells are developing blood corpuscles; but that they are reservoirs of nutriment which serve to supply the increased demand upon the blood in exigencies of the existence of the animal, cannot be doubted. It is a well known - fact that the number of bluod corpuscles, so called, likewise varies, and apparently under the same conditions. It seems altogether probable that the two facts may be considered as supplementary, 7. €. that the same process of depauperating of the blood, which deprives it of its corpuscles in an earlier stage, lays waste those supplies laid up in the cells referred to (whether by their actual separation as blood corpuscles or simply desolving of the contained material is of little importance). These cells also are thus paralel- lized with the “oil globules” of Copepoda. In such copepods as Cyclops and Canthocumptus, which appear to have no differen- tiated heart, there are always present drops of colored fluid, which are most numerous in well-fed and pregnant specimens. These ee 2 a a ee 96 TWELFTH ANNUAL REPORT. drops occupy the same relative position as the blood globules of other Crustacea, 7. e., they lie within a very thin membrane cor- responding to the vascular walls of other animals. This mem- brane, in general, invests the alimentary canal, as can be very readily seen in the abdomen, where it encloses a considerable space about the intestine, which is filled with fluid, investing more or less completely the muscles and other organs. As there is no rapid circulation of blood, these ‘oil drops” are comparatively stationary, and yet are moved slowly by the constant contraction of the walls of the alimentary canal which, in the anterior part, or stomach, are thick and glandular, while in the abdomen they seem to be more fitted for respiratory function. The above arrangement in Cyclops is correlated with its com- pact habit and thick carapace, and forms a simple starting-point for the study of the circulatory system in arthropods. It seems that the walls of the membranous blood cavity are themselves also, in places, furnished with muscles, so that the fluid is not depend- ent entirely on the vermiform or the peristaltic motions of the intestine for its escape from stagnation. If this be correct, we here have an indication of the origin of the central organ of the circulatory system. But to return to Daphnia, the heart lies in the dorsal region — over the intestine upon which it may be said to ride, as it were astride, though as we shall see, it is separated from the intestine by other organs. In Hwrycercus this is most evident, as here the ~ heart is more obviously bifurcate. The heart and circulation in Daphnia has been described — more or less at length by many authors, in particular Claus (Zur Kenntniss der Daphniden und _ verwanter Cladoceren. Zeitsch. f. Wiss. Zool. Bd. xxvii.) and Gruithuisen (the work of this author I have not seen), while Weismann (Ueber Bau und Lebenserscheinungen von Leptudora hyalina, 1874) describes the heart of Leptodora, and Claus (Zur Kenntniss des Baues und der Organ. der Polyphemiden), that of the Polyphemide. Other authors, except G. O. Sars, who elucidates some points in the circulation of blood in Sida, seem to have added little or nothing — to our knowledge of this interesting subject. As already often described, the heart occupies a place in a definite space—the pericardial chamber—the summit of which is the dorsal shield which, we believe, should |e distinguished from the remainder of the so-called cephalic shield. (It is usual to describe the shell of Daphnia as consisting of a bivalve posterior STATE GEOLOGIST. QF portion or ormostegite, and asimple anterior cephalostegite; but it seems much more proper to consider that portion of the shell which covers the pericardial space, and is the point of attachment of the powerful muscles of the abdomen and of the membranous | walls of the pericardium, as a distinct portion of the carapace, as it often evidently appears through the presence of a distinct suture, or, in its absence, through the peculiar sculpture of the shell. In such case it might also be proper to distinguish two regions on the lateral appendages of this dorsal shield, an upper and a lower, separated by the more or less obvious line, extending from the union of the lateral lines of the dorsal and cephalic shield in nearly a straight line toward the posterior portion of the shell, and indicating the insertion of the muscles which move the feet and post-abdomen. The lateral walls of the pericardial space are the shell-walls themselves, and the floor is formed by a mem- brane supported on, and investing in part, the strong muscles which connect the abdomen with the upper anterior part of the dorsal plate. Thus a space is left between the pericardium and the intestine which is occupied by a special blood sinus leading toward the posterior and lower part of the abdomen. The posterior wall of the space is formed by a chitinous partition which bounds the brood space, or its homologue, and is connected by chitinous processes (stutzbalken) with the outer skeleton. The anterior, on the other hand, is only bounded by the supporting ligaments of the abdomen above described and membranous partitions. As usually described, the heart lies suspended in the cavity thus de- fined, by slender muscular threads, more or less like those of the heart of Corethra larve and the like; and such seems to be the case at first, but a more careful study shows that this is far from correct. On the contrary, the chief supports of the heart are membranes which, seen in cross-section with the attached grains or blood globules, assume the appearance of exceedingly slender structureless threads. The action of re-agents indicates that these supposed threads are not muscles, but composed of connective tissue; while by changing the focus the sharpness of the line is frequently not altered, but its relative position is changed,—a simple test which often serves to dispel an illusion of this sort. That _ there are some threads of the character above mentioned is not to be doubted, as in connection with the valves of the heart; but the proper support of the heart is found in the membranes which invest it in part, and are reflected upon the walls of the shell and, anteriorly, of the intestine. It is not yet possible to fully describe 28 TWELFTH ANNUAL REPORT. the insertion of these tissues, as there is so large a number, especi- ally about the anterior opening, where they lie in all directions and at all angles, and are sotransparent, that only their vertical sections appear as dark lines. Thus the same membrane appears and disappears, only to re-appear in a different position where it might be readily taken for a distinct membrane. In general, however, I hope to make no serious error in the following sum- mary. Before going into detail, however, it will be necessary to consider the intimate structure of the heart, as well as its general shape and position. The general shape is that of an irregular oval with the greatest convexity posterior (Daphnia, etc.), or it may be strongly bifid and thus somewhat Y-shaped (Hurycercus, etc.). Itis held in position in the pericardial cavity by the membranes above alluded to, to which it is attached at definite points, the principal of which are two slight enlargements on the lower posterior portion, which are in part opposed to each other and also to a superior posterior point of insertion. All three of these points are thus held in relation with the shell with which the attached membrane is connected on either side below and.above. The membrane then extends part way along the heart wall towards the anterior and is then reflected to the shell wall. The result of this is that the pericardial space is an angular cavity opening in front. It would seem as though the membrane attaching the heart were identical with that lining the cavity itself. The heart proper is obviously composed of series of ~ muscular elements, which are considered as simple cells by Claus, and which in young individuals show very destinct nuclei of compar- atively large size. These are arranged like the meridian lines of a globe uniting above and below, thus forming the most effective apparatus possible for contracting the heart. In the smaller Daphnide, as stated by Claus, there seems to be but a single layer of muscular rays, but in D. schefferi and Simocephalus I have repeatedly satisfied myself that some of the longitudinal rays sink below the others and form a series of longitudinal muscles, as stated by earlier writers. These are furnished with a nucleus which is frequently more or less external, appearing like a spheri- cal appendage. In Leptodora Weismann has shown the heart to consist primarily of a membrane of connective tissue, upon which the muscular fibres or cells sit in somewhat the same position as in Daphnia, except that there is not the same regularity in the arrangement. There are many considerations which would lead — us to expect the same structure in Daphnia, though it is not yet STATE GEOLOGIST. . 29 demonstrated; and the structure of the anterior opening seems to point in the same direction. At any rate there is a close connec- tion between the muscular and connective parts of the heart. We have, then, in the heart of Daphnia a highly developed apparatus for closing it, but apparently none tor its opening. This certainly is not accomplished by the few fibers which connect the heart with the shell, the very contractility of which is doubtful. Nay, more, these are insufficient even to hold it in its place in the cavity. Still less can we assume that the heart, from any inherent power, can open itself. This must be explained by the operation of two factors which are interdependent, 7. ¢., the elasticity of the supporting membranes and the unequal pressure of the blood in _ different parts of the body. 1. The membranes which support the heart are attached not at right angles, but, on the contrary, in a direction more nearly parallel to the walls of the heart, and thus _whatever elasticity they possess is greatly increased; and the _ diminishing of the size of the heart draws these membranes out of their: position at the expense of their elasticity, which tends to restore them to their original position when the pressure is - removed, inthe same way a drum-head returns after a blow to its normal position. This factor is, however, only operative so long as the whole system of membranes to which these belong is dis- tended with fluid. If this blood cavity be punctured, the fluid - flows out and the heart shrivels. It may continue to beat for -some time, but it will be seen that the effort consists simply in a vigorous contraction which is followed by no perceptible enlarge- ment. 2. After the systele the blood of the heart is forced toward the head, whence it is prevented from re-entering the pericardial space directly by the valves and the membrane enclosing the arterial blood. The pressure is therefore increased in all parts of the system, except the pericardial. chamber where it is greatly diminished. The membranes supporting the heart are thus un- usually tense, and the muscular effort having ceased, the wails of the heart are distended, and blood flows in in the direction of the least resistance through the two lateral openings or ventral valves of the heart. The contraction of the heart during the systole is not simultaneous in different parts, but begins by the contraction of the posterior part where, being nearly free, the motion is more marked. At the close of the systole the heart is irregularly con- tracted, the points of attachment above described being more dis- tended than the remaining portions. The anterior of the heart is rendered very difficult to study by the fact that its opening is 2 eo = 30 TWELFTH ANNUAL REPORT. covered by the muscles of the mandibles and obscured by the many supporting and vibrating membranes alluded to. It is, however, suspended by two folds of membrane which I have ~ been inclined at times to believe blood-vessels through appearantes resulting from the confused currents flowing about them. The upper margin is also attached by a pair of cords directly to the superior part of the shell. The anterior opening or arterial valve is most perplexing, and the foliowing description which applies only to Daphnia schefferi mnst be subject to some doubt. It ap- pears however that it has been in a measure misunderstood by pre- vious writers, and namely by Claus, who compares it with that of Leptodora, which if correctly described by Weismann, is not at all identical in form, but quite comparable with one of the sides or lips of the venous opening. It does not seem to be connected by a thread, as stated for Leptodora, with the aortal bulb, for in reality there is no aortal bulb; the heart simply is connected with the system of membranes which more or less inclose the system. ‘The floor of the so-called aortal space is a membrane which separates the outflowing stream from a current which flows toward the abdomen and passes directly under the arterial opening, so that it appears as though there was a stream entering the heart from before as well as at the sides; the arterial opening being nearer the dorsal part of the heart than is naturally expected, and the slight enlargements at the attachment of the supporting membrane favoring the im- pression that there is here a veritable opening. The out-flowing blood stream is bounded at first by the membrane above mentioned, which is farther on reflexed onto the shell and,intestine so that the streams in the head flowing just under the shell are separated from the deep dorsal stream flowing from the heart.* This main current passes to the region of the eye between the horns of the cca of the alimentary canal, and thence beneath the stomach, and here divides, part becoming external and a deeper part passing un- der the intestine, thence in front of the heart, flows into the deep sinus which, as before said, passes beneath this organ. Other por- tions of the returning stream flow around the angle of the union of the head and body and constitute a stream just above the feet in which the current flows vigorously. | Yet other portions flow into the region of the shell-gland and are united with blood which here passes through the numerous sinuses described by Claus as surrounding this organ (Die Schalen- *In Pasithea rectirostris this septum is easily seen as a swaying membrane, which near the eye is reflexed to thetop of the shell. STATE GEOLOGIST. on druse der Daphnien) and thence flows into the abdomen, uniting with the other two streams. A part also of the current in the head flows into the antennz where it follows a deep course through the basal joint in which the corpuscles may be seen to emerge to the surface from two points where are spaces between the powerful muscles, the first being near the base and the second near the ex- tremity of this joint, and then to return and join the superficial current. The corpuscles appear to enter the rami very rarely if at all. That part of the superficial stream which reaches the interior of the pericardial chamber passes between the muscles of antenne and jaws and seems to find its way into the great current beneath the heart, though I have also thought to have seen it flow directly into the pericardial space as the lateral superficial streams do. That part of the superficial stream which reaches the posterior margin of the shell returns through a canal formed by the walls of the shell and the brood-space,between thestutzbalken’’of which the blood corpuscles can be seen to glide more rapidly than in the free lateral spaces. Lastly,it only remains to follow the fortune of the strong stream flowing along the neutral surface of the abdomen. The strong current flowing beneath the heart enters a broad sinus which lies over the intestine and extends for over a third of its length, where its walls unite with the surface of the intestine above and thus open downward on either side. The stream thus directed flows toward the openings of the base of the feet. The structure of the branchiz has not yet been clearly described. Instead of nearly spherical or oval chambers they are really tubes which connect, on one hand with the opening above, and below with the general cavity of the limb, whence the blood returns to the abdomen. The current is very rapid through these tubes. The blood having been returned to the ab- domen, courses in the well known manner through the post-ab- domen and flows over the intestine, thence over the back-flowing stream to the posterior lower opening of the pericardial chamber. The study of the actions of the heart isrendered more difficult | by the fact that in order to secure the greatest possible transpar- ency, the living animal must be covered and a little pressure ap- ' plied, which is frequently attended with abnormal variations of the circulation. In particular if the usual exit of the blood be stopped _ by the ceca of the intestine, as is frequently the case, the opera- | tion of the heart may be reversed, when a vigorous stream may be ~ bet W aT) ee, " . M " = \ ee LEE | | | 2 ia TWELFTH ANNUAL REPORT. seen to enter the arterial opening and emerge from the ventricles. This process would be impossible if the anterior valve were as de- scribed by Claus and Weismann; while being really more like the venous valves, it is easily and frequently permitted. The current. of the blood in this case stagnates except near the heart. The rapidity of the pulsations of the heart varies with age and condition of rest or motion. In D. schefferi this variation may range from about 150 per minute to perhaps 250, 200 being probably a fair average. In a young Simocephalus I have observed a heart beat 300 times in a minute. Again, in a specimen of D. Scheefferi at rest the heart — was beating 170, but during the spasmodic motion of feet and an- tenne the pulse rose to over 200. 1—GeENus Morna. Baird. The systematic position of this genus has been the theme of some discussion. it being claimed, with good reason, that there are many resemblances to the Lyncodaphnide (P. E. Mueller considers it a transition to the Bosminide and lyncodaphnids); on the other hand, Leydig and Kurz regard it more closely allied to the Sididx, with equally good reason. The long antenne, long narrow anten- nules and many peculiarities in form, etc., suggest the macrothroid erustaceans; the extended abdomen and especially the location of the male seminal opening are like Daphnella, which Moina resem- bles in motion and habit very strikingly. The absence of the pig- ment fleck is no more a characteristic of the Sidide than of other groups. After all has been said, the immediate affinities of the genus are acknowledged to be with the Daphnide. . The true place of the genus, as it appears to the writer, was hinted at by Birge (Notes on Cladocera). Moina seems to be the pivotal point of the Cladocera, at least of the families above men- tioned. Without going into phylogenetic speculation, it is sug- gestive that this genus can and does by preference live in. very im- pure water and may therefore have had an early origin. From Moina diverges the stem of the Daphnide by way of Ceriodaphnia, Simocephalus and Daphnia. These two latter genera are intimately — connected by Simocephalus daphnoides, Herrick. Scapholeberis - is connected with Ceriodaphnia through. §S. angulata, Herrick. The Sididz seem to diverge by the way of Daphnella, through which by means of Pseudo-sida the genus Sida is reached, and final- _ ly Limnosida, Latona and Holopedium. The relationships of the _ curious Polyphemide are less evident. | STATE GEOLOGIST. 3B The Lyncodaphnide make an easy transition to the Lynceids proper, while the Bosminidz are still quite isolated, but are sug- gested by Macrothrix pauper. The fact that Moina stands thus related to radiating groups is simply suggestive, but it 7s sugges- tive of its possible antiquity and synthetic character. The three species of this genus stand very poorly distinguished from one another and their specific validity may be doubted. The most exhaustive study of the embryology of the Cladocera was based on Moina. (Grobben, Entwick d. Moina, etc.) The genus is characterized by Weismann and Gruber! about as follows: Head prone; separated by a depression from the thorax; fornices obscure; rostrum none; pigment fleck absent; antennules of the female large, moveable, furnished with a sensitive seta near the middle, flagelliform; antennules of the male very large, hooked at the end. The setz of the antenne are all ciliate; the tri-articu- late ramus with five setz; posterior margin of the valves thicker in the median line; caudal setz very large, about twice in the. length of the animal; anus above the claws; feet of the first pair of the male with a strong hook. Weismann has shown that both summer and winter eggs origi- nate from groups of four cells, one of which only is transformed into the egg, the remaining three serving simply as a supply of nourishment for the egg, which absorbs it directly. Both eggs and nutrient cells develop from the epithelium of the termination of the ovary. The summer eggs have less yolk than the winter brood, and the yolkis bluish in the summer eggs and deep red in the winter eggs of Moina rectirostris; while in M. paradoxa the sum- _ mer eggs have yellow and the winter set snow-white yolk. There are never more than two winter-eggs in any of the Daphnide, but there are as many as twenty summer eggs in some cases in Moina. In M. rectirostris only one winter egg is produced, which is one of the best distinctions of the species, as this is, perhaps, the only case. (Naturgeschichte der Daphnoiden, Weismann.) The first genera- tion, springing from the winter eggs (impregnated eggs), is com— posed solely of females which reproduce parthenogenetically; the second brood contains sexual males and females, thus completing the cyclus. 1 Ueber einege neue oder unvolkommen gekannte Daphniden, Freiburg, 1877. 3 i\| i! 34 TWELFTH ANNUAL REPORT. Sp. 1. Moina rectirostris, Mueller. (Plate A. Figs. 2,5, 8,10, 11.) A. Var. vera. Daphnia rectirostris, O.¥F. MUELLER, LATREILLE, BOSC, DESMAREST,SCHRANK,LEYDIG. Monoculus rectirostris, GMELIN, FABRICIUS, MANUEL, JURINE. Pasithea rectirostris, KOCH. Moina rectirostris, BAIRD, WEISMANN, KURz, BIRGE. BR. Var. brachiatus. Monoculus brachiatus. JURINE. Dapania brichiata, - DESMAREST, EDWARDS, LEYDIG. Moina brachiata, BAIRD, WEISMANN. C. Both varieties. ? Moina brachiata. P. E. MUELLER. LILLJEBORG. The only tangible difference between the two forms thus united is the fact that M. rectirostris produces but a single winter ovum and hence has a one-chambered ephippium, while M. brachiata has a two-chambered ephippium. The head is separated trom the thorax by a marked depression; there is a deep depression above the eye; the margins of the shell have few bristles. The post-abdomen,which extends far beyond the edge of the valves, bears about eleven hairy spines on either side, the lower spine being two-cleft at the end; the base of the claws bears a comb of small teeth, and the posterior margins are bristled. The ephippium is oval; and the single cavity in M. rectirostris has its longer axis horizontal, while the two cavities of M. brachiata are vertical. The depression above the eye is deeper in the males, in which sex also the antenne are longer and bent at the middle. ‘The seminal bodies are stellate. Length 1,2 mm. The form is ‘subject to the greatest variation due to the varying number of sum- mer eggs. Birge finds this species abundant. I have found both ithis and the following species in various parts of the Mississippi valley trom Mobile to the upper river region. Sp. 2.—Moina paradoxa, Weismann. (Plate A. Figs. 1, 3, 6, 7, 9.) The species differs in a few very insignificant points from the previous one. The head is short and nearly evenly convex above, with no deep depression above the eye; teeth of terminal claws reduced to bristles which are only a little longer than the series extending down the claw as in the above species; the first 1“Gruber and Weismann, ueber einige neue oder unvollkmmen gekannte Daphniden Freiburg, 1877 STATE GEOLOGIST. 35 foot of the male is furnished with a long bristle; the lower shell margins are more bristly than in the previous forms; the ephip- pium has two cavities, while the seminal bodies are crescent-shaped. Sp. 3.—Moina micrura, Kurz. This form may be of specific value, but it is not suffiviently dis- tinguished to make this certain. As described by Kurz, it seems to be smaller (1 mm.) and most to resemble M. paradoxa, which was not at that time described. The post-abdomen is short and has few (6) spines, while the terminal claws are short and smooth; the head has a sinus above the eyes; the eyes are smaller, with numer- ous lenses; the antennules are shorter (?) than in M. rectirostris; the mandibles are partly exposed, while the shell margin overlying is notched. «Males and ephippial females were not observed. Not distinguished in America. . 11.—GeENus 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 antennz 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 asimilar form; the male antennz show a transi- tion in the various species from forms adapted for prehension to such as are found in Daphnia. The brood cavity is closed by twa 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 pres- ent; beak absent; antennules moveable, rather short; antenne with the three-jointed ramus with five sete; first foot of the male with a hook or flagellum. 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 asingle quart of such water. The genus is particularly perplexing, as the varieties named seem to be hardly entitled to specific rank and are so similar as to re. quire great care to properly distinguish. 36 TWELFTH ANNUAL REPORT. 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 Kurope. Of the twelve species here enumerated at least one-third may be synomyms and others of the remainder are with difficulty distinguished. ‘ i | ARTIFICIAL KEY TO THE GENUS CERIODAPHNIA. A. Shell irregularly striate. 1. C. megops, Sars. 2. C. cristata, Birge. B. Shell with hexagonal meshes. a. Shell with doubly contoured markings. Ht | (aa) Head broad, short. | 8. C. pulchella, Sars. (bb) Head narrowed, depressed. 4. C. rotunda, Straus, (antennules normal.) 5. C. alabamensis, Herrick, (antennules elongate.) b. Shell simply marked. (ec) Claws with teeth, 6. C. reticulata, Jurine. f [7]. C. dentata, Birge. | (dd) Claws without teeth. I. Antenne very long. 8. C. punctata, P. E. Mueller. Ir. Antenne normal or short. * Post-abdomen broad. 9. C. laticawdatus, P. E. Mueller. 1mm. long. [10|.. C. consors, Birge. 0.6 mm. long. ** Post-abdomen narrow. + Head not angled behind the eye. 11. C. quadrangula, Mueller. +t Head abruptly augled behind the eye. 12. C. scitula, Herrick. C. Sheil reticulate with rectangular meshes. 13, C. nitida, Schoedler. [14]. C. textilis, Dana. Wh | Sp.1. Ceriodaphnia megops, Sars. (Plate A. Figs. 16, 20.) Ceriodaphnia megops, SARS, P. E, MUELLER, KuRz. (The earlier synonymy is‘doubtful See note, page 26, Schoedler’s Neue Beitrage zur Naturgeschichte der Cladoceren. | STATE GEOLOGIST. OL This species is one of the largest and most readily distinguished as wellas rarest of the genus. Very characteristic is the fine an- astomosing striation which breaks up into reticulation only near the shell margins. This species seem3 to form the transition toward Simocephalus with Scapholeberis, which, however, diverges along its own peculiar track. ‘The length is sometimes 1 mm. The head is obscurely angulated in front of the antennules, which are large. The antennules of the male are long and have a hooked setz at the end. Typical C. megops has not yet been found in America, but the following form takes its place. Sp. 2 Ceriodaphnia cristata, Birge. The description given by Birge would apply in almost every par- ticular to C. megops, though he seemed to overlook the close con- formity. 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 thie effect of prominences such as are described by P. HK. Mueller; at any rate, in view of the fact that but few specimens were discovered, the sug- gestion lies near that C. cristata is the young or, at least, areduced form of C. megops. Found at Southampton, Mass. Sp 3.--Ceriodaphnia pulchella, Sars. (Plate A, Figs. 14, 19,) Ceriodaphnia pulchella, SARS, P. E. MUELLER, KURZ. Very much like C. reticulata, but smaller. Head large, turgid, and angled in front of the antennules, forming almost a right an- gle; fornices moderate; antennules rather large; shell oval, reticu- lated 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 antennze is but slightly hooked,0.5—0.6 mm. long. This species is not cer- tainly identified from America, though a form with smooth claws and small fornices occurs with C. dentata in some places. Sp.4. Ceriodaphnia rotunda, Straus. (Plate L. Fig. 1, Plate A. Figs. 13 and 23.) Daphnia rotunda, STRAUS, BAIRD. Ceriodaphnia rotunda, SCHOEDLER, SARS, P. E. MUELLER, KURZ. 38 _-» TWELFTH ANNUAL REPORT. As said by Kurz, this species is not easily mistaken; the smal? head (only paralleled by the following), the very evident reticula- tions and the broad abdomen give it a peculiar habitus which is. unmistakable. Head depressed, small, spiny below, not angulated; fornices: prominent, thorned; body rotund, almost spined above; shell doubly. reticulate; 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, Sp. 5. Ceriodaphnia alabamensis, Herrick, (Plate B, Fig, 2.) (American Naturalist, May 1888. Plate v, Figs. 11, 12.) This species was seen but once and is insufficiently known. The body is elongate, quadrate, the shell reticulated with double con- tour lines,the head very small and produced downward below the eye, which is very small, the antennules are longer than in any other species, obviously two-jointed, with a lateral seta; the antennze 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 mm. (?) Tuscaloosa, Ala. Sp.6 Ceriodaphnia reticulata, Jurine, Monoculus reticulatus, JURINE. Daphnia reticulata, BAIRD, LEYDIG. Ceriodaphnia quadrangula, SCHOEDLER. Ceriodaphnia reticulata, SARS, P. E, MUELLER, KURZ, HERRICK. 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 re- ticulations are sharp but simple. The flagellum of the male an tennule is either straight or moderately curved. Kurz says that. some varieties have the fornices blunt w —si thers are sharp. [ have seen only the blunt form which is then much like the next. Sp. 7. 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 ee __ l STATE GEOLOGIST. 39 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 intermedi- ate, some having fornices with an abrupt angle. It may be in- structive to quote Kurz on the Kuropean C. reticulata—‘Hxamples occur 0.8-0.9 mm. long, others on the contrary only 0.5-0.6 mm. long and combining with the smaller size some differential char- acters. In the larger variety I found the fornix obtuse, while in the smaller it extends in a sharp thorn directed upward and out- ward. In this small sub-species the secondary teeth of the claws. of the post-abdomen seemed to be absent, though in C. reticulata 3-5 are constantly present.” Sp. 8. Cerivdaphnia punctata, P. E. Mueller. (Plate A. Figs. 1-3.) 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, in- creasing toward the end; clawssmooth. Length 0.7 —. 9 mm. Found as yet only in Scandinavia. Sp. 9. Ceriodaphnia laticaudata, P. E. Mueller. (Plate A. Fig. 22.) Ceriodaphnia quadrangula, SARS, (fide MUELJ.ER,) Head small, depressed, rounded at the end, not angulated; forni- ces prominent; shell roundish, or sub-quadrangular, moderately reticulated; antennules rather large; post-abdomnen broad, nar- rowed from the middle to the end; the nine or ten small anal spines nearly equal; claws large and smooth. In P. EK. Mueller’s time males unknown. Length 1mm. 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 40 TWELFTH ANNUAL REPORT. ‘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 individuals seen were ephippial females measur- ing .55 mm. This may be. Sp. 10. Ceriodaphnia consors, Birge. This species differs from .C. laticaudata in one or two points, being about one-half the size and having fewer caudal teeth. Birge says the abdomen 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. Sp. 41. Ceriodaphnia quadranvgula, Mueller. (Plate A. Figs, 17-18.) Daphnia quadrangula, O. F. MOKLLER. Daphnia reticulata, BAIRD. Ceriodaphnia quadrangula, P. E. MUELLER. Head depressed, rounded at the end, only slightly angled; forni- ces 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. 7 Sp. 12. Ceriodaphnia scitula, (Sp. n.) (Plate B. Figs. 5-7.) One of the most abundant species of Ceriodaphnia in Minnesota is alarge form much resembling C. quadrangula. The post-ab- domen is exactly as in C. 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 hex- agonal lining; the upper angle israther 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 extend- ing down the entire inner side. The size is 0.8—1.0 mm.; color pinkish, opaque; antenna, especially, often bright pink. Male 0.6 SS STATE GEOLOGIST. 41 mm., flagellum of the male antennez long; sensory filaments Jateral, 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 com- monest 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 exceeds .55 mm. The claw is densely ciliated, but not spined; these smaller forms have but few eggs (two). The young have athorn on the angle of the fornices. Plate J. Fig. 1 represents the ephippial female of this species. There seems no reason to doubt that this is only avariety of C. scitula. The small _ form of C. reticulata mentioned by Kurz might be referred here, while the larger form with less prominent fornices is not so diffier- ent from the American C. dentata. Sp. 13. Ceriodaphnia nitida, Schcedler, Ceriodaphnia quadrangula, LEYDIG. 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. Sp. 14. Ceriodaphnia textilis, Dana. This species is not sufficiently fully figured to allow of a sug- gestion as to its affinities. Daphnia rotundata, Say, is very. probably a member of dius genus, though the description is hardly intelligible. ‘Body rounded behind; upper antenne three-brancbed, a small spine above at the joints; lower five-branched; color white. Length 0.5.” It is probable that we should read ‘upper branch of antenne with three setze”’, etc., in which case we may identify the above with Chydorus or the like. 111.—GENUS SCAPHOLEBERIS. The genus Scapholeberis stands rather closely related to Cerio- daphnia, from which it is at once distinguished by the angled or _ spined lower posterior angle of the shell. The head is rather 42 TWELFTH ANNUAL REPORT. clumsy, and the continuation of the fornices runs toward the apex of theincurved beak, which commonly lies within the valves of the shell. The lower anterior angle has a prominence and there is a basin-shaped area inclosing the base of the antennz, 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 along scythe-shaped spine which is directed backward. The shell itself is usually indis- tinctly reticulate or unmarked, and commonly is deep colored. The post-abdomen is very like Ceriodaphnia 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 moderate size, the pig- ment fleck rather small and the antennules short and hidden by the: beak. The antenne are of small size and generally dark colored. The ephippium contains but one egg; the males do not have al- tered antenne or feet. The sexual periods fall in early summer and in autumn, according to Weismann; the males appear but sparingly. The species S. mucronata is very abundant every- where, while the others are less frequently seen. Sp. 1. Secapholeberis mucronata, Mueller. (Plate J. Fig. 5.) Daphnia mucronata, MUvELLER, LEIVIN, LILLJEBORG, FISCHER, LEYDIG, BAIRD, HERRICK. Scapholeberis mucronata, SCHOEDLER, P. E. MUELLER, KURZ, WEISMANN, BIKGE, HERRICK. This wel!-known species with rather short spines below is found abundantly everywhere. In this country at least it is character- ized 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 deflection downward; it sets off the area which forms: a part of the basin of the antennz. A second line springing from just above the termination 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 vari- able length, but do not exceed one-fourth the length of the re- mainder of the lower margin. This species ranges over all Hurope and eastern United States. | Length 0.6 mm.—0.8 mm. . STATE GEOLOGIST. 