JONATHAN: DWIGHT hhc ; : / . \\ USS>~ SMITHSONIAN INSTITUTION c NOS UNITED STATES NATIONAL MUSEUM —— 03 hee oe PROCEEDINGS OF THE UNITED STATES NATIONAL MUSEUM, VOLUME 53 WASHINGTON GOVERNMENT PRINTING OFFICE 1917 ADVERTISEMENT. The scientific publications of the National Museum consist of two series—Proceedings and Bulletins. The Proceedings, the first volume of which was issued in 1878, are intended primarily as a medium for the publication of original papers based on the collections of the National Museum, setting forth newly acquired facts in biology, anthropology, and geology derived there- from, or containing descriptions of new forms and revisions of lim- ited groups. LEULNETOGACLYLILS MLCOTO Ieee eRe ee eC eee e eee eee 261 Fras. 8-12. Jeleutherodactylus curieatitss 02.64. Se ee ee 262 igs. 13-17, -Lleutherodactylus dimidiatussccc< 5220 ee eee 262 Hugs. 18-22. .2leutherodactylus varians .:2 2025250 a ee 263 Bas. 23-26. Hyla-sepbentrionalisa <<< 0.tc2t2% nt. csecs fotoe edeae oe eosee eens 263 Bras.'27=29. . Tarentola cubanassss aoe Wa ae ae ee eee 266 Fies. 30-33. Sphaerodactylus cinereus. Lepidosis of middle of back..-.......-.- 267 Fias. 35-36. Chamaeleolis chamaeleonides. 37 represents the side of the tail at about the fifth verticil; 38, the lepidosis of the side of back..............-- 267 Fras. 39-40. Deiropteryx vermiculata. 41, side of tail of same at about the fifth WEFLICH wes ocencevscact set srt Ghee Pos Sea ee ce ee eee 268 Fies. 42-43. Anolis equestris. 44 represents the side of tail at about the fifth verticil; 45, part of dorsal crest and lepidosis........-......---------------- 268 Fias. 46-47. Anolis homolechis. 48 represents side of tail at about the fifth WEL CU osc seenc ussic cove nsuiy acs cc saecehe cade teeessstateeeee ee aoe eee 269 Fies. 49-50. Anolis argenteolus. 51 represents the lepidosis of the side of the tail. at about the fifth: vertacilt 225s feeb tee soe mee ee seen aac 270 Fies. 52-53. Anolis sagrei. 54 represents side of tail at about the fifth verticil. 271 Fies. 55-56. Anolis porcatus. 57 represents side of tailat about the fifth verticil. 272 Fies. 58-59. Norops ophiolepis. 60 represents side of tail at about the fifth ver- MACH. wc avaetec Sarees decinde sda sade ce os sad eee eee ee net oe oa Seen 213 Fia. 61. Leiocephalus carinatus. 62 represents a head length of scales on the middie of, back of the same individual :.:222202.. Use s- 42 - se os ee eee 273 Fras. 63-64. Leiocephalus cubensis. 65 represents a head length of scales on the mirtddleof. back of .same individual.s.4:sssi2saste eer see ee eee 2 ane 274 Fie. 66. Leiocephalus macropus. 67 represents a head length of scales on mid- ale of back. of-sameindividualt..-...222 ses eee eee oe een 275 Bias. 68-70) Celestusvdelatwagnaes22). 25.8. See SE ee ee ne eels 275 Frias. 71-75. Ameiva auberi. 76, throat of another specimen................- 276 IGS: 77-60; | Cadea-bDlanoides ¢ 25.9 ee ee eee sche ae 277 LIST OF ILLUSTRATIONS. xI HELGA EB L-842) AMPNIIOGENG CUBGNE (0 <6 <5 oc conic woken cccecevesdececccesvcccee 278 Fias. 85-86. Epicrates angulifer. 87, same species..........-...-...------... 278 Fias. 88-90. Tropidophis pardalis. 91-92, same species; 90 represents the color pattern and shape of tail viewed from the side; 91 shows the color pattern across the middle of the body; 92 shows the cross section of the body at Bes EpEECRENCEMeet este 7 oes Soe eee Ce Dae fe) RS Tee eae he 8 280 Figs. 93-95. Tropidophis semicinctus. 96-97 represent color pattern and section through middle of body of same specimen..................--.--... 281 Fias. 98-101. Tretanorhinus variabilis. 101 shows the color pattern at about eM enan une WOM VCR 20st auto ene sts kat ne ere Ae ae 282 ste) 2 Lt ANG RIS AngUlape? s2.J5.46 Pe one c Sueded ote a.c. ccs 282 Bis. lO5—107- “Levmadophis andrege...<- 2... <2. once coe cnc ccc eles 284 Fries. 108-111. Arrhyton taeniatum. 108 represents color pattern at about the middle of the body. 112-115, same species. 112 represents color pattern eieano rented lev Od yarns sete ek ee en es ee 287 SPEER OMHADOC see esate vere oe ers ee EEN to ee 8 ee ae 288 oo Delncmuno same THGIVIO UAL. 2... ta ne eee bee ee 289 Fie. 123. Crocodylus rhombifer. Represents anterior portion of dorsal scuta.. 290 Hires 24-125. “Peeudemye palustris... 9.0.02. 02.0.0) ..00 2020 290 acs 9126-128, Pseudemys paliatris.. 00.2220. s.2.6es0e0-ledecec cle dl 291 Fies. 1-11.—1. Dorsal view of skull of Desmognathus fusca 3 X nat. size. A, Atlas; ExO, Exoccipital bone (the occipito-petrosal of Wiedersheim); F, Frontal bone; M, Maxillary bone; NA, Nares; NV, Nasal bone; P, Parietal bone; P if, Premaxillary bone; P MF, Premaxillary fontanelle; Q, Quadrate bone; Sg, Squamosal bone. 2. Ventral view of same, 3 X nat. size (teeth somewhat diagrammatic); Os, Orbitosphenoid bone; PaS, Parasphenoid bone; St, Stapes; V, Vomer; other letters as before. 3. Lateral view of same, 3 X nat. size; lettersas before. 4. A section of the skull of Desmognathus quadramaculata taken just anterior to the internal nares, 3.5 X nat. size. f, Frontal; m, Maxillary; n, Nasal; na, Nasal passage, which is indicated by shading; p, Pre-maxillary; 2, Vomero-palatine. 5. Dorsal view of a female Leurognathus marmorata, 3.2 X< nat. size. 6. Ventral view of same, 3.2 X nat. size. The internal nares are blackened, and the position of the * actual choanae in the entire head is indicated by a ring of dots. 7. Lateral view of same, 3.2 X nat. size. 8. A section of the skull of the same taken just anterior to the internal nares, 3.5 X nat. size. Letters as in fig. 4. 9. Dor- sal view of skull of Spelerpes ruber, 3 X nat. size. Od, Odontoid process of atlas; P¥’, Prefrontal bone; other lettersas before. 10. Ventral view of same, 3 X nat. size. Letters as before. (Teeth somewhat diagrammatic.) 11. Lateral view of same, 3 X nat. size. Letters as before.................... 396 Range of Desmognathus quadrimaculata. . . 2... 2.020022 cececececee cece eee... 402 Ranges of 1, Desmognathus fusca Jusca; 2, D.f. auriculata; 3, Leurognathus mar- BTML eter at ct ate Ue ole fate yey Serer ey ee Peta SA cy ay, fapnior a erator terra eases te cise Renee Ie ae 405 Ranges of Desmognathus brimleyorum; 2, D. Jusca auriculatc; 3, D. fusca fusca; tine ‘a é they tales NORTH AMERICAN PARASITIC COPEPODS BELONGING TO THE LERNAEIDAE WITH A REVISION OF THE ENTIRE FAMILY. By Crartes Brancir Wiison, Department of Biology, State Normal School, Westfield, Afassachusetts. INTRODUCTION. The present is the thirteenth? paper in the series dealing with the parasitic copepods in the collection of the United States National Museum, and comprises the family of the Lernaeidae. This is the oldest family of the parasitic copepods and includes some of the most eccentric and bizarre forms. The genera compos- ing the family have often been wrongly interpreted, and _ their systematic position and arrangement have been mere conjectures. This was largely because they were imperfectly understood and nothing was known of the male sex or of the life history. The development of Pennella consists of a broken series of larval forms described by different authors—Steenstrup and Liitken (1861), Lubbock (1860), Wierzejski (1877), Brady (1883), Liitken (1893), and M. T. Thompson (1905). The development of Lernacocera (Lernaea) was worked out in admirable shape by Pedaschenko in 1898 and by A. Scott in 1901. That of Sarcotretes was published by Jungersen in 1911, and the life history of Lernaea (Lernaeoccra) has just been completed by the present author. We thus have now a life history for each of the four subfamilies. These have all been included in a condensed form 1The 12 preceding papers, all of which were published in the Proceedings of the United States National Museum, are: 1. The Argulidae, vol. 25, pp. 6385-742, pls. S-27, 2. Descriptions of Argulidie, vol. 27, pp. 627-655, 38 text figures. 3. The Catiginae, vol. 28, pp. 479-672, pls. 5-29. +4. The Trebinae and Euryphorinae, vol. 31, pp. 669- 720, pls. 15-20. 5. Additional Notes on the Argulidae, vol. 32, pp. 411-424, pls. 29-32. 6. The Pandarinae and Cecropinae, vol. 33. pp. 323-490, pls. 17-43. 7. New Species of Caliginae, vol. 33, pp. 593-627, pls. 49-56. 8. I’arasitic Copepods from the Il'acifie Coast, vol. 35, pp. 431-481, pls. G6-S3. 9. Development of Achtheres ambloplitis Kellicott, vol. 39, pp. 189-226, pls. 29-36. 10. The Ergasilidae, vol. 39, pp. 263-400, pls. 41-60. 11. Descriptions of New Genera and Species, vol. 39, pp. 625-634, pls. 65-68. 