/ M a \ MBL/WHOI LIBRARY \ 1! ii ru CD m r- i m . _D m CD SMITHSONIAN INSTITUTION UNITED STATES NATIONAL MUSEUM Bulletin 93 THE SESSILE BARNACLES (CIRRIPEDIA) CONTAINED IN THE COLLECTIONS OF THE U. S. NATIONAL MUSEUM; INCLUDING A MONOGRAPH OF THE AMERICAN SPECIES BY HENRY A. PILSBRY" Special Curator of the Department of 3 folia sea, Academy of Natural Sciences of Philadelphia ^jji«»«« "••«•?•>. Iffi* PER\ /ORE WASHINGTON GOVERNMENT PRINTING OFFICE 1916 SMITHSONIAN INSTITUTION UNITED STATES NATIONAL MUSEUM Bulletin 93 ?' THE SESSILE BARNACLES (CIRRIPEDIA) CONTAINED IN THE COLLECTIONS OF THE U. S. NATIONAL MUSEUM; INCLUDING A MONOGRAPH OF THE AMERICAN SPECIES BY HENRY A. PILSBRY Special Curator of the Department of Mollusca, Academy of Natural Sciences of Philadelphia WASHINGTON GOVERNMENT PRINTING OFFICE 1916 BULLETIN OF THE UNITED STATES NATIONAL MUSEUM. ISSUED JULY 31, 1916. li ADVERTISEMENT. The scientific publications of the United States National Museum consist of two series, the Proceedings and the Bulletins. The Proceedings, the first volume of which was issued in 1878, are intended primarily as a medium for the publication of original, and usually brief, papers based on the collections of the National Museum, presenting newly-acquired facts in zoology, geology, and anthro- pology, including descriptions of new forms of annuals, and revisions of limited groups. One or two volumes are issued annually and dis- tributed to libraries and scientific organizations. A limited number of copies of each paper, hi pamphlet form, is distributed to specialists and others interested in the different subjects as soon as printed. The date of publication is printed on each paper, and these dates are also recorded in the tables of contents of the volumes. The Bulletins, the first of which was issued in 1875, consist of a series of separate publications comprising chiefly monographs of large zoological groups and other general systematic treatises (occasionally in several volumes), faunal works, reports of expeditions, and cata- logues of type-specimens, special collections, etc. The majority of the volumes are octavos, but a quarto size has been adopted in a few instances in which large plates were regarded as indispensable. Since 1902 a series of octavo volumes containing papers relating to the botanical collections of the Museum, and known as the Contribu- tions from the National Herbarium, has been published as bulletins. The present work forms No. 93 of the Bulletin series. RICHARD RATHBUN, Assistant Secretary, Smitlisonian Institution, In charge of the United States National Museum. WASHINGTON, D. C., June 8, 1916. in PREFACE. The sessile barnacles are one of the dominant groups of littoral animals. In vast profusion of individuals they inhabit the zone between high-water mark and the hundred-fathom line. Their free nauplii form an appreciable part of the food available for bivalve mollusks and other animals subsisting on the plankton. The adult barnacles, together with mollusks, are part of the food of bottom- feeding fishes. In Japan barnacles are extensively utilized for fer- tilizer, as fish and Limulus are with us. On the other side of the account, it may be mentioned that barnacles are most widely known as the chief organisms folding ships' bottoms. Although barnacles offer a wide field for systematic and ecological study, they have been neglected by American naturalists. In the early days of zoology they were classed with the mollusks, and were collected by conchologists. After the group was transferred to the Crustacea, conchologists lost interest, and but few students of Crustacea took it up. Fortunately the Cirripedes found a historian in Charles Darwin. His Monograph on the Subclass Cirripedia is one of the most brilliant morphologo-systcmatic studies to be found in the whole field of systematic zoological literature. In recent years the works of P. P. C. Hoek and A. Gruvel, inspired by the high ideals of Darwin, have stimulated renewed research, and a substan- tial advance in our knowledge of barnacles must result from the work of zoologists and paleontologists who have taken up the group in England, Germany, Italy, India, and New Zealand. In America there is opportunity for systematic and faunistic work on the southern and Pacific coasts especially, while the entire sea- board abounds in cirripede material for the investigator of the prob- lems of ecology and evolution. H. A. PlLSBRY. PHILADELPHIA, May /, 1916. CONTENTS. Page. Introduction 1 Acknowledgments 2, 3 Terminology of the plates of sessile barnacles 3 Homologies of the plates of sessile barnacles 6, 7 The cirri 7, 8 Material examined 9 Distribution of American Balanomorph barnacles 10 Notes on fossil barnacles 11 Classification 12 Descriptions of genera and species 14 Suborder Verrucomorpha 14 Family Verrucidae 14 Genus Verruca 15 Verruca (Metaverruca) coraliophila 21 Verruca (Verruca) stromia 24 Verruca (Verruca) laevigata 25 Verruca (Verruca) alba 25 Verruca (Verruca) alba caribbea 28 Verruca (Verruca) alba barbadensis 28 Verruca (Verruca) nexa 29 Verruca (Verruca) floridana 31 Verruca (Verruca) calotheca 33 Verruca (Verruca) calotheca flavidula 34 Verruca (Verruca) calotheca heteropoma 35 Verruca (Verruca) xanthia -. 36 Verruca (Verruca) entobapta 38 Verruca (Cameraverruca) euglypta 39 Verruca (Altiverruca) hoeki 41 Verruca (Altiverruca) rathbuniana 41 Verruca (Altiverruca) bicornuta 43 Verruca (Altiverruca) darwini 45 Verruca (Verruca) haloth^ca 46 Verruca (Verruca) intexta 47 Verruca (Verruca) albatrossiana 47 Suborder Balanomorpha 47 Family Balaninae 48 Subfamily Balaninae 49 Genus Balanus ; 49 Balanus (Megabalanus) tintinnabulum 54 Balanus (Megabalanus) tintinnabulum tintinnabulum. 55 Balanus (Megabalanus) tintinnabulum zebra 57 Balanus (Megabalanus) tintinnabulum spinosus 58 Balanus (Megabalanus) tintinnabulum occator 59 Balanus (Megabalanus) tintinnabulum volcano 60 Balanus (Megabalanus) tintinnabulum rosa 61 Balanus (Megabalanus) tintinnabulum azoricus 62 VII VIH CONTENTS. Descriptions of genera and species — Continued. Suborder Balanomorpha — Continued. Family Balanidae — Continued. Subfamily Balaninae — Continued. Page. Genus Balanus (Megabalanus) tintinnabulum antillensis G3 Balanus (Megabalanus) tintinnabulum californicus 65 Balanus (Megabalanus) tintinnabulum peninsularis. . . 66 Balanus (Megabalanus) tintinnabulum coccopoma 68 Balanus (Megabalanus) tintinnabulum concinnus 69 Balanus (Megabalanus) tintinnabulum galapaganus ... 