43 Sp. 2. Scapholeberis cornuta, Schcedler. (Plate T. Fig. 6.) Moncculus bispinosus, DEGEER. Daphnia mueronata, 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 Ripophilus, it serves to clear away rubbish in the filth in which these animals frequently live. This form, be it variety or species, is not known in America. Sp. 3. Scapholeberis armata, (Herrick.) ® (Plate B. Figs. 10-11.) _ Scapholeberis mucronata, var. armata, HERRICK. A very beautiful and unique species, which possesses the extreme development of the peculiarities ot the genus. The head isshaped very much as in the previous species, the fornix is squarish, the basin for the antennz is small. The upper lines from the fornix meet behind the eye; the form of the shell is as in the above, but the spines upon the lower margin are longer. The scythe-like spine 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 long. There are the usual lines parallel to the lower edge of the shell. The specimens hay- ing the longest spines were found in fresh water about Mobile, Ala., but the species occurs in Minnesota and intermediate points, though speringly. Sp.4: Scapholeberis 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 asin §S. mucronata, but backward, and in its natural position lies between the valves.” The usual reticulated and lined areas are present and the balance of the shell is covered with “small pointed projections.” ‘The anten- nules 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 open- ‘ 44 TWELFTH ANNUAL REPORT. ing of the vas deferens close behind the terminal claws; mucro short and blunt, length 1 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 ina ae converse to that pursued by the S. armata. Sp, 5. Scapholeberis angulata, Herrick. (Plate B. Fig. 9, Plate T; |. Figi:%.) American Naturalist, 1883. Form as in the above, but comparatively larger; valves quadran- gular, anterior margin strongly arched; head short, only slightly concave below the eyes; the beak is as in 8. nasuta, but seems to be directed more nearly directly downward than in that species. The anteunules are long and resemble those of Simocephalus, The pigment fleck is square and rather large; the antennz are of the usual size. The reticulated 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 corres- ponding situation in Simocephalus. On the whole, there is a similiarity to that genus in this as well as in the previous species. S. nasuta has a short spine and elongated pigment fleck; the pres- ent 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 of the five being found in the United States; the fifth, more- over, is more often regarded a variety of one of the others; in fact, the absence of S. cornuta from America is one of the most impor- tant supports of the specific independence of the two forms. All the species delight in disporting themselves near the surface in sunny weather. 1v.—GENUS SIMOCEPHALUS. Although a very well circumscribed group, this genus passes into the next rather directly by means of 8. macrothroides. The connection on the other hand seems to be by the way of Scaphole- beris, though there is a rather broad separation between even Scapholeberis angulata and any known Simocephalus. The en- STATE GEOLOGIST. 45 larged spines near the angle of the shell and the form of the an- tennules as well as some other points, show a transition through that species toward the present genus. The general form is quad- rate with the lower posterior margin sinuate; in young specimens the shell is nearly a perfect rectangle. The upper margin is pro- duced 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 prop:r is between the ante- rior 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 antennules 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 conspicuous of the family and are more persistent during the changing seasons than any other form. 8S. vetulus, the common- est 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 shelJ, which is finely reticulate; while the shell is usually marked by finefanasta- mosing 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. The opening of the vasa differentia is back of the anus, hence these ducts cross the course of the intestine. They have ejacula- tory muscles about the lower part. The smaller species are fre- quently deeply colored with pink, purple and brown fatty deposits and the markings are more conspicuous than in the American Eurycercus, which is itself often brightly spotted with blue or pur- ple. The aspect in the water is between that of Eurycercus 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 suffi- ii ii 46 TWELFTH ANNUAL REPORT. cient to identify the genus, and indeed to indicate that either 8. americanus or a related form is intended, but it is hardly compe- tent 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 ancle in the middle. Antenne with four filaments on the upper and five or the lower branch. Color white or red. Length 0.1; stagnant water in the forests of the Southern States.” Sp. 1. Simocephalus vetulus, Mueller. Daphnia vetula, BAIRD, HERRICK. Daphnia sima, MUELLER, LATREILLE, Bosc, RAMDOHR, GRUITHUISEN, DESMAREST LAMARCK, M. EDWARDs, KOCH, GMELIN, MANUREL, JURINE, LIL- LJEBORG, LEYDIG. Simocephalus vetulus, SCHOEDLER, P. E. MUELLER, KURZ, WEISMANN, CLAUS, LUTZ, BIRGE. This commonest and one of the largest species is apparently dis- tributed over the northern hemisphere and abounds in all the more shallow lakes. The head is rounded in front and is not an- gled 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 equalling the greatest hight of | the shell. The shell is covered with minute dense striations which spring from the free edges. The pigment fleck is elongated in old specimens and the upper angle follows up beside the suture sepa- rating 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 8mm. S&S. vetulus lives, by preference, among the leaves of aquatic vegeta- tion. With us this species seems to live in the smaller pools as well as in lakes of some size. JI am not able to see any difference in this respect between the various species. Sp. 2. Simocephalus serrulatus, Kcch. Daphnia serrulata, KOCH, LIEVIN. FISCHER, LILLJEBORG. Simocephalus serrulatus, LEYDIG, SCHOEDLER, P. E. MUELLER, KURZ. Head narrow, extending anteriorly into a sharp spiny angle in front of the eye. Dorsal line of the shell. abruptly angled or curved posteriorly, projecting to form a broad obtuse spine behind; net iri A Py STATE GEOLOGIST. 47 this spine is serrate with sharp teeth and lies somewhat above the middle of the hight of the animal, so that the free posterior mar- gins of the shell fall much short of reaching the greatest hight of the shell. Post-abdomen 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 tri- angular orrhomboidal. Length 2.0 mm., 2.5 mm. I am not sure that the three following species are more tkan varieties; the first in particular is very close to the European type. Sp, 3.—Simocephalus congener, Birge. My own observations of this form made throughout the Missis- -sippi 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 differs from 8. serrulatus in the following points. The head, although prominent and spiny near the eye, is not an- -gled between this prominence and the beak; in fact, it is either straight or simply curved. The pigment fleck is usually rhom- boidal and only occasionally 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 §. rostra- tus, but not nearly as inconspicuous as in §. vetulus. The termi- nal claws are rather evenly curved. This species is frequently col- ored 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 species. I have found this species from the gulf of Mexico to Minnesota. Sp. 4.—Simocephalus rostratus, (Sp. n.) This form is of the size and color of 8. americanus, and approaches mearest to Schodler’s S. expinosus in general characters. The back is arched above but not abruptly angled; the spine is asin S. amer- ‘icanus but not solow. The free posterior shell margins are some- | what shorter than the greatest hight of the shell. The head is _ produced below the eyes in an angle like a right angle, which is _notspiny. 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 48 TWELFIH ANNUAL REPORT. 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 pro- cesses 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, Missis- sippi, aad was very carefully compared with S. americanus. which is also found there. | Sp. &. Simocephalus exspinosus, Koch. Head extending into an obtuse angle at the eye, pigment fleck rhomboidal. Shell without a spine; maximum hight of theshell 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. Sp. 6. Simocephalus daphnoides, Herrick. American Naturalist, 1883. A curious transition form, found only south of the Tennessee river, was described in the American Naturalist in May, 1883, under this name. By an oversight a comparison made with 8S. americanus appeared as though made with 8. vetulus. The general shape is oval; the greatest hight of the valves lies near the middle and not posterior to it as in all the other species. The head is short, de- pressed, rounded in front; the beak is wanting; the lower margin of the head is straight. The pigment fleck is small, oval or irreg- ular; the fornices are small and short. The antennules are smooth. The post-abdomen is narrow, shaped more as in Daphnia; the terminal claws are straightish and fringed part way with spines; the anal spines are slightly curved. The processes of the abdomen are long, asin Daphnia. The shell is covered by the characteristic striations and extends into a blunt spine. In every detail, almost, there is an approach toward the genius Daphnia, while the general result is sufticiently like Simocephalus, The lower angle of the shell is not armed with the peculiar curved spines as in all the other STATE GEOLOGIST. 49 species. - This species becomes over 1-10 inch long. In such old individuals the spine is nearly midway of the hight. One could wish a trifle closer link to Scapholeberis than that furn- ished by 8. angulata; but. on the whole, the position of this genus can not well be ealled 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 too closely related. NotTe.—On p. 47 read S. Americanus, Birge, not S. Congener. v. Genus DapHnria. Long considered the type of the family, this genus is most fre- quently 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 ofa diverging line. Simoceph- alus is the link connecting it with the typical forms of the fam- uy. As might be expected, this genus presents more puzzling problems than any of the others. It contains more peculiarities of structure and diversities of habit and development than any other of the genera. Here the sexual differences are most inter- esting. ‘The young are hatched with a pendant appendage at- tached to the upper posterior angle of the shell, which soon be- comes 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 pro- cesses, of which the first is much the larger and curves forward. At stated periods in spring and autumn the males appear; the fe- males of the generation in which occur the males have a tendency to produce eggs of a different sort charged with a different mis- sion, At the same time the upper portion of the shell (that sur- rounding 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 re- mains to be learned with reference to this interesting modification of the shell. Some rather careful study has been devoted to this 4 50 TWELFTH ANNUAL REPORT. subject by the writer, but it was unfortunately interrupted before completion. The most promising method of persuing the investi- gation 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, and figures of some of the many sections made are drawn on plate P. Figure 10 is a ver- tical section through the middle of an ephippium which has been cast off. The outer and inner shell layers are distinct and one of the eggs is divided in the middle. No pigment or protecting ma- terial was deposited in this case, which is the simplest possible. Fig. 9 represents a section just back of the head; it passes diagon- ally, severing the heart longitudinally (h). The intestine (a), the ovaries (g), the mandible (m), the labrum (1), and certain suspen- sorial muscles (?) are seen in situ. Only a portion of the ephip- pium is cut and the double layers enclose a large mass of protec- tive matter. Fig. 8 is a vertical section through the middle of the animal, and the usual form of the ephippium is seen with its large amount of protective matter obscuring all else. Fig. 7 is a longi- tudinal section of an ephippium similar to that seenin Fig. 10. It is hoped to present at some more appropriate time a fuller account of the formation and process of moulting this saddle. DEVELOPMENT OF DAPHNIA. Although the careful researches of Claus and Grobben have ad- ded much to our otherwise rather meager knowledge of the develop- ment of the cladocera, there still remain many interesting points, particularly with reference to the individual species, which merit careful study. The following observations relate to the single species (D. scheefferi) which was available during a short stay in Leipzig: The winter eggs of D. schefferi are two in number and are lodged in 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 paralled to the axis of the body, but the posterior end is slightly elevated. 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 susceptible to pressure. It is thus reticulated, apparently through the simple pressure of the walls of the ephippium. STATE GEOLOGIST. 5] The length is 0.48 mm.; width .338 mm. in the average, though eggs were occasionally found of an elongated form, measuring .48, 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 quan- tity 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 evi- dently the fact 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 favorable circumstances the development proceeds farther and near one pole appears a slight indenture of the surface which grows deeper aiid seems to form a true invagina- tion. This blastopore, if such it really be, remains for some time, generally till the two ‘‘ scheitel” plates appear. These ‘‘ scheitel- platte”” are formed by a simultaneous thickening 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 ‘‘scheitel- platte” are situated at right angles to a plane perpendicular to the blastopore. The nuclei of the cells of the “scheitelplatte”’ are nearly .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 re- duced to two or three or rises to as many as fifteen or even more. In color the eggs also vary from green to brown. The fresh egg 52 TWELFTH ANNUAL REPORT. consists, as the winter egg, of two sorts of yolk spheres. The plasma or formative yolk contains 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 through- out the ealier stages of the embryo; second, smaller globules of ap- parently the same character, which are quite numerous and form a very considerable part of the contents of the egg, In an egg of about .85 mm.in diameter, the largest of the smaller size of oil drops measured .029 mm. while the larger three exceeded .060 mm. The oil drops are distinguishable by their light refractive power, pellucidity and the intense dark brown or black color assum- ed when treated with osmic acid. The latter reagent affects the formative yolk but slightly. It will be seen that though the sum- mer 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 schaefferi is throughout striking as compared with Moina, the only one of the Daphnidez the development of which is fully studied. In the summer eggs I have not been able to see the complete seg- mentation 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 antennz bud out and are soon followed by the antenna, 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 ‘antenne, a fact not before observed, and this persists as the small two-bristled wart found on the basal joint of the antenna. [tis 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 refraetive 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 de- scribed for Moina. The first indication of the shell appears as two folds of the max- illary 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 sac. A slight protuberance appears on the margin of the shell in STATE GEOLOGIST. 53 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 comparatively enormous tail, which curves under the animal between the shell valves which now extend be- yond the body. This “tail” extends well along the ventral mar- gin of the shell and reminds, by its position, of the tail of a fright- ened dog. The true tail, or post-abdomen, is, in the meanwhile, well developed and is constantly kicking the useless protuberence of the shell upwards. As the animal leaves the egg this projec- tion becomes straightened asin the young D. pulex, finally be- coming the still considerable spine, though it is proportionately 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 interest. Its length agrees pretty well with that of the brood ¢avity 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 €avity is narrow and the shell weak, so that while the outer shell is removed like a glove from the finger, it can not be pulled up- ward or downward, but directiy backwards. It is well known that male Daphnie 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 essentially 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 precesophagal ganglia, the commissures passing about the cesophagus. I have not been able to determine if the subcesophagal ganglia become fused. From the anterior ganglia spring the nerves to the autenne and 2 54 TWELFTH ANNUAL REPORT. jaws, which latter are the larger in the embryo, being exceedingly large nerves. This key contains the majority of the genus, but falls short of completeness. The following species are uncertain. W.Schman- kewitsch 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 can not be defi- nitely stated. His investigations seem to show that the proximity of salt waters influence the form of the body, or, perhaps, that there is a constant interchange between the sub-marine and fresh- water species. Daphnia brevicauda, Chambers, is an incorrectly figured and described Simocephalus. Key To THE Genus DAPHNIA. Section 1. Pigment fleck present. A. Head short, equally rounded. 1. D. psittacea, Baird. B. Head not regularly rounded, more or less beaked. (a) Claws spiny. I. Abdomen broad, series of analspines nearly equai, neither head nor back Keeled. + A marked sinuosity in the posterior outline of post-abdomen. 2. D. schefferi, Baird. D. ovata, Sars. D. pennata, Mueller. tt No well marked depression. 3. D. pulex, Mueller. 4, D. schedleri, Sars. D. hastata, Sars. D. obtusa, Kurz. 11. Abdomen narrow, shell keeled somewhat dorsally. 5. D. minnehaha, sp. n. 6. D. carinata, Sars. (b) Claws nearly or quite smooth. I. Head not crested. 7. D.longispina, Leydig. 8. D. rosea, Sars. 9. D. similis, Claus D. lacustris, Sars. D. cavifrons, Sars. LORD: hyalina. Leydig. 11. D. dubia, Herrick. STATE GEOLOGIST. 5D D. pellucida, P. E. Mueller. D. galeata, Sars, 12. (?) D. levis, Birge. Section 1. Pigment fleck absent. A. Head but slightly crested. 1. D. longiremis, Sars. B. Head strongly crested. 2. D. cristata, Sars.’ 3. D. cucullata, Sars. D. apicata, Kurz. 4, D. kalbergensis, Schoedler. D. cederstromii, Schoedler. D. retrocurva, Forbes, D. vitrea, Kurz. 5. D. magniceps,sp. 0. SEcTION I. A. Head short, evenly curved. Sp. 1. Daphnia psittacea, Baird. Mentioned by SCHOEDLER, FRIc and KURz. 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 une- qual size. This is one of the largest of the genus. Not yet found in America. B. Head more or less concave below, at least not evenly arched. Sp. 2. Daphnia scheefferi, Baird. (Plate M. Figs. 1—4.) Daphnia pennata, MUELLER. Daphnia pwlex, STRAUS, KOCH, (fide P. E. MUELLER.) Daphnia magna, LILLJEBORG, LEYDIG, ete. Daphnia schefferi, SCHOEDLER, KURZ. The largest species of the genus, is of an elongated oval and ventricose form. 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 beluw the anus so that the spines consist of two sets; the terminal claws are spiny at the base. Although 56 TWELFTH ANNUAL REPORT. very similar to D. pulex, it may be recognized at once by the con- cavity of the dorsal margin of the post-abdomen. The plate will make any detailed description superfluous. A common species in Europe, but not vet found in America. Daphnia ovata, Sars, seems probably this species, but Sars was troubled by Straus’ mistaken reference. | Daphnia pennata of Sars may also be this species or, more prob- ably, D. pulex. The Latin discription given by Sars is appended for convenience of reterence. Daphnia pennata, Sars. “Antecedenti (D. pulex) simillima, caput autem a latere visufm latius, rostro breviore, supra visum testa cetera parum angustius fere cordiforme, antice acuminatum. Pro- cessus anteriores duo disjuncti. Margo posterior postabdominis in medio sinulo parvo et infra hune utrinque aculeis 16-18 armatus. Color ut in antecedente. Longit.2344mm.” Daphnia ovata, Sars. “Caput alatere visum ante oculum fere angulatum,margine inferiore leviter concavo in rostrum longum apicem versus attenuatum, extremitate tenuissima exeunte, spura visum ut in D. pennata cordiforme. Testa cetera a latere visa ovata, margine superi- ore et inferiore in femina adulta fere zeques arcuatis, postice in medio spinam formans brevissimam vel omnino obsoletam. Processus anteriores duo abdominis disjuncti- Margo posterior postabdeminis in medio sinuatus, utrinque aculeis 20-22 armatus. Color albido—flavescens vel-virescens. Longit. circit 3mm.” Sp. 3. Daphnia pulex, M ueller This commonest of our Daphnids is apparently circumpolar in distribution. I have found it in Alabama near the Gulf and it also occurs near lake Superior. Oval, either elongate or short, spine springing from the upper angle of shell or in some cases near the middle. ‘The spine is rather long in young individuais but becomes very narrow in older ones or entirely disappears. ‘The abdominal processes are long, not coalescent, or slightly united at the base. The head is concave be- low and extends into a prominent beak. This species is either very variable or several species are frequently united under the term. ‘Two types have been recognized in America. One, abun- dant in spring in smaller ponds in Minnesota, is rather short, arched above, and in old females with the spine situated near the middle of the posterior margin. This form is quite typical for the species and occurs from April to mid-summer. Another variety was found in Alabama in late autumn, and similar animals in mid-winter in lake Calhoun, Minnesota. This type has a much more elongate body, the very slender but rather short spine springs from the upper STATE GEOLOGIST. 57 margin of the shell or is quite wanting. This longer form has the beak slightly arched so as to resemble a ‘“‘Roman nose.” The anal spines are less numerous (10-14 while typical D. pulex has nearly 20). The young of this form, which may be called Daphnia pulex, var. nasutus, (Var. n.) (Plate N. Figs. 1-4.) vary much among themselves but, in general, resemble the young of the Kuropean form. Daphnia pulex has been mentioned by a number of authors in America, Smith, Birge, Chambers and Herrick having noted its occurrence in various parts of the United States. D. obtusa, Kurz, is apparently only the spineless condition of the above or a related species. No Daphnia is without the spine through life; such a form would constitute a new genus at once. Sp. 4. D. schoedleri, Sars. Seems to resemble D. pulex very closely but differs in having the lower margin of the head nearly straight, terminating in a short straight beak. The spine springs from the middle of the posterior margin. The anal spines are 14-16 in number. Length 2.33 mm. This name is applied by Sars to Schoedler’s D. longispina which is not D. longispina of Leydig. Sars’ D. hastata is so insufficiently defined that it will probably be necessary to drop it from the list. Sp. 5. Daphnia minnehaha, (Sp. n ) (Plate K, Figs. 1,2; Plate L, Figs. 1, 2.) This species, which occurs in small pools in autumn (affluents of Minnehaha creek, etc.,) 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 posteriosly, terminat- ing 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 58 TWELFTH ANNUAL REPORT. down the back. In young females and in males the slight angle is replaced by a strong knife-like projection which extends into from 1 to 4 sharp teeth, the anterior tooth being directed forward. The males, in particular, have this feature emphasized. D. long- ispina has a somewhat similar projection but the more nearly re- lated 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 trans- parent but in peaty waters becomes brownish. The size is small but variable; 1.8 mm. is acommon measurement. The post-abdo- men 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 flageilum, which latter is more than twice the length of sensory setze 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. Sp. 6. Daphnia carinata, Sars. Very similar to the last but, according to Sars, the claw has no well marked teeth, ashort flagellum on the male antenna, and the abdominal processes are united at the base (which may indeed be sometimes the case in the above.) D. cavifrons, Sars, has a prominence on the forehead and the lower margin of the head is strongly concave, otherwise hardly destin- guishable save by the absence of the keel above. Sp. 7. Daphnia longispina, Mueller. D. longispina, O. F. MUFLLER. BAIRD, LEYDIG, SARS, P. E, MUELLER, KURZ, WEIS- MANN, ete. Oval, elongate; head large, rounded in front, lower margin some- what concave; rostrum long. Spine very long, springing from the middle of the posterior margin. Post-abdomen attenuated toward the end. Terminal claws smooth or simply cilate, spines few. The abdominal processes are united at the base a very little, Flag- ellum of the male antennule hardly longer than the sensory sete. The young have three teeth above as in D. minnehaha. There is STATE GEOLOGIST. 59 a great deal of diversity of opinion as to the vaiue of this name. Not that there is any doubt of the existence of a widely distributed 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. D, lacustris, Sars, is nearly related, if not a variety of the above. Sp. 8. Daphnia rosea, Sars. (Plate K. Figs, 10-12.) Tn 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 re-united with that species, but, as there seems little doubt of the identification with Sars’ va- riety, as above, I prefer to use his name. Body oval, moderately yentricose; 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. ‘I'he head is separated 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 14 in number. The abdominal processes are not coalesced or but slightlyso. Length 1.50 mm. to 2.0mm. The species was coilected sparingly in a large Spihering of D. pulex from a small lake in early spring. The size and conformation of the abdominal processes is very variable and the long and very slender spine is frequently absent. Sp. 9. Daphnia similis, Claus. 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 | now have access to, it belongs in the group of D. longispina, though in many particulars it resembles D. scheefferi. The form is elon- gate, the spiue 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. schefferi. The flagellum and hook of the first foot of male are rather small. 60 TWELFTH ANNUAL REPORT. We now come to a group of related species which are most dif- ficult to circumscribe on account of their extreme variability. Ac- cording to the view of Lutz they would all fall into the old D. hyalina of Leydig. More probably, however, some of these forms are of nearly or quite specific value. Sp. 10. Daphnia hyalina, Leydig? (Plate L, Figs. 8, 5.) Daphnia longispina, HERRICK. I have elsewhere given a brief account of the post-embryonic de- © velopment of a species which agrees best with Leydig’s figures of D. hyalina. The lower outline of the head is nearly straight, the eye being always approximated toward it. In young specimens the head is sharp in front and crested. The lower margin of the head appears very long and the beak turns backward. ‘The spine is very long in young forms but is short iu old females. The male resembles very much the young female. The post-abdomen is narrowed toward the end, the terminal claws are smooth, the anal teeth few and the abdominal processes united. Ourspecimens are from Paducah, Ky., south of the Ohio river. Ido not know how to distinguish D. levis, Birge, from D. hyalina, save that the abdominal processes are said to be distinct. Both forms were observed in the above mentioned gathering. If, how- ever, Birge’s figures are characteristic, he had a different variety before him from ours; it seems somewhat like D. galeata. D, pellucida, P. EK. Mueller, differs from D. hyalina in the pre- sence of aseries of small teeth on the caudal claws, and a more strongly curved beak. It is just now brought to my attention that P. E. Mueller, in a late work, identifies D. pellucida with D. hyalina, though he still holds D. oaloata distinct. Daphnia galeata, Sars. (Plate T. Figs. 7, 8.) According to P. E. Mueller, this species differs from D. pellucida in the absence of teeth on the caudal claw, and, in one variety, by the acuminate head, which seems the only form for which the name is distinctive. Kurz found ouly the var. frons rotundata. Accord- ing to Forbes, both varieties, the first of which he identifies with D. pellucida, occur in lake Michigan. STATE GEOLOGIST. 6L S. I. Smith finds both in lake Superior, and seems to have no doubt of their distinctness. One of the forms which | have seen differs a little from either of the above, and had a different habitat. Kurz has described the male, which has avery short flagellum upon the antennule. A single source for D. galeata was found in asmall pool known as Clarke’s lake. This is the more remarkable, as this species, which is almost confined to larger bodies of water, is found nowhere else in the vicinage of Minneapolis, while this minute lake, though as deep, perhaps, as any of the largest in the county (say 40 feet), contains a number of forms known otherwise only in the Great Lakes.. Kurz’s remarks on the specimens collected by him apply equally to these. Were the claws dentate, the animal would pass as D. pellucida. 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 1.2mm, long, excluding the spine which measures 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. The above statements regarding D. galeata require a modifica- tion, for in another deep lake the writer has since secured the typical crested D. galeata with even a higher crest than that figured by P. E. Mueller. The head ends in a sharp angle. The single female seen was in company with the rounded variety and numbers of D. kalbergensis, which it resembles in many respects. Our fauna therefore is quite complete in these remarkable forms. (See Plate U. Fig. 6.) Sp. 11. Daphnia dubia, Herrick. (Plate L. Figs. 7, 8.) American Naturalist, 1883. The life history of this form is insufficiently known, but there seems no reason for doubting that it constitutes a new and easily recognizable species. It is nearly related to D. hyalina, but the head is strongly crested all round 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 62 TWELFTH ANNUAL REPORT. 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. ‘T'he 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 trans- parent and the spine is longer than in any other Daphnid. In a young specimen the spine was 1. mm., the body 0.7 mm., and the head 0.4mm. _ In this specimen the spine was slightly curved, the head elongate with a slight ridge infront. Another individual had the spine 1.1 mm. long, while the remainder of the animal was 1.3mm. 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 this species are the well crested head, which in young as well as sometimes older specimens has a median hyaline ridge, the withdrawal of the eye from the margin and the very long spine. It resembles D. galeata in earlier stages. It is very much like D. levis or, in other words, is in the group of D. hyalina; out the study of a considerable number of specimens from different localities con- vinces me that it can not be united with that species in any of its varieties. This species has only been found in autumn, Sept.— Nov., lake St. Croix and Richfield in Hennepin county. Sxction II. - Pigment fleck wanting. Head crested. The small, hyaline spe- cies constituting this section, elevated by Schcedler to the rank of a genus ( Hyalodaphnia ) and by Sars to that of a subgenus (Cepha- loxus), are chiefly residents of the deeper parts of our larger lakes. These forms, from their rarity, have been little studied and it is uncertain how far the assumed specific distinctions are valid. Two species are known in America and they are not confined to large lakes. STATE GEOLOGIST. 63 Sp. 1. Daphnia longiremis, Sars. Hyaline, compressed, seen from the side, rounded, lower margin strongly arched; spine long, straight, oblique. Head rounded, lower margin nearly straight, ending ina beak directed downward, acute anteriorly. Hye sinall. Antenne very long. Length1 mm. The abdomen is said to be similar to that of D. longispina. From the brief description given by Sars it would appear that this spe- cies is characterized by a rounded and uncrested or slightly crested head. Though imperfectly described, it is here mentioned to direct attention toward any such species as may be found in America. Sp. 2. Daphnia cristata, Sars, Compressed, long. Head acute in front, strongly crested, lower margin nearly straight. Dorsal line of body little curved, spine long in the young, strongly curved. Head of male smaller, flagel- lum of antennule twice as long as the sete; first foot well clawed. Length of female 1.83 mm. Sp. 3. Daphnia cucullata, Sars. D. berolinensis, SCHOEDLER. Very like the above, but the margin of head is not straight be- low, is, however, extremely variable and ends in asharp 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. The flagellum of the male antenna is about as long as the terminal setz. 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 corresponds with Sars’ description. Sp.4. Daphnia kalbergensis, Schoedler. (Plate U. Figs. 1—3). Form oval, spine long. Head high, compressed, enormously elongated, beak obtuse. Eye small. Abdominal processes not united. Caudal claws ornamented with small sete. Antenne of male with ashort flagellum. Length of head nearly equal to that of body exclusive of spine. D. vitrea of Kurz seems not improbably a varietal form of the above though the crest is lower, the size is less and the post-abdo- 64 TWELFTH ANNUAL REPORT. men is more slender and has fewer teeth; the differences are, how- ever, hardly specific. I am not convinced that either D. cederstromizi, Schoedler, or D. retrocurva, Forbes, are really distinct species, although the latter, with its more strongly crested head, is said also to have a series of teeth on the terminal claw. Perhaps it forms with D. cederstro- mii the fifth and extreme phase of this group. Since writing the above account of Daphnia kalbergensis this truly monstrous species has come to light in the vicinity of Min- neapolis. The opportunity is thus afforded to verify the suspicion expressed above that a number of species must be united under this. name. P. EK. Mueller gives the following measurements for D. kal- bergensis: head 0.9—1.0mm.,body 1.0—1l.1mm., spine 0.7—0.75 mm. 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. 7 Our specimens measured as follows: No.1. 1.6 mm, head somewhat more than half the body and ‘i. most exactly like D. vitrea in form. No. 2. Head 0.6 mm., body 0.9 mm., spine 0.5 mm.; about 9 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 specimens 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 basa. 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, Minn. Sp.5. Daphnia magniceps, (Sp. n.) (Pilate U. Fig. 15). The peculiar form figured in the Tenth annual of this survey seems indubitably new and is distinguished by the peculiar shovel- shaped head, which is scarcely crested but is broadest beyond the STATE GEOLOGIST. 65 middle. The spine is long, the claws smooth, the abdominal pro- cesses 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. Famity BosmMINnIp2. The sole genus of the family, Bosmina, contains over a dozen nominal species which are among the most difficult to define of any cladocerans.. The number is here reduced to nine and the probable position of the rejected species is indicated. This is not done because the author presumes upon the slender material at hand to revise the genus; but simply from the fact that the descrip- tions of the earlier writers do not permit a proper discrimination; so that this necessity is entailed upon any one who would give a birds-eye view of the members of the genus. The B. diaphana is founded upon a different twist in the antennules and no hesitancy is felt in uniting it with Sars’ B. lilljeborgii. The other species, B. brevirostris and B. nitida, are omitted simply because there seems to be no way of separating them satisfactorily from B. mari- tima and B. obtusirostris respectively. Three species have been found in Minnesota, but practically no attention has been given to the genus here. | Bosmina macrorhyucha found in Egypt is not here included, its description being inaccessible to me. B. levis, Leydig, seems simply a smooth condition of other spe- cies. Whether B. curvirostris, Leydig, is or is not valid must, so far as I am concerned, remain at present doubtful. GrNnus BosmMIna. A. Shell extending into a spine behind. (a) Antenne curved outward. 