12. The Lernacopodidae, vol. 47, pp. 565-729, pls. 25-56. PROCEEDINGS U. S. NATIONAL MUSEUM, VOL. 53-2194, 77403—Proc.N.M.vol.53—17——1 ] 2 PROCEEDINGS OF THE NATIONAL MUSEUM. VOL. 53- in the present paper, because of the opportunity thus afforded for comparison and inference. A. Scott (1901) and Sir William Turner (1905) are the only authors who have verified the internal anatomy of the species they described by means of sections; the others have relied entirely upon what could be seen through the body walls. Scott described Ler- naeocera branchialis, while Turner portrayed Pennella balaenopterae, representatives of two of the four subfamilies. In the preparation of the present paper various species of the genera Lernaea, Ler- naeenicus, Peniculus, and Collipravus have been studied by means of serial sections, thus supplementing and completing the work of Scott and Turner. Tt was further found after trial with various reagents that if specimens were properly dehydrated in absolute alcohol and entirely cleared in clove oil, they became so transparent that the internal anatomy in all its details was clearly visible without sectioning. Nearly every species described in the present paper has been treated in this manner, and the internal specific and generic characters have been thus determined. Hence the systematization here proposed is the result of a careful study of the life history and of both external and internal mor- phology, and is substantiated by serial sections. Much of the work was done at the laboratory of the Bureau of Fisheries at Fairport, Iowa, during the summers of 1914, 1915, and 1916. That portion of the work which concerned the genus Lernaea, which is parasitic upon fresh-water fishes, and the material for which was collected at Fairport, has already been reported to the United States Bureau of Fisheries. The remainder of the work is incor- porated in the present paper, and as here constituted the family Lernaeidae includes 17 genera, three of which—Cardiodectes, Colli- pravus, and 7rifur—are new to science, and 80 species, of which 15 are new. There are seven generic names which have been intro- duced into this family, each of which is composed of the name Lernaea or the corresponding adjective Zernaios and some other word. Two of these compound names, Lernacopoda and Lernaeomy- zon, belong in the family Lernaeopodidae; two others, Lernaeonema and Lernaeopenna, are synonyms; the remaining three, Lernaeenicus, Lernaeocera, and Lernaeolophus, are still valid genera in the present family. In the author’s opinion, the first part of all these names should be spelled alike, since each represents the same word which was in existence and whose spelling had been determined long before any of the compounds were formed. = ee no. 2194. NORTH AMERICAN PARASITIC COPEPODS—WILSON. b HISTORY, Early literature and natural history.—Most of the genera and spe- cies belonging to this family are buried in the flesh of their host, with the posterior portion of the body and the egg tubes hanging free in the surrounding water so as to be readily seen when the fish are handled. Many of the species also are of exceptionally large size, reaching 4 and sometimes even 6 inches in length. Such remark- able size and prominence called them to the attention of fishermen at a very early date, and we find mention of these parasites in several! of the classical writers, the stories about them doubtless being de- rived from the fishermen. Aristotle, Pliny, Oppianus, and Athenaeus all described the suffer- ings of the tunny and swordfish in the Mediterranean in consequence of the irritation caused by these pests. Two of the early natural histories, Aquatilium Animalium Historiae by Salviani (1554, p. 126) and Libri de piscibus marinis by Rondelet (1554, p. 249), répeated these accounts, and the latter author gave a figure of a tunny with one of the copepods fastened near the pectoral fin. Conrad Gesner, in his Historia Animalium—De Aquatilibus (1560, p. 112), gave a more extended account of the parasite, described its structure and appearance, and presented an enlarged figure of it, besides repeating the figure given by Rondelet. But his description and figure resemble a Lernaeopod far more than they do a Lernaean. Boccone, in his - Recherches et Observations naturelles (1671, p. 284), tells us that the fishermen on the coast of Messina knew of another parasite which they called “ Sanguisuca,” and which buried itself in the flesh of the swordfish; and he adds with reference toit . . . “This sang- sue appears to be tormented by a louse which I have never seen on any other animal. It is of the size of a pea and attaches itself firmly to the animal” (p. 292). Boccone considered his species the same as that of Gesner, but the figures he gave proved it to be a Pennella, while the “louse” on it was doubtless a goose barnacie similar to those shown in figure 147. Lernaea and Lernaeocera—Linnaeus obtained from a European carp, to which he gave the name “ Cyprinus carassius,” a parasite upon which he established the genus Zernea in 1746, calling the species simply “ Lernea tentaculis quatuor.” In the following year he described another species, from the gills of a Gadus, under the designation “ ZLernea cauda duplici tereti.”* In the tenth edition of his Systema Naturae (1758, p. 655) he designated the first of these species as Lernea cyprinacea, the second one as ZL. asellina, and he transferred to this genus Lernaea a third species, salmonea, which 1Fauna Suecica, p. 367, fig. 1282. 2Iter Westrogotha, 1747, p. 171, pl. 3, fig. 4, a and Db. 4 PROCEEDINGS OF THE NATIONAL MUSEUM. VOL. 53. had been described by Gissler under the name Pediculus salmonis,* arranging the three species in the order named. Accordingly the species cypinacea, upon which the genus was originally founded, and which stands first in this tenth edition, be- comes the oldest species in the family. It was the ostensible genus type for nearly a century, and it may well be restored to that posi- tion. ' The second species, asellina, is a typical Chondracanthid, while the third, salmonea, is as typical a Lernaeopod, so that neither of them can be even retained in the family. In the twelfth edition another new species, branchialis, was added to the genus and was placed first, but the gentis diagnosis remained unchanged. For many years every newly discovered parasite, whatever its structure might be, was referred to the genus Lernaca, which thus came to include a large number of heterogeneous species. Many of these have since been established as distinct genera. The first to be thus established was the species branchialis, which was made the type of a genus called “Zerneocera” by Blainville in 1822 (p. 376). Blainville included in his genus, besides the species branchialis, Miiller’s Lernaea cyclopterina, a new species which he named sur- ripaiis, and unfortunately Linnaeus’s Lernaea cyprinacea. Ti he had only omitted this last species, which of course he had not the slightest excuse for including, since it was Linnaeus’s type species, the two genera would never have been exchanged, but, as it was, his mistake was copied by Desmarest (1825), Nordmann (1832), Bur- meister (1833), Krg¢yer (1837), and Milne Edwards (1840). The latter explained that Nordmann, Burmeister, and Krgyer had re- stricted Blainville’s generic name to such species as had soft sym- metric horns on the head and straight multiseriate egg strings, and he adopted their restriction. Blainville, however, distinctly stated in his genus diagnosis that Lernacocera had three immovable and branched chitin horns, two lateral and one dorsal (p. 375). And under the type species he said, “The egg sacks arise from just in front of the posterior extremity of the body and are much twisted or coiled” (p. 316). Furthermore, he stated plainly that he had never seen the species cyprinacea, but only the figure published by Linnaeus, which did not show the egg sacks. Tn other words, the authors above quoted deliberately exchanged the two genus names to suit their own fancy, took away from Lin- naeus’s genus Lernaca the species which had served as its type for 90 years, and substituted for it the species which Blainville had made the type of his genus Zernaeocera, and forced upon Blainville, as a ‘ Kongl. Svensk. Vetensk. Acad. Dlandlingar, 1751, vol. 12, p. 185, pl. 6, figs. 1 to 5. a ae weet eS a eI ee vw Coe ee ee aa ee » —s Te no. 2194. NORTII AMERICAN PARASITIC COPEPODS—WILSON. D substitute type, a species which did not agree with his genus diag- nosis and which he had never seen. In such a dilemma only one course is possible, and that is to re- store the two genera to their proper places, in spite of the great incon- venience which will result, and this has been done. The author sin- cerely regrets the necessity for such a change, especially when the genera are so widely known and so often quoted, but the evidence is so convincing as to leave no choice in the matter, and both Linnzus and Blainville have claims for justice which far outweigh any tem- porary embarrassment. Location of the Lernacans.—The early Lernaeans were so eccentric and apparently lacked so many of the usual crustacean appendages that Linnaeus did not suspect them of being crustacea, and placed them amongst the worms, characterizing them by the softness of their body and the absence of a shell. Hans Strém in the first part of his Physisk og Oeconomisk Beskrivelse (1762, p. 167), under the head- ing of insects, described both sexes of “ Lernaca salmonis” and the females of “ Z. uncinata.” On page 209 he described Lernaea corpore tereti flecuosa, which Linneus afterward identified as L. branchialis and placed with his other species among the worms. O. I. Miller, in Zoologiae Danicae Prodromus (1776, p. 226), gave 11 species of Lernaea; Fabricius, in Fauna Groenlandica (1780, p- 336), gave 7 species; Hermann (1783), Schrank (1786), Lamarti- niere (1787), Brugitres (1792), and Holten (1802) all added species of Lernaca and all adopted Linnaeus’s system of classification. Cu- vier, in his Tableau elementaire (1798, p. 389), placed the Lernaeans under “ Mollusques gasteropods” in the division of those having free motion in water. Lamarck, in his Systéme des Animaux sans vertébres (1801), also placed them under the mollusks but under “ Mollusques cephales.” Bose published an Histoire Naturelle des Crustacés in 1802, but although he gave an excellent historical summary and a good account to date of Caligus, Argulus, Cecrops, Dichelestium, etc., he included none of the Lernaeans, which was equivalent to saying that he did not consider them as crustaceans. In an Historia Vermium (n. d.) published shortly afterwards he described (p. 51) 15 Lernaean species, placing them among the mollusks, but stating that they approached the intestinal worms. Lamarck, dissatisfied with his first attempt, removed the Lernaeans from the mollusks in his Philosophie Zo- clogie, 1809, and placed them among the annelids. Three years later, in Extrait du Cours de Zoologie and again in Histoire Naturelle des Animaux sans Vertébres (1816), he showed the need of forming a separate class to receive these animals, which he named “ Epizoaires,” and which, he said, “ may properly fill up the great veid which exists between insects and worms.” 