70 Balanus (Megabalanus) algicola 72 Balanus (Megabalanus) ajax 74 Balanus (Megabalanus) psittacus 75 Balanus (Megabalanus) maxillaris 77 Balanus (Megabalanus) decorus 77 Balanus (Balanus) eburrieus 80 Balanus (Balanus) improvisus 84 Balanus (Balanus) amphitrite 89 Balanus (Balanus) amphitrite albicostatus 90 Balanus (Balanus) amphitrite niveus 92 Balanus (Balanus) amphitrite inexpectatus 97 Balanus (Balanus) amphitrite peruvianus 97 Balanus (Balanus) concavus 100 Balanus (Balanus) concavus glyptopoma 102 Balanus (Balanus) concavus proteus 103 Balanus (Balanus) concavus chesapeakensis 103 Balanus (Balanus) concavus pacificus 104 Balanus (Balanus) concavus coosensis 108 Balanus (Balanus) regalis 108 Balanus (Balanus) poecilus 110 Balanus (Balanus) alatus 110 Balanus (Balanus) poecilotheca 110 Balanus (Balanus) trigonus Ill Balauus (Balanus) spongicola 115 Balanus (Balanus) calidus 118 Balanus (Balanus) laevis 120 Balanus (Balanus) laevis nitidus 122 Balanus (Balamis) laevis coqtiimbensis 122 Balanus (Balanus) perforates 123 Balanus (Balanus) gregarius 126 Balanus (Balanus) aquila 127 Balanus (Balanus) nubilis 131 Balanus (Balanus) flos 135 Balanus (Balanus) rostratus 138 Balanus (Balanus) rostratua alaskensis 141 Balanus (Balanus) rostratus heteropus 142 Balanus (Balanus) rostratus apertus 144 Balanus (Balanus) rostratus dalli 147 Balanus (Balanus) balanus 149 Balanus (Balanus) balanus pugetensis 163 Balanus (Balanus) crenatus 1 65 Balanus (Balanus) crenatus curviscutum 175 CONTENTS. IX Descriptions of genera and species — Continued. Suborder Balanomorplia — Continued. Family Balanidae — Continued. Subfamily Balaninae — Continued. rage. Genus Balanus (Balanus) crenatus delicatus 177 Balanus (Balanus) glandula 178 Balanus (Semibalanus) balanoides 182 Balanus (Semibalanus) balanoides calcaratus 188 Balanus (Semibalanus) cariosus 189 Balanus (Hesperibalanus) hesperius 193 Balanus (Hesperibalanus) hesperius laevidomus 196 Balanus (Hesperibalanus) hesperius nipponensis 199 Balanus (Metabalanus) hoekianus 201 Balanus (Chirona) hameri 205 Balanus (Chirona) evermanni 210 Balanus (Chirona) kriigeri 214 Balanus (Chirona) tenuis 216 Balanus (Chirona) amaryllis 217 Balanus (Austrobalanus) imperator 219 Balanus (Austrobalanus) vestitus 219 Balanus (Austrobalanus) flosculus 219 Balanus (Solidobalanus) hawaiensis 222 Balanus (Solidobalanus) tantillus 224 Balanus (Armatobalanus) allium 228 Balanus (Armatobalanus) arcuatus 228 Balanus (Armatobalanus) cepa 228 Balanus (Armatobalanus) quadrivittatus 229 Balanus (Membranobalanus) declivis 230 Balanus (Membranobalanus) orcutti 233 Balanus (Conopea) galeatus 236 Balanus (Conopea) calceolus 238 Balanus (Conopea) scandens 239 Genus Acasta 241 Acasta spongites 242 Acasta japonica 243 Acasta cyathus 244 Acasta dofleini 247 Acasta pectinipes 247 Acasta idiopoma 247 Genus Tetraclita 248 Tetraclita squamosa 249 Tetraclita squamosa squamosa 251 Tetraclita squamosa japonica 252 Tetraclita squamosa rufotincta 253 Tetraclita squamosa stalactif era 254 Tetraclita squamosa panamensis 256 Tetraclita squamosa milleporosa 257 Tetraclita squamosa rubescens 257 Tetraclita radiata 259 Tetraclita costata 259 Tetraclita coerulescens 259 Tetraclita vitiata 259 Tetraclita (Tesseropora) rosea 260 X CONTENTS. Descriptions of genera and species — Continued. Suborder Balanomorpha — Continued. Family Balanidae — Continued. Subfamily Balaninae — Continued. Page. Genus Elminius 260 Elminius kingii 200 Elminius plicatus 261 Genus Creusia 261 Genus Pyrgoma 261 Pyrgoma anglicum 262 Pyrgoma crenatum 262 Subfamily Chelonibiinae 262 Genus Chelonibia 2G2 Chelonibia testudinaria 264 Chelonibia manati 265 Chelonibia caretta 267 Chelonibia patula 268 Subfamily Coronulinae 268 Genus Coronula 271 Coronula diadema 273 Coronula reginae 275 Coronula complanata 276 Genus Cryptolepas 278 Cryptolepas rachianecti 279 Genus Tubicinella 281 Tubicinella major 281 Genus Xenobalanus 282 Xenobalanus globicipitis 283 Genus Platylepas 284 Platylepas hexastylos 285 Genus Cylindrolepas 287 Cylindrolepas darwiniana 288 Genus Stomatolepas 288 Stomatolepas elegans 289 Stomatolepas praegustator 289 Family Chthamalidae 290 Genus Chthamalus 293 Chthamalus fragilis , 297 Chthamalus stellatus 302 Chthamalus stellatus stellatus 302 Chthamalus stellatus depressus 304 Chthamalus stellatus angustitergum 305 Chthamalus stellatus bisinuatus 306 Chthamalus challengeri 307 Chthamalus challengeri nipponensis 309 Chthamalus malayensis 310 Chthamalus moro 311 Chthamalus withersi 312 Chthamalus caudatus 314 Chthamalus dalli 316 Chthamalus fissus 317 Chthamalus anisopoma 317 Chthamalus panamensis 319 CONTENTS. XI Descriptions of genera and species — Continued . Suborder Balanomorplia — Continued . Family Chthamalidae — Continued. Page. Genus Chthamalus imperatrix 320 Chthamalus cirratus 321 Chthamalus scabrosus 323 Chthamalus intertextus 324 Chthamalus hembeli 324 Genus Pachylasma 327 Pachylasma giganteum 329 Pachylasma darwinianum 329 Pachylasma chinense 329 Pachylasma crinoidophilum 329 Genus Hexelasma 329 Hexelasma americanum 330 Hexelasma callistoderma 332 Genus Octomeris 334 Octomeria angulosa 334 Genus Catophragmus 334 Catophragmus imbricatus 335 Catophragmus darwini - 33& Catophragmus polymerus 336 Appendix 337 Explanation of plates 339 Index.. 359 THE SESSILE BARNACLES (CIRRIPEDIA) CONTAINED IN THE COLLECTIONS OF THE U. S. NATIONAL MUSEUM; INCLUDING A MONOGRAPH OF THE AMERICAN SPECIES. By HENRY A. PILSBRY, Special Curator of the Department of Mollusca, Academy of Natural Sciences of Philadelphia. INTRODUCTION. This work is a continuation of the author's report on the Cirripedia contained in the United States National Museum, of which the por- tion relating to pedunculate forms was published in 1907. It was at first intended to record the species of sessile Cirripedia in the Museum, with their localities, and to describe and figure new forms. As the collection was worked over, its wealth in American barnacles became apparent. It contains nearly every known species of the Western Hemisphere, many of them in hundreds, even thousands, of individ- uals, often showing aspects of variation special to American waters. This has led to an alteration hi the scope of the work, which may be described as a monograph on American sessile barnacles, with the records of foreign species contained in the Museum interpolated in sj^tematic order. In cases where extended investigation of Old World barnacles has been essential to a right appreciation of our own, the results have been included herein. It is behoved that these interpolations will not seriously detract from the use of the work for the determination of American species, while it is an advantage to have all the information relating to a given species or genus in one place. The deep-water barnacles of our coast are nearly all new to science, but a majority of the American littoral species have been described in Darwin's monograph.1 His grasp of detail was so comprehensive and his language so lucid that one can not expect to improve upon them. In the field he covered one can not do better than to imitate. Yet it has been possible to extend the work in certain directions. By the use of higher powers than were commonly used upon such objects 60 years ago, important features, unknown to Darwin, are found in the cirri. Various reforms in classification have been under- 1 A Monograph on the Subclass Cirripedia, the Balauidse, the Verrucidae. London, 1854. 