1. Bosmina cornuta, Jurine. (b) Antenne not curved outward, I. Shell reticulated, at least in part. + Flagellum midway between eye and the sensory setze of antenne, 2. Bosmina longirostris, Mueller. ++ Flagellum nearer eye. 3. Bosmina maritima, P. E. Mueller. 4, Bosmina longispina, Leydig. (B. brevirostris ?) il, Sheil striate. + Antennules long. 5 66 TWELFTH ANNUAL REPORT. 5. Bosmina striata, Herrick. tt Antennules short. * Rostrum long. 6, Bosmina lacustris, Sars. ** Rostrum short. %. Bosmina obtusirostris, Sars. (B. nitida, Sars?) B. Shell not spined behind. (a) Shell strongly arched above. 8. Bosmina lilljeborgti, Sars. (B. diaphana?) {b) Shell moderately curved above. 9. Bosmina microps, P. E. Mueller, Concerning the identification of Bosmina longispina, Leydig, with B. brevirostris, P. E. Mueller, it must be said that the bow is drawn at a venture, for Mueller, in his paper on the Cladocera of Swiss Lakes, in a fit of absent-mindedness refers to B. lacustris, P. HK. Mueller, citing p. 149 of Danmark’s Cladocera. On the page in question are descriptions of B. maritima and B. brevirostris of which the latter is probably the one meant. Sars’ B. lacustris seems quite different, being strongly marked by longitudinal lines, while Leydig says of B. lonyispina “shell striped and small reticulate,” and P. E. Mueller says in B. brevirostris the shell is “utydeligt reticuleret” i.e. indistinetly reticulate. ¥ The three species so far identified in America are B. longirostris, of which a figure is given (plate J, fig. 2,) B. cornuta and B. striata, which may possibly be yet identified with one of the European spe- cies, though it seems improbabie. I have also seen a species like L>ydig’s B. levis, but considered it a smooth variety of B. longi- rostris. FAMILY LYNCODAPHNIDA, Sars, 1861; Herrick, 1881. This is a rather small family with seven genera of minute ani- mals which are abundant only in summer. 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 collector. This family undoubtedly is the link connecting the Daphnide with the Lynceide, relationships to which are expressed by Macrothrix, on the one hand, and Lyncodaphnia, 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 Lynceidx. Later writers seem never to have found these genera and the group was STATE GEOLOGIST. 67 again included with the Daphnide. The writer, upon the dis- covery of the Lyncodaphnia, was forced to regard this group as of equivalent grade with the above mentioned families and again pro- posed the family name Lyncodaphnide. * The genus Ilyocryptus 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 prates 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 Macrothrix (?) 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 ephip- pium, 1. e. the saddie-shaped thickening of the shell walls to in- clude and protect the winter eggs; but I have discovered it in the ease of Macrothrix 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 I. 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 dispusition of the setz 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 La- thonura). In many forms there is no free posterior margin of the valves, while the lower is generally thickly beset with movable spines. ‘The Lyncodaphnidze will be distinguished from Cerio- daphnia, which they resemble, by their motion, which is a succession of quick bounds, while the broader Ceriodaphniz hobble along as though heavily weighted by the enormous mass of eggs with which they are generally laden. The abdomen is usually short and the. anus is behind the terminal claws, but in Ilyocryptus the claws are long and spined at the base. Inthe American I. spinifer the anal opening is elevated to a point nearly underneath the stylets, and there is a rudimentary anal cecum as in Lynceids. The males have the opening of the vasa deterentia in front of the claws, which may be absent; the antennules are also modified, oeing longer and curved. In Lathonura the abdomen is elongated 1 Notes on Some Minnesota Cladocera. 1881. 68 TWELFTH ANNUAL REPORT. posteriorly till it begins to suggest a transition to Polyphemus. The known genera and their distribution is as indicated below. Half of the known species are found in America; one sixth being peculiar to it. Total number | Europ- Also | Onlyin | Total GENERA. of ean. Amer- ;America| Amer- specles. ican. ican. i; Macrothanixicens sccocsee aouditerceene 4 3 2 1 De LATION UA see ac cuae oor nerameeie cies 1 1 1 Be err : 3.4 Pore pawmOthnix dc cess wees Ueoee « aek J V5.2 \ereveceletge ese sper eae ee eee a 4 SUTEDIOCENGUS SS. en ans Gee ne ees nes il 5 A HORRY mrss Ae oca5s || Sigce a4 coo% 5., (Acantholebentsys:.t)2 eneoce. Sass 1 DA siereier ete: 0's | eels leae eee a G2 OLryOXUS soso Safa eee ravetale ciowrne less 1 1 1 oe eee 1 Toy dayneodaphiig 225. seb eines eee i ae slete ue l 1 Ss a LIVOCryPtUSs sos seen uee wae we cree 3 Aa de (eR Sab eh 1 1 ROGUES hr: craraataeenincen cereale cece meee 13 10 4 3 7 1. Genus Macrorurix, Baird. Body oval, pointed behind; head broad; antenne of first pair long, nearly straight, beset with spines, olfactory threads terminal ; swimming antennz large and powerful, propelling the animal by bounds; three-jointed ramus with a greatly elongated seta which is thorned and jointed; labrum with the basal joint enlarged, resembling that of Lynceids; 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. Mueller whose Daphnia curvirostris is usually referred to Macrothrix 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.! Nearly two years later the male of M. rosea was described from Wisconsin by H. A. Birge. Descriptions of the male of Lathonura are also given in both the above mentioned sources: Sp. 1. Macrothrix laticornis, Jurine. (Plate ©. Figs. 7, 8 and 9.) Daphnia curvirostris(?), MUELLER. Monoculus laticornis, JURINE. Lynceus laticornis, DESMAREST. 1 Gruber und Weismann, Ueber einige neue oder unvollkommen gekannte Daph niden. Freiburg. STATE GEOLOGIST. 69 ° Macrothri«z laticornis, BAIRD, Ann. Mag. Nat. Hist. Acanthocercus curvirostris (?), SCHOEDLER, Hrichs. Archiv, 1846. Daphnia curvirostris, FISCHER. Macrothriz laticornis, LILLJEBORG, LEYDIG, BAIRD, P, E. MUELLER, FRIC, KURZ, SARS, LUTZ, CLAUS (Die Schalendruse d. Daphnien), NORMAN and BRADY (Monogr. Brit. Entom.), GRUBER and WEISMANN, WEISMANN, (Beitrage zur Naturgeschichte d. Daph.) This is the commonest European species and is the type of the genus, showing its rather conservative position by the broad tip of the antenna which is a feature exhibited by embryos and young of other species. The shell has a warty surface and is toothed above, while the lower margins are fringed with long unequal spines in - groups of threes or fours. The form is roundish with a blunt posterior angle, the ventral margin being regularly curved. The antennules are short and en- larged at the end. The form is an irregular pentagon; a pair of slender spines sits at the angle near the base. The swimming antenne with the seta on the first joint of 3- jointed ramus very long. Post-abdomen truncate at the end, short, posterior margin beset with series of bristles. Length of male 0.5—0.6 mm., of female 0.4 mm. This is the smallest of the genus and will undoubtedly be found in America. | Sp. 2. Macrothrix rosea, Jurine. (Plate C. Figs. 5, 6, 11, and 18.) Monoculus roseus, JURINE. Lynceus roseus, DESMAREST. Daphnia rosea, M. EDWARDS, JURRELL. Echinisea rosea, LIEVIN. Macrothriz rosea, BAIRD, LILLJEBORG, P. E. MUELLER, BIRGE. 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 antenne 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 setz; abdo- men more slender, sinuate in front, beset with short hairs. Length 0.6mm, male0.8mm. The male has no claws on the end of the post-abdomen, and the antennules are curved and elongated. Figures 5 and 13 are copied from Birge. 70 TWELFTH ANNUAL REPORT. Sp. 3. Macrothrix tenuicornis, Kurz. (Plate C. Figs. 1, 1a, 2, 3, and 12.) (See Notes on Cladocera of Minnesota, p. 245.) The body is oval, produced posteriorly infa sharp point; the ab- domen is strongly arched, while the upper outlinejof the head is a regular curve or slightly extended in front of the eye; the anten- | nules 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 setze 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 M. rosea, but 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 ihe 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 angie of the basal portion shows how the transi- tion 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 common about Minneapolis, Minn., but is not. yet noted elsewhere in America. Sp.4. Macrothrix pauper, Herrick. (Plate C. Fig. 4.) This species is described from a single specimen from L. Minne- tonka, and I can add nothing to the very meager notice given then. ! 1 Notes on some Minnesota Cladocera. 1881. C. L. Herrick. Sd laf STATE GEOLOGIST. il The body is broad and very narrow, the lower outline is angled and nearly unarmed; the pigment fleck and eye are small and ap- proximated; antennules very long and curved backward and out- ward; abdomen short, ciliate. below; claws short, ciliated. This female had a full complement of eggs but the antennz resemble those of a male. This is unusually interesting and should be redis- covered 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. m. GeENus LatHonvra, 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 antennze with five setz on each ramus; only four pairs of feet ap- parent; abdomen short, prolonged upward to the insertion of the caudal stylets; male similar but smaller. Sp 1. Lathonura rectirostris, 0. F. Mueller. (Plate D.) Laphnia rectirostris, 0. Fs MUELLER. Pasithea rectirostris, KOCH, Deutschiand’s Krust., ete. Daphnia brachyura, ZADDACH, Syn. Crust. prussicorum. LIEVIN, Die Branch. d. Danziger Gegend. Daphnia mystacina, FISCHER, St. Petersb. Branchiuop, Lathonura rectirostris, LILLJEBORG, De Crust. ex ord. trib. Pasithea rectrirostris, LEYDIG, Naturg. d. Daph. Lathonura rectirostris, NORMAN and BRADY, Monogr. Brit. Ent.; P. E. MUELLER, Danmark’s Cladocera, Lathonura spinosa, SCHOEDLER, Brauchiop. d. Umg. v. Berlin. Pasithea rectirostris, GRUBER and WEISMANN, Ueber einige neue od. unvollk. ge- kannte Daph. Lathonura rectirostris, BIRGE, Notes on Cladocera. HERRICK, Notes on Minnesota Cladocera. 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. The form is a rather quadrangular ova!, the head being strongly arched to the beak which is much farther posterior than in Macro- thrix, in this respect resembling the Daphnidae; the eye occupies the center of the lower part of the head margin, and is of moderate size; the pigment fleck is near the base of the antennules and well removed from the eye; the antenne are straight and long, with a lah. 2 TWELFTH ANNUAL REPORT. sensory bristle near the base in front and two bristles a third from the end; the second antennz 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 setz 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 orna- mented 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 setz; the abdomen is very short and terminates in inconspicuous teeth, the posterior part of the abdomen being ornamented with teeth flattened longi- tudinally 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 lke the spines of the abdomen; the caudal setz are seated on a high prominence of the abdomen, and are fringed along their whole lexgth, not merely at the end. The female is 1 mm. long, the male 0.5—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 irre- gularly round with small! nuclei. m1. GENUS STREBLOCERCUS, Sars. In form like Macrothrix laticornis, head terminating in a long rostrum bearing the long, twisted antennules. Antennules very large, curved backward and outward. Head not separated by a destinct depression from the body, very high, slightly arched above, abrubtly curved below with spines upon the margins. The anten- nee are large; four-jointed ramus much the longer, with four sete. Labrum with a large process. Post-abdomen as in Macrothrix lati- cornis. Hye near the beak; pigment fleck small, below it at the base of the antennules. Length .83 mm. 5S. minutus is the only species. 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. M. pauper is 1 mm. long. | SS ee STATE GEOLOGIST. 73 iv. GENuSs DREPANOTHRIX, Sars. The head not separated from the valves by a depression; fornices moderate; 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; swimming antenne with three ciliated sete on the 4-jointed ra- mus, the 3-jointed ramus with its basal joint armed with an un- jointed, strong, spinous seta and four ciliated setz on the remain- ing joints. The post-abdomen is broad. The male has longer an- tenn and a hook on the first foot. Sp. 1. Drepanothrix dentata, Euren. (Plate C. Fig. 14.) Acantholeberis dentata, EUREN. Drepanothriaz setigera, SARS. Drepanothrix hamata, SARS. This animal is only 0.5 mm. in length. The antennules are laterally curved in the middle and ornamented with notches on the margins; 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. Only found in Scandinavia as yet. vy. GENUS ACANTHOLEBERIS, Lilljeborg. Head separated by a depression from the body, with fornices above the base of the swimming antennz; rostrum erect, rather acute; shell oblong, truncate behind, ciliate below with long sete; macula present; antennules rather long, movable, sensory setz terminal, bifid at the apex. The tri-articulate ramus has along spiny seta on the basal joint; feet six pairs; no abdominal process; post-abdomen wide, large; in- testine without ceca. Sp. 1. Acantholeberis curvirostris, Mueller. Daphnia curvirostris, 0. F. MUELLER. Acanthocercus rigidus, SCHOEDLER, LIEVIN. Acantholeberis curvirostris, LILLJEBORG, P. E. MUELLER. This species of a genus approximating the Lynceids has not yet been fuund in America but is to be expected. The abdomen is rounded toward the end and spiny posteriorly; the terminal claws are furnished with two strong teeth at the base, 14 ' TWELFTH ANNUAL REPORT. followed by a series of fringing bristles. The length, according to. Mueller, is 1.5 mm. This isa rare form in Europe. vi. GENUS OFRYOXUS, Sars. The single species constituting this genus seems to have been seen by no writer save Sars. At the time my previous paper on Cladocera was published, Sars’ description seemed not to apply to the form called Lyncodaphnia. Since then several stages in the growth of Lyncodaphnia have been encountered, which so far agree with what is said of Ofryoxus gracilis that it is doubted if the two forms are not identical. : vo. Gernus LyncopapuHnta, Herrick. (Plate B. Figs. 12, 15; Plate B1, Figs. 1, 3.) Body elongated, somewhat rectangular as seen from the side, greatest width and hight of shell a little posterior to the heart; head separated by a depression from the body, truncate below; antenne and antennules much as in Macrothrix; 4-iointed ramus of antennz with no lateral sete; eye small, pigment fleck present; intestine twice convoluted, expanded posteriorly, with anterior but no posterior czeca, opening near the “ heel” of.the post-abdomen: post-abdomen large, triangular; terminal claws long, rather straight, with two accessory spines at the base. The species upon which this genus was founded! occurs in August and September in the larger lakes of Minnesota. | Lyncodaphnia is, as was suggested, a curious transition form linking the Daphnide with the Lynceide. A farther study of the genus shows that, in some respects, it is more closely allied to both groups than before suspected. The habit and appearance in the water reminds us of Simocephalus, a re- semblance which an occasional spot of pink or blue color hightens. L. macrothroides not only has the disc-like last foot colored but the swimming antenne are banded with purple as in Simocepha- lus rostratus, Her., and 8. americanus, Birge. The intestine has anterior czeca, which is not the case in lynceids nor, indeed, in other Lyncodaphnide. The four-jointed ramus of the antennze approaches Lynceide in the absence of a lateral seta, but the other ramus is as in Macro- thrix. The convolution of the intestine, the form of the post- abdomen and the situation of the anus, are all of a strictly lynceid 1 Notes on Minnesota Cladocera, p. 247. a STATE GEOLOGIST. Td type; moreover the flattened appendage of the last foot is like that of Eurycercus. Hiven in the form of the shell there is a combination of charac- ters; the anterior part of the shell has the form peculiar to Lynco- daphnide; but posteriorly it again expands and becomes truncate be- hind; 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 (Am. Naturalist, 1882, p. 815) to explain the origin of this appendage is probably the correct one. Professor _ Leuckart suggested that this spine was a balancing rod intended to keep the proper equipoise over the center of gravity; but it is - difficult to see why these long-bodied forms, in which the greater part of the weight lies ‘‘abaft” of the pivotal point—the base of the antennz—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 develop- ment of the head in the crested Daphnide may undoubtedly be ex- plained upon Prof. Leuckart’s theory. Sp.1. Lyncodaphnia macrothroides, Herrick. (Perhaps = Ofryoxus gracilis, Sars.) Notes on Cladocera of Minn.. p. 247. Sub-rectangular, greatly elongated, truncate behind, with a slight spine above; head and eye small, fornix moderate, beak truncate; antennules 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 setz smooth to the joint; labrum as in Daphnia; mandible attached behind a salient angle of the front margin of the shell;.no ab- dominal 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 posteriorly the ordinary branchial coil, here shaped like a thumb and forefinger. The young is of a different shape and bears along spine. The male is unknown. 76 , TWELFTH ANNUAL REPORT. vill. 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; sete terminal, 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, without ceca, 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 alge and filth till the animal is no longer able toswim. P. E. Mueller and Kurz, who seem to have seen cnly I. sordidus agree that Ilyocryptus can not swim, but poles along in the mud on the bottom by means of antennz and abdomen; our I. spinifer, on the other hand, swims freely till loaded up with old clothes and filth. This genus is also closely allied with the Lynceide. Sp. 1. Ilyoceryptus sordidus, Lievin. (Plate C. Figs, 15, 16, 17.) Acanthocercus sordidus, LIEVIN, LEYDIG. llyocryptus sordidus, SARS, NORMANN, P. E. MUELLER, KURZ. 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; antennae 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 described such czeca was an error; see Notes on Cladocera of Minn., p. 246). i = STATE GEOLOGIST. CF Sp. 2. Ilyocryptus spinifer, Herrick. (Plate C. Figs. 18—19.) Usually longer than high; head rounded, almost exactly like I. sordidus, but the form of the post-abdomen differs a little in the higher situation of the anus and the great elongation of four or five of the lower spines of the posterior margins; the margins of the shell are beset with pectinate setze which do not branch. The nearest approach to branching sete yet seen are figured on plate C, fig. 18a; this consists in the outgrowth of a spine from near the base, and such setz are found only on part of the posterior margin. It seems that our form is rather close to I. sordidus though clearly distinct. | This species occurs in many of our lakes, and is found most fre- quent in late summer. Sp, 3. Ilyocryptus acutifrons, Sars. This species,is only mentioned in the appendix to the paper of Sars on the Cladocera from the vicinity of Christiania. The follow- ing is a condensation of the description. Head large, acute in front. Shell truncate behind, with shorter sete 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 I. sordidus, posterior margin continuous, anus terminal; caudal claws straight, very long, with two minute basal spines. Pigment fleck almost touching the eye. Length less than in I. sordidus. This species seems in some respects more like a true lyncodaph- nid than either of the other species. It is doubtful if it belongs here. FAMILY LYNCEIDA. pmber I Total 0) : n Europ- | Also in . 5 GENERA. known ie America| Amer- species.| ©@- |America |“ only, ican. NEM CET CMG. oo. pice ctulvie © sic au,s! i acventse 1 i pea | ees a wen 1 oe A CLODETUS oaks oie ioe fe Saes.ctae ue ee 2 al eo Weed eee 8 eee Gee 1 ae aI GOCETCUS \a:io55.0 acts asic cnis al 06 6 5 1 1 2 4, Alonopsis............ frcece crete 3 2 1 1 2 PICT NST Ai) 01s Aeteie) a ceter onk hao oniere 2 2 Dire Nive paupeteales 2 Bre GVADLOIGDCLIS: 62. ccs ssn oes eicle es 2 2 ie ley eos eee i fe MOLEDICOCETCUS socc.c5 56 sncciee ee oe 5 VEC Ses Teas | ay ee 1 1 SPAN OMA estat MIC Oe. a ole dts capes ners 21 14 6 i 13 Se CLO IC L UA UMeE RC, Vere hl Seee Slat, Sis choy es 5 5 2 ane 2 6 lp ted A EE AL Ee ope es : 1 6 7 1. EPO MAM MCAS re ake n cad kmecent oR by Lak pec ceie neces fet swscsnen lone’ cons soe Sr ONTVUOTTS cs sects lc coe caweeee 8(?) 6(?) Sod iez eee .toee 38 t Peta PME MISITODUS.oc0 4. ce-vades cabs cues +s a 5 heey Seer ores Ceci eet i 1 (?) PACHA LO TLOS UMS = 5 <1 516 cle ao'rteim/e oy cine 6 reso 1 1 1 eee |e ee gee 1 EE 78 TWELFTH ANNUAL REPORT. Out of the fourteen genera, two (or perhaps only one) are not yet known from America, while one is restricted to it. The Amer- ican species, 45 per cent of which are new, aggregate 72 per cent of the Huropean. 54 per cent of all the known species are Amer- ican, and most of these have been found within a range of ten miles of Minneapolis. It is probable that the number of species peculiar to America is too high proportionately rather than the reverse, and the comparatively high per cent of new species is due to an actual larger fauna in the New World, while many Old World species remain to be identified. A few of the European species are very likely synonyms, permitting farther reduction. This family, which is numerically the largest among the Clado- cera, is, in the main, well limited, though there are transitions to- ward the Lyncodaphnide, which are quite direct. The genera Lynecodaphnia, Ofryoxus and Ilyocryptus lead toward the Lynceidz unmistakably. Most of the members of this family are small, com- paratively few exceeding one millimeter in length. The head is covered with an arched shield, which frequently passes with no in- dentation into the shell of the body. This head-covering generally extends forward and downward to form more or less of a sharp angle in front, while in several generait 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 antenne spring from well up under its posterior expansion. The rounded sides of this shield, which pro- tect 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 Daphnidz but usually shorter. Maxillz 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 antennz have both rami three-jointed. The terminal part of the body, or * The name “Lynceus” is derived from that of the son of Aphareus who was famous for the sharpness of his vision. STATE GEOLOGIST. 79 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 difficully. 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 ab- sent. On the other hand, sometimes the shell is considerably modi- fied, 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 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-abdo- men. 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 American species of Pleuroxus we find an approach to this structure in the female—an interesting example of inheritance of sexual peculiarities across the sexes. The altera- tions in the form of the post-abdomen consist in a narrowing or excavation of that organ to permit its introduction 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 par- thenogenesis. In some cases it would seem from Weismann’s ob- servations 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 (Kurycercus alone excepted). The males are usually but not always smaller. Plate EK gives views of typical Lynceide 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 maxille (not shown) which are exceedingly small, the largely de- veloped 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 developed limb. Fig. 3 shows the appearance of a differ- 80 TWELFTH ANNUAL REPORT. ent embryo trom below and in an earlier stage. Fig. 2 illustrates the relation of the brain to the eye and the very small optic gang- lion. Fig. 9 of plate G gives details of the feet in another species, and the modifications seen in the male of the same species are sufli- ciently shown in fig.,1 of the same plate, which also well illustrates the various sculpture of the shell displayed by this group. Figures 4 and 9 of plate Ff show curious modifications of the post-abdomen of the male, and fig. 7 exhibits the structural peculiarity of sexually perfect females which is correlated with it or, perhaps we may say, occasions it. | SUB-FAMILY 1—EURYCERCIN &. A single species constitutes the sub-family, and it will be necess- ary to point out only those points which are distinctive. | The Eurycercine differ from the true Lynceide and approach the Lyncodaphnide in having the digestive tract not coiled, with two ceca 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 Sidide. 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. | 1, GerNus EHurycercus, Baird. Characters of the sub-family. Eurycercus lamellatus, 0. F. Mueller. (Plate H, Figs. 5-6.) Lynceus lamellatus, MUELLER, EDWARDS, KOCH, ZADDAGH, LIEVIN, LEYDIG, ZENKER Eurycercus lamellatus, BAIRD, LILLJEBORG, SCHOEDLER, P. E. MUELLER, KURZ, BIRGE,. HERRICK. Eurycercus laticaudatus, FISCHER, SCHOEDLER. A gigantic lynceid, reaching the dimension of 3mm. 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 in- testine is bent upon itself but not coiled. The last foot is found in few other Lynceide. Acroperus has the same, and Pleuroxus uni- dens also has a rudimentary sixth foot. STATE GEOLOGIST. 81 SUB-FAMILY IL. —LYNCEIN &. Intestine coiled; anus near the end of the post-abdomen; open- ing 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. SERrEs A. Head or dorsal line keeled or ridged ; abdomen long; shell marked with diagonal strie. This section is proposed for the old genera Camptocereus, Acroperus and Alo- nopsis, which seem to form a natural group though passing directly into Al na. 11.—GENuUS CAMPTOCEROUS (>Camptocercus, Baird). This easily recognizable genus contains two groups, each with several nominal species, which are distinguished mainly by the width of the post-abdomen. In both the shell is elongated, more or less quadrangular, 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-abdomen is long and furnished with a lateral row of scales. The terminal claws have a single basal spine and are serrate. There is an ephippium, and the male opening is in front of the terminal claws. SuB-GENusS 1.—Acropervs, Baird. Post-abdomen broad, margins parallel; anal teeth very minute lateral scales large and usurping their place. Aatenne with eight setee (53). Three species are described, one of which is very abund- ant in Minnesota. Sp. 1. Acroperus leucocephalus, Koch. (Plate E, Fig. 5. PlateI, Fig, 9.) Lynceus leucocephalus, KOCH, FISCHER. Acroperus harpx, BAIRD. Acroperus leucocephalus, SCHOEDLER, P. E. MUELLER, KURZ. Acroperus sp., HERRICK. Acroperus striatus, JURINE, M. EDWARDS, LIEVIN, LILLJEBORG, LEYDIG, ete., seems to belong here, but I am able to add nothirg to the eluci- dation of the puzzle. Body rounded above, angled behind; head moderately arched and carinated. Lower margin of the shell pectinate, terminating in 6 ————— ee rr ee 82 TWELFTH ANNUAL REPORT. two teeth. The antenne are long and when reflexed the setzx reach nearly to the posterior margin of the shell. The posterior angle is not always as prominent as shown in fig. 5. Sp. 2. Acroperus angustatus, Sars. (Plate I. Fig. 10.) Acroperus angustatus, P. E. MUELLER, KURZ. 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 less 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 E differs from both the above slightly. The head is carinated and incurved almost as in C. angustatus; the antenne fall a little short of reaching the posterior margin of the too low and oblong shell; there is an ob- vious depression between the head and 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. KE. Mueller, is not known in the female sex. The male has a twisted caudal claw. | SuB-GENUS 2.—Camprtocercvs, Baird. Although the general form is similar to the last section, the body is usualiy longer; the post-abdomen narrows toward the end; the anal teeth exceed the lateral row; the antenne have usually but seven setae (=>). The species enumerated are so closely related as almost to baffle definition. Key TO THE SUB-GENUS CAMPTOCERCUS (verus). Beak pointed. (a) Head depressed. I. Pigment fleck larger than the eye. . | 1. C. biserratus, SCHOEDLER. II. Pigment fleck smaller than the eye. 2. C. macrurus, O. F. MUELLER. (b) Head directed forward. 3. C. rectirostris, SCHOEDLER. Beak truncate below. 4. C. latirostris, KURZ. STATE GEOLOGIST. -kSO Beak cleft below or with a forward projection. (a) Antennules shorter than the beak. 5. C. lilljeborgii, SCHOEDLER. (b) Antennules longer than the beak. 6. C. rotundus, HERRICK. Sp.1. Camptocercus biserratus, S8choedler. (Plate I. Fig. 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 distinguish this form. (Schoedler says that the pigment fleck in C. macrurus is smaller than the eye, P. EK. 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 slender basis. The basal spine of the claw, however, s¢ems to be peculiar in sitting on a distinct prominence. Sp. 2. Camptocercus macrurus, Mueller. (Plate E. Fig. 10.) 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 looking downward; the direction of the head is some- what variable (from vertical to an angle of about 30°). 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 ser- rate, the claw itself being nearly straight and armed with an in- creasing series of spines to beyond the middle. The lateral sales of the post-abdomen are inconspicuous. The shell gland is long. The antennules reach to almost 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 labrum is armed with teeth on the posterior face of the triangular process. The intestine is very trongly, almost twice coiled. The lower margins of the valves are 84 . TWELFTH ANNUAL REPORT. 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. Sp. 3. Camptocercus rectirostris, Schoedier. (Plate I. Figs. 1—3.) Camptocercus rectirostris, SCHOEDLER, P. E. MUELLER, KURZ. 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 hight of the body. The beak is sharp. I am not sure that Weismann’s figures (I. c., plate XI, figures 13 and 14) really belong to this species, for the drawing of the post-abdo- men does not agree with that of P. E. Mueller fully. Outline copies of the former are given in plate I, figs. 1 and 2. The male has a hook upon the first foot. Not yet recognized in America. Sp. 4. Camptocercus latirostris, Kurz. (Plate I. Figs. 5—6.) C” lilljjeborgii, 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. macru- rus 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. Sp. 5. Camptocercus lilljeborgii, Schoedler. (Plate I. Figs: 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. : Sp. 6. 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 STATE GEOLOGIST. 85 head is much as in the last, but it is not certain that the beak is left, although it has a peculiar form (not indicated in the figure) near the end. The lengthis0.7 mm. The terminal setze of the antennules are very unequal; but in most points, as in the armature of the post-abdomen, the details resemble C. macrurus. 111.—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 Pleuroxus, 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, aresemblance hightened 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, A. 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; an- tennules slender; antennz with eight sete; abdomen long, nar- rowed 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 theanterior margin. The young are more elongate and (sometimes) have hexagonal reticula- tions instead of the usual strong diagonal striz. Motion slow. Sp. 1. Alonopsis elongata, Sars. Synceus macrurus, LIEVIN. Lynceus macrurus, ZENKER, LEYDIG. Alona elongata, SARS. Acroperus intermedius, SCHOEDLER. Alonopsis elongata, P. E. MUELLER. The shell is wide, the upper margin forming an even curve: manifestly angled behind; ventral margin nearly straight, ciliated throughout, with a single tooth behind. Fornices large; head nar- row, 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 sete. 86 ; TWELFTH ANNUAL REPORT. This form I have never seen, and it seems somewhat doubtful that the following really belong with it. Sp. 2. Alonopsis latissima, Kurz. (Plate E, Fig, 8. Plate G, Figs, 1 and 9.) Body very high, compressed, with a high dorsal keel or ridge; the upper outline strongly and evenly arched, terminating be- hind in no angle; lower margin almost angled at the anterior third, rounded behind, 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, some- what 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 few strong striz which are diagonal except anteriorly where are a few parallel to the front margin. The male is small and lacks the crest on the back, while the lower margin is straight; the an- tenn 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, how- éver, 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 Minnea- polis (marshy off-set from Bassett’s creek near Oak Lake Addition).* *NOTE TO ALONOPSIS LATISSIMA., (See Fig.1, Plate G.) 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. Sp. 3. Alonopsis media, Birge. (Plate E. Fig. 9.) I give Birge’s description verbatim: “Rostrum prolonged, and shell sharp, somewhat quadrangular in shape, marked by strize. 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 sete. STATE GEOLOGIST. 87 The front margin is strongly convex. The post-abdomen is long and slender, resembling that of Camptocercus, and is notched at the distal extremity; 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 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 flagellum and sense hairs. The antennez are small and have eight (m7) setee and two (Gv) spines. The labrum resembles that of A. leucocephalus, but is slightly prolonged at the apex. The intestine, cecum and color resemble those of Acrope- rus. There is a trace of a keel present 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 abdomen 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 be- fore the lower curved angle. : The pigment fleck is nearly or quite as large as theeye. The antennule is shorter than the beak (which is almost as in Pleuroxus hastatus), and has a flagellum about midway; at its base it is nar- rowed and inserted on a prominence. The embryo still in the brood sac had 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. SERIES B. This section includes forms with (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 antennz 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 hight of shell about equal to the posterior margin. 1. Genus Leydigia. B. Greatest hight of shell moderately exceeding that of posterior margin ; post-abdo- men more or less triangular, armed with bristles; shell marked with hexagonal meshes. (a) Head nearly horizontal, blunt ; post-abdomen prominent in the anal region. 2. Genus Graptoleberis. 88 TWELFTH ANNUAL REPORT. (b) Head depressed, acute ; post-abdomen excised near the anus. 38. Genus Crepidocercus. CG. 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; hight of posterior shell margin usually less than the greatest hight of shell. 4, Genus Lynceus. D. Greatest hight of shell little less than that of posterior shell margin; post-abdo- men terete ; terminal claws very minute. 5. Genus Phrixura, E. Greatest hight of shell more than double that of posterior margin. (a) Eye aud first foot normal. 6. Genus Chydorus. ; (b) First foot with a claw which extends beyond the shell. 7 Genus Anchistropus. (c) Eye absent, only pigment fleck used for vision. 8. Genus Monospilus. 1v.—Genvs Lerypieta, Kurz. 