6 PROCEEDINGS OF THE NATIONAL MUSEUM. VOL. 53. In 1815-16 Oken published a Lehrbuch Naturgeschichte, in which he placed the Lernaeans as the third family in the order of * Erdleche oder Geschlechtsleche,” and in this family were included all the parasitic copepods then known (p. 181). Later, in the same book (p. 857), he revised his classification, which contained many errors and called the group “Armwurmer,” dividing it into two tribes, the Lernaeans containing four genera, Awine, Clavella, Pen- nella, and Lernaea, and the Argulids, containing also four genera, Anops, Dichelestium, Caligus, and Argulus. Thus was shown for the first time the relations between the Lernaeans and the other copepod parasites. In 1817 Cuvier, in his Regne Animal, adopted the view taken by Bosc, placing the Lernaeans among the intestinal worms, while he located the other parasitic copepods among the crustacea. Soon afterwards Surriray made the important discovery that the long filaments suspended from the body of these animals contained eggs and that the young when hatched bore no resemblance to the adults, but were very similar to the young of Cyclops—that is, they were crustaceans and not worms. Blainville, in his Mémoire sur les Lernées (1822), admitted the truth of Surriray’s statement and fully established the Lernaeans among the crustacea, where they have remained ever since. ECOLOGY. Sexual dimorphism —The females of the Lernaeidae are fixed parasites, and consequently there is a complete loss of the power of locomotion, although the swimming legs are usually retained, and there is great diversity in the means of prehension. Since the male does not finally become a fixed parasite, but remains upon his first host or swims about freely until his death, there is not the sexual dimorphism which was seen in the Lernaeopodidae. Indeed, it can not be said that there is any real dimorphism at all, because so long as the two sexes remain together and during the period of sexual union they are of the same size, and it is only after the female has become a fixed parasite for the second time and the male has perished, that the former increases enormously and becomes misshapen. The body. of the female is always a little longer than that of the male, and just before as well as for some time after fertilization the genital segment increases greatly in length, but remains of the same width, thus giving the female larva an exceptionally elongated form. A considerable portion of this increase takes place during the sec- ond free-swimming period, so that by the close of this period there is 2 marked difference in the length of the fused genital segment and abdomen between the female and such males as still survive; but in other respects the two sexes are alike. . xo. 2194. NORTH AMERICAN PARASITIC COPEPODS—WILSON. 21 naeenicus, end Lernaca,; and in Peroderma it is conical. Further- more, in this latter genus the head and neck are attached at right angles to the trunk, while in other genera the head alone stands at an angle with the neck. In Pennella the anterior surface and often the entire cephalothorax is covered with small globular or irregular processes which help to anchor the parasite firmly in position. In Peroderma and Car- diodectes branched processes are developed from ihe front of the head alone, while in Phrizocephalus these anterior processes take the form of small lobed and chitinous horns. Again in most of the genera processes, flattened dorso-ventrally, are sent out from the lateral and sometimes from the dorsal margins of the head and anterior thorax segment. These afterwards develop into horns, which complete the anchorage of the parasite to its host. There are no horns on Peniculus, aemobaphes, Cardiodectes, or Peroderma, the anchorage being accomplished by the strong claws on the second antennae, by the frontal processes, or by a flexure of the neck. In Lernaeocera and Lernaeolophus the horns are well developed and often branched dichotomously; in the other genera they are nearly always simple. These horns are outgrowths of the epidermal tissues and at first are short and wide and soft in texture; subsequently they elongate, become more or less cylindrical, and are gradualiy hardened into chitin. Too much systematic value must not be given either to the number or the arrangement of the horns in any genus or species, although a certain number and arrangement may be typical in each species; for example, the five radiating horns in Lernacenicus radiatus. But there is always so much variation that no dependence can be placed upon negative evidence; positive evidence is more conclusive. No specimen of any other species has thus far been found which possesses five horns radiately arranged, but there are many specimens of Lernacenicus radiatus which do not show them. The number and arrangement of the horns depend more upon the difficulties enecoun- tered by the parasite in attaching itself to its host, and upon the kind of configuration of the tissue of the host surrounding the point of attachment, than upon any specific inheritance in the parasite itself. When the head of Z. radiatus is buried in the muscles of the menhaden there is no trouble in developing five radiating horns, but the result is very different when the head is wedged between two of the bony plates of the operculum. The horns, therefore, must be given an insignificant place in the determination of the species, and it would be extremely rash to establish a new genus simply upon the possession of two extra horns, as Fowler has done. 22 PROCEEDINGS OF THE NATIONAL MUSEUM. vou. 53. The neck or free thorax is usually cylindrical and much narrower than the other two regions; it is sometimes straight (Lernaeenicus and Lernaea) and sometimes flexed (Lernaeolophus and Haemoba- phes). In Peniculus it is short and flattened dorsoventrally, while in some species of Pennella it is 100 mm. or more in length. Its length is largely determined by the thickness of the skin and underlying tissue that must be penetrated in order to bring the mouth of the parasite into close contact with some large blood vessel. Even the same species will have a longer neck on a thick-skinned and thick- muscled fish like the sunfish and a shorter neck on a thinner-skinned and thinner-muscled fish like the swordfish. The neck often becomes hardened into chitin like the horns and is always much firmer in texture than the following region, especially at the point where it emerges from the skin of the host. | Usually it is not segmented, the moniliform appearance of such species as Lernaeenicus sprattae being something very distinct from segmentation. In Lernaea the neck and body are the same width where they come together, and the point of union is indistinguishable; but the segments ure indicated by the attachment of the swimming legs. From these it can readily be seen that all the thorax segments have shared in the elongation of the body. In Pentculus the neck is very much narrower than the body, where the two come together, and is distinctly segmented, with a pair of legs attached to each segment. These show us that while all the thorax segments share in the elonga- tion of the body the size of the shares increases rapidly from in irent backwards. In Lernaeocera and Pennella the swimming legs are found at the anterior end of the neck, packed together as closely as possible just behind the head. This may possibly be a real migration in some of the genera—that is, the legs may have moved from the segment where they originally appeared onto preceding segments, as happens io the maxillipeds in the Lernaeopodidae. But the lengthening of the genital segment during the second free-swimming larval period indicates that the anterior thorax segments contribute very little to ihe neck and that the great bulk of the latter is made up of the ante- rior end of the fused fifth and genital segments. The swollen trunk is made up of the fifth and genital segments and the abdomen, and is much softer in texture than the preceding regions. It is usually greatly elongated as well as swollen, but is rarely short and stout. In Zernaeocera and its close relatives it is also convoluted or bent in the form of the letter S. The abdomen is the portion behind the attachment of the egg strings, it is always ae Se A) no. 2194. NORTH AMERICAN PARASITIC COPEHPODS—WILSON. 