2 BULLETIN 93, UNITED STATES NATIONAL MUSEUM. taken. Moreover, the vast collections from American waters extend our knowledge of the distribution of species, both geographic and bathymetric. The study of large series of the widely distributed or so-called cos- mopolitan species of barnacles shows that, with the exception of pelagic and deep-sea forms, they may be divided into subspecies which conform in distribution to the faunal provinces usually recognized by workers in marine zoology, and determined by conditions of tem- perature, currents, land barriers, and depth. The definition of these subspecies or local races has hitherto received but little attention in this group. The walls of Balani have been inadequately illustrated in former works. With the more intensive study of racial characters now undertaken in all branches of zoology, the external characters of barnacles become of importance. The extraordinary plasticity of the Balanid organization makes discrimination between racial char- acters and those controlled by environmental conditions a matter of extreme difficulty. Ecological and biomotrical studies of some of the abundant species are much needed in this connection. Numer- ous figures are given herein to serve as standards of comparison for those who may take up such local work. By the copious illustration of American forms, by large-scale draw- ings and photographs, their identification should be easier. Until one has studied barnacles deeply enough to have standards of com- parison, even the inimitable descriptions of Darwin are difficult to follow, especially if one is dealing with forms differing somewhat from those described. The appeal to the eye will often relieve the student from uncertainty. "Identifying by the pictures" may be a primi- tive and superficial method, yet such short cuts are permissible in case one merely needs the name of an animal which has been taken as the subject of embryological, ecological, or other non-systematic studies. The student must be warned, however, that many species have parallel mutations, vary in the same way under similar condi- tions, so that external form by itself is rarely a reliable criterion. The opercular valves, the details of structure of the plates of the wall, and the structure of the feet are the important characters. For the main facts of cirripede structure the student will naturally consult one of the standard treatises on zoology, such as that of Lankester. Matter relating to the group in general has therefore been restricted in this work to a brief explanation of the terms used in sys- tematic descriptions, in large part adapted from Darwin's monograph. The work is based upon the specimens contained in the United States National Museum, but to complete the account of American forms, some illustrations and descriptions have been drawn from material in the collection of the Academy of Natural Sciences of Philadelphia. By the courtesy of Mr. Samuel Henshaw, I have been THE SESSILE BARNACLES. 3 able to study a series of Antillean deep-water forms, collected by the United States Coast Survey steamer Blake, and contained in the Museum of Comparative Zoology. This material has added con- siderable to the account of American Verrucidae. Mr. John B. Henderson has furnished various deep-water species dredged by his yacht Eolis. Several illustrations from the Bulletin of the. Bureau of Fisheries were lent by the Hon. George M. Bowers, late commissioner. Dr. W. H. Dall generously placed in my hands his fine examples of Tamiosoma. Mr. Thomas H. Withers, of the British Museum, supplied photo- graphs of the type of Lepas balanus Linnaeus. Mr. C. Forster Cooper kindly lont the type of Balanus s&neas from the University Museum of Zoology, Cambridge. Miss Mary J. Rathbuii, Dr. Paul Bartsch, Dr. Thomas Barbour, and others mentioned in the text have furthered the work in various ways. For all of these favors I wish to offer sincere thanks. Filially, I would express my appreciation of the faithful work of Miss Helen Winchester, who made the drawings and retouched the photographs of the work. TERMINOLOGY OF THE PLATES OF SESSILE BARNACLES. The armor of sessile barnacles is essentially similar to that of the capitulum of pedunculate forms in being composed of calcareous plates connected by chitinous intervals. Only the plates (scuta and terga) bounding the cavity for the mouth, feet, etc., are movable, the rest being so interlocked that they form a rigid wall, the plates of which are termed compartments. The chitinous band surrounding the scuta and terga (or opercular valves) and connecting them with the wall is called the opercular membrane. This membrane is moulted like the exoskeleton of the limbs, and unlike other external hard parts, which are permanent.1 The terminology of the plates is shown in figures 1 to 5. The scuta, terga, carina, and rostrum are clearly homologous with those of pedunculate barnacles. The lateral compartments are homologous with part of the latera of the genus Mitella; probably they are homologous with the three pairs of latera which are retained in the genus Calantica. The exposed median triangle of each compartment is the paries (pi. parietes). The edges of the compartments overlapping adjacent compartments are called radii when they are differentiated from the parietes by an alteration in -the direction of the lines of growth. The undeiiapping edges are called alse. The membrane or calcareous plate upon which the barnacle stands is termed the basis. '.It should be noted that in some genera, such as Tubicindla, the upper layers of the wall, and in various Coronulinx the upper layers of the opercular valves are deciduous. BULLETIN 93, UNITED STATES NATIONAL MUSEUM. liaaia Basis Structure of the individual compartments. If (ho basal margin of a compartment, for instance of Inilunns tintinnabnlitm, be examined, it, appears sullieiently compli- cated, being composed of an outer and inner lamina, separated by longitudinal septa, which are denticulated at their bases; and the tubes formed by these longitudinal septa are crossed by transverse septa. On the other hand, in some cases, as in the genera ChlJnniuilns and Klminin.t, each com- part ment consists of a simple shelly layer. These two extreme states graduate into each other tin different, genera V we have, firstly, on the internal surface, unite irreg- ular points and ridges, these become regular i in some other genera \ causing the internal surface to be longitudinally ribbed: then these ribs themselves become finely fur- rowed on their sides and at their lower cuds, producing sharp, minute ridges, the ends of which 1 have called the denticuli; and lastly, some of the denliculi on the adjoin- ing longitudinal septa become united into a solid layer, forming the internal lamina i -I the wall. (Darwin, p. -13.) FIG. l.