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 hight 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 Ilyocryptus; 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 striz; the lower margin is covered with long spine-like sete. The post-abdomen is armed with several sets of 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 czcum is rudimentary. The antenne are heavily spined and have eight set; 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. Sp. l. Leydigia quadrangularis, Leydig. (Plate H. Fig. 4.) Lynceus quadrangularis, LEYDIG, FRIC. Alona leydigii, SCHOEDLER, P. E. MUELLER. Leydigia quadrangularis,. KURZ. The shell is comparable to that of Alona quadrangularis, but higher behind; the markings are not very distinct; shell trans- parent. 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 STATE GEOLOGIST. 89 posterior margin nearly the segment ofa circle, armed with numer- ous very long unequal spines which extend only about half the hight, 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, Alabaina. Sp.2. Leydigia acanthocercoides, Fischer. Lynceus acanthocercoides. FISCHER, LEYDIG. Hurycercus acanthocercoides, SCOHOEDLER. Alona acanthocercoides, P. E, MUELLER. Leydigia acanthocercoides, KURZ. Leydigia quadrangularis, HERRICK. This species, reported in a previous paper, is, as was said, nearest like L. acanthocercoides; and I am now able to verify the very in- conspicuous 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 claw of the post-abdomen is present, while in the present species the pigment fleck is much larger and furnished with lenses; the spine of the claw is wanting; the labrum is densely hairy; the abdo- men is narrower, and the shell higher. The shell is very obviously striped in the posterior portion. The anus is higher than in the previous species. In other respects the two seem alike. v.—GENUS GRAPTOLEBERIS, Sars. A genus containing two closely allied species, having some affinities with Alonella. The shell is entirely reticulated, and there is a sort of crest along the back; while, on the other hand, the head is flat- tened 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 antenne 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. 90 TWELFTH ANNUAL REPORT. Sp.1. Graptoleberis testudinaria, Fischer.” Lynceus testudinarius, LEYDIG, LILLJEBORG. Lynceus reticulatus, FRIC. Alona testudinaria, SCHOEDLER. Graptoleberis testudinaria, KURZ, 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 an- tennz 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 toward the end, rounded in front; the terminal claws are small and have two basal teeth. The dorsal margin of the post-abdomen is covered with tufts of hairs. The winter eggs have no ephippium. Length 0.55 mm.to0.7mm. 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 typical European form seemed to be the absence ofthe 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. Sp. 2. Graptoleberis reticulata, Baird. Alona reticulata, BAIRD, P. E, MUELLER. Lynceus reticulatus, LILLJEBORG, LEYDIG. Alona esocirostris, SCHOEDLER. Graptoleberis reticulata, SARS, KURZ. 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 covered 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. STATE GEOLOGIST. Ot - vi.—Genus Creprpocercus, Birge. The characters of this group place it rather near Alonella or be- tween 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 moderate 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 asingle 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 setz and the usual spines. Shell smooth or reticulate. Sp. J. Crepidocercus setiger, Birge. (Plate F. Fig. 13.) Length 0.4 mm. to 0.6mm. Minnesota specimens measured 0 5 mm. This, the only species of the genus, is but rarely encounter- ed, and is so peculiar as to be easily recognized when seen. Alona intermedia has a post-abdomen with clusters of bristles, but in Crepidocercus the post-abdomen is more as in species of Graptoleberis. than any other genus. The markings upon the shell are very indistinct. | vit.—Genus Lynceus, O. F. Mueller. The perplexing inter-relations between the three genera Alona, Alonella and Pleuroxus give rise to the utmost confusion. No two. autkors are agreed as to their respective limits, and the points given by Kurz, who has carefully gone over the ground, are obviously insufficient. 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 theoreti- cal 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 quadrangulata, may be conveniently distinguished as a transition to species like Ilyocryptus. 92 TWELFTH ANNUAL REPORT. ‘Phrixura, Graptoleberis and Crepidocercus, each contaming few ‘species vrhich can be readily recognized, fill a place in the system; but it is practically impossible to distinguish Alona from Pleurox us without instituting 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 antenne, and more rectangular shell, is, per- haps, the pivotal point of the group. According to this view, then, the old name Lynceus is revived for the aggregate; and the other names are retained, in part, as titles of largely conventional groups or sub-genera, thus: | ‘Genus LyNcEUs. Sub-genus ALONA. Section A. Alona vera. Section B. 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 Huropean. No other genus is so difficult among the Lynceide, for the most minute differences 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 antennz have eight setz. The claw of the male post-abdomen is removed from the lower angle. About twenty species are known, all of which that seemed recog- nizably defined have been included in the following key, which is believed to be more nearly natural in its arrangement than that of Kurz, which would separate the European and American represen- tatives of the A. parvula group. Many more forms remain to re- ward the labor of American students. Those mentioned from Minnesota could probably all be found by a few days search in one locality. 7 Kry to Section A, ALONA. “A. Shell reticulate. (a) Reticulations horizontal. 1. A. guttata, Sars. _ 77 (b) Reticulations oblique. 2. A. angulata, Birge. B. Shell lined, smooth or tuberculate. (a) Over 0.5 mm. in length. I. Shell densely striate. 3. A. sanguinea, P. E. Mueller. II. Shell normally, evidently striate. * Post-abdomen narrowed at the end. + Armed with elongate teeth below. 4. A. tenuicaudis, Sars. ++ Teeth of post-abdomen nearly equal. 5. A, lineata, Fischer. (Shell arched.) 94 TWELFTH ANNUAL REPORT. 6. A. modesta, Herrick. (Shell straight above.) ** Post-abdomen not narrowed. + Antenne with seven sete. (?)7. A. costata, Sars. tt Antenne with eight setz. 8. A. quadrangularis, Mueller. III. Shell faintly, irregularly striped; eye of same size as pigment fleck. 9. A. oblonga, P. E. Mueller. ; : IV. Shell smooth. 10. a. ee ee eee 206 TWELFTH ANNUAL REPORT. 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 shelb 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 mm.—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 plications rather than striz, which arch over the back. Sp. 7. Alonella straiat, Schoedler. This species is said to resemble A. 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 anten- nules with their setee extend beyond the beak; the pigment fleck is: smaller than the eye and half way to the beak. The post-abdomen is long and narrowed toward the end; there are seven or eight anak spines, and two spines on the terminal claw, Length about 0.5 mm. SUB-GENUS PLEUROXUS. Section A. Plewroxus (verus), Baird. This group of lynceids is most obviously defined by the lone “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 case 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 for- ward. The fornices, or lateral 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 hight 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— STATE GEOLOGIST. 107 abdomen is slender, usually truncate and armed behind with asingle 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 3 modified, 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 10 Section A, PLEUROXUS VERUS. § Beak not curved ferward. A. Shell reticulate. (a) Post-abdomen very narrow. 1, P. hastatus, Sars, 2. P. stramineus, Birge. (b) Post-abdomen not very slender. * Terminal claws with two spines. 3. P. trigonellus, O. F. Mueller. (?) ?. P. ornatus, Scheedler. ** Terminal claws with a single spine. 4. P. acutirostris, Birge. B. “Shell smooth, except upon the front margin. >. P. adunctus, Jurine. C. Shell striped, (a) Shell very long and low. * With one toeth below. 10. P. unidens, Birge. ** Without a tooth ; female with a hook upon the first foot. a 8. P.hamatus, Birge. : ; *** Without a tooth on the shell or claw on the foot. : 9. P. affiinis, Herrick. , a (b) Shell high. i * Lower angle spined. + Antenne with eight sete, anterior margin of valves toothed. ‘ 7. P.denticulatus, Birge. Mg +t Antenne with seven sete. 6. P. bairdii, Schoedler. ** Whole posterior margin of shell spined (Percantha.) li. P. truncata, O. F. Mueller. S$ Beak procurved (Rhypophilus.) A. Shell reticulate. * Faintly and regularly. 13. P. glaber, Schoedler. ** Strongly and irregularly. + ~_ - —_— «= -e ee ee 108 TWELFTH ANNUAL REPORT. 14. P. personatus, Leydig. B. Shell striped. * Posterior margin toothed. 12. P. procurvus, Birge. “ ** Only lower abgle toothed. 15. P. uncinatus, Baird. Sp. 1. Pleuroxus hastatus, Sars. (Plate I. Fig. 16.) Pleuroxus levis, SARS. Pleuroxus hastatus, P. E. MUELLER. 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, 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—0.55 mm. The male has a shorter beak; the first foot has a weak hook, and the spermatozoa are spherical. ? Sp. 2. Pleuroxus stramineus, Birge. This form is the American representative of the preceeding, 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 ap- pears 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. EK. Mueller’s figure does not furnish positive evidence of this. Length C.6 mm. Sp. 3. Pleuroxus trigonellus, O. F. Mueller. Lynceus trigonellus, 0. F. MUELLER, LIEVIN, LILLJEBORG, LEYDIG, FRIC. Pleurozus trigonellus, SCHOEDLER, P. E. MUELLER, KURZ. 2 Pleuroxus ornatus, SCHOEDLER, Dorsal line strongly arched; the beak rather long, straightish; pigment fleck smaller than the eye. Shell faintly reticulate, the markings 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 tS any Tin aie ee ee hs ce et os . Pitas ‘ Ad ~ elas i . 4 ae. % ‘ Ay a es i z,) Oe) ie ie a 7 a an ta? nal ead ae , ‘ STATE GEOLOGIST. 109 , 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, sdk tales is not. specifically distinct. Not yet identified in America. Sp.4. Pleuroxus acutirostris, Birge. » This form, with Harporhynchus, imitates in some respects the _ Alonelle, from which they differ in having the beak elongated and recurved. Birge’s description does not state what the form of the _ fornices is, but he intimates that the general resemblances are with Pleuroxus: The general shape is as in P. hamatus. “The post-abdomen is broad, compressed, truncated, with numer- ous fine caudal teeth. The terminal claws have only one basal spine.” ‘‘The valves are reticulated asin P. [ Alonella] insculptus,. although not so plainly.” Length 0.85 mm. Southampton, Mass.. Sp. 5. Pleuroxus adunctus, Jurine. Monoculus adunctus, JURINE. Pleuroxus adunctus, SCHOEDLER, P. E. MUELLER, KURZ, 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 discover- able. 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. Sp. 6. Pleuroxus bairdii, Schoedler. Pleuroxus trigonellus, BAIRD. Pleuroxus bairdii, KURZ. This form, so far as can be a uel from Baird’s brief deser:p- tion and figures, differs from the others in having the shel] marked by straight parallel lines running diagonally backward and upward, and in lacking one of the terminal bristles on the 5-setose ramus of the antenne. 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. 110 TWELFTH ANNUAL REPORT. Sp. 7, Pleuroxus denticulatus, Birge. (Plate G. Figs. 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 (gener- ally three) teeth. The beak is very long. The character most emphasized by Birge is aseries of teeth along the anterior margin of the valves. The same thing is found in P. procurvus, as I have repeatedly satisfied myself. In certain posi- tions these teeth do not show, or the smaller teeth on the lower | margin only appear. PP. adunctus, as figured by Schoedler, has similar teeth on the lower margin, and very likely has them anteri- orly. The edges of the valves are heavily fringed with pectinate sete. The male has a shorter beak and the post-abdomen simply rounded without the peculiar modification seen in P. adunctus. There seem to be two varieties in Minnesota both of which have the characteristic irregular striations of the shell, which radiate from an irregularly marked or unmarked area in the center toward the edges; both have the toothed posterior angle and the serrated post- erior 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 abnormality, 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. Sp. 8. Plieuroxus hamatus, Birge. (Plate H, Wig. 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, STATE GEOLOGIST. EE ‘there is a set of horizontal strix all over the shell. The post-abdo- amen is widest in the middle and almost exactly as in P. denticula- _4us. 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 contain no reference to the minute striations, which could perhaps be hardly seen with the instrument employed. The process of the _ dabrum is long and rather acute, the beak moderate, and the pig- ment 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.) Sp. 9. Pleuroxus affinis. (Sp. n.) (Plate H. Fig. 2.) A small species with elongated shell and longitudinal striz, form- ang a link between the preceding and the next, to which it is ¢losely related. Shell broadest in front, upper contour nearly straight; anterior part of the lower margin evenly arched, posterior margin rather low. Head very short; beak very long, narrow and -somewhat incurved; antennules and antenne very small; eye evi- -dently larger than the pigment fleck. The post-abdomen is as in P. denticulatus, or a little longer proportionately. The markings, so far as observed, consist of diagonal, faint, numerous and parallel lines posteriorly, and others springing from the anterior margin. ‘There is no tooth behind; the teeth on the post-abdomen are small -and not numerous. The upper margin of the shell is not sharp but rounded. Thus this pretty and unique form is clearly distinguished from al] its allies althongh unfortunately only this very imperfect ‘description and schematic figure can be given. Found in Weakly pond, Culbert county, near Florence, Alabama, where with an Alona, Chydorus sphericus and Scapholeberis, it formed the clado- -ceran fauna of the pool. Sp.10. Pleuroxus unidens, Birge. (Pilate F. Fig. 15). -Anextreme among these elongated species, the length of body fall- ang little short of double the hight. The dorsal line is very flat _-and slightly but evenly arched; the lower margin is evenly convex 112 TWELFTH ANNUAL REPORT. ~ or nearly straight, covered by long pectinate bristles. The head is short, and the beak is long and sharp; the antennules are of moder- ate size, with a lateral seta one-fourth from the end; pigment fleck - less than the eye; antenne rather long, with strong thorns on the terminal joints. The post-abdomen is long, as in P. hastatus, sides nearly parallel; anal teeth sharp, small and numerous; claws pec- tinate, with two strong basal spines. The shell is strongly striate with longitudinal strize, which are parallel with the different mar- gins. Birgesays that there is areticulated area. The lower angle is rounded, and anterior to itis asmall tooth directed backward. This species is distributed throughout the Mississippi valley. I have notes of it from Swan lake, near Decatur, Alabama. It is often rather abundant about Minneapolis, but 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 appear to the eye like dark specks as they swim about. The length 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 Kurycercus and other lynceids, according to Schoedler. Sp.11. Pleuroxus truncata, Q, F. Mueller.. Lynceus truncatus, MUELLER, KOCH, ZADDACH, LIEVIN, FISCHER, LILLJEBORG, LEY- DIG, 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 con- vex, setose; posterior margin straight, armed with very strong teeth entirely across it; the anterior margin also is dentate, as in the next. The valves are covered with strong stri#, springing from the an- terio-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 considerably 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 0.6mm. Percantha brevirostris,Schoedler, differs in the — length of the beak only. STATE GEOLOGIST. 113 Sp. 12. Pleuroxus procurvus, Birge. (Plate E. Figs. 3, 4.) In size and general appearance this most interesting species is similar to the above, and, especially, to P. denticulatus. The gen- eral form and even the details of structure agree almost to identify _with the latter. The structure of the posterior margin is like Per- cantha, while the rostrum is bent abruptly upwards as in Rhypo- philus. In small individuals the length is greater proportionally. The lower margin is slightly convex or nearly straight, and fringed by bristles which are stronlgy pectinate; the anterior and lower margins are tuothed 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. denticu- latus. The male post-abdomen 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. bairdil, respectively, which have turned up their noses at a super- ficial 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 “Schmutz- peterchen” lynceids would find a long straight beak in the way is suggestive. Sp. 13. Pleuroxus (Rypophilus) glaber, Schoedler. Pleuroxus personatus, P. E. MUELLER. ¢ The shell is high and squarish, the fornices narrow, the beak slightly pro-curved, the lower margin nearly straight, with two or more teeth at the posterior angle. The antenne have seven sete only. The male is almost exactly as that of P. trigonellus. Length 0.55 mm. to 0.65 mm.; male 0.5 mm. Sp. 14. Pleuroxus (Rypophilus) personatus, Leydig. That this species is really distinct is by no means certain; how- ever, it is stated that the shell is less regularly aud more markedly reticulated, and the markings lack the elevations described under P. trigonollus, which are present in the previous species. It lives in filth and covers itself with it. 8 — 114 TWELFTH ANNUAL REPORT. Sp. 15. Pleuroxus (Rypophilus) uncinatus, 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 England. This completes the list of swine-like members of the genus; these well deserve to be studied from a morphological stand-point. Pleroxus nasutus, Gay, is a poorly described form from Chili, re- sembling, according to Schoediler, P. ornatus — trigonellus. A species of Percantha (Lynceus armatus, Gay) is found in Chili. NOTE TO PLEUROXUS.—The two species P. unidens and P. affinis are quite diverse from the type of the genus and approach in some respects to Leptorhynchus. P. affinis, particularly, has a recurved beak. I amin doubt about P. hamatus and P. acutirostris, which is said to be reticulated ; but it seems likely that the species above mentioned stand in closest relation to Leptorhynchus. Section B. Leptorhynchus, Herrick. ! The species for which Sars formed the genus Harporhynehus is of Alona-like habit, but has a beak which exceeds that of any known. Pleuroxus in length, being simulated in this respect by the Amer- ican P. acutirostris, which is, however, in other respects more nearly allied to Pleuroxus. Leptorhynchus falecatus, Sars. Harporhynchus faleatus, 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. vil.—Genus Purerxura, P. HB. Mueller. Oblong, wide; posterior shell-margin little less than whole hight. Post-abdomen terete, obtuse at the end, which is armed with a cluster of spines of which the terminal ones are similar to the others. 1 Harporhynchus is preoccupied in ornithology. STATE GEOLOGIST. 115 Sp. 1. a9 accra rectirostris, P.E. Mueller. (Plate I. Fig. 18.) Beak acute; shell striated longitudinally, slightly arched above; _ ventral margin rounded, with a round and unspined angle behind. Length 0.5 mm. Not yet encountered in Minnesota. 1x.—GeENus Cuyporus, 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 arolling, wavering hobble; and they live by preference upon vegetation, or in slime at the bottom of ~ pools. Occasionally they may be seen in sunshiny weather, dis- porting 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 in probability is not confined to any periods. The males, which only rarely are found even in these periods, have the abdomen narrowed or excavated to accomodate it to the peculiar alteration of the brood-cavity which takes place in the sexually mature female. The connection takes place by the insertion of the abdomen 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 F, 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. 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; abdomen flattened, excavated in the male; intestine with nc anterior ceca, doubly convoluted, with ananal cecum. Three spe- cies found in Minnesota. 116 TWELFTH ANNUAL REPORT. Sp. 1. Chydorus sphezericus, Mueller. (Plate F. Figs. 4, 7, 8 and 10.) Lynceus spheericus, 0. F. MUELLER, M. EDWARDS, KOCH, ZADDACH. LIEVEN, FISCHER TILLJEBORG, LEYDIG, TOTH, ZENKER, FRIC, Monoculus sphoericus, JURINE. OChydorus muelleri, LEACH. Chylorus sphcericus, BAIRD, SCHOEDLER, P. E. MUELLER. LUTZ, KURZ, BIRGE. 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 mar- gin; 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 8—9 sharp teeth; shell reticulated with polygonal meshes. Color light, unspotted. Length 0.50 mm. . This species occurs in Spring earlier than most forms, and is ranked as the most abundant of the micro-crustacea, being found over the whole circumpolar lend-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 follow- ing species which is more common in Minnesota in the clearer lakes. A small form in our large lakes measures 0.8 mm.; it may be distinct. Sp.2. Chydorus globosus, Baird. (Plate F. Figs. 1, 2,3 and 9.) Chydorus globosus, BAIRD, LILLJEBORG, SCHOEDLER, LEYDIG, P. E, MUELLER, FRIC, é KURZ, BIRGE. ; Form globose, very broad; antennules very large with a strong lateral 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 reticulated and spotted; color dark; length 0.7- | 0.8 mm.; male 0.55 mm. The males have the abdomen very nar- | row for the entire length. | This species is considered rare elsewhere, but is not infrequent in | August near Minneapolis, | STATE GEOLOGIST. TAT Sp. 3. Chydorus ovalis, Kurz. (Plate F. Fig. 11.) Form oval, nearly twice as long as high; beak long; antennules two-thirds as long as the beak, with two elongated sensory filaments above the others; pigment fleck nearly as large as the eye; antenne small; shell margins heavily fringed anteriorly; post-abdomen of moderate size, rounded at the end, with about 8 teeth near the end; shell smooth. Length 0.4 mm. This species is rather near C. spheericus, differing in having the shell smooth, antennz shorter, and beak longer. This species is not yet known in America. Sp. 4. Chydorus czlatus, S -hoedler. (Plate F. Fig. 12.) Chydorus aduncius, 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 ali known spe- cies 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, aud the only other author who appears to have seen the animal is Kurz, who adds that the sensory filaments of the an- tenn are unequal in hight, and that the so called elevations are really depressions. A form with a few depressicns about the edge and characters of this species was once seen in the vicinity of Min- neapolis. Sp. 5. Chydorus nitidus, Schoedler. (Plate F. Figs. 5, 6.) Shell smooth and regularly punctate; the head resembles CU. sphe- ricus, 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—12 teeth on either side. (?) Sp. 6. Chydorus latus, Sars. Very possibly a variety of C. globosus, from which it differs in the shorter beak and greater size. Length 0.66 mm. 218: TWELFTH ANNUAL REPORT. Sp. 7. Chydorus piger, Sars. Sub-rotund, prominent above, sinuate behind; lower and poster- lor 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. Anten- nules with seven setze and two smali 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 setz long and flexible. Pigment fleck of medium size, much nearer to the eye than to the beak. Length about 0.383 mm. | (?) Chydorus latifrons, Dana. (U.S, Exploring Expedition, Rep. on Crust., vol, II, p. 1274.) Very tumid; in side 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. (?) Chydorus albicans, Gay, from Chili, is imperfectly described; but it is interesting to note the occurrence of this genus there. x.—GENUS ANCHISTROPTS, Sars, (?) Very similarjin form to Chydorus; valves gaping below anteri- orly; antennules small; process of labrum rounded. Post-abdomen attenuated 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 inspec- tion it would be taken for the young of Chydorus globosus. He found but few specimens, about 0.35 mm. long. The suggestion is still possible that the young males ef some Chydorus are here mis- taken for anew 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 isnot much curved. I have ouce found a peculiar lynceid measuring 0.46 mm., with STATE GEOLOGIST. 119 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 some- what mutilated; hence I am unable to determine its real position. x1.—Genvus Monospitus, Sars. Head separated by a depression trom the body; shell high, com- pressed, posterior margin somewhat less than the greatest hight of the shell. Post-abdomen broad, ornamented with lateral and post- erlor spines; claws large, with a single basal tooth. The compound eye is absent, its place being taken by the pigment fleck, which is the functional eye. ! Monospilus dispar, Sars. (Plate I. Fig. 21.) Lynceus tenuirostris, FISCHER, Abh. ueber einige neue Daph. und Lynceide. Pr 427, tab. ITI, figs. 9—10 (fide Sars). : Monospilus dispar, SARS, Crust. Cladoc. iOmgn. af Christiania, p. 165. Monospilus dispar, MUELLER. Danmark’s Clad., p. 196. Shell roundish; ventral margin setose; posterior angle rounded, marked above with numerous impressions. Antennules small; an- tenne long, with seven setz. Post-abdomen short and broad, bear- ing 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 Ilyocryptus, covering the greater part of the new shell. The figure shows an old indivi- dual with its successive coverings still clinging to it. Like Ilyo- 1 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 disjunctum, deorsum in rostrum rec- tum et breve apice obtuso exiens. Animal supra visum sat compressum, latitudine maxima capite majore ante medium sita. Pars superior testz et capitis impressionibus numerosis rotundatis notata. Antennz l-mi paris minute structura ut in ceteris Lynceidis; 2-di paris sat longze, ramo altero setas 4 et aculeum unum apicalem, altero setas 3 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 duabus acu'eorum inque lateribus setis vel spinulis brevi- bus 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; macule infra oculari in ceteris Lynceidis simillima, in eapite conspicitur, que, quum oculus verus compositus in omnibus ceteris Crustaceis Cladodoceris distinctus omnino absit, organum quamquam rudimentare visus habenda est. Animal parum pellucidum, colore fulvescente. Longit. parum supra 44mm” 120 TWELFTH ANNUAL REPORT. cryptus, 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 ofall 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 developed, and the first thought would be that this must be a primitive 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 lyn- ceid, it stands in close connection with the higher members of the family and perhaps has more than asuperficial resemblance to such degraded lyncodaphnids as Ilyocryptus. All things considered, however, our diagram stands with this genus as adegraded offshoot of the more typical stem of Lynceide. | SUB-ORDER II.—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 prehensile, with but slight indications of branchial appendages. FAMILY POLYPHEMID. Feet five pairs. Antenne with the rami three- or four-jointed. © 1.—Genus PotypHemus, De Geer. Head very large, separated by a depression from the compact STATE GEOLOGIST. 13 body; shell covering but a part of the dorsal region. Feet all with an internal dentate, and an external lamellate appendage. Caudal seta upon a long process of the post-abdomen. A Sp.1. Polyphemus pediculus, Linn. (Plate Bt . Figs. 4—6.) Monoculus pediculus, LINNZUS, 1746. GMELIN, Linn. Syst. Nat. FABRICIUS, Ent. Syst., etc. SULZER, Insecten. MANUEL, Encyclop. Meth. Monoculus pediculus ramosus, DE GEER, Mem. pour serv. a l’Hist. des Ins. Polyphemus oculus, MUELLER, Zool. Dan. Prod. et Entomost. CUuVIER, Tab. element LATREILLE, Hist. Nat. Crust., ete. LEACH, Edin. Encyc. Polyphemus stagnorum, LEACH, Dict. Sc, Nat, LATREILLE, Cuv. Rig. An. DEMA- REST, 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, Scalicerus pediculus, KocH, Deutsch. Crust. Polyphemus pediculus, BAIRD, Brit. Entom. Polyphemus oculus, LIEVIN, Branch. d. Danz. Polyphemus stagnorum, FISCHER, Ueber die ind. Umg. von St. Petersburg, vorkom. Crust. Polyphemus pediculus, LILLJEBORG, De Crust. ex ord. trib. Polyphemus oculus, LEYDIG, Naturg. d. Daph. Polyphemus pediculus, SCHOEDLER, Neue Beitr. zur Naturg. d. Cladoceren. Polyphemus kochii, cs we es re Polyphemus oculus, ie = i ig 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 in a very shallow weedy marsh. The difference in size is quite remarkable. Our ordinary form measures less than 1 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. Number two may be called 1 Polyphemus occidentalis, Dekay = Limulus. ee fe ee, a es 192 TWELFTH ANNUAL REPORT. Sp. 2. Polyphemus stagnalis. (Sp. n.) In order to make the relation clear between these forms, I add measurements of this species, tollowing each with the correspond- ing 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 0.86 mm. (0.26 mm.); caudal filaments 0.36 mm. (0.8 mm.). Whole length of antenne 0.54 mm. — (0.42 mm.); first, second and third joints of the 3-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 partheno- genetic reproduction. 1.—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 B. longi- manus, which was found in the stomach of Coregonus wartmanni. B. cederstromii, of Schoedler and P. E. Mueller, the latter author now identifies with the above, and concludes that the supposed differences arose from “‘l’etat de maceration des examplaires exa- mines.” (Les Cladoceres des Grands Lacs de la Suisse, p. 11.) This species may be looked for in the depths of the Great Lakes. (See plate U, fig. 10.) 111.—GENus Popon. Iv.—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 LEPTODORID. Feet six pairs. Antenne with both rami four-jointed. Body elongated, not curved; shell very much reduced. STATE GEOLOGIST. 123 Leptodora hyalina, Lilljeborg, (Plate N. Figs. 6, 7), the only species, is found rarely in the larger lakes of Hurope and America. | See Bau und Lebenserscheinung von Leptodora hyalina, Weis- maun, 1874; also, Om en dimorph Udvikling samt Generationsvexel hos Leptodora, G. O. Sars, 1873; also, Bidrag til Cladocerenes For- plantningshistorie, P. H. Mueller. The work of Sarsis particularly valuable, showing that the young produced from the winter eggs pass through a metamorphosis not experienced by the summer or parthenogenetic brood. P. HE. Muel- ler mentions the pathological condition induced by the plants of the Saprolegnia. 7 ee _ 22) 2S Oe er oe ers — 124 TWELFTH ANNUAL REPORT. CHAPTER IIL. ORDER COPEPODA. This extensive order contains minute and predominatingly pre- daceous animals which constitute no inconsiderable part of the fauna of fresh and salt waters. They serve a beneficent purpose both as scavengers and as providing food-supply for the fry of fishes and other aquatic animals. | Copepods are never enclosed in a bivalved shell but ordinarily exhibit a more or less elongated cylindrical form composed of two obvious sub-divisions. There are a few species which, by the great prolongation and expansion of some of the tergites or dorsal shields, seem to simulate shelled crustacea. The anterior part of the body, or cephalothorax, is composed of ten somites which are frequently considerably united or fused. Five of these segments constitute the head and bear respectively the following appendages: first, a pair of several- to many-jointed antennz which are never prim- arily sensory in function, although they usually are provided with sense hairs or other like organs; second, a pair of two-brancned an- tennules, which sometimes become almost simple or prehensile; third, a pair of mandibles in the form of masticatory or piercing organs, these being usually provided with a palpus; fourth, a pair of maxille of various form and function; fifth, a pair of maxillipeds which not infrequently subdivide in Jater life to form what appear to be two distinct pairs. The five thoracic segments have each a pair of swimming feet consisting typically of a two-jointed base and two like, three-jointed rami. The symmetry is frequently broken by the retardation of the development of the inner ramus, while the fifth pair of feet may become rudimentary and in various ways subserve the organs of sex. The five abdominal segments are nearly devoid of appendages and are continued posteriorly by two caudal stylets which bear strong setz constituting, in many forms, a tail-fin or spring. STATE GEOLOGIST. 135 All copepods, even such as are, in later life, parasitic, begin their existence as free-swiming nauplii, such as are represented on plate S, fig. 18, and plate K, fig. 8. Though the vast majority of genera and species are marine, it would seem that fresh-water copepods make up in the number of individuals what they lack in variety. As we are dealing primarily with the fresh-water species, no lengthy description of the group is here necessary. The earlier history of our knowledge of the animals of this order is given by Baird. According to this authority, the first to mention any fresh-water species of this group was Stephan Blankaart} in his Schou-burg der hupsen, Wormen, Ma’den, en vliegende Diekens tot Amsterdam. Leeuwenhoek adds numerous interesting details and is accredited by Hoek with being to first to discover the relation between the remarkably diverse stages which occur in the history of the cyclops. However, itis evident that he had a very incomplete knowledge of the metamophoses. De Geer gives rather characteristic figures of acyclops in Memoi- res pour servir a l' Histoire des Insectes, vol. vii, 1778. Mueller, in his great work on Entomostraca, adds new facts, defines species and forms the genus Cyclops. Ramdohr in 1805 gave sundry additions to the knowledge of these animals in his Beitraege zur Naturgeschichte einiger Deutschen Monoculus-arten. In this work the post-embryonic history is quite fully outlined. | Jurine, in his classic work Histoire des Monocles qui se trouvent aux Envirous de Geneve, 1820, crystallized what previous authors as well as his own original experiments had brought to light of the anatomy and biology of these animals. Ferussac (Memoire sur deux novelles espices d’Entomostraces) redescribes known species. Gunner, Stroem, and Viviana, seem to have had little effect on the knowledge of the group, though they wrote prior to Juriue. A recent author attempts to revive the names of Jurine, though hitherto it has been thought hazardous to attempt a specific identifi- cation. The German author, C. L. Koch, who only incidentally studied this group, distinguished more or less perfectly, a variety of species which have been reinstated in our literature by Rehberg. Although 1 Latinized Stephanus Blanchardus. Hoek recognized Cyclops brevicaudatus or C. bicuspidatus as the one described, chiefly through knowledge of the present inhabitants of the locality. 126 TWELFTH ANNUAL REPORT. this proceeding seems quite unjust to the careful authors whose descriptions are recognizable in themselves, the law of priority must probably prevail. Koch’s Deutschlands Krustaceen appeared in 1838, Baird’s British Entomostraca, without greatly extending our knowledge of this order, put in readable form and made available to English readers what was known, and added interesting facts. He distinguished two families of Copepoda, (1.) Cyclopide, (2.) Diap- tomidee. The first included the genera (1.) Cyclops, (2.) Canthocamp- tus, (3.) Arpacticus, (4.) Alteutha; and the second the general (1.) Diaptomus, (2.) Temora, (8.) Anomlocera. Fischer, who contributed not a little to our knowledge of the distribution of fresh-water Cladocera, was the next to describe valid species. He described the species found near Moscow and St. Peters- burg, Russia. Ouchakoff is likewise a Russian author, but his writings are quite unknown to me. The justly famous Swedish naturalist, W. Lilljeborg, who has left his mark on so many branches of natural science, has not neglected the microscopic crustacea of his fatherland. Om de inom Skaane foerekommande Crustaceer af ordningarne Cladocera, Ostra- coda och Copepoda is the somewhat formidable title of his work, published in 1855. He recognized the following genera of Cope- poda: Diaptomus, Temora, Dias, Ichtyophorba, Tisbe, Tachidius, Harpacticus, Canthocamptus, and Cyclops. A species each of Diap- tomus and Canthocamptus is described, and two species of Cyclops. (It would seem from authors’ quotations that other species are de- scribed in an appendix, but the copy I have seen lacks this.) The author who has done most for micro-carcinology in general is Carl Claus, of Vienna. His principal works are: 1. ‘Das Genus Cyclops,” etc. In Wiegmann’s Archiv fuer Natur- geschichte. 