23 narrower than the genital segment, and is often reduced to a mere knob. To this abdomen are attached various kinds of appendages in some of the genera. In Pennella and Pegesimallus there are very long rows of branched barbules, from which the former and better known genus derives its name. In Lernacolophus there are similar appendages massed together closely, so that they bear more resem- blance to a yarn mop than to the barbules of a feather. In Waemo- baphes and Haemobaphoides there are two or three large knobs or processes along either side. In the other genera the abdomen is with- out appendages. The egg strings vary greatly in the different genera, not only in their general makeup, but also in the arrangement of the eggs in- side the string. In the Lernaeinae the cases are sacklike and the eggs are multiseriate; in all the other genera the cases are thread- like and the eggs are uniseriate. The multiseriate egg strings are shorter than the body and straight, while the uniseriate egg strings are often many times the length of the body, and are either cylin- drical and straight, or coiled into a loose snarl, or flattened laterally and curled into a tight spiral. The appendages.—These are the same as those of the Lernaeopo- didae, namely, two pairs of antennae, a pair of mandibles, two pairs of maxillae, a pair of maxillipeds, and four or five pairs of swim- ming legs. These are all present in the sexually ripe male, but some of them are usually wanting in the female. The first or anterior antennae are simple jointed cylinders, well armed with short setae, and are evidently tactile sense organs. The second or posterior antennae are also simple jointed cylinders, short, stout, and strongly chelate. They serve as the principal organs of prehension during the larval stages and often maintain that func- tion in the matured female (Peniculus, etc.). The proboscis is made up of a fusion of the upper and under lips, often combined with a considerable portion of the ventral sur- face of the head. In this latter form it is very extensile and may be protruded a considerable distance from the head and moved about freely, the movements being controlled by numerous powerful muscles. When strongly retracted, as sometimes happens during preservation, it is drawn in so far as to produce a saucer-shaped or bowl-shaped depression of the ventral surface of the head. When protracted the maxillae are carried along with it and are then found near the tip of the proboscis, a considerable distance from the ventral surface of the head. In those genera (Lernaeolophus) where the ventral surface of the head is chitinized and takes no part in the movements of the mouth tube. the latter is alwavs withdrawn in preservation ~~ 24 PROCEEDINGS OF TIE NATIONAL MUSEUM. VOL. 53. and forms a pit or shallow depression. In //aemobaphes the pro- boscis is apparently confined to the mouth tube proper and the max-, allae are attached to the ventral surface of the head at its base. The mandibles are simply curved claws or spines, one-jointed and entirely devoid of teeth. The first maxillae are also one-jointed and armed with short setae; the second maxillae are two or three jointed and terminate in one or two stout claws. There is also usually a stout spine on the inner or outer margin of the basal joint. ‘These appendages are important organs of prehension in the copepodid larvae, and doubtless assist in the burrowing of the female into the flesh of her final host. The maxillipeds are found in both sexes of Lernaea, but so far as known only in the males of other genera, and are made up of a large swollen basal joint, a smaller distal joint, and from one to five terminal claws. The swimming legs, as Claus pointed out, do not increase in size from the larval condition and, therefore, appear rudimentary and degenerate upon the greatly enlarged body of the adult. There is, however, no actual degeneration or retrogression in their structure, but it often, perhaps usually, happens that the rami or even the entire legs get broken off. This may result either from the move- ments of the parasite itself or during its removal from its host and subsequent separation from the cyst which envelops it. But in such cases there is always left the scar at either end of the chitin rib which connected the legs or the stumps of the rami. We can not, therefore, regard the swimming legs as having actually degenerated or retrogressed, but simply as having failed to increase in size with the rest of the body. And we must not conclude from an examina- tion of one or two specimens that the legs are destitute of rami, when further search will likely yield a specimen on which they are still retained. In general we may say that the genus Zernaea possesses five pairs of swimming legs, of which the first four pairs are biramose with. three-jointed rami, while the fifth pair is uniramose and unseg- mented. In most of the other genera there are but four pairs, even in the larval form—the first two pairs biramose, the third and fourth pairs uniramose, all the rami two-jointed. In Peroderma and Sarcotretes there are but three pairs—the first two pairs biramose, the third pair uniramose, and all the rami two-jointed. In l7aemobaphoides there are only two pairs of legs, both biramose with two-jointed rami. The copepodid larvae of Sarcotretes possess only three pairs of swimming legs in contrast to the four pairs found in the larvae of Lernacocera and Pennella, and the five pairs in the larvae of Lernaca. no. 2194. NORTH AMERICAN PARASITIC COPEPODS—WILSON. 25 It will be of great interest to find the larvae of Peroderma and Taemobaphoides and ascertain if they also show a reduction in the number of legs, the latter genus having only two pairs. INTERNAL MORPHOLOGY. The body wall.—The body wall is composed of two layers—an outer transparent layer, which may or may not become chitinous, and an inner opaque and cellular layer, the chitinogen membrane of Claus and other authors. The outer layer is made up of thin lamellae, lying one upon another, with no intervening spaces. In Lernaca barnimii Hartmann described quite a complicated pattern of raised sculpture on the ex- ternal surface of the outer layer. This may be seen on fresh and liv- ing specimens but usually disappears during preservation. Through this outer layer run pore canals, which vary in proximity in different parts of the body, being closest together along the center of the body and farthest apart on the antennae, swimming legs, and furca. These canals are connected more or less intimately with the soft inner layer of the wall and probably function in excretion. The inner layer of the body wall is softer than the outer and is never hardened into chitin. It is composed of polyhedral cells, which vary greatly in thickness, those lining the posterior body and abdo- men being much thicker than those found in the anterior body and arms. The cells are not much flattened but are more or less inflated and filled with a fine-grained brownish substance, glandular in nature, and having spherical nuclei with small nucleoli. This layer normally lies in contact with the inside surface of the outer layer, but in alcoholic specimens the two layers are often separated. In the living animal the cells of the inner layer undergo certain changes, thus described by Hartmann: “Some cells break loose, stretch out, become narrower, take on the appearance of threads, anastomose with one another, and send out many irregular processes ” (p. 736). This wandering of the cells takes place in all parts of the body, in the horns, and in the appendages. As a result they form a meshwork of active protoplasm over the inside surface of the inner layer and fill such spaces as the inside of the abdomen around the intestine. This meshwork is particularly thick inside the posterior body of the copepodid larva and probably contributes greatly to the nour- ishment and increase of that part of the body during its rapid development. The muscular system.—In the copepodid stages the muscular sys- tem is well developed and very closely resembles that of the Caligidae, thus furnishing another evidence of the close relationship of the two families. But as soon as the female has fastened herself to her final 26 PROCEEDINGS OF THE NATIONAL MUSEUM. Vou. 53. host and has begun her retrogressive metamorphosis the muscles share in the changes produced. As the body fuses and becomes swollen and tumid and the appendages cease to be used the muscles also fuse and disappear until there is nothing left in the adult female but a simple network between the integument and the alimentary canal to be noted under the digestive system (p. 27). There are still the usual muscles connected with the antennae, especially the second pair, with such of the mouth parts as are still used, with the swimming legs of those genera in which they are bet- ter preserved, and with the anal papillae in Lernaea, Peniculus, ete., and in even the most retrogressive genera there are still muscles con- nected with the external openings of the oviducts, which control the passage of the eggs into the external sacks. But the other muscles, including all those which flexed or moved the body of the copepodid larva, entirely disappear. In Lernacenicus the proboscis is highly developed and possesses a complicated system of muscles whereby each part of it, as well as the mouth parts connected with it, can be moved independently. But the swimming legs are less well preserved and their muscula- ture is correspondingly reduced. In Peniculus the jointed thorax retains more or less of its capability of motion, and with this most of the muscles. The alimentary canal—-The mouth opens into a short esophagus, which is usually straight or but slightly curved, and is inclined to the axis of the head. It opens into the stomach on the ventral sur- face of the latter, near or at the anterior end, and the opening is guarded by a powerful sphincter muscle. In those genera (Ler- naeenicus, Peniculus, etc.) in which there is a protrusible proboscis the extension and retraction take place principally in the mouth tube, and are shared only incidentally by the esophagus and at its anterior end. The muscles, which control these movements, are at- tached chiefly to the base of the mouth tube (fig. 69) and draw it in or push it out without affecting the esophagus very much. When the proboscis is protruded the stomach is drawn forward by the muscles at its anterior end, and this shifts the position of the esophagus and allows it to follow the movement of the mouth tube without itself undergoing much change of length or diameter. Its walls, however, are einstic and are probably stretched a little dur- ing the extension of the proboscis and recover their normal form when it is retracted. The stomach is abruptly enlarged behind the sphincter muscle and is sometimes straight and sometimes convoluted. In the genus Lernaea it also sends out a lobe on either side, but these lobes are not connected in any way with the horns, nor can they be said to enter the base of the horns, as Claus, Hartmann, and some others have a no, 2194. NORT'H AMERICAN PARASITIC COPEPODS—WILSON. 