— W.M.I. OK A BALANOHOBPH UAKNACI.K. a. a. AI..K. /i. />. P.VKIKTKS. r. r.RAWi. I'ART OK Tiir. SHEATH is \ i^ir.i.i: IN THE DKIKICE. IN MAI. AMI'S VM> MVNY OTHK.lt (U'.NEUA THE KOS- TIU'M ANH KHSTKOl.ATEUAL Ci'MIVVK I'MENTS VKK O'Xl'KKSCENT. NOT SKPAKATE AS SHOWN UE1JE I,!'1 of the compartments takes place at the basal margin and usually at the sutures also, where the increment is at right angles to that of the- parietes, and forms the radii. In species which do not increase the diameter of the cono and orifice by the interposi- tion of radii, the orifice is onlnrgc.il as the animal grows by wearing away of the summit of the cone. FIG. 2.— (1, CoMlVVRTMENT WITH TWO RA1UI. SERVING EIT1IEU AS A ROSTROI.ATERAI. OU AS A ROSTRUM CONCRESCEXT WITH THE ROSTROLATERALS, AS IN BALANUS. 6, LATERAL OK CAKINOLATERAL COM- rvKTMENT. C. CARUJ.V OR ROSTRUM. LETTERS AS IN fhi. I (.AKTEK 1>ARW1N). The upper ends of the pores or tubes in the parietes are more or less extensively tilled up with calcareous material, occasionally differ- ing in color from that of the rest of the wall. In the genus Tttraclitit, inter alia, the outer lamina of the wall is ordinarily disintegrated and fugacious in adults, leaving a columnar or tessellated surface, formed of the harder tilling of the parietal tubes. The lateral edges of the radii are often provided with fine trans- verse ridges or septa, usually having dentieiilate edges. These fit THE SESSILE BARNACLES. Occludent margin Pit for adductor muscle X~ Adductor ridge ••• Tergal margin -. Articular ridge into recipient grooves of similar shape on the opposed sutural edges outside of the aUe. In a few forms the radii are permeated with pores which open in the intervals between the septa, and have a direction at right angles with the pores of the parietes. (See plate 10, fig. 2, where the denticulate septa and the ends of the parietal pores are shown.) The basis, when calcareous, may be either solid or provided with radiating pores, or it may have radiating ridges on the upper surface. Homologies of the plates of the watt.— In the absence of paleontologic evi- dence, we may assume that all acorn barnacles descended from a primitive stock having eight mural compartments. The most general- ized genus now ex- isting, Catophrag- mus, has eight main compartments, with numerous smaller ones outside, the latter representing the upper scales of the peduncle of pedunculate ancestral forms. Apex Articular ridge JV- -\- . Articular furrow Pit for lateral df- pressor muscle Basal margin FIG. 3.— INTERNAL VIEW OF SCUTUM. Scutal margin Crests for depressor muscles Basal margin Spur FIG. 4. — EXTERNAL AND INTERNAL VIEWS OF TERGUM. Darwin and others have compared this structure with that of the pedunculate genus, Pollicipes ( MiteUa) . A nearer likeness, perhaps, exists with ScyUselepas, in which there has been further specialization of the plates. Brachylepas, though superficially like Catophragmus, is evidently not in the line of descent of the Balanomorpha. On account of the different system of imbrication of the plates, it does not seem likely that the Balanomorpha descended from Mesozoic ScyUselepas, but rather that both had a common ancestor. 4729°— Bull. 93—16 2 6 BULLETIN 93, UNITED STATES NATIONAL MUSEUM. In most recent barnacles the number of compartments has been reduced, and it becomes important to determine the homologies of those remaining. This is partly to be done by attention to the articulating edges of the compartments. The carina and rostrum are nearly alike in primitive forms, both being bilaterally symmetrical, and having alse, on both sides, therefore overlapped by the adjacent compartments. There is no certain means of distinguishing them apart when detached, but the carina is usually more narrowly curved or bent than the rostrum of the same species. The carinolateral and lateral compartments are asymmetrical, having alse. on their rostral edges, and radii, or an overlapping border, on the carinal edges. There is no significant difference between these two compartments when detached, though the lateral is wider in most genera. The rostrolateral compartments have no alae, both sides over- lapping the adjacent compartments, thus differing essentially from all of the other plates of the wall. Departures from the structure just described are due to concres- ence of compartments. Reasoning from the conditions in species still in transition stages, we may infer that reduction in the number of compartments has taken place by two modes: 1. Reduction by elimination. In Acasta and Conopea the carino- lateral compartment is usually very narrow. In Acasta sporillus it has been almost crowded out, and does not reach to the basis. In Conopea cornuta it has entirely disappeared. In some other genera this compartment appears to be wanting.1 2. Reduction by concrescence. In Chelonibia the rostrolateral compartments and rostrum are calcified together, but traces of the sutures are usually discernable. In Pacnylasma crinoidopliilum the same compartments are united by fine linear sutures, but can be separated; in P. darwinianum they are calcified together externally, but the sutures are visible inside; finally in P. giganteum these com- partments are united by sutures in the earliest sessile stage, but afterwards they become completely concrescent, so that no trace whatever of the tripartite nature of the compartment is visible. The result of this concrescence is that the composite rostrum (rostrum plus rostral latera) has radii or overlapping borders on both sides, these being the original overlapping borders of the rostral latera. Having this transition series, among others before us, it seems highly probable ' In such genera as Tctraclita and Chthamalu*, in which the carinolateral compartments are absent, they may be fused with the lateral compartments or with the carina; but seeing that they are normally developed later than the other valves, it appears to be the simplest theory to assume, until the contrary be proved, that they are aborted. Finally, the somewhat unexpected conclusion that the shell (not includ- ing the operculum) of sessile cirripedes normally consists of eight valves ^four belonging to an upper whorl and four to a lower whorl , all forced