1857. 2. “* Weitere Mittheilungen ueber die einheimischen Cyclopiden.” The same, 1857. 3. Die Freilebenden Copepoden, 1863. The later work especially is indispensable to the student of Co- pepoda, though in reality it is more important in respect to marine Copepoda. In the meantime a work appeared in Norwegian, with Latin de- scriptions, from the pen of G. O, Sars. This has been largely over- looked. It is, unfortunately, unaccompanied by plates, but the de- scriptions bear the stamp of the naturalist. STATE GEOLOGIST. 127 A little later a second brief contribution from this author was published, but I have not seen it. Sir John Lubbock in 1863 describes species of fresh-water cope- pods, but the publication seems no longer necessary. Heller, in Tyrol, Fric, in Bohemia, and Uljanin, in Asia, ae studied the copepod fauna. A Russian paper by Poggenpol and Uljanin is quoted as “A Catalogue of the Copepoda, Cladocera and Ostracoda of the vicinity of Moscow,” by Rehberg, and as from the Protokolle der kais.-na- turw. anthropol. und ethnogr. Ges. in Moskau, but by Cragin who publishes a translation apparently of the same paper, in part, as from the “ Bulletin of the Friends of Natural History.” Hoek, in the Tijdschrift der Nederlandsche Dierkundige Vereeni- ging (Magazine of the Zoological Society of the Netherlands) 1875, and later in German inthe Niederlaendisches Archiv fuer Zoologie, gave excellent figures and descriptions of some species which Claus had too hastily treated. In 1878 A. Gruber gave descriptions of ** Two fresh-water Cala- nide.”’ In the same year the first volume of Brady’s fine “British Cope- oda” appeared. A purely technical work and briefly written, it is yet very comprehensive and in the main reliable. This is a worthy successor of the Ray Society’s earliest publication on entomostraca —Baird’s great work. In the sixth vol. of the Abhandlungen d. naturwissenschaftlichen Vereine zu Bremen, Herman Rehberg gives a systematic review of synonomy, and in the revision unites several species in a manner that the present writer had independently been driven to do. Itis probably impossible either to substantiate or positively deny some of this writer’s identifications of the species of the older authors. This paper also contains an observation of a hermaphroditic cy- clops, which it is interesting to compare with similar anomalies, described by Kurz in Cladocera. In the vii Band of the same periodical, Rehberg adds to and modifies some of the views expressed above. Jn the same number is a description of a new species of Temora by Poppe. (The same species occurs in the semi-saline waters of the Gulf of Mexico, and had well-nigh gone into print under a new name when this was seen.) In the above review we have noticed only the more important | foreign works on the Copepoda and those including fresh-water forms. Dana’s magnificent Crustacea of the Wilkes’ Explorin 3 ji g a 2 ue, Le} ee — — — s, eee 128 TWELFTH ANNUAL REPORT. Expedition is not included because it is essentially restricted to the marine species, the few descriptions of fresh-water species, being quite valueless. Among important contributors to the exclusively marine Copepoda, are Boek (Oversigt over Norges Copepoder and Nye Slegter og Arter af Saltvands-Copepoder), Brady and Robertson, Lubbock and Claus. The history of the American literature can be quickly traced. | Say described imperfectly an American species of Cyclops in 1818. Haldeman describes in vol. vii, of the Proc. of Phila. Academy of Science, p. 331, Cyclops setosa (which may be C. serrulatus). Pick- ering very imperfectly described a new genus of copepods from lake Ontario in Dekay's Zoology of New York. This genus is, most likely, Epischura of Forbes and, in strictness, ought to rank it. In 1877 appeared “A List of Illinois Crustacea,” by Prof. Forbes, in which two species of Copepoda were described which may rank as the first descriptions at all adequately framed of American members of the order. In the annual report of the Minnesota state geologist for 1878, a brief article by C. L. Herrick outlined, in the light only of the then English literature, the micro-erustacea of Minnesota. No attempt was made to treat the Copepoda, but two species of Diaptomus are indicated which will prove valid. Occasional papers in the American Naturalist and elsewhere follow till, in July and August of 1882, Prof. Forbes added two new genera and several species of Copepods, constituting by far the most considerable addi- tion to the subject yet produced. In the report of the state geologist of Minn. for 1881, C. L. Herrick makes a considerable addition tu the knowledge of American Cyclo- pide, enumerating ten species, of which six seemed new. This writer also describes a new genus and several new species of Cala- nid, some of which unfortunately are identical with those described by Forbes and published about simultaneously. Several articles in the Naturalist bring the bibliography up to May, 1883, when fF. W. Cragin published in the Trans. Kansas Academy of Science, “A Contribution to the History of the Fresh- water Copepoda.” In this paper ten species of Cyclops are described or mentioned. The author ignored previous American literature and thus adds somewhat tosynonomy. The plates are lithographic, and are carefully, if not artistically, prepared. A valuable feature is the translation of the descriptions of Poggenpol’s species from the Russian. } These papers, together with the outline presented beyond, it is hoped, will form a basis for future work. STATE GEOLOGIST. 129 Since writing the above, it is brought to my notice that in April, 1881, V. 7. Chambers gave some account of a species of the Hai- pacticide referred by kim to Tachidius. This species is particularly interesting on account of its novel habitat. Tachidius (?) fonticola, Cham., is found in the saline waters of Big Bone Springs, Ky., and thus is very distant from any marine congeners. It is perhaps doubtful if the generic reference can be sustained, but the species is worthy of further study. The Diaptomus described by the same author is hardly recognizable. — FAMILY CALANIDA. This group is pre-eminently marine and contains diverse and graceful forms mostly with very elongated bodies and antenne. Of the six genera here enumerated as more or less habituated to the use of fresh water, two are found as yet only in America and one is confined to Europe. _ Heterocope, namely, is very near Epischura, both being restrict- ed to fresh water. Diaptomus and Osphranticum are likewise only accidentally found in the seas, though their nearest allies are marine. The genus Limnocalanus is as yet found in America only in the Great Lakes. In the distribution of genera we here follow Brady, whose defini- tion of the family Calanide, including Calanide and Pontellide of authors, we quote: ‘‘ Body elongated; composed of from ten to twelve [obvious] segments. Abdomen nearly cylindrical, much narrower than the cephalothorax and prolonged at the posterior extremity into two more or less cylindrical caudal branches [stylets]. First segment of thorax often anchylosed with the head; fourth and fifth segments also often coalescent. Head only rarely divided into two segments. Anterior antenne very long and com- posed of twenty-four or twenty-five joints; that of the right side in the male often modified for grasping [geniculate]. Posterior antenne large, composed of a basal joint, from which spring usually two branches, the primary branch consisting of two, the secondary of several joints. Mandibles strongly toothed at the apex, palp (usually) two-branched. Maxille strong, and provided with a many-lobed paip. Foot-jaws strongly developed: first pair very broad; the basal joints having on the inner margin wart-like pro- cesses, from which spring long ciliated bristles; the distal extremity divided into three short joints which are thickly beset with strong 9 _.eaawr27 ssh RRO O™SeW. eee Cee oa 130 TWELFTH ANNUAL REPORT. and long, ciliated sete; second pair longer and more slender, basal portion forming two long oval joints; apical portion usually 4-6- jointed. First four pairs of feet 2-branched, the outer branches always three-jointed. Fifth pair either like the foregoing, or much modified, unlike on the two sides, and in the male forming clasp- ing organs. A heart is present. Eyes either median and stalked or paired (lateral) and sessile; in the latter case being often coales- cent and composed of several lenses. Sexual organs in the female symmetrical, in the male asymmetrical. Ovisac single, borne in front of [below | the abdomen. 1.—Genus Heterocopsg, Sars. Cephalothorax 7-jointed; abdomen of female three-jointed; caudal stylets short, with three large setze and other small spines. Anten- ne long, slender, 25-jointed; right male antenna geniculate, the six joints preceding the nineteenth swollen slightly, the previous ones coalescent; external ramus of the antennules 7-jointed; labrum tri-lobate; feet of the four anterior pairs with the inner rami one- jointed; fifth feet of female with a single ramus, three-jointed, with a terminal spine, The right foot of the male is cheliform, four-jointed, second joint extending into a long cylindrizal process, the terminal joint with two apical claws. The writer is familiar with but three species—H. appendiculata, Sars, H. saliens, Lilljeborg, (= H. rubusta, Sars,) and H. alpina, Sars. None of these have as yet been positively identified in America* and their place seems supplied by the following genus. 11.—GENuSs EpiscHura, Forbes. (= Scopiphora, Pickering ?) Undoubtedly the most remarkable of fresh water copepods are the two American species of this genus. It is not yet certain that the second species may not be a young stage of the first but it seems quite improbable. Related with Heterocope, Sars. The antenne are 25-jointed, the right of the male being geniculate. The thorax is 6-jointed, the last two segments being partially coalesced. ‘The abdomen is five-jointed in the male and four-jointed in the female, one branch- ed, in the male modified for prehension. Abdomen of male with a *Heterocope is said by Patten (Cragen) to be common at Watertown, Conn. STATE GEOLOGIST. g hesy Eas prehensile appendage on the left side, often more or less distorted. Inner rami of swimming feet one-jointed. Caudal stylets with three long sete. The first mention of an animal of this genus seems to be Pickering’s description of Scopiphora vagans from deep water in lake Ontario. It seems almost certain that the species so imperfectly described in Dekay’s Crustacea of New York. is none other than a species of Epischura, but [ hesitate to substitute for a name accompanied by good descriptions and figures, and one which has already been incorporated, to some extent, into our literature, one which is founded on a description so imperfect and general that one incidental character alone enables one to guess its application. The following is Pickering’s description: ‘“* Body small, eye single, near the anterior margin of the shield. _ Antenne large, and as !ong as in the preceding genus [Cyclops], and has the same motions in the water. Abdomen terminating in two styles, each with three sete; last or three last joints. Ova- ries none; legs spiny.” What is meant by the “brush” fails to appear, unless the speci- mens were ornamented with some parasitic plants or animals. The three setze of the caudal stylets and long antennz will place this form in no American genus save Epischura. But even this statement of Pickering may be held doubtful. Sp.1. Epischura lacustris, Forbes. (Plate Q. Fig. 15.) “The scond segment of the abdomen of the male is twice as long as the first, and produced to the right as a large, elongate, trian- gular process, somewhat hooked backwards at the tip, The third segment is similarly produced, but rounded and expanded at the tip, which is roughened before and behind. From the right side of the fourth segment arises a stout process bearing at its apex a hatchet-shaped plate with seven broad obtuse serratures on its anterior margin. This process is roughened be- hind, where it is opposed to the concave side of the left ramus of the furca. From the same side of the fifth segment, a short flat- tened plate, of a spatulate or paddle-like form, extends forward above or beyond the toothed process just mentioned. The antenne are 25-jointed, and reach to the second segment of the abdomen. There are especially prominent sensory hairs on the a i OO e—e—eee—eE_coee e_————_— aS eee ee —_———] — ws Be. «Se > ee 132 TWELFTH ANNUAL REPORT. first and third joints, borne at the tips of long spines. The anten- nules are short, the ramus apparently but three-jointed, the short, median joits common in this appendage being only obscurely in- dicated. The mandible has but seven teeth, the first siniple and acute, separated from the second by an interval about equal to the second and third, the second to the sixth bifid, the seventh entire and acute. The usual plumose bristle is replaced by a sharp, simple spine. The outer ramus of the fourth pair of legs has two teeth at the outer tip of each of the two basal joints. The terminal joint of this ramus is armed as follows: a short simple spine at middle of outer margin and another at the distal outer angle; asingle and long termiual seta, strongly and sharply toothed externally and plumose within, and four long plumose setz attached to the inner margin. The left leg of the fifth pair in the male, viewed from behind, has the basal joint very large, broader than long, with the inner inferior angle produced downwards as a long, stout, curved process or arm as long as the two remaining joints. The second joint is trapezoid- al, shortest within. The third joint is about half as wide at base as the first, is straight without, with a sharp, small tooth at its distal third, and bifid at tip. On the inner margin this joint is at first dilated a little, and then deeply excavated to the narrow tip, to receive the lower end of the left leg, the lower two-thirds of this margin forming the segment of a circle. The right leg is two-jointed, the first joint twice as broad,gnlarg- ed at the lower end, forming an auriculate expansion at i inner inferior angle. The second joint is conical in outline and about two-thirds as long as the first. The terminal bristles of the rami are very broad and strong in the female, the outer one especially having an extraordinary size and thickness. There is also at the outer angle of each ramus a short, stout spine, that on the left ramus being inflated like the outer bristle. Length .065 in. The legs of the fifth pair in the female are three-jointed and similar, the basal joint short and broad, the second two and one- half times as long as wide. The leg terminates by four diverging teeth, preceded by two others, one on each side. Taken in the towing net abundantly in October, 1881, at Grand Traverse bay; also obtained rarely by Mr. B. W. Thomas, from the city water of Chicago.” Occurring in Minnesota, probably in lake Superior. STATE GEOLOGIST. 153s Sp. 2. Epischura fluviatilis, Herrick. (PlateQ. Figs. 14 and 16.) Similar to the above but smaller (.04 in.) The females are very similar, though the fifth feet are more elongate and differently spined. The abdomen is perfectly straight and the three caudal setz are of nearly equal size. The claw is armed with eight teeth, all but the first of which are emarginate. The abdomen of the male is straight, but has a strong process on the left side which bears a movable claw Jaterally and a small second segment which terminates in two small spines. The fifth foot of the male is peculiar;-the inner ramus (or the left foot) lamelliform, one-jointed, with two opposable claws; the right branch is simple and 3-jointed, in form like that of the female. Here we have the most marked difference between the two species. Found in Mulberry creek, Cullman county, Alabama. Although a considerable number were examined no oviferous females were found, while the males contain- ed the spermatophores and can hardly be thought immature, and, as it is in the male that the most marked differences appear, the two species seem certainly distinct. 111.—GeENus Temora, Baird. (Plate H. Figs. 8—16.) This genus contains several marine forms and two which are found also in streams opening into the sea. The species seem to be as follows: T. velox, Lilljeborg, T. longicornis, Mueller, (—T’. jinmarchia, Baird, —Diaptomus longicaudatus, Lubbock), T. armata, Claus, J. inermis, Boeck, and T. affinis, Poppe. T. _clausii, Hoeck, is said by Puppe to be certainly identical with T. velox. Hoeck’s figures are incomparably better than any of the preceding, but he seems to have been misled by errors in Lilljeborg. The species described by me before the Academy of Sciences of Minnesota (but still unpublished) as T. gracilis, from the brackish waters bordering the gulf of Mexico, agrees very closely with T. affinis, Poppe. (Abhandlungen v. naturw, Vereine z. Bremen, 1880, p. 55.) This name must therefore take precedence. This. species has been found in the Rhine and rivers flowing into the gulf of Mexico, as well as in the marine or brackish waters into _ which these rivers flow. The occurrence of the genusin American fresh waters, justifies its mention here. i ; ES ae ti 134 TWELFTH ANNUAL REPORT. 1v.—GENUS OsPHRANTICUM, Forbes. (=Potamoichetor, Herrick.) First reported as Potamoichetor before the Minnesota Academy of Sciences in 1879, but owing to a disastrous fire, publication was prevented. Priority probably belongs to Forbes’ name, since, although first printed in the tenth annual of this survey, the edition was not distributed till after the August issue of the American Naturalist of 1882, containing the description above alluded to. Forbes says this genus has antenne 23-jointed; all the specimens we have gathered from Minnesota to Alabama had 24-jointed anten- ne. The original description of ‘‘Potamoichetor” is appended. “Cephalothorax six-jointed, distal segments evident; abdomen, in the male, five-jointed, in the female four-jointed; antenne twenty-four-jointed, the right geniculated as in Centropages (= Ichthyophorbia); first pair of feet with the rami both three- jointed, like the following; feet of the fifth pair, in the female, like the preceding, but with a spine of the joint preceding the terminal one enlarged and divaricated somewhat as in Centropages; in the male, the right with a two-jointed outer ramus, the terminal joint — of which is spined and bears near its base a blunt expansion of its inner margin; outer ramus of left foot three-jointed, armed with unequal spines; inner branches smaller, similar, three-jointed; the terminal joint bearing curved spines; ovary and testes as in Diap- tomus, with which the mouth parts agree in the main; eyes me- dian, confluent.” Our own experience is that the single species of this genus prefers estuaries of running water. Forbes, however, has taken it from swamps and wayside pools. | Sp.1. Osphranticum labronectum, Forbes. (Plate Q2. Figs. 1—8 and 13—14.) Potamoichetor fucosus, HERRICK, Cyclopids of Minnesota, etc., p. 224. ‘‘ Rather slender, and in size, as well as general appearance, re- sembling the smaller forms of Diaptomus; antenne rather stout, reaching but little beyond the feet, appendaged as in Diaptomus; in the male strongly geniculated, but somewhat variously so; the six joints preceding the terminal four are thickened; those preced- ing the joint or hinge are arcuate on the distal margins; the secondary antenne are about as in Diaptomus; mandibular palp two-branched, the outer three-jointed, the inner two-jointed; the terminal joint of STATE GEOLOGIST. 135 the shorter branch bearing seven sete, of the other four, the proxi- mal joint of the former with three stout spines; the maxille nearly like Diaptomus; the processes have respectively the following numbers of setze: the basal plate eight, the small processes at base of posterior branchial appendage one, the appendage itself tweive, terminal portion three groups, first containing nine, the second three, and the third four or five, the upper of the anterior processes two, and the lower three; fifth feet nearly like the others in size; the right in the male having the outer branch but two-jointed by the coalescence of the two outer to form an arcuate and deformed appendage, armed at the end with three stout equal spines; corres- ponding branch of left foot three-jointed; the terminal joint bearing _ three unequal spines, each of the preceding joints only one; inner branches similar, three-jointed; terminal joint being short and armed with three short lanceolate setz and three longer ones, two of which are curved so as to be slightly prehensile; fifth foot of female with both rami three-jointed; inner ramus much smaller; antepenult segment of the outer ramus extending into a large lanceolate pro- cess; ova-sac long-ellipsoidal or spherical, reaching nearly to the end of the caudal sete.” v.—Genus Diaptomus, Westwood. The most widely distributed and well-known of fresh water Cala- nid, inhabiting in various species the smallest as well as the largest bodies of standing or sluggishly-flowing fresh water. Apparently a recently formed group whose nearest known ally is the curious Pseudo-diaptomus, found in the gulf of Mexico. The animals of this genus are apparently very susceptible to the influences of the environment, and are consequently extremely variable not only in color but in minor structural points. In America there is a curious fact, which is susceptible of different explanations, one of which was given in the American Naturalist at various times during the year past. The species or varieties fall in pairs, one of which is smaller and less highly differentiated, while the other is greatly en- larged and has the peculiarities emphasized. These sets occur in open and shallow water respectively. The large varieties are, as the rule, restricted te such shallow weedy pools as dry up during summer and freeze solid in winter. The forms intermingle slightly, but there are seasonal differences of greater or less extent. The body is composed of an elongated thorax, with which the head is united, forming a six-jointed cephalothorax. Theabdomen a ee ee SE EE EE ae 136 TWELFTH ANNUAL REPORT. is five-jointed, though in the female these joints are so united as to cause the abdomen to appear three-jointed. The antennz are twenty-five-jointed, and the right male limb is modified by a coal- escing of some of the terminal joints, a thickening of others and the development of certain spines, hooks, and knife-like ridges to form a prehensile organ. The first pair of feet has two-jointed inner rami. The remainder have both rami three-jointed, save the last. This fifth foot is differently formed in the sexes, the inner branch of the fifth foot being one or two-jointed. Terminal joint of the outer ramus of this limb in the female very small or apparently absent, second joint produced to form a stout curved claw. The left foot isreduced in the male, serving, in some species, to affix the sper- matophore to the body of the female, while the abdomen is held by the right foot. The last segment of the thorax has one or two sharp spines below. The spermatophore, or sperm case, is a long tube with coagulating expansive lining, which forces out its contents on exposure to the water. The colors are frequently brilliant. Three or four species of this genus are known in Europe, the first being Diaptomus castor which seems universally distributed. It can hardly be doubted that the six forms mentioned below belong among the varieties of this species; yet these forms can be disting- uished very well, and are deserving of distinct names. Two other forms are nearest D. gracilis of Sars, but sufficiently distinct. These stand related as do the pairs of the other section, and can not be readily distinguished. The following is the most convenient arrangement of the genus I have been able to devise. Key To THE GENUS DIAPTOMUS. I. Form robust; right antenna of the male with a hook, much swollen anterior to the geniculating joint. A. Head not greatly dilated. * Last segment of therax prolonged into a sharp-spined angle or tooth. + With but one tooth (?). 1. D. castor, Jurine. +t With two teeth. $ Length under 5 mm, § Inner rami of fifth feet in the female 1-jointed. 2. D.sanguineus, Forbes. 4, D. armatus, Herrick. §§ Inner rami 2-jointed. 3. D.minnetonka, Herrick. tt Length over 3 mm. a eee STATE GEOLOGIST. 183i 5. D. stagnalis, Forbes. ** Last segment of the thorax more or less united with the previous one, bearing very small spines. 6. D. longicornis, Herrick. (a) Length under 2 mm. var. leptopus, Forbes. (b) Length over 2 mm. var. similis, Herrick. B. Head enlarged. 7. D. laticeps, Sars. II. Form slender, elongate; head divided into two portions; antenne long, slightly altered in the male. A. Antenna of male with a hook. 8. D. gracilis, Sars. B. Antenna of male without a hook. 9. D. pallidus, Herrick. (a) Antenne finch longer than the body, inner rami of fifth pair of feet in the male 1-jointed. var. pallidus, Herrick. (b) Antenne little longer than the body, inner ramus of fifth feet bi-articulate. var. sicilis, Forbes. Sp. 1. Diaptomus eastor, Jurine. [Sars.] “Corporis forma sat robusta. Cephalothorax in femina postice parum antice vero magis attenuatus, angulis laminarum segmenti ultimi obtusis. Segmentum 1-mum abdominale absque mucrone laterali. Rami caudales brevissimi segmento antecedente vix longiores setis crassis et brevibus. Antenne 1-mi paris mediocris longitudinis reflexe segmentum 3-tium abdominale vix superantes, animali natante leviter arcuate adque latera vergentes ; articulus ultimus [?] antennz dextre maris in hamulum exiens acuminatum, Ramus an- tennarum 2-di paris exterior interiore parum modo longior, articulo ultimo quam antece- dentibus 5junctis breviore. Articulus ultimus pedum 5-ti paris in femina perrudimentaris tubereulum solum minimum aculeo uno parvo instructum formans; unguis intus curvatus maximus validusque ; appendix interna indistincte bi-articulata longitudinem articuli 3-ti- superans; unguis terminalis pedis dextri maris longissimus leviterque arcuatus. Saccus oviferus parva et multa continet ova colore castaneo. Color animalis variat ex fulvo, cz- ruleo vel rubro. Longit. fem. interdum fere3 mm. Habitat in aquis stagnantibus.”’ The description quoted above from Sars does not agree with Claus’ or Brady’s account of the same species. From what Brady says of the English Diaptomi one would conclude that the same variations occur there as here. D. westwoodii, which he unites with D. castor, is certainly as different from that species as our D. stagnalis is from D. sanguineus. An actual comparison of specimens will be necessary to clearly define the relation of the American and European species. ee. eas aLaaQeca_™ Er ey oa eee 138 TWELFTH ANNUAL REPORT. Sp. 2. Diaptomus sanguineus, Forbes. (Plate Q, Fig. 12.) A species found with us in stagnating pools in early spring, frequently following D. stagnalis and giving place to D. leptopus. It prefers pools less foul than those affected by the latter, though not rarely found with it temporarily. The species is quite variable, and the variations are in directions suggestive of other species. Measurements taken of specimens from a gathering from two pools, one being more stagnant than the other, showed the follow- ing results:—males from the less stagnant 1.7 mm.; males from the other pool 2.0 mm.; a difference of 0.8 mm. (Males of D. stagnalis from the latter gathering measured 3.4 mm., while the females of that species vary between 3.8—3.9 mm.) Females measure about 1.8 mm. on an average, of which 1.3 mm. is the length of the thorax. Such individuals have antenne 1.7 mm. long. The greatest width is anterior to the middle, being about 0.5 mm. This species differs from D. stagnalis of which, in most respects, is a miniature, by the long antennz, short abdomen and peculiar armature of the fifth feet. In the female the fifth foot is about 0.5 mm. long, and the outer ramus has two small spines on the terminal joint, while the seg- ment before the last hasa powerful toothed claw. The inner ramus is not evidently two-jointed. The first abdominal segment is spurred on either side. The last thoracic segment extends into a strong angle which bears a heavy spine terminally, and a smaller spine dorsally. On the dorsal median line is a protuberance or “hump” on this segment. In the male the outer ramus of the right foot of fifth pair is long, and terminates in a powerful curved, toothed claw. The inner ramus is small and narrowed toward the end; on the outside of the segment from which it springs is a blunt spine, which is nearly as large as the ramus itself, and has been mistaken for it. The left foot is very fleshy and its inner ramus very rudimentary. The color is brilliant red or purple but variable. Found in the southern states in autumn. Sp. 3. Diaptomus minnetonka, (Sp. n.) (Plate Q. Figs. 8—10.) A small species, smaller than either D. longicornis er D. sangui- neus, was gathered in a pool bordering lake Minnetonka, which contained also D. longicornis. It unites the characteristics of both STATE GEOLOGIST. 139 species. The antenne reach beyond the stylets, the color is dark, the margins of the last segment of the thorax is rather strongly spined, very much as in D. sanguineus. The fifth feet of the female resemble very much those of D. leptopus, but the first seoment of the abdomen has astrong spine. The fifth foot of male resembles that of D. sanguineus more than that of leptopus, This species was seen but once, and no measurements can be given save that of the male which was 1.4 mm. Sp. 4. Diaptomus armatus, Herrick, Is founded upon an imperfectly known form in which the an- tennee do not reach the end of the abdomen; the thickened part of the male antenne short; the antenna armed as in D. sanguineus; the terminal claw of the fifth foot of the male with a tooth near the base; the claw being nearly as long as the ramus. Sp. 5. Diaptomus stagnalis, Forbes. (Plate Q. Figs. 11 and 13.) D. giganteus, HERRICK. The largest species of the genus and, not improbably, too close to D. westwoodii, Lubbock. The general characters are like those of D. sanguineus, but the form is much more robust and the anten- _ne only moderately exceed the thorax. The proportions may be gathered from the measurements given, In the female the length of thorax is 2.5 mm.; abdomen 1.2 mm.; antennz 2.3 mm.; stylets 0.1mm. The caudal stylets are as broad aslong,or nearly so. The last thoracic segment extends into an irregular process 0.1 mm. long, bearing a spine dorsally. The first abdominal segment is spurred on either side. The fifth feet in the female have two-jointed inner rami. The terminal segment of the outer ramus is more than ordinarily distinct, while the claw is biserrate. The right foot of the fifth pair in the male is very long, its claw being strongly tooth- ed. On the inside of the second joint from the base is a disc-like ap- pendage peculiar to this species. The left foot is short. The longer ramus is three-jointed, but the terminal joint is a mere curved spine, opposing a spine from the penultimate segment, which is covered with minute spines or teeth. The basal joint of the ramus has a brist- ly protuberance distally. The inner ramus is marked with oblique ridges. The right antenna has a powerful hooked spine on the antepenult segment, the two segments beyond which coalesce in oo _ OE et P< 2 PP Bie) eee 140 TWELFTH ANNUAL REPORT. maturity as in the other related species. For measurements see above. Color deep opaque red or purple. Appearing in early spring as soon as the ice is melted from the pools which it inhabits. In the south it occurs in autumn. The name above given seems to have the priority, although this species was figured and described at about the same time in the annual of this survey. Sp. 6. Diaptomus longicornis, Herrick This name was applied somewhat loosely, the description given being incomplete, but re-examination of types shows it to belong unquestionably to the form since described as D. leptopus. in our state we have found another variety, in general, almost identical with the type specimens, but nearly twice as large. It is now proposed to extend the significance of this name so as to include both varieties, which will undoubtedly be found connected by intermediate forms, thus retaining the name given by Forbes Hor the variety to which it in particular applies. (a) var, leptopus, Forbes. This species is the commonest member of the genus in small lakes and clear pools. It is tolerably constant in coloration, but varies somewhat in size, The original description is insufficient to identify the species definitely, but taken in connection with the figure and the measurement, could hardly be_ refered to either of the other American forms. This species is characterized by the very compact thorax, the margin of the last segment of which has two very minute spines; and by the form of the fifth feet. The antenne reach nearly to the end of the caudal sete, while in the next they fall short of the length of the stylets. The outer spines of the swimming ‘feet are denticulate on the outer margin and setose within. The fifth feet of the female are compact, the inner ramus is more or less obviously two-jointed; the third joint of the outer ramus is almost obsolete and has two short spines; the claw of second joint is strongly denticulate. The male fifth foot has a rather long inner ramus which is very imperfectly two-jointed; the left foot is rather long; the claw of the right foot is armed with crenulate teeth. Length 1.5—1.7 mm., without. seta. The body, which is broadest anterior to the middle, is bluish; the tips of the antenne are deep purple. The eggs are not as numerous as in the next. 3g STATE GEOLOGIST. _ 141 (b) var. similis, (Var. n.) (Plate Q. Figs. 5—7.) This form is twice as large as D. leptopus, but otherwise scarcely distinguishable. It occurs in autumn (and spring?) in shallow pools, which can but be frozen solid. The following differences are the only points yet noticed. Females of both of the species were placed side by side upon a slide and examined. D. leptopus measured 2.4 mm., exclusive of caudal setze; the antennze reached hardly to the base of the stylets; the eggs measured 0.12 mm., while those of D. longicornis measured 0.8 mm.; the egg-sac measured 0.8 mm., while that of longicornis was 0.5 mm. A few other minute differences were noticed, but the general form and color was iden- tical. The peculiar doubling of the edge of the last segment is characteristic of these two forms; each has a small spine on either side of the abdomen. The base of the inner ramus of left foot of fifth pair of the male has a double series of spines. Sp. ¢. Diaptomus laticeps, Sars. “Cephalothorax autice dilatatus, latidudine maxima in parte antica capitis sita, postice sensim attenuatus, segmento ultimo femine ad latera parum extante angulis lateralibus acuminatis. Segmentum 1-mum abdominale femine antice latum mucrone brevi laterali armatum, postice sensim attenuatum.. Rami caudales sat magni seg- menta antecentia 2 juncta lengitudine _s _ es ae 2 gee 22 289 Le he See” a 2 ze 150 TWELFTH ANNUAL REPORT. vergentes, reflexze segmentum 3-tium corporis fere attingentes. Pedum natatoriorum structura fere eadem ac in speciebus antecedentibus ; aculeorum apicalium rami interi- oris pedum 4-ti paris exterior dimidiam fere interioris attingens longitudine. Pedum 5-ti paris articulus basalis minimus ultimo multo brevior parumque latior. Sacci evi- feri mediocres rotundato-ovales abdominique appressi. Longit. circit. 