27 declared. There are always two of them, no matter what the num- ber of the horns may be, and sometimes they are not opposite the base of the horns. Furthermore, they are present in the larva long before the horns have started to grow. The stomach is lined with a digestive epithelium of very irregular thickness, from which scattering spherical cells project into the central cavity. ‘These contain the digestive fluids and also a large nucleus with distinct nucleoli. The stomach passes insensibly into the intestine, which, in most of the genera, is narrowed to a mere thread where it passes through the neck and then widens again in the trunk. Sometimes (ZLer- nacolophus) the intestine is convoluted in the lower portion of the neck, but it is usually straight. In the trunk it lies nearer the dorsal surface, between the ovaries and the oviduct, and is sometimes flattened dorsoventrally (Sarcotretes), again laterally (Lernae- olophus), or may even assume a three-cornered shape (Pennella tridentata), but is usually cylindrical. In species like Phrixocephalus triangulus, where the trunk is short and wide, the intestine becomes baglike, and in the new genus (/olli- pravus it is looped and folded back on itself, owing to the misplace- ment of the neck. The intestine passes into the abdomen in those genera (Lernacolophus, Pennella, etc.) which have a comparatively large abdomen, and is bluntly rounded near the posterior end of the latter. In the genera (Sarcotretes, Peniculus, etc.) with a small abdomen it does not leave the trunk, but is bluntly rounded just in front of the vulvae, and the rectum is given off from its upper pos- terior corner. The rectum is very narrow and threadlike, and is connected with the side walls of the abdomen by numerous muscles. It is straight when the abdomen is large, but in the other genera is inclined dorsally. In every genus thus far examined there is an anal lamina on either side of the external opening of the rectum, sometimes fair sized and armed with setae, sometimes minute and destitute of setae. But no matter how small the lamina may be there is an opening through the body wall into its interior that shows its real nature (fig. 57). The anterior end of the stomach is suspended from the dorsal wall of the head by two long and narrow muscles, and in the genus Ler- naea there are additional sets of muscles on each of the lateral lobes. The posterior end of the intestine is similarly connected with the dorsal wall of the abdomen or trunk. The alternate contraction and expansion of these muscles produce a forward and backward move- ment of the entire digestive canal. This is most marked in the cope- podid larvae, but persists to some extent in those adults whose bodies are straight and not bent into a sigmoid loop. In addition to these 28 PROCEEDINGS OF THE NATIONAL MUSEUM. VOL. 53. muscles the digestive canal is suspended by connective tissue from the dorsal or lateral walls of the various regions of the body through which it passes. The walls of the stomach and intestine also contain both longitu- dinal and transverse muscle fibers, which produce strong peristaltic movements, so that the food is moved about and pushed back and forth over every portion of the digestive epithelium. The nervous system.—The copepodid larva has a nervous system almost the same as that of the Caligidae, which has been described in detail elsewhere; but, like the muscular system, this, too, gradu- ally disappears, and but little of it can be found in the adult female. There is enough of it left, however, to control such movements as persist, and especially the working of the reproductive organs. In a median section of the head (fig. 69) the remains of the supra and the infra esophageal ganglia can still be seen, with scattered nuclei representing the nerve centers. Even the nerves themselves may be detected, but only those leading to muscles and organs which are active in the adult. Of the other nerves and even of the ventral chain of ganglia only traces are left, which are difficult to detect. In all the genera the tripartite eye of the larva persists in the adult, and there is usually a more or less distinct nerve connecting it with the supra-esophageal ganglion. But it is buried deeply in the tissues over the base ofthe esophagus and has evidently been covered with the surrounding tissues during the growth of the various horns and cephalic processes. The lenses are usually no longer visible and, indeed, the eye itself can not be seen except in specimens which have been cleared in oil or some similar medium. The nervous system, therefore, shows the greatest retrogression of any portion of the body; it not only fails to increase proportionally to the growth of the body, like the various appendages, but it really diminishes and partially disappears. The male reproductive organs.—The male reaches sexual maturity during the fourth copepodid stage, and the sex organs consist of a pair of testes situated in the posterior part of the cephalothorax and separated some little distance from each other, a pair of straight vasa deferentia, and a pair of sperm receptacles, containing the spermatophores and located in the genital segment. Each testis is an ovoid or ellipsoid and is somewhat flattened dorsoventrally; the vas deferens leads from the testis directly back alongside the intes- tine and into the genital segment, where it is enlarged into a recep- tacle to hold the spermatophores. In the fifth segment the vas def- erens is convoluted once, and this fold has glandular walls which supply the cement material for the outside covering of the spermato- phores. The opening through which the latter are extruded is on the ventral surface of the genital seement. a ee ee es a eas! ee Pee ae xo. 2194. NORTIT AMERICAN PARASITIC COPEPODS—WILSON. 29 UMMA SU ERM Latienn eck ee sere he The female reproductive organs.—In the copepodid stage, when fertilization takes place, the ovaries of the female are ovoids or ellipsoids, like the testes of the male, and are similarly situated in the posterior portion of the cephalothorax, near the dorsal surface. The oviducts correspond in every particular with the vasa deferentia, leading back alongside the intestine to an enlargement in the genital segment, which is to receive the sperms from the spermatophores deposited on the outside of the segment by the male; and in the genus Lernaea the posterior portion of the oviduct secretes cement substance, like the vasa deferentia. During the retrogressive metamorphosis which follows the fixa- tion of the female to her final host a great change takes place in both the location and structure of the reproductive organs. The ovary migrates from the cephalothorax through the entire length of the free thorax into the genital segment, where it assumes a position near the dorsal surface at the anterior end of the segment, except in the new genus Collipravus, where it is near the posterior end at the base of the abdomen. In most of the genera the ovary also reverses its position, the anterior end becoming posterior and the posterior end anterior, so that the oviducts in the adult always arise from the anterior end. Furthermore, in some genera (Lernacocera, Pen- nella, etc.) the two ovaries move inward toward the midline and finally come together and fuse, leaving only a pair of anterior and posterior horns to mark their dual origin. The oviducts now pass down around the intestine to the ventral surface and strait back to the vulvae without convolutions, except in Pennella, where there is a single fold just as they leave the ovaries. A pair of cement glands is also formed, whose anterior glandular portion originates at the anterior end of the genital segment at the base of the neck and ventral to the oviducts. Each gland is cylin- drical and without convolutions, and the two lie side by side along the midline. At about its center each gland is contracted and passes into a duct which empties into the oviduct of the same side just inside the vulva. These ducts are also without convolutions in all the genera except Lernaecolophus and Lernaeocera, in which they are vertically convoluted. In the genus Zernaea the cells at the posterior end of the ovary gradually loosen themselves from the epithelium and become asso- ciated in longer or shorter filaments or strings, each of which is made up of many cells flattened together like a row of coins and which increase in size toward