into a single ring, and often more or less fused together, though not strictly proved, is rendered highly probable. (Darwin.) THE SESSILE BARNACLES. that in all cases where the rostrum has radii, or overlaps the adjacent com- partments, it is a composite plate, formed by the concrescence of both rostral latera with the true rostrum. This is the case with all recent BalanidjB and part of the Chthamalidse. It is inexact to term the compartment formed by fusion of rostrum with the rostral latera a "rostrum," in Balanus, for example, as it is not equivalent to the rostrum in the less modified Chthamalidse, the Verrucidse, or the pedunculate cirripedes. So long, however, as the true constitution of the plate is understood, the inconsistent terminology is perhaps of no great moment. The chief modifications in the arrangement of the compartments due to concrescence or to elimination are represented diagrammatically in figure 5. Having examined a very great majority of the known species of sessile cirripedes, I find that the evidence supports Darwin's x/~r"Nv b / CHTHAHALUS . RL CHAM/ESIFHO FIG. 5.— DIAGRAMS SHOWING THE MODES OF IMBRICATION AND THE HOMOLOGIES or COMPARTMENTS IN CHTHAMALID.E AND BALANID.E. c, CARINA. cl, CARINOLATERAL COMPARTMENT. I, LATERAL, r, ROSTRUM, rl, ROSTROLATERAL. THE SECOND DIAGRAM REPRESENTS OCTOMERIS. views of the homologies of the compartments, so far as he definitely expressed himself, and is opposed to the interpretations of Grovel.1 The question of homologies of the wall plates is by no means aca- demic. Our conceptions of the classification and phylogeny of the group depend upon our understanding of these homologies. The cirri are always well developed in sessile barnacles, and there is much less diversity in the arrangement of the spines than in the Lepadomorpha. The first two or three pairs of cirri bear dense, brushlike tufts of spines; the later cirri bear spines in pairs, two to eight or ten pairs on each segment. The number of pairs of spines is a useful specific character, though subject to some variation in polymorphic species. In descriptions the count is made in the median third of the cirrus, where the maximum number is found. i Gravel, Monographic dcs Cirrhipedes, p. 194, fig. 213, where Professor Gravel's views of the homologies of the compartments are given. 8 BULLETIN 93, UNITED STATES NATIONAL MUSEUM. There are sometimes bunches of short spines on the anterior face between the spines of the pairs. In the species figured (fig. 6) the posterior ramus of the first cirrus and both rami of the second are formed of what Darwin termed "protuberant segments." In many species of Balanus there are minute "spinules" variously arranged on the outer faces of the segments of some of the cirri, par- ticularly the third and fourth, as shown in figure 8 and many others. Sometimes the spinules are enlarged on the anterior margin, of the cirrus, forming "teeth," as in Acasta (fig. 80) and some Balani. In the evolution of barnacles the cirri have been successively modi- fied from before backward. In the least modified forms the second cirrus, or only its anterior ramus, has assumed the form and chseto- taxy of the first cirrus. In more advanced forms the second and third cirri are so modified. In a few, the fourth cirrus also shows FIG. 6.— CtBRI OF THE EIGHT SIDE OF BALANUS KOSTRATUS ALASKENSIS, FROM IvODIAK, X3. CAT. NO. 3415. THE PENIS IS SEEN AT THE BASE OF THE SIXTH CIRRUS. THE SPINES ARE NOT SHOWN IN THIS PHOTOGRAPHIC FIGURE. some modification. The modification of the cirri is therefore one of the indices to the evolutionary rank of a species. On account of the fact that a barnacle grows at the base and sutures, and not at the orifice, it receives the impression of the supporting surface, and often reproduces its sculptural features. A specimen growing on a scallop shell may bear, vicariously, the ribs of the shell, as in plate 33, figure 2a. Exactly the same effect, from the same cause, is sometimes seen in sedentary, limpetlike mollusks. This vicarious sculpture may be superimposed upon that proper to the barnacle, or the conflict of the two patterns may result in neither being distinctly expressed. Very often the sculpture of the support- ing surface seems to have no effect whatever on that of the barnacle, even when the latter has a smooth surface. The shapes of barnacles are often controlled by the size and shape of the supporting object, but they show little if any choice between such solid objects as occur in their vicinity. Many, but apparently THE SESSILE BARNACLES. 9 not all, of the littoral species attach to ship bottoms; a few forms are known from no other source. Such specimens are often found in museums, labeled merely with the locality where they were taken off of the ship, or picked up where they had dropped or been cleaned off. Such specimens may often be known by the paint or rust adhering to the base, or they may show the grain of the planks. On such smooth surfaces a barnacle is likely to develop a beautifully symmetrical cone, whereas others of the same race, growing on an uneven natural surface, are likely to be irregular, unsymmetrical, or cylindrical. Most of the species which develop a conic wall when growing alone become lengthened and cylindric when crowded. The transitions of form are frequently seen in the same group, as in plate 44, figure 2. Very much lengthened forms often result where barnacles grow soli- tary on small objects, as in figures 5-5& of plate 40. Like many originally bilateral animals which have become fixed, the sessile cirripedes approximate more or less to a superficial radial symmetry. This is especially marked in the whale and turtle bar- nacles, in which the incidence of external forces is practically equal on all sides. MATERIAL EXAMINED. In the census of species and subspecies of known recent sessile cir- ripedes, given in the first column of the following table, several forms of doubtful specific or subspecific status are admitted. The other columns contain species and subspecies contained in the National Museum. Genera. Total of recent forms. Contained in the U. S. Nat. Mus. Types contained in U. S. Nat. Mus. Species. Sub- species or "va- rieties." Species. Sub- species. Species. Sub- species. Balunus 75 10 7 7 1 11 1 4 14 18 2 5 6 1 2 3 50 46 50 6 6 2 1 2 28 13 3 19 I'QtTQClitCL 7 7 4 2 2 1 4 3 9 16 2 1 3 1 .1 7 Chtha wains 3 4 2 3 2 1 2 18 1 17 VcTTUCd • . . 