2mm. (b) Terminal segment of fifth foot with two rather long setz. * External and internal caudal setz not extremely short. Sp. 14. Cyclops oithonoides, Sars. (Plate S. Figs. 2—6.) ? C. hyalinus, REHBERG. ? C. tenuissimus, HERRICK. This most interesting species occurs under peculiar circumstances. It is perhaps the rarest member of the genus and seems, beyond a doubt, nocturnal in its habits. It was first found by Sars in saline water and named, on account of its slender form, from the marine Oithona. A similar species which, though about half as large, is hardly distinct, was found by Rehberg near Bremen. Rehberg men- tions particularly that it was found oftener at night than during the day. In America a similar species was described from near Paducah, Ky., under the name C. tenuissimus; but the possibility of identity with the Scandinavian species seemed excluded by the habitat. A gathering taken at night from one of the lakes near Minneapolis contained a few specimens of similar characters, and there no longer seems to be a doubt of the identity or very close relation between these forms. The antenne are longer than described for C. tenuissimus, nearly equalling the thorax. The last joint of the antenne is short, but. the toothed character was not noted. The fifth feet are small, the spines are very long and slender. The margins of the abdominal segments are irregularly toothed. The species will be confused with no other. It is marked with blue in spots. Length 0. 5—1. mm. Sp. 15. Cyclops simplex, Poggenpol. Cyclops Leeuwenhoekii, HOEK (fide Rehberg). This species is of more compact form than the last, which it re- sembles in the form of the caudal stylets and the fifth foot. The antenne are nearly as long as the thorax, the last two joints being elongate and having a knife-like ridge which has at the end teeth like those figured in C. tenuissimus. Length 1.—2. mm. STATE GEOLOGIST. 151 ** The two median setz much longer than the external. The species of this section are the most perplexing of the genus. The best that [ can now do is to indicate the relations of the nom- inal species and express the conviction that most are of varietal value simply. Sp. 16. Cyclops pulchellus, Koch. C. bicuspidatus, CLAUS. + Terminal joint of outer ramus of feet with two spines outwardly. 16a. C. thomasi, Forbes. 16b. C navus, Herrick, ++ With three spines. 16¢. C. bisetosus, Rehberg. = C. bicuspidatus, Sars. = (?) C. insectus, Forbes. There are at least three well marked varieties in America, which may probably rank as species and have been ranked as such by Forbes. I give verbatim Forbes’ description. (16a) Cyclops thomasi, Forbes. (Plate U. Figs. 4, 5, 7 and 8.) ‘“Klongate, slender, broadest in front and tapering backward, antenne 17-jointed, reaching the middle of the third segment. The first abdominal segment in the female is broad in front and slightly emarginate on each side before the anterior angles, and the last segment has a terminal circlet of small spines. The rami of the furca are more than half as long as the abdomen, and each bears two short rows of transverse spinules outside, one at the anterior the other at the posterior third. With the latter a spine occurs about as long as the outer terminal seta. The inner seta at the tip of the ramus is about half the length of the furca, the outer still shorter. The inner median seta is as long as the abdomen and furca, and the outer about half-as long. In the outer ramus of the first pair of legs the terminal joint has one spine and two sete at the tip, one spine on the outer mar- gin and two setz within. In the second, third and fourth pairs the last joint has one spine and one seta at tip, two spines externally and two sete within. The inner rami of the second and third pairs terminate in one spine and one seta, that of the fourth pair in two spines, the inner of which is only half as long as the other. The legs of the fifth pair are two-jointed, with the basal joint ) *) Ree! ArT 2. kee oo... £4 £2 2. be Sv eee 152 TWELFTH ANNUAL REPORT. quadrate, broad, and bearing one long spine. The second joint is narrow and longer, parallel and truncate, with one terminal spine about equal to the preceding, and one about half that length. From C. bicuspidatus, Claus, this species may be distinguished by the armature of the outer ramus of the first pair of legs, and from C. bisetosus, Rehberg, by the armature of the outer rami of the other legs. It shares with Diaptomus sicilis the responsibility of affording to the young white-fish their earliest food.” (16c) Cyclops insectus, Forbes. (Plate U. Fig. 9.) “Closely allied to the preceding, but more robust in all its parts, and with the second cephalothoracic segment widest. The abdo- minal segments are all bordered with spinules posteriorly. The two median caudal setz are much more nearly equal than in tho- mast, the outer and the inner are very short, but longer than in that species. The inner in our specimens is longer than the outer —the reverse being the case in bicuspidatus as described by Claus. ‘The legs are armed nearly as in thomasi, but the last joint of the outer ramus of the first pair has two spines externally besides the one at the tip, and the terminal spines on the last segment of the inner ramus of the fourth pair of legs are about equal.” Both forms probably occur in Minnesota, though the second has been seen but once, and the identification lacks confirmation. The differences between the two are almost exactly those prevailing between C. bicuspidatus (= pulchellus) and C. bisetosus, Reh., if I correctly understand Sars. Claus’ description does not agree with that of Sars. Further study of the European types will be necessary before a satisfactory settlement can be reached. (16 b) Cyclops navus, Herrick. Cyclops navus, HERRICK, Copepoda of Minnesota, p. 279. This name, proposed at nearly the same time as C. thomasi, ap- plies to a very closely related form which I can but regard as a variety of that species. It seems constant in its differential char- racters in given localities, but we are now familiar enough with the fact that changed conditions in the water occasion changes in forms in the copepods. This form inhabits shallow pools. It is larger than C. thomasi, STATE GEOLOGIST. 153 ~ has much shorter stylets and differently proportioned antenna, etc. Length 15 mm. Thorax 0.9 mm.; abdomen 0.6 mm.; stylets 0.14 mm.; last two abdominal segments 0.16 mm.; antenne 0.7 mm.; first segment of body 0.5 mm. The basai segment of the antennz is long and ornamented with several transverse series of spines, the last two segments are equal and longer than the preceding. The armature of the first and fourth feet is identical with C. thomasi, as is the form of the female openings and the fifth feet. The form of the first feet, caudal stylets and other details were correctly figured on plate V of the Cyclopide of Minnesota. Specimens of Cyclops pulchellus (thomasi) were obtained from a cistern which is supplied solely by rain-water. The eggs must have been introduced in ice which had been placed in the cistern at least a year previously. The cistern is entirely dark, so that these ani- mals must have been deprived of light for many generations. The general color was of course very white; the eye spots were pale, but present with some pigment and the lenses. No noticeable altera- tion in form had resulted. : (c) Terminal segment of fifth foot with three sete. Sp. 17. Cyclops tenuicornis, Claus. (Plate R. Fig. 16.) var. a. Knife-like ridge upon the antennz smooth. U. albidus, JURINE, C. quadricornis, var. b, BAIRD. C. tenuicornis, SARS ,LUBBOCK, HELLER, FRIC, ULJANIN, HOEK, BRADY, HERRICK. C. clausii, POGGENPOL. C. annulicor nis, SARS. war. b. Knife-like ridge of antenne toothed. C. obesicornis, TEMPLETON. C, signatus, KOCH, SARS, ULJANIN, BRADY. C. coronatus, CLAUS, LUBBOCK, HELLER, FRIC, HOEK C. signatus, var. fasciacornis, CRAGIN. Cyclops tenuicornis, as thus comprehended, is widely distributed | and variable. European specimens in our collection have longer stylets, but seem otherwise identical. The nearest relation is C. ater, which is easily distinguished by the compact oval form of the thorax and the one-jointed fifth foot. In the stage previous to maturity the “signatus” form has no teeth upon the ridge of the last segment of the antenna; it is then similar to the C. tenuicornis. Cephalothorax broad; abdomen rather slender; antenne reaching about to base of thorax, attenuated at the end; terminal joint with ) a knife-like ridge; formula -~~—~-~—-~~~ ~~ ~~ -—-—-— ; fifth foot composed of a long basal joint bearing a long spine and a ter- ee ——_ oe — —— — —————— 154. TWELFTH ANNUAL REPORT. minal three-spined division; caudal stylets twice as long as last ab- dominal segment; setz all nearly terminal, inner one long. Length 2.5 mm. iW Common in America, England, continental Hurope, etc. C. clau- sii, Poggenpol, is known to me only from the citations of Rehberg and the translation given by Cragin, hence I can not judge authori- tatively of its validity. Certain points in the translation are obvi- ously erroneous, as where the larger branch of the fifth foot is spoken of. No distinctions sufficiently clear to enable us to separate it from C. tenuicornis can be gathered. 11.—FrrtH Foot 3-soINTED. (See Cyclops modestus.) Antennz 16-jointed. There are a few forms which, although they might more properly be ranked with the previous section, seem rarely or never to acquire more than sixteen joints. Sp. 18. Cyclops languidus, Sars. Thorax attenuated posteriorly, caudal stylets exceeding in length the two preceding segments, internal seta short, half as long as the outer, the inner of the median set as long as theabdomen. Both rami of the first foot and the inner of the second are two-jointed. Second joint of the fifth feet sub-linear, armed with a seta anda spine. The fact that some of the feet have two-jointed rami sug- gests a young stage of some other forms. This species has not been seen in America. Sp.19. Cyclops modestus, Herrick. (Plate R. Figs. 1—5.) American Naturalist, 1883, p. 500 (May). This small species, 1.0 mm. long, was first recognized in Cullman county, Alabama, 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 STATE GEOLOGIST. 155. all 3-jointed and are peculiar in their armature. The fifth foot is obscurely 3-jointed, the second joint bearing a short spine and the terminal joint two spines of varying length. The stylets are once and a half as long 4s the last segment and are peculiarly excavated for more than the lower third, from the point where the lateral. spine is situated. The outer terminal seta is short, the others being sub-equal and also short. The opening of the spermatheca is elong- ated, oval. The antenna of the male is divisible into five regions, the third being formed by the thickening and coalescing of four or more segments. Antenne 14-jointed. Sp. 20. Cyclops insignis, Claus. The two forms here belonging might be considered atavic varie- ties of Cyclops pulchellus. Brady’s figures and description of his C. insignis (= C. lubbockii) agree almost exactly with what Reh- berg says of Cyclops helgolandicus (Abh. v. naturw. Vereine zu Bremen, vil. 1. pp. 62—64). Rehberg regards that species as an atavic sub-species or variety of C. pulchellus. With C. insignis, Claus, the case seems to be different. The occurrence of this species is not conditioned by marine influence. I found it abundant about Leipzig, Saxony. ‘The differences between it and the C. insignis of Brady are, as the latter says, very slight. Figs. 11--14 of plate T are drawn from Leipzig specimens, from osmic acid preparations. The first foot, outer ramus, has three external spines on the distal segment, two setz at the end, and three within; the inner ramus has one internal seta, a spine and a seta terminally, and three ex- ternal sete on the distal segment. The outer terminal segment of the fourth foot is like the first; the inner one has only two external sete. The external setz of the caudal stylets exceed half the length of the stylet and are pectinate. The fifth foot has a- short basal joint armed with a single seta, the second joint being slender and armed with two unequal sete. The gathering above mentioned, taken near Leipzig, Dec., 1881, contained scarcely a female among scores of males in various stages of development. This is so con- trary to what is expected that, notwithstanding the apparently good characters on which the species is founded, an uncertainly exists in the mind of the writer as to the permanent adult charac- ters of this species. i I. ? 156 TWELFTH ANNUAL REPORT. Antennee 12-jointed. 1.——FirtH Foot 2-soINTED. A.—Terminal segment of fifth foot with a seta and a ihtatt spine. Sp. 21. 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 sete short and © nearly equal; the interior of the median setz as long as the abdo- men; lateral seta about in the middle of the stylet. Antenne of the first pair robust, slightly exceeding the first segment of the body when reflexed, 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 setz; 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. Ova-sacs small, nar- row and divergent. Eye very small. Length nearly 2 mm.” Very close to C. viridis in many points. Found only in Scan- dinavia. Sp. 22. 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 equalling the last two segments of the abdomen, External apical seta longer than the internal, both short; median sete 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 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 segment short. Ova-sacs oval, somewhat divergent. Length 0.75 mm. Found only in Scandinavia. STATE GEOLOGIST. Lt u.—Firra Foor 1-JornTEp. | Sp. 23. Cyclops varicans, Sars. “Cephalothorax ovate, attenuated about equally in front and be- hind, with the last segment wider than the abdominal segments, produced laterally and bearing a long seta. Abdomen elongate; caudal rami scarcely as long as last two segments; the internal apical seta twice as long as the outer; median pair elongated, the internal one as long as the abdomen. Antenne 12-jointed, robust, shorter than the first thoracicsegment. , , Bothramiofswimming feet two-jointed. , , Feet of fifth pairrudimentary, with a single linear oes Pe a long spine. Ova-sacs long, divergent. Length 1 mm.’ Very possibly the young of some species not now identifiable.. Only mentioned by Sars. (Compare C. diaphanus below.) Sp. 24. Cyclops serrulatus, Fischer. (Plate O. Figs. 17—19.) 2? Cyclops agilis, KOCH (fide Rehberg). Cyclops serrulatus, LILLJEBORG, CLAUS, SARS, LUBBOCK, HELLER, FRIC, HOEK, BRADY. Cyclops longicornis, VERNET. Cyclops pectinifer, CRAGIN. Although Rehberg positively asserts that Koch’s name applies to the present species, none of the numerous authors who have men-. tioned this most widely distributed form have ¢employed any other than the familiar designation, and the practical advantage to be derived from its use seems to outweigh a quibble of doubtful. synonymy. Cephalothorax oval, compact; abdomen slender and short, sud- denly enlarged previous to its union with the thorax; antenne- slender, reaching nearly, but not quite to the last thoracic segment; the last three joints are attenuated and furnish the most evident character of the species; formula —-<~—-~~ Y—-~——-— ; during life the antennze tend to assume the form of a rude Z, the proximal four joints forming the base; antennules small, reaching about to the sixth joint of antenne; jaws small with large teeth; the single segment of the fifth foot with three equal spines; egg-sacs oval, as long as the abdomen; eggs few, dark; caudal stylets very long and slender, spined along the outer margin; lateral setz small and ap- proximated to the upper one; outer terminal seta short, spine-like, in life set nearly at right angles to the others, spined or beaded on. — " 2 . — — . —— . . " _—— _—— —— — : - = vig Pe Se > oe eee a y a oe > ae a a =) " ae Se: ee mz os ; ag ar — ' ms, any ‘ — - = Poo y — a hid * ane ay —_ * PS 4 * . p . eo Fj } a = c ine Sie ~ “pe erg 158 TWELFTH ANNUAL REPORT. one margin and bristled on the other; the next seta is as long as the abdomen, being somewhat exceeded by the following one; inner seta as long as the outer, but feeble; upper seta nearly as long, ap- proximated; length less than 1 mm. A well marked variety of the above occurs in America, which might rank as a species, were it not probable that it is simply a post-imago form occurring only under favoring circumstances. This variety has no connection with Brady’s var. montanus. Cyclops serrulatus, var. elegans. (Var. n.) Distinguished from the type by the greater size, and the elonga- tion of antennz-and caudal stylets. We will first of all give the measurements 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 segment of the thorax is long proportionally (0.40 mm.) The antenne are very long, reaching to the base of the third seg- ment (.68 mm.). The egg-sacs are elongate-oval, being more slender even than in typical C. serrulatus; in the animal measured they were 0.50 mm. long, by 0.19 mm. wide. The caudal stylets are slightly shorter than the last two segments of the abdomen. The antennules are very short, and each joint has its series of fine teeth. The free lower margins of the thorax are ornamented with series of prominences, while the last segment is extended into a blunt angle bearing long teeth. The last segment 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 C. 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. Sp. 25. Cyclops macrurus, Sars. Cyclops macrurus, BRADY. Closely allied with C. serrulatus. Cephalothorax ovate, rounded STATE GEOLOGIST. 159 anteriorly; last segment fringed at the angles with numerous fine hairs. Antenne much shorter than in C. serrulatus, about as long as the first thoracic segment, otherwise similar. Abdomen attenu- ated, penultimate segment margined posteriorly with spine-like sete, the other segments pectinated. Caudal stylets very long and slender, about equal in length to the three segments preceding, bearing a group of four to five spines on the outside near the end, otherwise unarmed. Length 1.3 mm. Here is the natural place for C. spinulosus, of Claus, but there is strong reason to suspect the validity of the species so very imper- fectly characterized. Sp. 26. Cyclops fluviatilis, Herrick. (Plate Q*. Figs. 1—9.) Cyclops magnoctavus, CRAGIN. This small species with twelve-jointed antennz and conspicuous coloration is widely distributed through the Mississippi valley. The original description is appended. “Body elongated; thorax very long; abdomen slender; stylets about as long or longer than last abdominal segment; sete all very short, not [always] pectinate; lateral and dorsal setz very small; outer one spine-like, short and stout; two median setz short; inner one very small and inconspicuous; antenne reaching nearly to the base of abdomen [or beyond]; formula -~~—~——-—-—-—~-— ; the three joints following the six basal are much elongated, while the terminal ones are but moderately so, a character which is peculiar to this species; terminal segment slightly but evidently hinged and, together with pair preceding, somewhat curved; feet with the ter- minal spines strongly toothed; fifth foot very small, one-jointed, bearing three small setz; operculum vulve heart-shaped; egg-sacs sub-quadrangular; eggs large; abdomen in the young much elongated. Color deep indigo. Length 0.7 mm.” The first foot has upon the last joint of outer ramus three ex- ternal spines, two apical setz and three internal sete; the outer branch of fourth foot has three external spines, apically aspine and seta and internally four sete. __ Males of this species are slender, measuring about 0.75 mm.; the abdomen being 0.28 mm., stylets 0.6 mm., first thoracic segment 0.28 mm., and the longest caudal seta 0.24 mm. The antenne are long and much modified so as to resemble superficially the antenne of Diaptomus. ‘160 | TWELFTH ANNUAL REPORT. Antenne 11-jointed. Sp. 27. Cyclops diaphanus, Fischer. ‘(Plate R. Fig. 12.) 2? Cyclops bicolor, SARS. 2 Cyclops minutus, CLAUS, aan If not the young of other species, this is a widely distributed form, being known from Russia, Norway, continental Hurope, Madeira, and America. ‘T'he synonyms above given are upon the authority of Rehberg. The followimg description applies to our American form found always in connection with C. thomasi, C. parcus, or C. navus. Very small, measuring 0.81 mm., setz not included. The thorax is 0.5 mm., the abdomen .31 mm., the stylets .06 mm., the longest caudal seta 0.4 mm., outer median seta .36 mm., the first thoracic segment 0.3 ntm., and the egg-sacs sometimes 0.4 mm. The thorax is oval, the first segment being quite large, as in larval eyclops. The antenne rarely reach the end of the first segment and are either 11-jointed or obscurely 12-jointed; their formula is —~—- 61 4 see 21 Hy. IACUSULIS oy. sais ee ee 131 LL. frontosa ....... 7-2 peanee 21 Ereastlus, Genus... bhscuateert 174 JLophophorus ...... .. 22 -5eeeee 148 dt. UEPLESsins wc. sss + sea perane 174 luynceide, Family .. eee trl Hy... SYEDOMGH: so cee sree Ieee 174 Lynceinz, Sub-family.......... 81 Eurycercine, Sub-family....... 80 Lynceus, Genus. (See Alona and Huryeercus, Genus A dence kor 80 Pleuroxus). Een 2321 2) 1b fe Pd 80 Lynceus acanthocercoides...... 89 KE. laticaudatus. 2.0). .4- Jaap (OO clas ALINIS. |... . + s+ es 98 BVAUNG to reste cee Re ae 122 IL. CXCISUS ... ...:...> ation 103 Heme Perchlomge oo. ce weet 179 «Ls. @XIGUUS ......'. 5. ee 105 Graptoleberis, Genus .......... 89 /L: lamellatus.... | />.- eyes eee 80 Gs WICTNUS’ olen ob 8 5 co ebhene 90 -L. laticornis. ... <.. . eee 68 Gc TEGRCUIAUR.. antlers wih cen bade 90 -L. leucocephalus ... . . seen 81 G. TEstediniaria .si0) oe ewe see 90 -L: lineatus .... <4. i) ee 96 k INDEX. 191 Page. Page. MEPMACTIITUS... 55 2... 0 eves 2s Bape Wie WENELONS tare ena o Pe LET MMS hs ee ee La Podon."G ens co a ee 122 | Seerquddraneularis .....:....... 88 Poecilostomata, Order ......... 174 : MEePepICMATIS. 5-52... 0. ves se Me Morane ee ey Sesh ays kos aie 129 j SRS 102 Polyphemide, Family.......... 120 y MeeseMeTICUS = 2. Se oe ek 116 Polyphemus, Genus............ 121 MPPeMIITOSLTIS.. .. 0.5.50. 2 MO Ee OUnIMOLERELOL..... 7. 0.2 SLR Jie Mevcsiudimariuis. .......06..5.. SUM Pseudo-Cyclops .2. 2 0 62.2... 14 Merrisonelus .... 0.0. .....05.. 108 Pseudo-diaptomus, Genus...... 180 . MMPMUMCAGUS 2)... wen. va we ees M2 ee PRLOICUS si Su ais hla oy eR Aue 180 Lyncodaphnide, Family ....... 66 Pseudo-sida, Genus............ 20 Lyncodaphnia, Genus.......... free IGEN GEA. ch 4 2 ede ohn Mea w 20 L. macrothroides ........ Petes aw OOM MAUS fo 85) fos Dok 107, 113 miacreuirix Genus... ..5....... 68 Scalicerus pediculus ........... 12] Mee WICOUMIS i028. Sic dee Se ss 68 Scapholeberis, Genus .......... 4] WLS TOF 02) a Oe Ss. me Ula. 35 2. 2 eee ee 44 Li SU ceanmniatas £05 k-,¢: > eee 43 MieteHIGOINIS.... 5... 6. 0. ses MS aU. GS bie. ee ka aan 175 Metrida........ Te ih as as LSZeS COEMUM A: otal = hs a ei a 43 OLN SORSM IMA as ee Scns evens » ecu 's 1 eS IMCrONaAba. os.) oe ees 42 Monoculus (= early synonym for SS MASHUd sic hee 2 hee ee Lie 4S i Lynceus, etc.) Scophiphora vagans............ 180 Monospilus, Genus ............ 119 Sectioning entomostraca....... 179 , “COIS, 02 8 ie i ae renee LtomSIGa GreNUSiaG ac. a5 0. 1 adel 5: 19 ; ove wo, Cladocera,........ 03... Mae CLV SUA. cro o's Care we tes 20 i More to Copepoda ....°)........ SGP Se OM GALA Te OF i. Sages ote en 20 4 BEREAN Bay oo) alo in's «ict ee 4S pordides, Family iene. oss Gane. 19 | Osphranticum, Genus.......... 134 Simocephalus, Genus .......... 44 } W@altabconcetum.:. (4. 2... ISAS americanus... 62 ss... Ae 47,48 fi eit epe eyes Poult AMS ECONO OND 2. i.e. Bo 48 ES Percantha truncata. 2.50.2. 2.0% 112 75. ,CapUNOldeses sake oe. Rees i 48 a ? emirE RUM, (OMS. ss. 2 ci ihe oe vs oe HA SP OXPMOSUS . x fo. fen. Ca ee AT e Pere HILO SITING 8S oe aie the ws MMS TOSUEATIS So Sa. Sab eee pare \ (ICUroxus, SUD-Senus.......... WO Gens SORPUNUIS. 6. oie ks Jie wameen en 46 3 BPM ARMMILOSLTIS os ot Se ce bs Oo pese VMEbus A. ae oer ea amas 46 J Pera hUS sb e ok Keeal s 109 Streblocercus, Genus........... 72 | RePMA MANS So ow he Ss a ee ooo oe MN re, TIMUTT UL OUTS. 5 5m cae a wa aces eto, ODT EVO Sa a HOS RACHTOIUIS sac. aaa hae canoes 129 PE MOCMTICUIALUS. 200.5020 6.00. LO, SPemora, GeMUs = :o2%. 5.49: 133, 182 EEC STIS gs SAU ts 9 aa oe gag MRO cea AS cd ys acer ete wien oF ane 133, 182 Pee MNAMOALUS 22056 ooo execs ws Bi es AD eas Arie 25. okie etm santos 133 OTT SS) SE ae Biot.) finmane nian. dy0).').7. 2 aslpatee 133 Perr PERSOTMAIIG cose vis ye ee eb ane hee ORME TG su ores Vaan eo a 133, 182 OTE RUS 6g a hae? LomeiCOrnis: hse lee eo ks Sig os 133 ReeBTACOMOWITS! «i. sic x's seals bos es GS ols; WOON Se ea We aie . .133, 182 Meer EMMC HUIS 000 lea lait Gn a ews ioe POreias 7a Maes ae wets 143 Pe IRCAMIPGUS) 02.60 2s wea ss 42+ 114 Utricularia yulgaris.. . 2... 20. 8 ei Or AgOTs: * oo a Bers Ne. H, : | " BER LE 37, : st gh “35 Savona ney 2 at 2 * a3 oT 24: ay f » it : banks Fig. Fig. Fig. Fig. Fig. Fig. > Fig. Fig. Fig. Fig. = Fig. Fig. Fig. t=) Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. > Fig. Fig. Spal lo PLATE A. abdomen of Moina paradoxa, female, from “Minnesota. . spine from post-abdomen. post-abdomen of Moina rectirostris. head of M. paradoxa, female, showing (a) eye with pig- ment and lenses, (b) supra-cesophagal ganglion, anten- nule with (c) its muscle, (d) its nerve, and (e) its terminal sensory filaments, (f) the cecum of stomach, (g) optic ganglion, (h) stomach, (i) wsophagus, (j) the muscles which move the eye, also part of the labrum. antenne of same. ephippium of VW. rectirostyis. 7 of M. paradoxa. seminal cell of M. paradora; Ta, a group less magnified. seminal celis of MW. rectirostris. first foot of male of M. paradoxa. Hees eM, rectirostris (from Weismann male M. rectirostris (from Weismann). head of Ceriodaphnia rotunda. (This and the following ~ numbers after P. KE. Mueller.) head of C. punctata. x C. pulchella. 3 C. reticulata. C. quadrangula. C. quadrangula. post- oes of C. quadrangula. C. pulchella. C. megops. C, reticulata. 3 C. laticaudata. C. rotunda. bs = —— MINNESOTA CRUSTACEA. 12th Annual Report PLATE A. Geol. & Nat. Hist-Sur: Minn. eh. kor a Per te. REA tyler SET RE | aN Chtverreck + ue PLATE B. Ceriodaphnia rotunda, male (after Kurz). C. alabamensis. female. C. reticulata, post-abdomen of male with opening of vas deferens (after Weismann). C. consors ? ? C. scitula, head of female. do., post-abdomen. do., antennule of male. do., semen cell of male. Scapholeberis angulata, adult female; 9a. first foot. Schapholeberis armata, a do., view from below. Lyncodaphnia macrothroides, young. do., labrum. do., antennule. do., last foot, purple pigment in lower part. MINNESOTA CRUSTACEA. 12th Annual Report PLATE B. Geol. & Nat. Hist. Sur. Minn. Meee ey ) MORRO oO SOR e, 1p) O7F?, S Vas SEU SQsoR et a aaa % CL.Herrick | a =z ule en Ma a eco ~ = em Se ee a — ett et Bios Ve enone ' Y f ' . ae ' ri P Pra ‘on ) t E / o4 » ; 2 f mi it if " ie, uh: : 7 ¢ ar. : ‘pia RE Sey ARS * ef Pe BORD Wo Misti8 : ' Ts) ry ¢ ; fo 4 ar. %, fir i—~ lee i Hl - Ras {5% fv { — . . # ’ i ‘ PaATKAs j ean , ES Ire way ae oS manne pool woos hetavals on ofr La DRE: GHer 1G Rie oni te uty xe GARE gh 4 Av eC Ty oa Ae \ ee go Caw Fe oe PLATE B', - Fig. 1. Lyncodaphnia macrothroides (= Ofryoxus?), ai a Fig. 2. post-abdomen of the same. . Fig. 3. antennule. . | m. Figs. 4--6. Polyphemus pediculus, young and adult 7 ma. | | - i 1 nein MINNESOTA CRUSTACEA. From the 10th Annual Report. PEATE BB. Geol. &: Nat. Hist. Su. Minn. ° Fig. Fig. SO 0 ID OT O9 PO PLATE C. Macrothrix tenuicornis, 1a. labrum. do., first foot. do., antenne of young. Macrothrix pauper. Macrothriz rosea, antenna of male. do., spines of shell-margins. do., post-abdomen. Macrothriz laticornis, male. do., semen cells. Pasithea rectirostris, male antenna. Macrothrix rosea, post-abdomen. Macrothrix tenuicornis, ‘ Macrothrix rosea, post-abdomen of male. - Drepanothrix dentata, antenna. Llyocryptus sordidus, marginal spines. do., antenna. do., post-abdomen. Ilyocryptus spinifer, 18a. marginal spines. do., antenna. Macrothrix tenuicornis, heart and accompanying vessels. Ilyocryptus spinifer, post-abdomen. MINNESOTA CRUSTACEA. 12 th Annual Report PLATE C. Geol. & Nat. Hist. Sur. Minn. CL. AHerrieck oS Se ee PLATE D. Lathonura rectirostris, female. from above. a. eye. b. optic ganglion. c. mus- cles of eye. d. muscles of antenna. e. dorsal sucking disc. f. stomach. g. young in brood cavity. female, from side. head seen from below. maxille. first foot. ovary. antennule. last foot. a MINNESOTA CRUSTACEA. | 120 Annual Report PLATE D.— Geol. & Nat. Hist. Sur. Minn. | ay er Oi | | fe! P| (a 9 CLA errick Se . . \ts ihr i 4g ‘ey tk i | . P| : ‘ ' 4 . a i F “ ¢ < 4 , KL P ' f ‘ ane ; F ai Sty ee cs feat So Se eee PLATE E. Alona quadrangularis, female. A. antennule. Lb. labrum. Md. mandible. P-a. post- abdomen. An. anus. F. c. musculus flexor caudalis. EK. c. musculus extensor caudalis. A. g. anal gland. n. g. nutritive globule inembryo. t. tail of embryo. I, I, U1, LV, V. five pairs of feet of embryo. mx. maxilla of embryo. at?. antennze of embryo. at!. antennules of embryo. H. heart. Sh. g. shell gland. Ov. ovary. Md. m. muscleof mandible. At.? m. muscle of antenne. KE. eye. s. ce. g. supra-cesophagal ganglion. P. F. pig- ment fleck. brain, eye and pigment fleck of same. Pleuroxus procurvus, female. foot of same. Acroperus leucocephalus. Alonella excisa, female; 6a. shell of same. antenne of same. Alonopsis latissima, female. Alonopsis media, female. Camptocercus macrurus, post-abdomen. . 10a. lower angle of shell of same. ek ed re a I oe ——— errr rt = Ss = S € % : 5 aes < % Ws O < ee wn —- . oh O < ra O ap) LJ Zz Win); u Wings = ye = Wen g is) + RK S 8 aS = 8. x! 2 x. ¥ ) } r ‘ “4 3 ¥ 1 - . he - ‘ 9 ‘ = n ’ oi. rt 7 7 ' ' ~ ” ba + , . 7 . * ’ . \ ' ~ ’ 4 i * er) < oy ‘ , ries PT ye Bie 5 - m a HA : a re raed ; ot Nye A $ " i pea? 2a Ss Uy aod , ne nr ‘ rr 7 ; i P 4 ~ e ’ \ ‘ 4 ‘ee is re J ae 7 £ } s { 5 et , , ; - . ¥ : ‘ ( , t i Pv ies PMT in 2 € : ati . i = 4 f ’ § 4 ° : ) . = y AAT) , , A ' : % ° \ _———— — oe = a Fig. Fig. Fig. > Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. = Fig. Fig. CO WY SD OK HH G9 DO EE PLATE F. Chydorus globosus. do., first foot. do., end of post-abdomen. Chydorus sphericus, male. Chydorus nitidus, post-abdomen of female. Chydorus nitidus, head. Chydorus sphericus, ephippial female. do., female. 3 Chydorus globosus, post-abdomen of male. Chydorus sphericus, trom above. Chydorus ovalis. Chydorus celatus. Crepidocercus setiger. Alona affinis. , Pleuroxus unidens; 15a, antenna. MINNESOTA CRUSTACEA. PEATE fF. 12 Annual Report Geol. & Nat. Hist. Sur. Minn. yy CERRSERRD SS ass CLHerrick x h . i, 9 eden tll fale : - y- PLATE G. Alonopsis latissima, male. Alona glacialis ? female. do., male. Alona tuberculata. do., post-abdomen. do., labrum. do , antenna, setose branch. Alona glacialis, antenna. Alonopsis latissima, fect. Figs.10, 11. Alonella excisa, details of shell sculpture. Fig. 1. Fig. 2, Fig; > Fig. 4. Fie. 5. Fig. 6. Mig. 7. Pig, 8. Fig. 9. Fig. 12. Fig. 18. Fig. 14. Pleuroxus denticulatus, female; 10a. outline of ephippium, | do., common variety. | Alona tuberculata, var. MINNESOTA (CRUSTACEA. i? th Annual Report » PLATE G. Geol, & Nat. Hist. Sur: Minn: (BEE , = ie Zi BOOT a; | | | \\ ‘| CL: Herrick ® J a i - % . - - Ws. : ee : > Pa . -~* * > © . , - 2 ee eee PLATE H. Pleuroxus hamatus, post-abdomen and antenna. Pleuroxus affinis. Alona modesta ( = lineata?) Leydigia quadrangularis. Eurycercus lamellatus, male; 5a. posterior margin. do, antenna of female. Alonella pygmea. . Temora affinis, Poppe. female. do., do., do., do., Go., do., do., abdomen of female. male. abdomen of male. fifth feet of male. * “© of female, jaw. antennule. Nauplius larva of this or a related species. MINNESOTA CRUSTACEA Geol. & Nat. Hist. Sur. Minn. PLATE H. Ii th Annual Report Seba ee bs — 2 : . ss ee ee beeeasaeianeeel Cnn REIT i Se 7. a Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fie. Fig. Fig. Fig. Fig. Fig. Fig. Fig. 1 SO HAD Or oo bo HA PLATE I. Camptocercus rectirostris, post-abdomen of female. do. post-abdomen of male. do. male. Camptocercus biserratus, head. Camptocercus latirostris, head of male. do., head of female. ; Camptocercus lillgeborgii, head. do., post-abdomen of female. Acroperus leucocephalus, post-abdomen of male. Acroperus angustatus, si ¥- Alona tenuicaudis, post-abdomen. Alona dentata, post-abdomen. do. female. Alona elegans. Alona intermedia. Pleuroxus hastatus. Leptorhynchus faleatus. Phrizura rectirostris. Eurycercus lamellatus, first foot of female. Alona sanguinea? shell markings. 2 Monospilus dispar; 21a. do., head seea from in front. Figures 19-21 original, others from Kurz, P. E. Mueller and Schoedler. MINNESOTA CRUSTACEA. 12th Annual Report PLATE I. Geol. & Nat. Hist. Sur. Minn. SS, y ' Any 283 BS r= aa SK iM 1 i a Se ae Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig, Fig. Fig. 1 po fe Se ee ee PLATE J. Ceriodaphnia scitula, (small var.) ephippial female. Bosmina longirostris. Bosmina lilljeborgit. After P. E. Mueller. Bosmina, hook on the first foot of male. Scapholeberis mucronata, Scapholeberis cornuta, head. Scapholeberis angulata, head; Ta. angle of shell. Pleuroxus denticulatus, male. Simocephalus americanus, head of female. . Bosmina, post-abdomen of male (after Weismann). Ry 4 MINNESOTA CRUSTACBA, by i \ i Geol. & Nat. Hist: Sur. Minn. PLATE J. 12th Annual Report We yerrick eS ao ie La ; 7) ES ne <— Ce es pone N ” ‘ Lig. 7. PLATE M. Daphnia schefferi, post-abdomen of female. be 66 6b be male. male antennule. brain and nerves. inf. ce. g. infra-cesophagal ganglion with nerves to antenl| ne; ce. cesophagus; n.f. frontal nerve; g. opt. optic gang- lion; m. opt. muscles which move the eye; p. f. pigment fleck; n. opt. optic nerve. Daphnia schefferi, posterior part of embryo. Eurycercus lamellatus, heart, showing the anterior bifid portion between the lobes of which is the arterial opening | and valve. The vaned arrows represent deeper enrrentl | while the unvaned indicate superficial ones. The dotted | line represents the position of the pvlsatins 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; ec. frontal | nerve; d. nerve to antennules; e. commissure connecting | upper and lower cesophagal ganglion; f. nerves toantenne | and mandibles. bt bb bs 66 a MINNESOTA CRUSTACEA. 120: Annual Report PLATE M. Geol. & Nat. Hist. Sur. Minn, eI ic INE ln ee a atau > 7 = = “Ly prerrick 4 i eee > s—- = = Fig. r=) Fig. Fig. Fig. Fig. Fig. Fig. Fig. t=) Fig. Fig. Fig. Fig. Fig, D> Fig. PLATE N. Daphnia pulex, var. nasutus. outline of head and (a) beak of D. similis. Leptodora hyalina, seen from above. zi oy larva. Latona setifera, female. Limnosida frontosa, female. . ‘ antennule of male. Holopedium gibberum, female. Sida elongata, head outline. Sida crystallina, head outline of young female. a ' antennule of male. " i - of female. Daphnia galeata, outline of head. 6b “oitrea”’ 66 te 66 MINNESOTA CRUSTACEA. PLATE iN- © hh. Geol & Nat Hist. Sur Minn. kAnnual Report 12 vn Ch Aer ruck: i ca : ys! * zi . : : \ ‘ td a3 =: 3 5 + 4 ; a ' 7 4 i oe Wig rf é Ur BMDS / . 7 ) Be se a ii 2 a? .6lhiget ‘to } Mont Peal laa: ; ‘ Joly te yer ee : oY u % a : plan 20), gh 04 i { 2 hay tele ee A: i 4 . ‘ ; ae dot AJaio! weinit to Joul asiii ay rs - . MTS Jb i 3 ] 7 Fy : ‘ } ‘ pik a Oo . pL Gee eee j oO MIR ITOT 20 Gist 3 : ‘ nm ; ei " - ‘ al By 7 : ; wef) a Pee | 7 o< 5 Fig. Fig. ‘Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. a a en PLATE O. Comthorsmpioe illinoisensis, antenna of female. tS fifth foot of female. 1 ‘3 = antennule. ; | 7" first foot. j = = caudal stylet. 7) Canthocamptus northumbricus, var. americanus, fifth foot of female. re ve antenna of female. 6 ve maxilliped. “ ve caudal stylet. ; be “ antenna of male. ; ‘s vs first foot. q 0 vs fourth foot. | re Nita fifth foot of male. | 4 us frontal area. Canthocampius tenuicaudis, stylets. ts fifth foot of female. Cyclops serrulatus, fifth foot. a fourth foot. ‘6 ‘ outer ramus of first foot: Canthocamptus northumbricus, inner ramus of third | male foot. | bb ee beak. Ks v6 maxilla. MINN ESOTA% CRUSTACEA. 12% Annual Report Pain o. Geol. & Nat Hist. Sur Minn. C.L.Herrick iF in ES A Bhccuntntl: BEC AY AY, os Prades? fin ¢ aca + Pe: bot wes Ee, 2 i} a) | fe ¥) | hte Sil ‘ ie bt ys hi Hebd » ofan aa} “4 Figs 1 Fig. 2. Fig. 3. Fig, 4, Fig. 5. Fig. 6. Fig... 7. Fig. 8. Fig, 9. Fig. 10. PLATE P. Heart of Simocephalus vetulus. a, tendons attached to’ | lateral walls of heart. b, venous opening of heart. 6 muscular bands supporting the abdomen, connected t re transverse bands. 