the anterior end of the ovary and there break up into separate eggs as they pass into the oviducts, the con- ditions being thus similar to those found in the Lernaeopodidae. In all the other genera thus far studied the ovary consists of a mass of tiny nucleated cells, with no arrangement into filaments or 30 PROCEEDINGS OF THE NATIONAL MUSEUM. VOL. 53. strings but with all the eggs separate and in close contact one with another. Those near the opening of the oviduct are about twice the size of those at the center and these in turn are much larger than those at the posterior end. The increase in size is accomplished by the absorption of food material or yolk, which goes on with much greater rapidity at the anterior end just as the eggs pass out into the oviducts. In the latter the eggs are arranged in a single row and are strongly flattened, so that they look like coins standing on edge. ° The external egg sacks are short and bag-shaped in the Lernaeinae, and the eggs are piled loosely into them, with almost no flattening and without definite arrangement. In the oviducts also of this sub- family the eggs are spherical instead of being flattened, and they do not quite touch one another. In the other genera the egg sacks are filiform and very long, reaching 12 to 15 inches in the genus Pen- nella, and the eggs are arranged in a single row and flattened as they were in the oviducts; but there is this difference: In the oviducts the. eggs are in actual contact, while here in the external sacks each is separated from its neighbor on either side by a partition formed of the egg membranes. In the Lernaeinae the developing larvae are not arranged in any order with reference to the walls of the egg sacks, but in the other subfamilies there is the same arrangement as in the Caligidae— namely, the body of the nauplius appears on one of the flattened sides of the egg, with the head on the edge of the egg that is nearest the outer lateral margin of the sack. The long axes of the nauplii are usually parallel, but occasionally one is reversed in position; and, similarly, while most of the nauplii are on the proximal surface of each egg, occasionally one will be found on the distal surface. Fertilization, as already stated, occurs during the last copepodid stage; the spermatophores are attached by the male in pairs to the ventral surface of the genital segment of the female, their openings being brought into contact with the vulvae. The contents of the spermatophore then pass into the enlarged end of the oviduct inside the vulva and the emptied sack drops off. According to A. Scott in Lernaeocera branchialis the first pair of spermatophores are re- placed by others in succession until the receptacula are filled, each receptaculum holding the contents of four spermatophores. At first the four lots remain separate in the oviduct, but they soon mix and become one homogeneous mass. A. Scott concluded that in Lernaeocera “the spermatozoa at once pass up the rudimentary oviduct to the ovary and fertilize the eggs.” (1901, p. 43.) But there are several considerations which render such an action highly improbable: no. 2194. NORTH AMERICAN PARASITIC COPEPODS—WILSON. OL 1. The eggs are not ripe at the time the spermatozoa are intro- duced into the oviduct, and it requires at least four to six weeks for them to reach maturity. It is hardly possible for an egg to be fer- tilized so long before it is fully developed. 2. Segmentation does not begin until the eggs pass out into the ex- ternal sacks; consequently if they were fertilized in the copepodid stage they must then lie dormant during the four to six weeks before they could begin to segment—an extremely improbable pro- cedure. ; 3. If the spermatozoa swarmed up the rudimentary oviduct they would go in sufficient numbers to fertilize every egg and leave a considerable surplus. We could hardly concede to the spermatozoa that were left after fertilization the ability to pass back down the oviduct, and they would have to remain in the ovary; but an ovary filled with dead spermatozoa, or for that matter with living ones, would hardly be a favorable place for egg development. 4. The fact that no sperm receptacle can be definitely made out in the adult is what would naturally be expected. It has already been stated that the spermatozoa pass out of the spermatophores into the enlarged end of the oviduct when the copepodid female is fertilized. There is never, therefore, any separate sperm receptacle and none ought to be expected in the adult. Again, this enlarged end of the oviduct in a larva only 1 or 2 millimeters in length is of necessity very small, and it could easily persist in the adult and still escape detection. In every genus examined there are convolutions in the oviduct, where it is narrowed before passing out of the vulva, that are posterior to the last egg. Any one of these convolutions is large enough to hold several sperm receptacles the size of the one in the copepodid larva, and it would seem more reasonable to conclude that one of them serves such a purpose. 5. But we are not confined wholly to negative evidence. Im a young Pennella filosa, examined by the present author, the ovaries have already migrated from the cephalothorax into the genital seg- ment, although the larva was only 18 mm. in length. But at the posterior end of this segment, a short distance inside of the vulve, there is an enlargement in each oviduct filled with a mass of some- thing that has every appearance of being spermatozoa. This speci- men could not be sectioned to complete the proof, but there would seem to be but little doubt that this is the same enlargement into which the spermatozoa were originally introduced, and, if so, they did not pass up into the ovary. Consequently we can only conclude that the spermatozoa remain near the vulva, and that each egg is fertilized not in the ovary Sos PROCEEDINGS OF TIE NATIONAL MUSEUM. vou. 53. EE I ES eg Ce when it is immature but after it has acquired its yolk material and become fully ripe, just before it passes out into the external sack. SYSTEMATIC TREATMENT. Family LERNAEIDAE. Family characters of female.—The largest of the parasitic cope- pods, sometimes reaching a length of 200 to 250 mm., exclusive of the egg strings. Body more or less cylindrical, elongate, and unseg- mented; separable into three regions—a cephalothorax furnished with horns or processes, a free thorax in the form of a narrow cylin- drical neck, and a trunk comprising the rest of the body, more or less swollen and either straight or sigmoid; anal laminae present but often minute; egg strings paired, either short club-shaped sacks or long threads, straight, coiled into loose masses, or twisted into regu- lar spirals. Antennae distinctly dorsal, second pair chelate; mouth in the form of a sucking tube, more or less protrusible; a tripartite eye buried in the tissues above the esophagus; mandibles and two pairs of maxillae, but no maxillipeds except in Zernaea; three, four, or five pairs of swimming legs; at least the first two pairs biramose, rami two or three jointed, the others uniramose with jointed rami. Adult female with the head and part of the neck buried in the tissues of the host and firmly anchored in such a way as to bring the mouth in contact with some copious blood supply. Family characters of male-—Not developed beyond the fourth copepodid stage, at which time it becomes sexually mature. Body like that of Cyclops, comprising a cephalcthorax covered dorsally with a carapace, a free thorax, a genital segment, and a jointed abdo- men armed with a pair of large anal laminae; antennae and mouth parts like those of the female; proboscis also more or less protrusible; sometimes a sixth pair of rudimentary legs on the genital segment; a pair of large prehensile maxillipeds a little distance behind the mouth tube. d The male never bores into the tissues of its host nor becomes perma- nently anchored in any way, nor is it ever found attached to or in company with the adult female. KEY TO THE SUBFAMILIES AND GENERA. 1. Trunk straight; swimming legs widely separated, the posterior pair close to the vulvae; egg cases sacklike; eggs multiseriate____________ Lernacinae 2 1. Trunk straight; first two pairs of swimming legs close together and near the head, the others at short intervals; egg cases filiform and straight or coiled into regular spirals; eggs uniseriate_________---__ Lernacenicinue 3 1. Trunk with sigmoid curve; all the swimming legs close together and near the head; egg cases filiform and convolute or coiled into spirals; eggs uni- seriate and veryinumerous2 =. 5 22. eee Lernacocerinae 8 Ko. 2194. NORTH AMERICAN PARASITIC COPEPODS— WILSON. 83 1. Trunk straight; all the swimming legs close together and near the head; egg cases filiform, straight, and very long; eggs uniseriate; abdomen with a row of feather-like processes on either side_______-_______ Pennellinae 11 . Head with 2, 3, or 4 soft and swollen horns symmetrically arranged; neck and trunk smooth and without transverse grooves, the one passing grad- TAIN GOL tNe OUNCT aces ere eer ee ee Lernaca Linnaeus, 1758, p. 36. . Head with irregular protuberances; neck and trunk transversely wrinkled, the one passing into the other abruptly with a great difference in di- PUI eee ek ae EE nd try reeds Sed oS ee Leptotrachelus Brian, 1903, p. 40. Dorsal portion of head extended straight forward, longer than the body, and bearing on its swollen tip the antennae; head and trunk the same diame- Fernwicnout done 22 aa Le Se Therodamus Kr¢yer, 1863, p. 41. . Head and thorax smooth, without processes or horns, and in line with the SEEISOL CheMtEUD kei es LEh: ieee eS Peniculus Nordmann, 1832, p. 44, . Cephalothorax with horns or processes, or both, and often bent at an angle Nth GN OP NEG 228 25s Se ee ee es a FS ee 4 4. Bilateral symmetry perfect; branched frontal processes covering the ante- rior head, but no horns or lateral processes; egg strings straight--______ 5 4. Bilateral symmetry perfect; lateral horns or cushion-like processes, but no £LOnEAL processes!:esey strings straight tess Le Es eee ees 6 4, Bilateral symmetry considerably distorted; head and neck attached to the side of ‘the trunk; egg strings coiled into spirals.