5 2 2 223 67 122 43 47 29 10 BULLETIN 93, UNITED STATES NATIONAL MUSEUM. In addition to material tabulated above, I have had available for study several species contained in the collection of the Academy of Natural Sciences of Philadelphia, including the types of five species and four subspecies, and from the Museum of Comparative Zoology the types of two subspecies. So far as I know, this includes all but one of the types of recent sessile cirripedes contained in or described from American museums.1 The British Museum, containing the types of Darwin's monograph and of Hoek's Challenger report, etc., possesses more types of sessile cirripedes than any other museum, at least 34 per cent of the total number of accepted species. The United States National Museum stands next, having types of about 21 per cent of the valid species and about 43 per cent of the subspecies. Other museums contain comparatively few types. Many types of the older (pre-Darwinian) species are lost, or at least the present location of the type-specimens is not known. The calculations above do not include types of forms generally admitted to be synonyms. DISTRIBUTION OF AMERICAN BALANOMORPH BARNACLES. The distribution of Verrucidee has been considered separately (p. 18). In the following list the species are arranged systematically, the geo- graphic ranges of Atlantic species being printed in roman, of Pacific species in italic type. Species. American distribution. Occurrence elsewhere. Balanus tintinnabulum antil- lensis. t. californicus t. peninsularis t. coccopoma t. galapaganus t. concinnus psittacus eburneus improyisus amphilrile iiireus a. t nerpectatus pemvianus concavus pacificus... regalia pocci/us trigonus Cuba to Brazil. Santa Barbara to San Diego, Cal Cape St. Lucas, Lower California Muzatlan to Panama Galapagos Islands Peru to Strait of Magellan Peru to Strait of Magellan Massachusetts Bay to Caribbean Sea Nova Scotia to Patagonia; ? West Colombia Vineyard Sound to southern Brazil Gulf of California Peru. spongicola. California to Peru West coast of Lower California West coast of South A merica West Indies to southern Brazil; sou/hern California to Peru. Venezuela to Brazil . . calidus Isetis aquila nubilis flos rostratus alaskensis . . r. apertus r. dalii r. heteropus balanus 6. pugetensis crenatus c. curvisnttum. c. delicatus glandula We*t Florida to Yucatan and St. Vincent. Rio Negro to Cape Horn, north to Peru Monterey to San Diego, Cal Southern Alaska to Santa Cruz, Cal California A laska Bering Sea Bering Sea Puget Sound Arctic Ocean to Long Island; Bering Sea. . . Puget Sound Arctic Ocean to Long Island; Bering Sea to Santa Barbara, Cal. A laska California A leutian Islands to San Diego Europe; Red Sea. West and South Africa; Japan to Australia. English Channel to South Africa; Seychelles. Northern Europe. Europe, Mediterranean; northern Japan. The type of Euraphia hembcti Conrad appears to be lost. THE SESSILE BARNACLES. 11 Species. American distribution. Occurrence elsewhere. Balanus balanoides Arctic Ocean to Delaware Bay; Alaska Northern Europe. b calcaratus . . south to Sitka. A laska cariosus ReTing Sea to Oregon Northern Japan. hesperius A laska Saghaliu Island. h Isevidomus A leutian Islands to Monterey hoekianus Bering Sea hameri Nova Scotia to off Chesapeake Bay (in deep Northern Europe. evermanni water southward). Bering Sea to southern A laska Kuril Islands. ftosculus Peru and Chile f, sordidus Tierra del Fuego seclivis Bermuda; Antilles orcutti Lower California galeatus South Carolina to West Indies; southern Acasta cyathus California. Florida to Colon Madeira; ? Gulf of Manaar. Tetraclita squamosastalactifcra s panamensis Florida to southern Brazil; Gulf of Califor- nia to Nicaragua. Panama to Peru s in illeporosd Galapagos Islands .... s. rubcscens Farallones to southern California i ad iut a West Indies ? New South Wales; Su- Elminius kinsjii . . . Tierra del Fue?o; Falkland Islands matra. Chelonibia testudinaria Rhode Island to Brazil; Lower California to World-wide in Tropic and ma.no.ti lobatibasis Galapagos. Florida warm Temperate Zones. C. manati West African. caretta Delaware Bay to Cape Fino, Brazil Nearly world-wide in warm patula . Florida and West Indies seas. Do. Coronvla diadema Greenland to West Indies; Bering Sea to World-wide. regime Lower California. Newfoundland; Aleutian Islands to Oregon. . North Atlantic and Pacific. co ijiplanata Chile Southern Hemisphere gen- Cryptolcpas rachianecti Bering Sea to Lower California erally. Hawaiian Islands ? .JY tnobdlanus globicipitis New England North Atlantic. Platulepas hexdstylos Delaware Bay to West Indies Mediterranean; Tropics. h ichthyophila Florida, western dccordld Galapagos Islands ... ....... CyliTidrolepds darvinidna West Indies Stomatolepas prxgustdtor Dry Tortu?as ? Mediterranean. Chtha mdlus frdgilis Woods Hole to West Indies stellatus angusti- Florida ; Bahamas C. stellatus, Europe; West lergum. s bisinudtus Southern Brazil Alrica. dalli . . Unalaska fissus Southern California anisopoma Gulf of California pandTtiensix Panama imperatrix Panama cirrdtUS Peru; Chile scabTosus Peru to Tierra del Fuego; Falkland Islands. HcxelasTnd dtnf'ficdnum Off South Carolina C'dtophrootnus iinbricdtus Bermuda; Antigua . NOTES ON FOSSIL BARNACLES. The limits of this work do not allow of any discussion of the Ameri- can tertiary barnacles, except in the case of Balanus concavus, which also occurs as a recent species. On account of the importance of the subject, some notes are given on supposed Palaeozoic Balanidne. Protobalanus hamiltonensis Whitfield 1 from the Marcellus shale, Hamilton group of the Devonian of New York, is described as having 12 wall plates and perhaps 7 opercular valves. It has a certain superficial resemblance to Balanus, but is morphologically inconsistent with the Balanornorph barnacles. I doubt very much whether Proto- balanus is a cirripede, but if so it must represent a group unrelated to any known Mesozoic or later form. > Bull. Amer. Mus. Nat. Hist., vol. 2, 18S9, p. 67, pi. 13, fig. 22. 12 BULLETIN 93, UNITED STATES NATIONAL MUSEUM. In Paldeocreusia devonica J. M. Clarke, from the Corniferous lime- stone of New York,1 the form is practically that of Pyrgoma. It is embedded in a Favosites colony, which has also overgrown the upper surface. No compartments are visible and no opercular valves found. While the fossil presents no characters differentiating it from the modern Pyrgoma, yet it is also utterly without features definitely placing it in the Cirripedia. The question is not whether Palxocreusia is a close relative of Creusia— this is practically excluded by the fact that Creusia and Pyrgoma are highly specialized forms of the most recent family of barnacles — but whether it is a cirripede at all. CLASSIFICATION. The modern classification of cirripedes began with Leach, who, in 1825, proposed the folio whig arrangement. I add the contents of the families in brackets: Class CIRRIPEDES. Order 1. Campylosomata. Family Clytiadse [Conchoderma]. Pollieipedidae [Lepas, Scalpdlem, Pollicipes, etc.] Ibladte [Ibla]. Order 2. Acamptosomata. Family Coronuladte [Tubicinella, Coronula, Chelonibia]. Balanidse [Pyrgoma, Acasta, Balanus, Tetradlta, Eliminus, etc.]