4d, cells of nutritive matter hiding the arterial opening. e, thin membrane seen in section which separates the venous from the arterial blood et rents, is in focus near the side, but its situation in the center is shown by the dotted line. Above this or out side it is the attachment of the powerful antennary | and mandibular muscles. f, posterior arterial sinus. brood-sac. h, alimentary canal with thick glandular cell walls. i, shell gland or excretory organ. j, power ful muscles supporting and moving the abdomen. An early stage of the embryo of Duphnza schefferi. a” anus. n, nutritive globules or fat drops characteristic) of the summer embryo. m', m’, outer and inner enve- lope of the embryo. This is a nauplius stage, but not the first or proper nauplius. The portion darkly shaded is nutritive yolk. q A well advanced winter embryo of D. schefferi. a, sh growing over the eyes. b. c, inner shell. d. outer shell. e, lateral part of the head. f, antennales. g, labru h, mandibles. i, maxilla. j, second maxilla ? k’, | m/’, n’, branchial appendages of the 2d—5th pairs of fi representa by k, 1, m,n. 0, first foot. p. antell | q, anus and intestine partly completed. ss, shell growit out from the maxillary region. Older embryo bursting outer shell. Egg after extrusion into the brood cavity. Head of young embryo. a, lenses in formation. b, ey | appearing as dark flecks. c, shell eronane over head. d, labrum. e, antennule. Longitudinal section through an ephippium. Vertical section through an ephippial Daphnia scheffe Somewhat oblique section through the ephippium b, c), heart (h), mandibles (m), and labrum (1). q A vertical section through the ephippium and its egg. | : | ; ai 1 oy Bf ‘ ‘ 1 MINNESOTA CRUSTACEA. 2th Annual Report PLATE FP. Geol. & Nat. Hist. Sur: Minn. = = LE BAEZ \) Zip, GFZ; ZB \ == \ NN AK\| hy Ss S RIWVOTs. Se ~ BSS SSa% SN SS NSS CLiHerrictr | | PO AINMESUTA 6° Bare oi oe Seige Aten ty per ey res v4 “ice F sine t i ah nad sslean cae re) | ants sortie asawoda nil f se 7 : with rine be as 4 ! ite o ak : be, hy sk ony / : ah ¥ ait re } : ee Ns jie P platad -w\indiniou Misael. * z iii an 4 e sat Se © Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig, Fig. 17. al Se Se er ee PLATE Q. Alonella pulchella, female. x . reticulations. % ‘* post-abdomen. Alona modesta, male. Diaptomus similis, female. 5a. jaw. : “fifth foot of male. 66 66 ‘79 66 6s female. * minnetonka, fifth foot of male. bb 66 be oe oe female. “ te abdomen of female. bb oe 66 66 66 sanguineus, sy stagnalis, fifth foot of the male. Epischura fluviatilis, abdomen of male. A lacustris, fifth feet of male. % fluviatilis. Diaptomus pallidus “ ‘“* “ “ inner ramus. 66 sicilis 6b bb 66 66 bb (a stagnalis, margin of last thoracic segment. PE ee en Ra oy eg os: ai ————————————— ——S a MINNESOTA CRUSTACEA. _ -12"%h Annual Report PLATE Q. Geol. & Nat. Hist. Sur: Minn:: Sy ‘a "6 é 40 Z = $ ‘oe Chow Za: Cz,He rreek Fig. Fig. Fig. 2. Figs. 3-4. Figs. 5-6. a PLATE Q1. Diaptomus sp. Young male; external parts as yet but partly developed showing alimentary and reproductive © || systems as well asa portion of the muscular system. The looped tube is the vas deferens. The small irreg- © ularly coiled tube anteriorly is the shell-gland or — kidney. : , female with ovary, oviducts and heart. Nauplius larva of same. fifth pair of feet of male and female. mouth appendages, anteriorly the base of antenne fol- lowed by antennule, labrum, mandible with palp, max- illa and maxilliped. Lav at ent M Bin Hib ot i uy Y Geol. &: Nat. Hist. Sur. Minne LEze| y | PLATE Q1. < - *” ~ cc = /-) = ‘ =" \ we r - . yr . ad x ) A > "a ? Oa So ee PLATE Q:3. 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, female. antenna. terminal portion of abdomen. female fifth foot. second antenna. Nauplius form. MINNESOTA CRUSTACEA. Geol. ¢&: Nat. Hist. Sur. Minn. ane Se ~ SR as ot eer See £2 | From the 10th Annual Report. | PLATE Q3. | Rt te ii eo YO | i ‘ i aN J a i SSS SSS SESE SSSSssans <> — PAE ce ten etter £ 4 4 ‘ ’ i - ‘ . Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig’ Fig. Fig. Fig. Fig. tao] Fig. Fig. Fig. ot 2 et ee eae PLATE Q‘. Cyclops tenuicornis, female. mandible. maxille. stylet. fifth foot. maxillipedes. antenne. Cyclops “signatus,”’ abdomen. antenna. fifth fuot. male antenna. Cyclops parcus, abdomen. antenna. fifth foot. Cyclops “adolescens,’ opening of spermatheca and cement gland. Cyclops “‘adolescens,” abdomen. foot. antenna of female. eye. antenna of male. Cyclops “‘signatus,” end of antenna. MINNESOTA CRUSTACEA. From the 10th Annual Report. PLATE Q¢. Geol. & Nat. Hist. Sur. Minn. Pia rp ass a “\ hee OND “Sf ee e e t Saeco ee . ee rr tes j er fa BET pee ne ee OEE ee renee ST Ee TR a EES STE TOR SOE oN EPIL fo ae Se RT ES EN BELT POS UE Ee ~~ Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig, PLATE Q5, Cyclops fluviatilis, female. antenna. antenna of young. abdomen of young. foot of young. foot of adult. fifth foot. eye. C. serrulatus, young. Daphnella brachyura, female. Daphnella brachyura, male. edge of valves. abdomen of male. abdomen of female. antenna of male. ed i i i a TE ae Geol. ¢& Nat. Hist. Sur. Minn. " MINNESOTA CRUSTACEA. PLATE Q5. From the 10th Annual Report. CE ES, Ss ae ee ad PES a weAS f \ at er SANDS r SS See 7) fa ess 7 ve a pees wv ni Ot 2 aTALd a tacoma! enh “slant Preteen ah io} ~) Seek BY anion Ree Joo! Ana : Rais ah} fet Ave evot aa tb mnneine alae. Garnontue? ty i t if + wy St ag Spe a picts yh peadmtiiw mY. oe 4 i ay ey oa q r i" » t ! t . orc Lj 7 } # A % Pie Aq . é 5 + . Tey , " es % Pe a cae Ce un . : ‘ t , i. a fe es i i . ’ » is ie 5 + ay - i A La - -¥ ¥ yw . ~ A : ae Fy, ‘ a oe ar € t ue , eo a ‘ - yA yi ‘ ‘ « ity ‘ 3 - : ‘ } . ' f F Q a . ‘ he & é Hind 7 eke a ; q j +3 . a . ue » a 4 es : oe ne ar ra : aT at high Th cr tas ‘ 4 x x Me ’ 7, UJ . ra vay ’ - ane 4 J iN Z ™ st U 4 $$ KP PLATE R. ; | Dyas een Cr yelops modestus. q Hig, 2. of end of abdomen. | | Pig. 2 ey outer ramus of first foot. = = 8 8 =| | Fig. 4 A : “ “*S second footy. aman Fig. 5 7 et fifth foot. a Fig. ' 6. ‘* phaleratus, fourth foot. ) — |, Bigs <7. $3 - outer ramus of first foot. 4 Fie Beane “fifth foot. eS || Hig) o . ne caudal stylets. e | | Fig. 10 - = antenna of young otherwise 0€ | Fig, 11. : fimbriatus. end of abdomen. mii Fig. 12. diaphanus, abdomen. ah Fig. 13. “ ater, inner ramus of first foot. Fil Fig. 14. ih outer) 00S sae Fig. 15. ys a ** _* fourth tem Fig. 16. 3 Sere ” fourth foot. Wie. 17. |“ ater, inner ramus of fourth toom Pies US. = ** stylet. Pig. 19) 1) spe? iinet toot: eae Figs, 20, 21. * ‘* terminal segments of foukat foot. — Fig. 22. - fifth foot. Fig. 23. Chydorus globosus, first foot of male. MINNESOTA CRUSTACEA. 12th Annual Report PLATE R. Geol. & Nat. Hist. Sur: Minn. S (J : 6 sae iN yi Yl L iy y th, ¥ f I IN lr : y NY AME = =a) <= ELLIE = 77, Lae SS = LLL ae 1S anbawn eh gas any 7 vised EN aon } gapiarety Riiy eae ao ia Ot A. he - Bitte erage iageh rtd Polo. x ete / nits eee 2 ‘ ay gy yas aay!) a ecg ee PLATE S. Fig. 1. Ergasilus depressus, male, Fig. 2. Cyclops oithonoides (Amer. C. tenuissimus, var.), stylets. Fig. 3. = . fifth foot. Fig. 4, sh 0 antennules. Wig. 5: i . fourth feet. Fig. 6. is antenna of male. Fig. 7. a “ brevispinosus, stylet. | Fig. 8. Fe a - inner maxilliped. Fig; 8 +i 9 i swimming foot. Fig. 10. re oe fifth foot, Fig. 11. . * ‘3 antennule. Fig. 12 v6 ce (i opening of spermatheca. Fig . 13. Cyclops sp.?, nauplius. MINNESOTA CRUSTACEA. CLHerréck. 1? th Annual Report PLATE S. Geol. & Nat. Hist. Sur. Minn. Nese Ts i r ‘ r PLT ET eT EE a ae : J - 9 e wo eH a Be Baga fee eee SO 9 29 So 1 pm g9 Fig. 14. Nore. 2. ee ‘ i | i Fig. 15. On pages 43 and 44, for ‘’ Plate T.”’ read Plate J PLATE T. Poe 8 minnesotensis, first foot. leks ies tgplenasy iy . Se antenna of 66 he 6b c — : cs 7 antenna of m: Daphnia galeata, young. *s = Tale. Camptocercus leucocephalus, male. Alonella excisa, male. . adh Cyciops insignis, first foot, outer ramus. | " Me fifth foot. | a4 _ fourth foot. stylet. Worm parasitic in arterial sinus of Daph i I? th Annual Report MINNESOTA CRUSTACEA. Z / 2 Y ANN SC VA We 4 \ , SNBAAG yea QW \ PLATE T. | "Gaal LUNAS Fst Sil: Movant, : HH KEW SNES) ' S 2 NY IED Ho} b . A J x’ Lory ~ J SPAN fi Cpe " ah Sk 4; SAG | - BZ AABZ B pf b 9 . : A fp j ; ™~ C4. Herrick — ak Moar 7 ts ba ahi Ws esa | 7h THONG G egpuit! TRANG beam ae ite as : wie A elouey t ut Ranges | ey Hein’ rt ae id te Pig. A. Fig. 2: Bis! .3. Fig. 4, Fig. 5. Fig. 6. Mie, “% Fig. 8. Fig. 9, Fig. 10. Fig. 11. PLATE U. Daphnia kalbergensis, of moderate size. 2 antennule of male. . " head of var. Cyclops thomasi, fourth foot. a m outer ramus of first foot. Daphnia galeata, typical form, Cyclops thomasi, fifth foot. 7 a stylet. Cyclops (insectus 2 ), fourth foot. Bythotrephes longimanus, female. 7 A curious large protozoan; a. infundibulum frame work b. pulsating vacuole; c. nucleus; d. food and digested mat- ter; e. protective rods: 11a, spicules of the infundibulum. MINNESOTA CRUSTACEA. | 12 t2 Annual Report PLATE'U Geol. & Nat. Hist. Sur Minn. j li \ le f 5 ) Yj ' ,. & : Ws | Ajj 4 4 : SS a ec A tg a rg a < Mes MEENES C1 va WV ‘ ( . aie aOR rent! 8 Kons ; ey ; i a PLATE U!, Figs. 1-14. Limnetes gouldii, Baird. | Fig. 15. Daphnia magniceps, female. Fig. 16. * Daphnia minnehaha, female. MINNESOTA CRUSTACEA. From the 10th Annual Report. PLATE U1, Geol. & Nat. Hist. Sur. Minn. fl SS pall os, G = mn, \ we: WY ™ \ee ‘ ZC = } \ yy) / yas ies eRe) eee, oe Libel wy Oke ‘it : eo if Sai he wine Sede * eed oe we _ Pi Pt Lo as = oe aie 1: ik ee ue of ti sen hs whos " iSisiertzn ‘) Tyee take wat No ea tieiea ., ci Gide head ier steak i ye igi neato mito oy TD 4 eee | Laah, A obeed bein: Ps & raiyland- as p Honan ie. coal here i wsorecksitn ee erg +4) eee a > vee poh eater ha? FOP Sy SINR TO BR i) vk. P ie 3 e rich : ere en ‘, afiaetd told era ome + PLATE V. Fig. Fig. i wig be appendiculata, head of larva. , * portion of heart with its muscles. a. chitinous projection of the body wall to which are at- |} tached two muscular threads; b. peripheral muscle; ¢ proximal muscle attached to the wall of the heart; d.— muscles scattered over the surface of the heart, serving as contractors; e. venous opening. . Fig. 3. do., extremity of body. Fig, 4. ie, abdomen of the pupa. Figs. 5, 6, 7. Rotifera found with entomostraca in Minnesota. Fig. 8. Flask-shaped rotifer, hermaphrodite, with eggs and sperm. a. jaws and head; b. shell gland; ec. glandular portion of — the stomach; d. testes; e. cesophagus; f. one of several — embryos. Fig. 9. jaws of the above. Fig. 10. similar animal, female, deadly enemy to Clipdiie Fig. 11. jaws of same. Figs. 12,13. ? pedicularis, ecto-parasite of Diaptomus. Bo ates Sadia MINNESOTA CRUSTACEA. 12 @Annual Report. PLATE Vi Geol. & Nat. Hist. Sur Minn. Ee oe ee ne ee Ce howe ee OS! eee 4. Be eae eee an : 4 - OO EO = \. meer ik. Ea N %. Rathbun OF THE SCIENTIFIC LABORATORIES OF Dew isON UNIVERSITY, EDITED BY © ie HERRICK “Mes. PROFESSOR OF GEOLOGY AND NATURAL HISTORY. VOL. I. GRANVILLE, OHIO, DEC., 188s. Downs & Kussmaut, PRINTERS, Granville Ohio. + . ‘ % ae 7 MOAT S 2 | , = EE aT Bulletin of Denison University Laboratories Vol.I. nes Vasile irene ENR GOEL BET AGEL DNR NN IOY aN BO NEC ae ecg! Fe ee ae ee ee a ee a a ee ee ee ee B. Bathbun, BULLETIN OF THE SCIENTIFIC LABORATORIES OF DENISON UNIVER- SITY, GRANVILLE, OHIO. EDITORIAL STATEMENT. Every well conducted institution of learning should form a recog- nized centre of scientific activity ; and legitimately concerns itself, not only with the instruction of those who directly entrust themselves to its charge, but with the dissemination and conservation of information relating to the subjects taught. Moreover, in connection with the laboratory drill, it often happens that facts of general scientific interest are brought to light which the student may be ill prepared to appreciate in all their bearings. Such facts, if preserved, may, at another time, become very valuable, while, if not thus preserved, they would be lost. Still again, instructors will, as a rule, be unable to instill enthusiasm if they themselves do not come in contact with nature at first hands, while the fragments of time, which are often frittered away, can be made most useful to themselves and others by being applied to studies in advance of the work required by the curriculum. The present publication, which we are able to present through the generous co-operation of numerous friends, is a step toward filling a need hinted at in the above paragraph. ‘The bulletin is intended to represent the life of the college in its scientific departments and may incidentally serve to illustrate to distant friends the facilities for work afforded, as well as needs still unsupphed. To the scientific students of the country we confidently appeal for support and indulgence, since it is hoped to devote an increasingly large portion of space in each number to technical papers which have more interest to the student than to the general public. To the teacher, with still greater confidence, we look for encouragement, as it is entirely in the interest of better school work that this bulletin is prepared. While limited means has, in this first number, prevented the use of costly illustrations, it is hoped that the generous patronage of this volume will enable us to extend to the con- tributors to the following one more elegant, if not more perspicuous graphic aids. a : ; i | F 3 | | : | | : A considerable number of papers prepared for this number have been necessarily delayed, on account of the limited space allotted, and yet our limits have been extended. The lithographs were executed by the editor and printed by a process making them cheaper than any other available, and any failure to realize the ideal of such work will, no doubt, be pardoned on this account. For information relating to the departments here represented, the reader is referred to the advertisement appearing elsewhere. The fact that the chemical laboratory has afforded us no material for this num- ber, may be attributed to the change in administration in that depart- ment, occasioned by the death of the lamented Prof. Osbun. ee * ie THE EVENING GROSBEAK—Ffesferiphona vespertina, Bonap. | PLATE I AND FRONTISPIECE. | Among the rarities in the cabinet of most ornithological collectors is the Evening Grosbeak, which excites interest as much by its com- parative rarity and exceeding capriciousness in distribution as on ac- count of its odd note and eccentric behavior. — First found by Mr. Schoolcraft, in 1823, near Sault St. Marie, in Michigan, it was de- scribed by Cooper. The indefatigable naturalist, Sir John Richard- son, encountered it upon the Saskatchewan, where seems to be its nat- ural home, and from whence it issues forth, guided by any whim, and wanders far to the East-and South, though seeming to avoid the coast. The genus is Asiatic and our two species are obviously derived from the Old World, via Alaska. In Europe there is a closely allied genus Coccethraustes, which differs in the shape of the secondary wing feath- ers. The genus 1s distinguished from all other finches of the United States by the very large beak and the following points: «‘ Feet short ; tarsus less than the middle toe; lateral toes nearly equal, and reaching to the base of the middle claw. Claws much curved, stout, compressed. Wings very long and pointed, reaching beyond the middle of the tail. | Primaries much longer than the nearly equal secondaries and tertials; outer two quills long- est; the others rapidly graduated. Tail slightly forked ; scarcely more than two thirds the length of the wings, its coverts covering nearly three-fourths of its extent.” —Lazrd. |In America we have the two species, 1. vespertina (with its two varieties), and FT. abeilliz, Scl., which lives in the mountainous por- tions of Mexico, southward. | In very few places in the United States does this bird appear with sufficient constancy to be set down as more than an accidental visitor. In this respect Minneapolis, Minn., is particularly favored for, during a number of years, these grosbeaks have rarely failed to make a longer or shorter winter visit, sometimes coming early in the Autumn and re- maining until the trees are in full leaf, when, in a few cases, their much 4 6 BULLETIN OF THE LABORATORIES mooted song has been heard. The most eastern point yet reached by these birds seems to be Cleveland, Ohio, and isolated cases of their oc- currence in Wisconsin and Illinois are also known. ‘The species is highly gregarious and individuals are rarely or never met with singly. Even the destructive inroads of the collector, before whom they are absolutely defenseless, do not scatter or break up the flock. | Unsus- pecting and without fear, they continue to feed until the last individual falls a victim. The migrating colony seems well satisfied with itself and its temporary home and, while feeding, a constant chorus of an- swering cries is kept up. The note is not loud but is remarkably piercing, and yet not unmelodious. The early belief that these birds are silent except at evening is entirely erroneous. _ In spring, upon the approach of the breeding season, the males cultivate the muses in an odd but not displeasing little song. This song consists of several suc- cessive repetitions of a short warble, followed by a similar strain clos- ing with a shrill cry, like the finale of a black-bird’s song. The phrase which makes up the body of the song is musical, but is so abruptly ter- minated (as though from lack of breath or of ability, ) that it is annoy- ing when heard singly, for one is subjected to much the same nervous expectancy felt in listening to a hen’s cackle when quite leisurely ‘working up the agony” sufficiently to sound the final note. % i < “hoes Ne NOTES ON AMERICAN ROTIFERS. BY C. L, HERRICK. |Plates TI—IV, and Plate X.| Introduction.—In the series of papers here begun, it is expected to treat the subject in somewhat the following order: First, in an intro- ductory section, an outline of the general characteristics will be given, then we shall proceed to a description of species without attempting to treat them in systematic order, finally, if permitted, space may be de- voted to a review of the classification and a more detailed discussion of anatomy and development. The present installment attempts simply to describe a few of the common species of a number of genera. A rotifer may be described as a worm-like, bilateral, metazoan, _ moving by means of a circum-oral trochal disc, and either adherent or free-swimming. Many of the animals of this group are exceedingly small and are greatly exceeded in size by certain Infusoria, and it was this circumstance, as well as a certain outward similarity in appearance, which led Ehrenberg to include both under the one head and to as- cribe to Infusoria the same complicated structure: he was able to make out in rotifers. | Living in all fresh waters, these animals are among the most accessible objects for the microscope, yet, on account of the care necessary in their study and the scattered literature, they have been much neglected in America. The body of all rotifers exhibits a tendency to segmentation, which is, however, mainly confined to the integument. The inner organs are but slightly affected by the jointing, except the muscular system which is, moreover, largely responsible for the number and arrange- ment of the segments. Very generally the body terminates posteri- if en = mie Mr. = a. =). = =< | ., a SS 44 BULLETIN OF THE LABORATORIES orly in a several-jointed abdomen or ‘‘foot,’’ which bears two caudal stylets and contains glands which secrete a gummy fluid used by the animal in temporarily adhering to other objects. |The form varies from nearly spherical or round lense-shaped to terete and extended. The cuticle is modifided in various ways, sometimes appearing like a bivalve shell and thus hightening the resemblance to certain entomos- traca and explaining why older naturalists classed the rotifers under crustacea. The cuticle may be smooth or beautifully ornamented and produced into long spines or marked off into areas outlined by im- pressed or raised lines. The cuticle is secreted by a hypodermic layer which is often seen obviously to consist of cellular tissue. | Notwith- standing the protection afforded by a chitinous shell, some species (as Melicerta ringens) build for themselves a tube composed of ma- terials gathered from the water and apparently connected by a cement secreted in a gland near the mouth. Such an envelope may be com- pared to those swallows’ nests eaten in Asia, or the case of a caddis-fly. Some of the species live in colonies, and when the colony is spherical, as in Conochilus, it is a veritable microcosm—a sphere of active, vora- cious creatures whirling through aqueous space. _In only one case is it certainly known that a moult takes place, and facts seem to be un- harmonizable with the theory that such a change of coats is affected. The cilia of the trochal disc or ‘‘ wheel” are arranged in the greatest variety of ways in different genera. The attempt is made to refer all these forms back to a fundamental form—z. ¢. a double circlet of cilia, the outer of which is largest and serves as locomotory, while the inner set is under the control of voluntary nerves and serves simply to bring food within the pharynx. In many cases there is really no indication of such a distribution and the cilia seem to be merely iso- lated clusters of hairs scattered about the oral end of the body. Several of the rotifers are parasitic and cling to the less exposed parts of the body of certain Amphipods, or on Annelides, or are endopara- sitic. The muscles are often very conspicuous and, when large, show the striated structure well. The alimentary canal, maxtax, and the contractile water vessel have muscular tissue af another sort. The nervous system is most difficult to study and little is certainly known of its structure. | Usually there can be made out a considera- ble granular mass over the maxtax and in close proximity to the eyes, this is assumed to be the principal ganglion. From the chief or cen- tral ganglion fine nerves pass to the muscle and organs of sense. OF DENISON UNIVERSITY. 2B The eyes are double or single and are sometimes supplied with a lense; they are always furnished with a dark red pigment and, very generally, rest directly upon the ganglion. ‘There are occelli at vari- ous points in the trochal disc of some species. |The sense.of touch is delicate, and there is often a special tactile tentacle, or palpus with minute tactile rods. This may be reduced to a slight papilla or a pit, with sensory hairs. No other sensory organs have been discovered, al- though Huxley fancies that to be an octocyst, which the Germans call the ‘¢ Kalk-beutel,” z.e. the lime-sac. This is a spheroidal sac, contain- ing irregular grains of lime. The function is unknown, but it may be simply a reserve supply to be used in preserving the rigidity of the indurated parts of the body. . ' The mouth is more or less ventral, while the anus is dorsal. The mouth leads by the pharynx into a roomy and expansible crop or directly into the maxtax or masticatory organ, and this is armed with chitinous appendages of the most various form, but referable to a sim- ple type. Here there is a central anvil-like part called the zcus and two lateral mallei which consist of a handle (or manubrium) and a head (wnzcus) which beats upon the incus and reduces the hard parts of the food. The maxtax opens into a narrow ciliated cesophagus which, in turn, leads to the stomach proper. The stomach is sometimes quite distinct from the succeeding parts of the system, but sometimes can only be distinguished by the large size and absorbtive character of its cells. Into the stomach is poured the secretion of a pair of glands which may be compared to the so- called salivary glands of insects or the liver and salivary glands of ver- tebrates. The size of the glands is dependent on the diet of the ani- mal. In carnivorous species the glands are small, while in others they become quite conspicuous. The intestine is clothed with long cilia and opens into the cloaca or common receptacle of the reproduc- tive, water vascular, and alimentary systems. In some species, how- ever, the stomach isa ccecum and has no anus. Males uniformly lack the alimentary system and are short-lived creatures of love. In some cases evident messentaries support the digestive tract. The excretory system consists of a pulsating bladder, opening into the cloaca, and two lateral vessels of various form, upon which are flagellate chambers which contribute to keep up a circulation between the cavity of the body and this vascular system. Respiratory and circulatory organs, in the received sense, are absent, 46 BULLETIN OF THE LABORATORIES respiration taking place, as in many small entomostraca, through the body surface, and circulation is affected by the rythmical movements of the digestive tube and the ciliary action in the later vessels. In mature females much of the body cavity is filled by the ovary and the yolk masses or eggs. The ovary is disc-shaped, botryoidal or variously contoured and in the grey substance exhibits hyaline spots containing the nucleated ovule cells. A part of the ovary temporari- ly secretes the yolk when the egg reaches maturity, so that the appear- ance of the viscera differs greatly at different times. The egg, after extrusion, 1s commonly carried about in a delicate external brood-sac as in copepoda. To add here the details of the development of the egg would lead us too far. The male, as before said, has no functional digestive tract and is not only much smaller than the female, but suffers a reduction in many organs. ‘The sensory organs are, however, well developed. ‘The testis is spindle-shaped or oval and opens in a papilla, which also con- tains the opening of the water chamber or pulsating vessel. The spermatozoa are rod-like or thread-like and motile. The Rotifera are found in fresh and salt water over the entire globe. Some species may be found in damp situations on land. They exceed even the lower crustacea in their great adaptability to changes in out- ward surroundings. Not only is drought not destructive to the eggs, but the animal itself endures a long period of dissication. Other notes upon the habits must find their place under the special descrip- tions. Descriptive Part.--As above stated, the following descriptions are given without attempt at orderly arrangement, with the expectation of ultimately attempting a systematic review. In cases where lack of literary aids make positive identification impossible, the description alone will be given, awaiting future identification. GENUS FLOSCULARIA, Oken. The head is margined by five oval processes bearing exceedingly long sete of excessive fineness. |The mouth is central, with a funnel-form opening. There is a crop-like vestibule, separated by a partition from the pharynx, except in the cen- tre, which is perforate, the opening being margined by several pendulous cilia. The adult is attached by a long, jointed foot, but the young is motile and possesses eyes, which are aborted after the metamorphosis. OF DENISON UNIVERSITY. ‘47 FLOSCULARIA ORNATA, Lf. is not a rare inhabitant of the pools of Minnesota. The very full. de- scriptions of this species, given by various authors, would seem to have exhausted the subject, but we do not even yet feel sure that the so- called species are not local or age variations. |The other species are fF. appendiculata, F. proboscidea, F. complanata, F. longiloba, and F. trifoliune. Of Rotifer and Callidina we find a number of species, but reserve the consideration of the group for another occasion. LVotommata furnishes several species which are very abundant and striking, but a large number of works are necessary for their study. GENUS EUCHLANIS, Enr. The lorica is oval and composed of an arched dorsal shield and a plane ven- tralone. The lorica in front is broad and presents a large opening for the head. The shell often has a carina above, while the dorsal shield is movable upon the ventral. The trochal disc is strongly ciliate and bears two terminal sensory or- gans with clumps of tactile hairs. There is a single cervical eye and the viscera are highly differentiated. The foot has four short segments and two terminal lanceolate claws. EUCHLANIS (DILATATA) HIPPOSIDEROS, (osse. prelate TTT, Pig. 2.) The identification of our species with the above is made in spite of minor points of disagreement which may be looked upon as the result of faults in the descriptions or slight variations in structure. Eckstein gives the length at .45 mm., while Eyferth says.23 mm. Our spe- cies varies only between .22 and .24 mm. and is quite uniform, so far as observed. The form is oval, the lorica being excavated before and behind, as shown in the figure, although it is not often seen as clearly as drawn. The trochal disc has two broken circlets of cilia, and on either side the head is a pit densely ciliated within. The drawing given by Eck- stein shows the arrangement well. Two curious sensory organs oc- cupy the very front of the head. The ganglion is very large and quadrate, the eye being near its anterior part and quite large. The maxtax is quadrate, showing the component parts well. | ‘The stomach is ob-pyriform and there are two accessory glands. The ovary has very large nuclei and the egg is of great size. The contractile vessel 48 BULLETIN OF THE LABORATORIES is clearly seen and all the details of the water vascular system may be made out with ease. The lateral vessels are tortuous canals, while upon them are seated beaker cells, the flask-shaped base of which con- nects directly, by means of a curved tube of less diameter, with the main canal. The mouth of the flask is directed downwards and has a small opening near which is the point of insertion of a long cilium which extends upward into the flask, where it is constantly in motion. There seems to be no reason to doubt that by means of these beaker-cells the vascular system is in communication with the perivisceral cavity. ‘The foot is comparatively slender and has, aside from distinctly cross-striate muscles, two large foot glands which open in the ends of the rather long dagger-shaped claws. A pair of fine bristles springs from the dorsal surface of the last segment of the foot. The following measurements were taken: No, «a:., lorica .22 mm. Jong. No. .2. .22 Noe eo tA OO, wade, .14 Are foot .o6 mm. long. .06 = claws .o7 mm. long. oF .072 jaw capsule .o6 mm. long. .06 .048 Found in Minnesota during the whole summer among water plants. EUCHLANIS AMPULIFORMIS, SP. 2. [Plate 17, Pee) This species, which deviates toward Sa/fzna, is smaller than the above and, in outline, is somewhat flask-shaped. . The back is cari- nate and the flat ventral plate is excavated posteriorly with a cordate opening. The head is produced’ and densely hairy below. The maxtax is small, but the cervical eye is very large.» The nuclei of the ovary are very conspicuous, although the egg is not as large in propor- tion asin the above. The foot is four-jointed and the claws are elon- gated and somewhat curved. The lorica is .16 mm. long, the claws .o8 mm. Another individual measured .20 mm. and the claws were .12mm. long. This species was seen but twice, June 18th, 1884, in Minnesota. POLYARTHRAEA. The family includes the two genera, Z7zarthra and FPolyarthra. In both genera the foot is wanting and appendages of the sides of the body take its place. The body is not segmented except anteriorly and the form is not definite. The genus first mentioned has two lateral and a ventral appendage, while in Polyarthra the appendages are collected in groups upon the opposite sides. In both genera the egg is carried about as in Anuree, OF DENISON UNIVERSITY. 49 GENUS POLYARTHRA, Enp. A single species has so far been encountered and I am able, with the works at hand, to discover no reason to doubt its identity with P. platyptera of Ehrenberg. When swimming freely this animal seems to consist of two quad- rilateral segments, the first, or head segment being considerable shorter than wide in outline, while the body is a third longer than wide. The trochal ciliation is slight. | Two sensory organs are conspicuous upon the front of the head and the eye occupies the middle of the first segment near its posterior margin. The maxtax is very large and the stomach is short, with a tubular intestine. | There are two prominences on either side of the body near the front, each bearing three lanceolate spines. The egg is very large and is perhaps half as bulky as the whole body. The contractile vessel is small and little could be seen of the lateral vessels. The length is .1omm.; width, .o8 mm.; setz, .0o88 mm. long. Thisspecies seems rare and was found among plauts in standing water during June and July of 1884 and 1885 near Min- neapolis. The group of genera termed MJacrodactylea or Longiseta includes such animals as have a more or less elongate and frequently cylindrical body, often strongly curved, and possess the following characters. The cuticle is considerably indurated; the terminal segment of the foot is long; there is usually a lack of symmetry exhibited by the claws or maxtax; and the cilia are sparse upon the trochal disc. The following genera are at present included in the family: Scaridium, Monura, Furcularia, Distemma, Monocerca, Mastigo- cerca, Diurella, Heterognathus, Rattulus. GENUS DIWRELLA, Bory DE St, V. The body is more or less perfectly cylindrical, and curved either ventrally or dorsally. The claws are rather long and frequently seem united, and are curved ventrally, The eye is cervical and single. There is a sensory tube upon the upper (dorsal) part of the disc. Three species are described, although doubt ex- ists as to the specific value of one of these; they are D. tagrzs, Ehr., D. Rattulus, Eyferth, and D. sty/ata, Eyferth, to which a species is added below under the name D. insignis, The common species in America is DruRELLA TIGRIS, (Z/Ar.) Bory. The descriptions and figures of European authors vary remarkably in this instance, but from them all we are able to gather sufficient te 50 BULLETIN OF THE LABORATORIES — make it reasonably sure that our species is really D. ¢zgrvzs. It is quite variable in size and form. The cylindrical body is strongly curved ventrally. The head is distinctly set off from the body by a suture as represented by Eyferth but not by Eckstein. The sides of the neck extend into a sharp spine on either side, which, however, may be easily overlooked. There is a sensory cylinder which forms a third prominence upon the front. The foot consists of but a single evident segment which is quite short. The appendages assume a variety of appearances. Usually they seem to form a flattened triangular plate curved in the same plane asthe body. This appearance is figured by Eckstein, though he describes the appendages as consisting of two pairs, the outer half as long as the inner, both being united at the tips into one plate. Eyferth says, on the other hand, that the foot bears two unequal, bristle-like, curved claws, but his drawing shows two egual claws. Our experience confirms Eyferth’s account. Like Rattulus, this species moves in circles or arcs of circles when lashing its tail, but has the power of moving in a straight line by the use of the cilia alone. The maxtax is nearly as drawn by Eckstein. The chief organs are two anchor-like indurated processes which are unlike in length and form. The walls of the maxtax are furnished with ring-muscles. The stomach is glandular and its cells contain large globules of fatty matter. The intestine is pear-shaped and furnished with numer- ous cilia. The contracting vessel is large but the lateral vessels are not easily seen and I can add no details. |The single cervical eye is large and seatedon a large elongate ganglion. The ovary is small and the egg, when present, occupies the left side of the body on its ventral aspect. The total length is about.20 mm. of which the body forms .16mm. ‘The longer claw measures, in large specimens, .048 mm. and the shorter only .0o36 mm. Sometimes I fancied that I saw two lateral spines as described by Eckstein. |The width of the lorica is about .65 mm. ‘This species was encountered in Ohio and Minne- sota in all situations and seasons. DIURELLA INSIGNIS, sp. 7. (Plate LV Fig. 6.4 A larger species than the above is found in Minnesota. The length, exclusive of the claws, is from .17 to .20 mm. ‘The claws are .o6 mm. long, one being much longer than the other. There are spines in the cervical region similar to those described in in the above, OF DENISON UNIVERSITY. 