__._.__.--__.-~_-_ 7 5. Cephalothorax and neck straight and attached at right angles to the side of the trunk some distance behind the anterior end. Peraderma Heller, 1865, p. 49. 5. Cephalothorax and neck with a sigmoid curve and attached to the anterior endvrofs they tims 22s Beek eke ek 5S Cardiodectes, new genus, p. 50. 6. Two to ten chitinous horns, or two or three small posterior knobs on the cephalothorax; neck not enlarged behind the swimming legs; one pair of past ee = ee eee Lernacenicus Le Sueur, 1824, p. 56. 6. Two lateral horns on the cephalothorax, soft and unbranched; neck enlarged behind the swimming legs; two pairs of maxillae, Sarcotretes Jungersen, 1911, p. 69. 7 Neck attached to a lateral anterior corner of the trunk; abdomen minute and Hemispheric yee ee ees we ee Se Phrizocephalus Wilson, 1908S, p. 74. . Neck attached to the center of the dorsal surface of. the trunk, abdomen as long as the trunk and turned sidewise_______ Collipravus, new genus, p. 78. US Stine ST OOPeU, 1NtOy LOOSE \MASSES =25 =e eee Ao oY 9 webeeestrines coiled into recular tight spiralso22 2 eS ee es 10 . No abdominal processes; trunk soft and fleshy; cephalic horns very irregular. Lernacocera Blainville, 1822, p. 83. . Five or six branched processes along either side of the abdomen; integu- ment of every part of the body thick and chitinized; cephalic horns regu- Ey E TONG. ae ee eee Lernacolophus Heller, 1865, p. 89. 10. Head and neck with lateral processes, simple and soft; neck reflexed upon itself; abdomen two-thirds as long as the trunk and regularly tapered. Haemobaphes Steenstrup and Liitken, 1861, p. 93. 10. Cephalothorax with branched chitin horns; neck very short and not re- flexed; abdomen as long as the trunk and expanded at the tip. Iaemobaphoides T. and A. Scott, 1913, p. 100. 77403 —Proc.N.M.vol.583—17—— 3 wo ro to wo a oo oe “A © 34 PROCEEDINGS OF THE NATIONAL MUSEUM. VOL. 53. 10. Cephalothorax with three simple chitin horns, two lateral, one dorsal; neck much longer than the trunk, not reflexed; abdomen half the length of the genital segment, without processes_____-_- Trifur, new genus, p. 101. 11. Abdomen with a row of feathery processes along either side; cephalotho- rax with numerous frontal processes and two or three horns, chitinous and asually.simp) Gee =e es ae eee eee Pennella Oken, 1816, p. 105. 11. Abdomen twisted spirally and covered with papilliform villi; neck with small excrescences attached by threads; no horns or frontal processes, Pegesimallus Krgyer, 1868, p. 126. Remarks.—At first the genus Lernaca was the only one in the en- tire group of parasitic copepods, and everything that was parasitic and that seemed likely to be, or even to become, a copepod was placed in this genus by the early investigators. One after another of these species have been removed and made the types of new genera, until all that are left are those included in the present paper. Dut even after they began to separate new genera investigators still placed them all with Zernaea in the family Lernaeidae, which thus became the final dumping ground for everything that was bizarre in form and that could not be located elsewhere. Many of these genera have already been removed and correctly located elsewhere, and it is pro- posed now to remove all the others that do not show sufficient rela- tionship in morphology and development. Accordingly the five genera, Sphyrion, Strabax, Trypaphylum, Opimia, and Lebellula, which have heretofore been included in the Lernaeidae, must be dropped for the following reasons: The adult females of these genera have processes at the posterior end of the genital segment in addi- tion to the egg strings, from a single pair (Opimia) up to large bunches (Sphyrion); the second antennae are neither dorsal nor chelate; there are no swimming legs or anal laminae, and the female carries a pigmy male attached to the posterior end of her body. This Jast proves at once that the life history is entirely different from that here set forth for the Lernaeidae. These genera will be taken up in a future paper. The genus /ve which was provisionally placed in the Lernaeidae by its founder, Mayer (1879), can not possibly be left there, since it is not a fixed parasite at all and the two sexes are found together moving about freely, with the male 5 mm. in length, or half the size of the female. The genus Zernaca presents so many differences from the other genera that it might seem a question whether it ought to be in- cluded with them or established in a family by itself. But from the account of that genus already given (see Bibliography under Wilson) it will be found that the resemblances far overbalance the differ- ences, especially in the matter of the peculiar life history, and the genus is accordingly retained in the present family. Ko. 2194. NORTH AMERICAN PARASITIC COPEPODS—WILSON. 35 LERNAEINABE, new subfamily. Subfamily characters of female-—Cephalothorax armed with soft horns or processes, two, three, or four in number and unbranched; trunk straight without a sigmoid curve; genital segment enlarged on the ventral surface, just in front of the vulvae, into a pregenital prominence; egg cases short and sacklike, eggs multiseriate. Two pairs of antennae, second pair uncinate; a pair of curved and spine- like mandibles; two pairs of maxillae; one pair of mavillipeds; swimming legs widely separated with a fifth pair close to the vulvae. Subfamily characters of male (genus Ler- naca).—Body like that of Cyclops, composed of a cephalothorax cov- ered with a dorsal cara- pace, three free thorax seoments, a genital seg- ment, and a three-joint- ed abdomen; anal Jami- nae each armed with a single jointed seta, more than half the length of the whole body. Anten- nae and mouth parts like those of the female; a fifth and often a sixth par of swimming legs on the genital segment. Parasites of fresh-water Fic. A—THE MALE (LEFT) AND FEMALE (RIGHT) COPE- A ih PODID LARVAE OF LERNAEA VARIABILIS : ACTUAL LENGTH fishes exclusiy ely. OF FEMALE, 1.50 MM., INCLUDING THE LONG ANAL SETAE, Ontogeny of genus Lernaca.—The genital protoplasm at the posterior end of the ovary gradually forms onto long threads or filaments, transversely seg- mented into cells. These increase in size toward the anterior end of the ovary, and as they pass into the oviduct the filaments break up into their separate cells, each of which forms an egg. The eggs pass down the oviduct to its posterior portion, which serves as a cement gland. Just before entering this portion they are fertilized. and after entering they are covered with an egg membrane composed of the cement substance. AAG TZ \ a 07 CY Ges ue 36 PROCEEDINGS OF THE NATIONAL MUSEUM. VOL. 53. In the external egg sacks development takes place up to the nauplius stage. The larva hatches as a typical nauplius with the usual three pairs of appendages and one pair of balancers. It swims about freely in the plankton during the nauplius and metanauplius stages, undergoing several molts. On reaching the first copepodid stage it seeks as a temporary host some fish other than the one which is to serve as the final hcst of the female, and both sexes cling to the gill filament by means of their second antennae and max- illipeds, and feed on the fish’s blood. Four copepodid stages are passed here on the gills, the genital segment and abdomen becoming gradually perfected, the reproduc- tive organs being developed, and the swimming legs increasing in number and in the number of segments in the rami. During the fourth copepodid stage both sexes become sexually mature and fer- tilization occurs. After fertilization the female leaves the gills and swims about freely again in the plankton in search of a final or per- manent fish host. She fastens to the skin on the outside of the fish’s body by means of her second antennae and maxillipeds, and bur- rows into the underlying tissues with the aid of these organs and the powerful maxillae. Soft horns or processes then develop from the sides of the cephalothorax, the body is greatly elongated and enlarged, the ovaries migrate back into the genital segment, and the mature adult stage is reached, in which she continues until death. The male remains upon the gills of the first fish host until death, without further increase in size or other transformation, or he may sometimes leave and swim about freely in ‘the plankton; but he never attains a length of more than a millimeter and a half, does not seek another host, undergoes no changes corresponding to those of the female, and is never found subsequently in the company of the female. Genus LERNAEA Linnaeus. Lernaea LINNAEUS, Fauna Suecica, 1746, p. 367. Lernaca LINNAEUS, Systema Naturae, 10th ed., 1758, p. 655. Schisturus (part) OkeEN, Lehrbuch Naturgeschichte, 1816, p. 182. Lerneocera (part) BLAINvILLe, Journ. de Physique, vol. 95, 1822, p. 375. Lernacoccra (part) NorpMANN, Mikrograpische Beitriige, 1832, p. 123. Lernacocera BurMEIsTER, Acta Acad, Caes. Leop. Carol. Nat. Cur., vol. 17, 1833, p. 309. Lernacocera (part) Mitne Epwarps, Histoire Naturelle des Crustacés, vol. 3, 1840, p. 526. Lernacocera, all subsequent authors. External generic characters of female—Head a rounded knob projecting from the anterior margin of the cephalothorax and placed nearly at right angles to the body axis, with a deeply buried, tripartite eye near the center of the dorsal surface; one or two pairs of horns, simple or forked, on the lateral margins of the cephalo- thorax; sometimes an unpaired horn on the center of the dorsal no. 2194. NORTH AMERICAN PARASITIC COPEPODS—WILSON. 