. Clistadte [ Verruca]. Darwin revised this classification in 1852-1854. His chief addi- tions to the system of sessile barnacles were the demonstration of important differences in the morphology of the turtle barnacles (CTielonibia) and the whale barnacles, and the separation of the Chthamalinae from the Balaninae. In addition to this, he estab- lished the genera upon sound morphological characters, demonstrated their affinities with wonderful insight, and denned the species, which had before been in the greatest confusion. Darwin's monograph has been the basis of all subsequent systematic work, and is still the chief work of reference. The family and generic classification of this work is substantially that of Darwin. The principal departures are that the turtle barna- cles are removed from the Balanihse to form a separate subfamily; the arrangement of the Coronulinse is altered, considerable changes have been made in the subgeneric arrangement of the Balani, and the grade of supergeneric groups has been raised. I consider Darwin's subfamilies as families, and his primary divisions of subfamilies may then be ranked as subfamilies. Such an alteration of taxonomic values has been general throughout zoology during the last half cen- tury. It should in no way obscure the fact that the system of the Cirripedia Thoracica is still essentially Darwinian. 1 Palaeontology of New York, vol. 7, 1888, p. 210, pi. 30, figs. 24-2(5. THE SESSILE BARNACLES. 13 The new classification of sessile barnacles proposed by Professor Gruvel,1 cast aside Darwin's principles. The families were based upon the number of compartments in the wall — eight, six, or four. This system seems to me to be retrogressive at every point. His family Octomeridse is a natural group, though Pachylasma forms a complete transition to his Hexameridae, and Ohelonibia should logically have been included. His Hexameridse contains genera with six com- partments, but they are not the same six in the different genera, as may be seen by a comparison of Balanus and Ohiliamalus, the walls being constituted as follows, counting from the carina. Balanus. 1. Carina. 2, 3. Carinolatera. 4, 5. Latera. 6. Rostrolatera+rostrum.2 Chthamalus. 1. CarLna, carinolatera wanting. 2, 3. Latera. 4, 5. Rostrolatera. 6. Rostrum. The numerical agreement upon which Professor Gruvel's family is based is, therefore, due to the incident that members of two collateral phyletic series have independently reached the hexamerous stage. In Balanus it has been reached by complete concrescence of the rostrum with the rostrolatcra, while in CTitliamalus the rostrolatera remain as large, independent compartments, but the elimination of carinolatera brings the number of mural plates down to six. Mean- time, the characters of the labrum, mandibles, and cirri show that the relationship between the genera is not close, wholly confirming the conclusion drawn from the homologies of the wall plates. The family Tetrarneridse Gruvel is heterogeneous by including CJiamsesiplw. This genus has a simple rostrum with ala3, as in Clithamalus, while the other genera have the rostrum composite, as in Balanus, with which they also agree in the structure of the labrum and cirri. The usual classification of sessile barnacles as a suborder Operculata, with the tribes Symmetrica and Asymmetrica, is unsatisfactory for the reason that the two divisions or tribes are not directly related. The Asymmetrica (Verrucidae) and the Symmetrica (Balanidse, Chthama- lidse) are two entirely independent derivatives from the pedunculate group. We have, then, the following Suborders of the Order Thoracica: Suborder TURRILEPADOMORPHA. The elongated body is not differentiated into capitulum and peduncle and is cov- ered with longitudinal series of large, similar, imbricating plates. Palaeozoic. Families: LEPIDOCOLEHXE, TURRILEPADID.E. 1 Monographic des Cirrhipecles ou Thecostraces, 1905, pp. 8, 9, Paris. 2 The rostrum in Salami* is morphologically the rostrum concrescent with the rostrolateral compart- ments, but it is not so in Chthamalus. Professor Gruvel's diagrams, Monographic, p. 194, are inaccurate as to the homclogies of the compartments. 14 BULLETIN 93, UNITED STATES NATIONAL MUSEUM. Suborder LEPADOMORPHA. Usually elongate and differentiated into capitulum and peduncle, the former pro- tected by larger plates of specialized shapes, or sometimes all plates are wanting. Mesozoic to Recent. Families: LORICUUD.E (Loricula, Archseolepas) , BRACHYLEPADID^E (if distinct from SCALPELLID^E), SCALPELLID^E, LEPADID.E. Suborder VERRUCOMORPHA. Depressed, sessile, protected by an asymmetrical wall of four dissimilar plates immovably articulated together- — carina, rostrum, a tergum, and a scutum; some lateral wall-plates are sometimes present on one side. The other tergum and scutum form a movable lid closing the orifice. Mesozoic to Recent. Family: VERRUCID^E. Suborder BALANOMORPHA. Sessile, the wall bilaterally symmetrical, composed of carina, rostrum, and one to three pairs of lateral compartments; opercular valves paired, furnished with depressor muscles, or rarely wanting. Mesozoic to Recent. Families: CHTHAMALID^E, BALANIDJE. The first two suborders have hitherto been grouped together as Cirripedia Pedunculata; the last two as Cirripedia Operculata or Ses- silia, with the divisions Asymmetrica and Symmetrica. The Pedun- culata and Operculata of recent authors are exactly equivalent to the groups Campylosomata and Acamptosomata of Leach.1 DESCRIPTIONS OF GENERA AND SPECIES. Suborder VERRUCOMORPHA. Family VERRUCID^E Darwin. 1825. Clisiadse LEACH, Zoological Journal, vol. 2, p. 210. 1854. Verrutidae DARWIN, Monograph on the subclass Cirripedia, etc., Balanidae, Verruoidee, etc., p. 495. 1914. Verrucida; WITHERS, Proc. Zool. Soc. London, p. 946. ' 'Sessile, asymmetrical, boxlike barnacles, in which a scutum, ter- gum, rostrum, and carina, with or without a rostral and a carinal latus in addition, are immovably united to form the wall; the remain- ing scutum and tergum are movable, and form the lidlike top" (Withers). Basis membranous; caudal appendages present. La- brum with a concave edge. Although the Verrucidse are grouped as sessile barnacles, they have no near relationship with the Balanidse. The family comprises two genera: Verruca Sowerby (see below) and Proverruca Withers, a Lower Devonian genus, "in which a rostral and a carinal latus are present on the rostrocarinal side, and in which none of the valves has developed interlocking ribs." 2 New light has been thrown on the phylogeny of Verrucidse by the recent discovery of the Lower Devonian genus Proverruca and the > Zoological Journal, vol. 2, 1825, pp. 208, 209. 