51 The body is much more slender, while the viscera do not differ essen- tially from D. tugris. GENUS MONOCERCA, Enr. This genus includes elongated, nearly cylindrical or conical forms, having a single greatly elongated claw and more or fewer accessory spines on the last seg- ment of the foot, The maxtax is elongate, with unequal indurated ridges. The stomach is oval and the intestine cylindrical. The only specimens of this genus as yet seen resemble very closely M. rattus of Ehrenberg but are somewhat longer. The lorica is .30 mm. long while the claw is .22 mm. The foot consists of two seg- ments, both of which are very short, while the last carries four or more unequal spines. -The pulsating vessel is elongate oval but the details were not studied. ‘This rotifer it quite rare. GENUS DINOCHARIS, Enr. The lorica is cylindrical or prismatic, with a wide opening in front. The head is distinct and feebly ciliated. Theeyeiscervical. The foot is long, rigid, and three jointed. The claws are long and the foot bears, beside these, long spines anteriorly and behind. . The whole shell is densely covered with granula- tions or spinules. DinocHARIS PociLLtuM, hr. (?) (Plate "ME: . Hig. 1?) The most abundant form of this genus in America varies so greatly in both size and details of structure that one is tempted to identify it with the most frequent species of Europe in spite of variations from the descriptions of authors. The outline of the lorica is cup-shape and its symmetry is broken by two ridges near the posterior edge, pass- ing transversely. Itis 11-5 timesaslongas wide. The first segment of the foot is short and bears two long curved spines above. The middle joint is twice as long and nearly cylindrical. The third seg- ment is about as long as the first and bears two curved claws four times as long as the segment and also a short spine about as long as the segment. The whole body is about .24 mm_ long, including the claws, which measure .o8 mm. ‘The eye is large and is seated on an ovoid ganglion. The ovary is large and the nuclei are quite distinct. The egg is obliquely placed and nearly as long as the width of the lorica. Two curved elliptical glands lie in front of the stomach. The lateral ves- sels of the vascular system are large. | Encountered only in Minnesota. 52 BULLETIN OF THE LABORATORIES A somewhat larger form, also found in Minnesota, has more slender claws and seems to lack the spine on the last joint of the foot. The shape is otherwise the same. The cast-off shell of still a different form,in which there is an in- dication of segmentation near the anterior of the lorica, was once seen. GENUS SALPINA, Exp. Somewhat resembling Zzch/anzs, but having spines upon the front and posterior margins of the laterally compressed lorica. There is amedian area above, which is less perfectly indurated than the sides, giving rise to two ridges. The foot is short, three-jointed, and bears two lanceolate claws. The eye is single and the ciliation of the trochal disc rather strong. The maxtax is large and the digestive tract well differentiated. | Water-vascular system with two or three beaker-cells on either side. The egg is carried about with the parent after extrusion. SALPINA AFFINIS, sf. 7. (Plate II., Fig.4. ) This species is so allied to S. mzacronata, Ehr. that it is with some hesitation that a new name is proposed. While agreeing in most characters, it differs from that species in having the upper pair of anterior spines much longer than the lower and curved downward and in having the lower pair of posterior spines much longer than the single upper one and curved upward. .S. mucronata is said to measure but .15 to.16 mm., while our form is .22 to .24 mm. long and .Io mm. wide. Theanterior spines measure .045, length of claws, .06 mm. ‘The whole shell is granulated and there is a band in front, set off by a distinct line. There is a sensory tube which bears a bundle of cilia at its end, and which usually projects from between the two dorsal spines of the lorica. The eye islunate and seated on a very large, almost spherical ganglion. The maxtax is very large and opens into a slender cesophagus. The stomach is glandular and saccate. The very large egg is ventral. No careful study was made of the viscera. Minneapolis, May. The species of the genus, aside from those mentioned, are S. spinigera, Ehr., S. brevispina, Ehr., S. ventralis, Ehr., S. dccarinata, Ehr, S. vedunca, Ehr., S. dentatus, Duj., and S. polyodonta, Schm. There is reason to suppose that several of these are but varietal forms. OF DENISON UNIVERSITY. 53 GENUS MONOSTYLA, Eur. Shell depressed, oval ; head opening large, notched before and behind. The foot has two short basal segments and a long terminal one ending in a small spine, hence appearing as though bearing one long spine. The eye is single and situ- ated at the base of a large ganglion. The maxtax is large and quadrate. The viscera are simple. MONOSTYLA (QUADRIDENTATA, Zr. ?) Two species of Monostyla have been thus far encountered, one of which may be identical with JZ guadridentata of Ehrenberg. The body is bell-shaped or inverted pear-shaped, the oral margin being produced into two sickle-shaped spines turned outward, which are dis- tinct from the acute margins of the shell itself. The body is com- posed of two segments or apparent segments, the second being small and conical. The terminal joint of the foot is slender and elongate, bearing a thorn-like spine. The ganglionisverylarge. The maxtax is also large and opens into a sack-like alimentary canal not evidently subdivided. The shell in this species is ornamented with granules. Length of lorica, .15 mm., width, .11 mm., terminal caudal joint, with spine, .o8 mm. Found in June, in Minnesota. A second species is smaller, measuring from .11 to.12 mm., foot .04 to .o8 mm., width,.r1 mm. ‘The shell is smooth and the curved spines are absent. The following species are known :— Monostyla lunaris, Ehr., M. cornuta, Ehr., MM. closterocerca, Schm., WW. oophthalma, Schm., and AZ. macrognatha, Schm. GENUS DISTYLA, ECKSTEIN. Shell ovate conical, closed behind, except for the small opening admitting the foot. In front, the opening is wide and guarded on either side by projecting an- gles. The foot is one-jointed and bears two equal, divaricated spines. The shell may be smooth or ornamented with raised lines and serrations. ‘The eye is single and seated upon a considerable ganglion. Two species are described by Eckstein from Europe (D. géssensés and D. /udwigit) and two additional ones occur in America. DISTYLA MINNESOTENSIS, sf. 7. This is a large species, .25 mm. long, with a pear-shaped body of two segments, the first being .20 mm. long and of equal width. The second segment is .o5 mm. long and has an oval slit behind for the in- sertion of the foot and permitting its free lateral motion. The claws 54 BULLETIN OF THE LABORATORIES are .13 long and slender, the terminal third being attenuated. The ganglion is small and bears a single red eye. ‘The trochal disc is retracted by four powerful muscular bands. |The stomach is globular and glandular. The short segment of the foot is moved by pairs of evident muscles. This species was but once seen in July. DISTYLA OHIOENSIS, sp. 72. The lorica is .12 mm. long and its form is much as in the previous species. Width of lorica .084 mm., length of claws.oz28mm. The sides of the lorica project in front to form a tooth on either side of the head. The lorica is sculptured into regular areas upon the first seg- ment. There is a quadrate plate projecting over the base of the claws. ‘The latterare attenuated towardtheend. The details of struc- ture are not known. | GENUS SQUAMELLA, Exp. The three genera Sguamella, Metopidia,and Lepadella agree closely together, be- ing characterized by the presence of four, two, or no eyes respectively. The or- ganization is muchas in Euchlanis. The lorica consists of an oval, arching, scale- like shield above, anda flattened plate below. The foot consists of three short joints terminating in two acute claws The head terminates above in an oval scale- like appendage. They only species belonging to this group as yet seen was hastily identified with Sguamella bractea and, in absence of further informa- tion, we will simply give measurements in addition to the figure, in which, by the way, but one pair of eyes is represented, leaving us to infer that the animal is AZefopidia rather than Sguamella. Length .o8 mm.—.14 mm. Width (in the latter case) .12 mm. Found several times in Minnesota. GENUS STEPHANOPS, Eup. The lorica is depressed, and frequently extends into spines posteriorly. Head covered with a shield, which, when viewed from before or behind, is in shape like a halo. ‘There are two eyes, occupying the extreme sides of the head. The foot is three-jointed and ends in two lanceolate claws, between which springs an awl-shaped spine. STEPHANOPS MUTICUS, LAr. (Plate X, Lig. 9.) A specimen of this species was taken in July, 1885. The lorica is oblong oval, seeming two-jointed behind. There is a slight crest i OF DENISON UNIVERSITY. 55 above. Both segments extend dorsally into prominences which only appear when the animal is viewed from the side. The head is cov- ered by a thin semi-circular shield, which is slightly arched. The cilia of the disc are feeble, but the sensory tube is distinctly seen. The first joint of the foot is quadrate, the two following being of equal length but different diameter. The claws are ovate lanceolate and short. The accessory spine is awl-shaped and shorter than the claws. The length is about.10 mm. _ Eckstein gives very good and accurate figures of this species, his description of the viscera is also valuable. , The following species of this genus are known: 5S. damelleris, Ehr. with three spines behind. S. cirratus, Ehr. with two spines behind. S. longispinatus,Tat. S.ovalis,Schm. S. tridentatus, Fr. GENUS BRACHIONUS, Ear. A large genus containing curiously armed and ornamented species. The body is depressed, oval or quadrate in outline, presenting a very large anterior opening always guarded by spines or teeth. Behind, the shell may be rounded or armed with spines like those in front. There is only a small opening upon the ventral aspect through which extends the foot. The ventral surface of the body is gener- ally plane while the back is arched and may be set off into areas by elevated lines. The maxtax is prismatic and complicated. The egg is carried about attached to the body of the parent, asin Azwrea. The males are said not to be rare in this genus. BRACHIONUS BAKERI, hr. A single gathering taken in Granville, O., in September, contained a species belonging in the section of this genus characterized by the multiarticulate foot. Our species is sub-quadrate in outline and more or less expanded back of the middle. |The whole length, including spines, is from .30 to .40 mm. for adult females. The oral margin, above, is produced into six spines. The median pair are longest and curve decidedly outward and may be from .o5 to .o8 mm. long ; between them is an incision, through which ordinarily projects the sensory tube. The outer pair of spines are half as long and also curve outward. Mid- way between these pairs is a short spine or tooth. The ventral edge is notched in the middle, but not toothed. The width of the body is from .18 te.22 mm. ‘The posterior portion of the shell extends | into two pairs of spines, of which the outermost are very long (.10- .14 mm. ) and project directly backward or slightly outward or are uni- a formly curved. The inner pair of spines immediately border the 56 BULLETIN OF THE LABORATORIES opening for the exit of the foot and are curved plates. The foot, which can be almost wholly withdrawn within the lorica, is composed of a closely ringed basal portion terminated by a short rigid joint, bearing two conical claws and blunt processes. |The claws are perfora- ted by the ducts of large cement glands. The flexibility and extensi- bility of the foot are truly wonderful. The whole shell is covered above with fine granules, but is not otherwise marked. ‘The eye is large and is seated on the ventral side of a large ganglion. The max- tax is very wide and short. The manubrium is a curved plate and ‘the uncus consists of several fused plates (see drawing). I have seen the animal attempt to masticate a large diatom and, after failing to crush it, reject it by reversing the usual movement of the jaws. The pharynx is ciliated and funnel-form. |The cesophagus is not ciliated, but has ringed muscles which, when in motion, give the appearance of a valvular arrangement. The stomach and intestine are strongly curved upon each other, the former being glandular with fatty spheres in its walls, while the latter is furnished with a dense coating of cilia.’ The pulsating vessel is not large, but the lateral vessels with their beaker cells are quite conspicuous. This species, which agrees with Lr. Bakeri closely, is common in Ohio, (September). Another species, known only from a single gathering and imper- fectly studied, differs from all known species in having a single pair of spines before and behind and a foot which at the base is multiarticu- late, but ends in the two long segments, the last with two quite long claws. The shell is nearly smooth. ‘This species may be called Br. intermedius, as it partakes of the characters of both sections. BRACHIONUS MILITARIS, Zhr. ( Pilate, X) f1g. 104) It is interesting to compare with the above a related species which is quite common in the west and which belongs to that section of the genus characterized by the absence of the ringed basal arrangement of the foot. This form, which may not be properly Brachionus, resem- bles decidedly the above in the form of the body. The anterior mar- gin extends into ten teeth, of which the superior median are longest and curve ventrally. All the other anterior teeth are doubly curved, the points extending outward. The posterior part of the body bears two pairs of spines, the relative position (and size) of which is not constant. The outer pair are always longer and project outward and ee ee OF DENISON UNIVERSITY. 57 backward. The foot consists of three slender joints, the last of which bears two lanceolate appendages somewhat longer than the segment preceeding. The whole shell is covered with minute points. ©The trochal disc is broken up into five lobes and the cilia are of two sizes. The measurements of one specimen are given as illustrating the pro- portions. Length .20 mm. exclusive of foot, width .14 mm., termin- al stylets .024, lateral, posterior spines .o28 mm., anterior spines about .04mm.. From the side, the ventral surface (in outline) 1s seen to be plane while the dorsal is composed of two inclined planes (or is ‘“‘humped.”) The foot is moved by two pairs of muscles. The con- tracting vessel is unusually large. ‘The maxtax and the position of the viscera seem to be as in other species of Brachionus. The animal seems most to resemble 4. mz/itaris, Ehr. of the European species. ILCSOMUA\ WENTICULARE, )2¢72. 2 Sp. 1. (See figures facing Index.) The animal for which the above generie name is proposed, was several times seen in a gathering taken at the reservoir near Hebron, Ohio, in November. The general form is very similar to that of many minute bivalved crustacea ( Ciydorus), with which it was asso- ciated. ‘The lorica is composed of two ovate valves, which are par- tially united below, so that the foot springs from the middle of the ventral margin. The animal is laterally compressed. On the dor- sal aspect of the lorica are several distinct ridges arranged about as follows: A pair of short transverse markings occupy a point poste- rior to the middle of the dorsal aspect; anterior to these, and begin- ning at either end, spring diverging lines which lead to notches of the anterior margin; behind, two ridges lie on either side the median line and extend to the acute posterior end of the shell. Several lines border the above described markings on either side and are approxi- mately parallel to the axis of the body. Seen from the side, the lor- ica is elliptical and is truncate in front and acute behind. The dorsal line is a uniform curve, while the ventral is prominent near the middle at a point some distance in front of the point of union of the valves. Seen from above, the front half is quadrate, while the posterior half is triangular. The lorica is lenticular, considered as a whole, and is marked by minute hexagonal or irregular depressions. The head is armed with two long sensory organs and has two sorts of cilia. The outer series is quite feeble, but the ventral prominenc¢ 58 BULLETIN OF THE LABORATORIES bears several elongated sete. The maxtax is oval and seems to be but slightly armed. It is furnished, however, with distinct annular bands of muscles. The eye is cervical, and is seated on the under side of a considerable ganglion. The foot is multiarticulate at the base, as in Srachionus. Two distinct joints follow this portion, the last being longer and bearing two oval, appressed spines. Of the internal’ organs little was seen. The stomach is glandular and the egg of but moderate size. |The vascular system was not seen. Length, .24 mm., height, .15 mm., width, ,1o mm. _‘ Frontal pro- cesses, .03 mm., spines of foot, .o25 mm., last joint, .o2 mm. GENUS ANURAHA, Ear. Closely related to Moteus and Brachionus isa genus of curious rotifers in which the foot is entirely absent ,so far, at least, as can be seen. As in Brachio- nus, the anterior opening is protected by spines or teeth, while there may or may not be simtlar teeth behind. The lorica is usually distinctly separable imto a dorsal and ventral shield, and the dorsal scutum is marked off into geometrical figures by raised lines. There is a single cervicaleye. Tbe egg very generally remains attached to the body and may be mistaken for a part of it. ANURA SP. A species differing from all European forms is very common in the West. The form is hexagonal in outline, the length being 1.4 times the width (exclusive of spines). |The anterior margin of the hexagon is wider than the posterior. The dorsal scutum is produced into six long spiny teeth, of which the middle pair are much the longest and are strongly curved outwards and downwards. The remaining pairs are sub-equal and project outwards like the horns of an altar. The ventral part of the anterior margin is excavated in the middle and bears a series of small sharp teeth. The whole shell is ornamented with circular prominences, and, in addition to this, above there are strongly raised lines blocking off the shell into thirteen regular areas and leaving two other areas about the front. The character of these ridges is best seen from a side view. The eye is cervical and the trochal cilia are strong for the genus. There is also a sensory tube. The following measurements, owing to an accident, may not be accurate, but will give the proportions : Length, .1 mm,, width, .054 mm,, longest spine, ,o24 mm. OF DENISON UNIVERSITY. 59 GENUS PTERODINA, Emr. _ The lorica is flattened, round, or ovate in outline and flexible. Head funnel. shaped, entirely withdrawn into the body when at rest, furnished with two lines of cilia. Stomach ‘sac-like with large cilia. The foot is ventral and consists of a ringed basal portion and a short terminal joint which bears no claws. ‘The intes- tine is said to be continued through the tail having the anal opening at its end. The Pterodina is a good subject for use in obtaining a knowledge of the rotifers as the viscera are quite distinct, the cross striation of the muscles and the ciliated or beaker-cells of the lateral vessels being particularly distinct. PTERODINA PATINA, E/Ar. (Plate te, Hig. LLL.) The form is circular with a slight emargination in front for the withdrawal of the head. The head is funnel-shaped and bears a double disc having good sized cilia. When extended, the eyes are seen to occupy a position about one-third the width of the disc from its sides. ‘The pharynx is closely ciliated and leads into a comparatively large maxtax in which a partial fusion of parts has taken place. The _ stomach follows upon a very narrow oesophagus and is a curved sac composed of large cells, each of which is filled with granular contents and has fatty spheres within it. On either side the stomach isa strong muscle passing from the sides of the head to the posterior third of the body where it is fastened. | When the head is withdrawn the muscles are curved, but upon the protusion of the head become straight. On either side the stomach is a large glandular mass composed of numer- ous lobes made up of fused cells with large translucent flecks which may be globules of the secretion: These glands open back of the maxtax. | While the stomach is curved to one side, the intestine lies behind the tail and is curved upon itself, opening, as claimed by Eck- stein, into a canal excavated in the tail. It is indeed certain that the tail contains a canal and is ciliated at the distal extremity but we have never been able to verify the statement referred to.. The tail seems to be more slender in our specimens than figured by European writers, though it is exceedingly contractile. The contractile vessel seems to be absent but two very distinct lateral canals are to be seen. The breaker vessels are long and the cilia active. | The ovary occupies one slde of the body, while the egg nearly fills the other when mature. Large nuclei are discernible imbeded in a granular mass of yolk. The 60 BULLETIN OF THE LABORATORIES margin of the shell seems to be granulated and extends beyond the body-cavity. The tail often is directed at right angles to the body and is then overlooked. ‘The lorica is about .20 mm. in longest diameter. The tail measures over.o7 mm. The trochal disc, when expanded, is.o5 mm. wide. A smallspecimen, but fully adult was but.17 mm. long. Mr. Stokes mentions a species of this genus but does not iden- tify it. There are two other species, viz. P. eliptica and P. clypeata, Ehr., which latter occurs as a parasite on species of Assellus. I have a confused recollection of having seen such a rotifer parasitic upon Gammarus. Pterodina complanata of Gosse is almost certainly identical with Pt. patina. FAMILY ASPLANCHNAHA. This family includes abberant rotifers, which lack the posterior opening of the digestive organs and are considerably reduced in other respects. The foot is sometimes almost entirely absent, its position being marked in these cases by the glands simply. |The body is sac- like and often consists of a single segment in which the various inter- nal organs are very readily seen. The head is broad and sparsely ciated. The maxtax is enlarged and to it is appended an extensible crop, while the incus is not highly indurated and the mallei are modi- fied to form a prehensile pair of nippers or pliers. |The stomach may be very extensible and a part is very highly glandular. The water- vascular system is highly developed and there is generally an accessory canal bearing the minute beaker cells, while the lateral vessels them- selves are tortuous and elaborate. | Most of the species are carnivor- ous, while others live upon alge and like plants. GENUS ASPLANCHNAAA, GossE. The genus is characterized by the sac-like body and the large size and well differentiated organism as compared with Ascomorpha. The details mentioned under the family apply. ASPLANCHNA MAGNIFICUS Sf. 7. (Plate TL, Fig, 2.) This, the largest species of the genus, is most like A..AZyrmeleo, but is considerably larger and appears to differ from it in several other par- ticulars. |The general form is a prolate spheroid truncated anteriorly and slightly flattened ventrally. The oral end is furnished with six aie ) i | 4 OF DENISON UNIVERSITY. 61 discrete clumps of cilia and two sensory processes. The crop is large and distensible, the forceps are smooth and toothless. The cesophagus is long and muscular. The stomach is composed of very large cells and is held in place by bands of connective tissue. | There are accessory glands between the stomach and crop. ‘The ovary is _ pear-shaped (not horse-shoe-shaped, as in A. Myrmeleo),.and can be seen to be made up of an elongated nbband of ceils folded upon itself. The pulsating vessel is exceeding large and powerful, while the lateral vessels are convoluted canals ; accessory to the latter, there are nearly straight tubes bearing about twenty beaker-cells. The foot is two- jointed and contains small glands. The muscular spstem is highly developed and consists of strong bands passing backward from the head and frequently branching before they are inserted upon the very pliable external wall. Two pedate cells lie upon the viscera and may represent the visceral nervous system. The nervous system was oth- erwise found to consist of gangha upon the oral aspect, one of which bears a single red eye, and which send nerve-fibers to all parts of the body. The animal feeds upon species of minute crustacea, especially of the genus Chydorus. ‘The greatest length is .g mm,, width, .66 mm.. foot,.15 mm. This species was figured in the writer’s Final Report on the Crustacea of Minnesota, where also may be found the figure of ASPLANCHNA Sf? This species, which seems to resemble 4. Arightweli of Gosse, is purse-shaped, being constricted about the head. The jaws are bi- dentate at the end and ribbed. ‘The foot is entirely absent, but its position is indicated by the orifice of small glands. The stomach of the only individual of this species seen contained a number of the lorica of what may be Anurea longispina, Kellicott. EXPLANATION OF PLATES. Plate JT. Fig. 1. Dinacharts pocitlum, Ehr.? fig. 2. Asplanchna magnificus, sp. 1. Fig. 3. LEuchlanis ampuliformis, sp. n. fig. 4. Salpina affinis, sp. n. Plate. IIT. fig. Pterodina patina, Ehr. Lal . 62 Fig. fig. Fig. BULLETIN OF THE LABORATORIES | . 2. Luchlanis hipposideros, Gosse. Jt do portion of lateral vessel with beaker cell. 2 - 2. _Undetermined: 4 Amphileptus gigas, C. & L. Plate IV. I. Undetermined. 2. Sguamella bractea, Ebr. 3. Monostyla guadridentata, Ehr, (?). the drawing. fig. fig. Fig. fig. fig. Fig. fig. Fig. fig. 4. Lolyarthra platyptera, Ehy. 5. Undetermined. 6. Diéurella insignis, sp. n. Pilate KX. 5. Sperostomum teres. 6. Ophridium taradoxum., 7. Pe : a » H K SS) a ey | ees ai . SF \ Bulletin of Demmson Unversity Laboratories Vol.I. Bulletin of Demson Umversity Laboratories Vol.I. Plate IL. os Dy» = }} [] BQ tS Bas SSS SEES NG Bulletin of Denison Umversity Laboratories Vol.1. Plate IV. ee SI Rey Pt Byte ihn A nt gt il Ute RN an te ee i: - Lar RR ar tS Sw Eg UTE Raine ats CLH, ~ da ;. i | oe oi ees ein of Derison Universily Laboratories. Vol.1 oS EBD eaten Ancragceeaa ig i =e oe ee <2 > “aay X Oe ~ CP ant ate pt Silt sy ee A ie El ae a a. : . , Qe nes. 2 oh, “2. = i ‘ ns es » y Geek. Ang vol, /3, 1895. — ci hs y) 40 tS i . 1p , of the State of New York, p. 52, also in the Aquarium, Jan. 1894, | ' p.91, and again in the Fishing Gazette of May 31, 1894, with references. } in each case to the original. I am pleased to see that Mr. F. H. Herrick, in the Zoologischer Anzeiger, No. 454, Aug. 13, 1894, p. 29, confirms my observations on times, rates, and on variations along our coasts, etc., | even though he does not make it entirely clear why he should prefer J to give the impression that my work was first published in the Aqua- ‘ rium of January 1894. 3. Microcrustacea from New Mexico. By C. L. Herrick, Professor in Denison Univ. eingeg. 30. November 1894, The valley of the Rio Grande passes through a region which is # by nature almost a desert, although capable of great fertility under _ irrigation. Although the year is almost rainless there are a few weeks during which copious showers fill such natural Teservoirs as exist. In these pools there soon appear large numbers of Phyllopod Crustacea, |” Apus, Branchipus, Nebalia, etc. — a fauna sufficiently known through ° § the labors of Professor Packard and others. Among these types » which are characteristic of the western plains are a few species of the | * strictly Microcrustacea which deserve special study. These are chiefly members of the orders Copepoda, Cladocera and a few Ostracodes. ! Although one would expect a priori a rather limited representation of such types, there is no lack of individuals. The numbers of Moina | which appear in fresh rain pools is enormous, and curiously enough, we find M. rectirostris, M. brachiata and a third form either asso- ciated in the same pool or in adjacent waters. Moina and several species of Certodaphnia may rank with the Phyllopods as »occasiona- list« or desert crustacea. We were also surprised to find in the less transient pools numerous examples of the American Latonopsis ocei- dentalis Birge , which is closely allied with the Australian L. australis Sars. Simocephalus and Scapholeberis with Chydorus and a small Pleuroxis are not uncommon, but a single example of a new species of Daphnia almost completes the list of Cladocera so far encountered. The Cyclopidae are represented by C. tenuicornis Claus, C. bicolor, C. serrulatus and C. viridis americanus Marsh. No unique species occur, while the Calanidae and Harpacticidae are all new. With these introductory words I beg to pass to the description of a few forms which seem worthy of present notice though all will be illustrated in full in the forthcoming report to the state Zoologist of Minnesota upon the Microcrustacea of Minnesota. 41 Genus Marshia!, gen. nov. Allied with Attheyella. Inner branch of first foot 3-jointed, scar- cely elongated, barely sub-prehensile. Second and third feet with outer rami 2-jointed, short. Fourth foot with outer ramus l-jointed. Fifth feet l-jointed. Antennae 6-jointed, the fourth joint with a slender hyaline process longer than Antennae of the male Strongly modified. Fresh or brackish waters of — 4 the Rio Grande valley. Be Mar shia albuquerquensis n. sp. (Figures 1—11,) Body with ten obvious segments, having the aspect of Cantho-— Camptus. Antennae short, 6-jointed. The proximal joint enlarged Fig. 1, Fig. 2. Fig. 3. Fig. 4. ss SOS Se Fig. 5. Fig. 6. : a PES a f G —_*< Fig. 1. Caudal stylet of Marshia albuquerquensis, Q. Fig. 2. Antenna of fema e. Fig. 3. Antennule. Fig. 4. Feet of right and left sides of a female, the right foot anomalous, Fig. 5. Anterior foot-jaw. Fig. 6. Posterior foot-jaw. Fig. 7, Mandible. Fig. 8. Fifth foot of male. * In compliment to Professor C. Dwight Marsh of Ripon, Wisconsin. oA wey ae fr 42 and spinous; second joint also tumid, with three or more cilia; third joint longer; fourth with a long seta and a still longer flagellum; fifth joint very short; apical joint elongate, bearing about ten setae. An- tennules short, prehensile, with four geniculate setae apically and se- veral short spines, especially a transverse row of sharp teeth on the dorsal aspect. Mandibles with six sharp teeth. Anterior maxillipeds with a minute unisetose palpus and three processes bearing claw-like — spines. Posterior maxilliped with an apical claw longer than the pre- ceding segment. First foot with the outer ramus nearly as long as the inner, 2-jointed, bearing at the apex three pectinate setae. The basal Fig. 10, Fig. 11. t\ - AX a is ag t Fig. 9. Stylet of male. 4 N . Fig. 10. Fourth foot. ; Fig. 11. First foot. Nasi joint has one pectinate seta externally and a spine internally. The inner aspects of all the joints of both rami are spinous, the outer se- tose. The outer ramus of the second foot is two-jointed and has one pectinate seta apically, one spine internally and a spine externally, while the corresponding segment of the third foot has two pectinate setae apically, one internal seta and two external spines. The fourth foot has a minute one-jointed outer ramus which bears one long pectinate seta and a short external spine. The fifth foot seems en “ “i ‘ah 43 to consist of one piece which is armed as follows: Externally a coni- cal projection near the base with a long simple seta; outer apical lobe = the homologue of the second joint) with five setae, the second and fourth of which are pectinate and longer than the rest; the inner api- cal lobe bears six (sometimes only five) setae, all but the innermost being pectinate. The two lobes are separated by a simple rounded incision and repeated examination of a number of individuals failed to discover any signs of division or segmentation. The abdomen is very slender, and, like the thorax, its segments are all ornamented | along the caudal margin with a row of teeth. Caudal stylet two and ¢ St) 45 Diaptomus albuquerquensts 0. sp. (Figures 16—26.) | ss Species of moderate size. The cephalothorax is widest near the middle. The last two segments are fused and the last projects laterally where it is armed with two strong spines; there is also a dorsal pro- tuberance from the last segment. The first abdominal segment is Fig. 17. - Fig. 48. Fig. 20, - ” Fig. 21. fi , i Fig. 26 . Am | 4 ie) Ae Wy is : Fig. 25. Fig. 22. ig. 23. Fig. 24. ae y, Fig. 16. Diaptomus albuquerquensis, Fig. 21. Jaw. orsal view. Pig. 22. Maxilliped. Fig. 17. Lateral view of female. Fig. 23. First swimming foot. Fig. 18. Abdomen. Fig. 24. Fourth foot. _ Fig. 19. Fifth foot of female. Fig. 25. Male antenna. Fig. 20. Antennule. Fig. 26. Fifth feet of male. longer than the remainder and projects laterally into two strong spi- nes; second segment very short, invaginately concealed in the preced- ing. Caudal stylets short but nearly as long as the preceding segment; 46 ciliated on the mesial aspect, setae strongly pectinate.. Antennae ex tending to or beyond the end of the stylets, purple-tipped, 25-jointed The antepenult joint of the right male antenna with a curved hook The fifth foot of the female with very short inner ramus which is more or less distinctly two-jointed or simply attenuated beyond the middle, armed apically. with two or more spines and setae. External branc 3-jointed, third segment obvious and armed with one long and one shorter spine. Claw rather straight, armed for the middle third of its concave aspect with sharp teeth. The right fifth foot of the male has, on the outer ramus, a long sickle-shaped claw with few teeth or none,| it being nearly as long as the remainder of the leg. The penult joint is long and bears a long thick spine which is slightly curved and ma be dentate and is affixed at a point of the segment one fourth its lengt from the end. The basal joint of the outer ramus is very short and, like the next following has a lateral hyaline plate. The inner ramus is very short and 1-jointed. The second protopodite segment of th left foot is nearly as long as that of the right, the inner ramus i 1-jointed and simply ciliate at the end. The apical segment of the outer ramus is acute and bears a short, ciliated, conical process and a minute spine apically as well as a ciliated internal lamina. The preceding joint also has such a lamina or a patch of short ql upon a protuberance. | Color pellucid, with purple upon the tips of the antennae and caudal stylets. : Length of female, 1-4—1-6 mm. Waters about Albuquerque New Mexico very abundant. Diaptomus novomexicanus D. sp. (Figures 27—29.) A species of moderate size, rather robust, with the greatest widelt of the thorax near the middle. Last two thoracic segments distinct) the last with two small spines. First abdominal segment very long, much exceeding the remainder. Second segment short. Stylets about as long as the preceding abdominal segment. Antennae reflexed reach to the base or end of the stylets, 25-jointed. Antepenult segment of right male antenna with a hyaline lamina which does not extend the entire length of the joint and ends in a rather short scar4 cely hooked process distad. The outer ramus of the fifth feet is ob4 viously three-jointed, the apical joint being small and armed with twa tz 4 7" | ‘. ? a. oe ra Be Sh mi 47 the apex with two subequal spines. The inner rami of the fifth feet of the male are both 1-jointed, acute and minutely ciliated. The apical claw of the right foot is long and slightly curved. The acces- sory spine is weak and inserted one-third the length of the second Fig. 27. Fig. 28. — ‘Big. 29. Fig. 27. Diaptomus novomexicanus. End of right male antenna Fig. 28. Fifth feet of male. Fig. 29. Fifth foot of female. joint from its end. The apical joint of the outer ramus of the left foot is armed with a cushion of short spines and two longer ones and also bears a ciliated lamina internally. Length of female, 1-1— 1-2 mm. Il. Mittheilungen aus Museen, Instituten etc. Zoological Society of London. 15th January, 1895. — The Secretary read a report on the additions © that had been made to the Society’s Menagerie during the month of Decem- ber 1894, and called attention to two Tapirs recently deposited in the So- ciety’s Gardens, which he believed to be referable to Dow’s Tapir (Tapirus Dowt) of Central America. — Mr. P. Chalmers Mitchell, F.Z.S., exhibited and gave an account of a tibia and other bones of an extinct bird of the ge- nus depyornis from Central Madagascar, which had been lent to him for exhibition by Mr. Joseph H. Fenn. With these bones was associated a skull of a species of Hippopotamus. — Prof. G. B. Howes, F.Z.S., exhi- bited and made remarks on the photograph of an embryo of Ormthorhynchus. — The Secretary exhibited, on behalf of Mr. R. Lydekker, a life-sized drawing of Idiurus Zenkeri, a new and remarkably small form of Flying Squirrel from West Africa, recently described at Berlin. — Lord Lilford, F.Z.S., sent fort exhibition the skin of a Duck, believed to be a hybrid be- tween the Mallard (Anas boschas) and the Teal (Querquedula crecca), that had been caught in a decoy in Northamptonshire. — The Rev. T. R. R.Stebb-