87 margin; all the horns conical and soft; neck soft, slender, and cylindrical, enlarging gradually into the trunk which is also cylin- drical; trunk with a pregenital prominence in front of the vulvae; abdomen short and bluntly rounded, terminating in a pair of minute anal laminae; egg strings elongate-conical or ovoid, eggs multi- seriate. Two pairs of antennae, second pair uncinate; proboscis conical and very short; mandibles claw-shaped and without teeth; two pairs of maxillae; one pair of maxillipeds; four pairs of biramose swimming legs, first pair just behind the head, others at increasing distances posteriorly; a fifth pair of one-jointed stumps just in front of the vulvae. Internal generic characters of female—Esophagus short, nearly straight, and diagonal to the body axis; anterior stomach with lateral lobes and more or less convoluted; posterior stomach passing insensibly into the intestine, which is straight, of the same diameter throughout, and abruptly contracted into a short rectum; ovaries paired, close to the dorsal surface and near the posterior end of the trunk; matured oviducts with two long posterior and two shorter anterior loops; eggs remaining spherical and never flattened antero- posteriorly; no separate cement glands, the thickened glandular walls of the posterior oviducts serving that purpose. No separate excretory glands, the chitinogen layer of the skin apparently serving for excretion through the pore canals. Genus habitat—This genus fastens to the outside surface of the fish’s body, usually in the vicinity of the fins, and bores into the underlying tissues a short distance until it finds an adequate blood supply without seeking any particular organ or blood vessel. Generic characters of the copepodid male.—The external generic characters have already been given under the subfamily. Inter- nally the esophagus is long and nearly parallel with the body axis; stomach passing insensibly into the intestine and that into the ree- tum, the entire tube lined with digestive cells filled with black gran- ules; supra ganglion comparatively small, infra ganglion very large and stout and extending back into the genital segment; testes paired, but not always side by side, situated in the head and anterior thorax above the stomach and intestine, spindle-shaped with the sperm ducts leading from their anterior ends back to the large spermato- phore receptacles in the genital segment. Type of the genus.—Lernaea cyprinacea Linnaeus, first species. (Lernaea, Aépyn, a fabled abode of the hydra.) Remarks.—In a monograph of this genus by the present author, submitted to the United States Bureau of Fisheries and soon to be published, will be found the complete morphology and life history. together with a full revision of all the known species. 38 PROCEEDINGS OF THE NATIONAL MUSEUM. VOL, 53. KEY TO THR SPECIES OF LERNAKA, i Ewo) cephalothoraciesnorhs: a) lateral (pair22 22 eee 2 1. Three cephalothoracic horns, a lateral pair and one dorsal and unpaired_-_3 J. Four cephalothoracic horns, a dorsal pair and a ventral pair_—2—----—- = 5 2. Horns directed laterally at right angles to body axis; trunk not much wider than neck; pregenital prominence inconspicuous (8.40 mm.)* diceracephala (Cunnington), 1914. 2. Horns diagonal to body axis, directed posterodorsally; trunk suddenly en- larged to four times the diameter of neck; pregenital prominence very larce (Sanit) ae ek bk ee aie ae a ee a aie new species*. 8. Lateral and dorsal horns all dichotomously branched___-______________ 4 3. Lateral horns simple, dorsal one bified at apex; pregenital prominence incon- Spicuous; abdomen short (G0 mm ))a 222 ee eee ee new species”, Lateral horns three or four pronged, dorsal horn bifid at apex; pregenital prominence conspicuous; body clubshaped; abdomen long and wide (7.50 VAIY IE) ees sata See ae er ae eee a pectoralis (I orcs Chondracanthus...| radiatus. Balmoned......--..- INMAeUS, iOle estes Salmincola....... salmonea, BUA Mee) e = [1a Sowerby, 1806.......... Lernacenicus....-- sprattae, tentaculis quatuor...| Linnaeus, 1746........ Lernaed.< cn~ ines cyprinacea, RETEE ERIC a eo e's | LLICE L1G, sein deta ciate Clinelleren: acces uncinata. In addition to the above species, which can be located with reason- able certainty, there are also others which have never been described with suflicient accuracy to enable one to locate them with any cer- tainty, nor even with any probability. LERNAEA BASTERI Blainville, 1822, p. 437. “The body is white and divided into two parts by a constriction; the abdomen is very large and oval; the cephalic enlargement is globular; the mouth is inferior and provided with a double pair of 40 PROCEEDINGS OF THE NATIONAL MUSEUM. vob. 53. hooks, by means of which the animal fastens itself. I know this spe- cies only through Baster, who observed that this animal bore consid- erable resemblance to that figured by Gissler. (Acta Holmiae, 1751, p. 90; pl. 6, figs. 1-5.)” This is the only description ever given, and while it shows that the creature can not belong to the genus Lernaea, it does not tell us where it can be placed. LERNAEA GADUS-MINUTUS Hesse, 1891, p. 191. In the text Hesse spoke of this “ Lernée du Gade petit” as though it were a new species, but in the explanation of the plate (pl. 7, figs. 1-9) he distinctly called it the larva of “ Lernaea branchialis du Gade petit,” which seems to be what it really was. LERNAEA LOTAE Hermann, 1783. Oken in 1816 separated the genus Schisturus, in which the body was soft, from the genus Zernaea, in which it was covered with a horny skin. He placed the species Zofae in this new genus and gave for it the following description: “ Vier ungleiche Eierschniire, am Mund zwei Hikschen.” This was probably some genus that possessed paired posterior processes, since none of the copepod parasites have four egg strings. At all events it was not a Lernaean. LERNAEA MULTICORNIS Cavier, 1830, p. 256. “T] y en a une a cornes petites, inegales et tres nombreuses (L. mul- ticornis, Cuv.) sur les ouies d’un serran des Indes.” This has never been seen or mentioned by any other author, and its attachment to the eye renders it highly improbable that it belongs to the genus Lernaea. Genus LEPTOTRACHELUS Brian. Silvestria Brian, Atti del Soe. Ligustica di Scienze, vol. 13, 1903, 6 pp. fe tect he. Leptotrachclus Brian, Zool. Anz., vol. 26, 1903, p. 547. External generic characters of female-—Cephalothorax with two or three soft, cushionlike protuberances or horns, varying in size and shape; head considerably swollen; neck long, straight, and slender, or sometimes bent into a U-shape, covered anteriorly with a cutaneous sheath, monilliform posteriorly; trunk abruptly enlarged. subcylindrical, thickest anteriorly, tapering posteriorly, with nu- merous transverse wrinkles but without a pregenital prominence, straight or slightly curved; no abdomen; egg strings, antennae, mouth parts, and swimming legs unknown; male also unknown. — no. 2194. NORTH AMERICAN PARASITIC COPEPODS—WILSON. 41 Type of the genus.—Leptotrachelus truchae Brian, monotypic. (Leptotrachelus, \errés, slender and rpaxndos, neck.) Remarks.—Brian established this odd genus upon several speci- mens sent to him by the Italian investigator, Filippo Silvestri, and obtained from “ Percichtys trucha,” taken in the Santa Cruz River, Patagonia. He first named the genus Si/vestria, but this name being preoccupied he changed it to Leptotrachelus. It apparently bears more resemblance to the Lernaeinae than to the other subfamilies, and, as it came from fresh water, we may leave it here until further data are obtained. Genus THERODAMAS KErfgyer. Therodamas Kr¢éyER, Bidrag til Kundskab om Snyltekrebsene, 1863, p. 316, pl. 15, fig. 4, a—f. External generic characters of female—Body divided into two parts, the anterior one resembling a slender neck ending in a swollen spherical head, the posterior one considerably wider, distinctly seg- mented, and tapering backwards. Anterior portion really a median dorsal process, but carrying on its swollen tip a pair of stout uncinate second antennae. First segment of the posterior portion the true head, bearing the proboscis and mouth-parts on its ventral surface. First, second, third, and fourth thorax segments the same width as the head and each bearing a pair of swimming legs. Genital segment strongly tapered posteriorly; abdomen short and deeply parted in the center; anal laminae small and armed with stout setae; egg strings spindle-shaped; eggs small, multiseriate, and not definitely arranged. First antennae unknown; second pair stout and uncinate; proboscis short and blunt; one pair of mandibles, two pairs of maxillae, no maxillipeds; swimming legs well separated, all four pairs biramose, rami 3-jointed and armed with plumose setae. Type of the genus.—Therodamas serranit Kr¢yer, monotypic. (Therodamas, O