2 Proc. Zool. Soc. London, 1014, p. 94C. 1 HE SESSILE BARNACLES. 15 admirable exposition of its structure and significance by Mr. T. H. Withers. Taking such a form as Scillsdepas— If we imagine ths almost equal development of the rostrum and carina and the suppression on one side of the lateral valves, the scutum and terguin would be allowed to form that side of the wall, and the opposing scutum and tergum would have to lean over at a greater angle to meet them. We should then have only to suppress the subcarina, the median latus, and the peduncle to get a form such as Proverruca. This was evidently the history of the form, and although Scillselepas may not have been the actual ancestor, it must have been a form somewhat similar. (Withers.) Further reduction of the wall by loss of the lateral plates', together with the more efficient articulation of the remaining wall compart- ments, are all that is required to transform Proverruca into Verruca. Genus VERRUCA Schumacher. 1817. Venuca SCHUMACHER, Essai d'tin nouveau systeme des habitations des Vers Testace"s, pp. 35, 91. Monotype, Verruca str6mii=Lepas stronia Muller. 1817. Clysia Saviguy, LEACH, Journal de Physique, de Chimie, d'Histoire natu- relle et des Arts, vol. 85, July 1817, p. 69. Monotype, C. striata=Balanus striatus Penn. 1817. Ochthosia RANZANI, Opuscoli Scientific!, vol. 1, p. 275; 2, 1818, p. GG. Monotype, 0. stroemia. 1824. Clisia LEACH, Encyclopedia Britannica Suppl., vol. 3 (according to Darwin). 1825. Clisia LEACH, Zoological Journal, vol. 2, p. 210. 1827. Clitia Leach, SOWERBY, Genera of Shells. Type, Lepas verruca Gmelin. 1854. Verruca DARWIN, Monograph, p. 496. Verrucidse without lateral plates additional to the four composing the wall. Type, V. stroemia. The genus is readily distinguished from all other sessile barnacles by the wall composed of four dissimilar plates, the movable top, like the lid of a chest, composed of two plates hinged to the wall along one side. Terminology of plates. — The scutum in Verruca is always smaller than the tergum. The inner face is more or less concave, with raised occludent and tergal borders, an impression or pit for the adductor muscle, and very rarely an adductor ridge. Externally the tergal side or area slopes at an angle with the rest of the valve. The upper border of this slope forms an apical ridye, often not visible in a top view. Below this rib there is invariably an articular furrow. This is followed by the articular ribs, variable in number and position. The last one, terminating at the basotergal angle, is the most con- stant of all.1 I have termed it the crescent rib, since it defines the semilunar tergal area of the scutum. The tergum is trapezoidal, and usually flat or lightly concave within. The exterior is divided into two areas by the last articular 1 This rib, terminating at the baso-tergal angle, was not counted as an articular rib by Darwin, but Hoek and others, I think properly, regard it as articular. 16 BULLETIN 93, UNITED STATES NATIONAL MUSEUM. rib, also termed the diagonal rib. The upper articular rib terminates in the articular furrow of the scutum; rarely there is a weak rib above it, forming part of the occludent border of the plate. The fixed scutum and tergum have structures analogous to the lateral plates of Balanidae. There are median raised triangular areas or parietes, and sunken or diversely sculptured sutural areas like the Balanid radii. These structures are well shown in plate 7, figure 2a. The radius and ala along the scutotergal suture of the fixed plates have been homologized by Darwin with the articular ribs of the movable plates, the parietes being then homologous with the lower articular ribs. The fixed scutum may be quite plain inside, or there may be a pit for the insertion of the scutal adductor muscle. The lower edge of this pit is sometimes raised, forming an adductor ridge. When this ridge projects as a semicircular or spatulate process, I have termed it a myopJiore. (See pi. 1, fig. 3.) The wall plates are indicated by letters on plate 7, as C, carina; R, rostrum; F. Sc., fixed scutum; F. T., fixed tergurn; M. Sc., movable scutum; M. T., movable tergum. V. strotnia sometimes excavates its basal support when this is calcareous, according to Dai-win. I have seen no evidence of such action in any American species. The surface sculpture of shells or coral, whether living or dead, seems perfectly sharp and uninjured under the Verrucas I have investigated. Verrucas are modified in shape by the form of the support and sometimes by crowding, but the wall plates do not reproduce the irregularities of the supporting surface, as in Balanus, or, at all events, only to a very small degree. On echinoid spines Verruca almost always sits with the carinorostral axis parallel to the spine. On corals the position is more variable. Mouth parts. — I have not found much difference between the man- dibles and maxillae of the various Verrucas examined. The lower point of the mandible is always multispinose, and the edge of the maxilla very irregular. In these characters Verruca resembles the Lepadidae. Cirri. — In all but two of the species examined the anterior rarnus of cirri i and ii is from two-thirds to as long as the posterior, the rami of other cirri being subequal. The cirri show great specialization in V. stramia and V. alba. In V. stramia the rami of cirrus i are nearly equal, but in ii and iii the anterior ramus is extremely short, less than half as long at the posterior. V. alba has the anterior rami of cirri i and ii very short, one-third the length of the posterior, that of cirrus iii being three-fourths the length. In this species the cirri are unusually slender. THE SESSILE BARNACLES. 17 In all species examined the rami of cirri iv, v, and vi are nearly alike in length and armature. The segments in nearly every speci- men examined have three pairs of spines on the anterior side, the lower pair being very small, and usually there are two unequal spines at the posterior distal angle of each segment. The chajtotaxy is so similar that it is hardly necessary to figure cirri of the several species. FIG. 7.— VERKUCA ALBA, MAXILLA (LE SEGMENT OF CIRRUS VI. 6, MANDIBLE. C, MAXILLA. d, LAB RUM. Compartments. — The radii are wide, with level summits. The outer lamina of the wall bears numerous short lamellae on its inner edge (pi. 10, fig. le) between the septa. The parietal tubes are entirely open, except quite near the summits, where they have numerous transverse septa. The interlocking septa of the radii and sutural edges are straight, regular, and denticulate on both sides. The labrurn has a straight, shortly hairy edge and narrow notch. In the specimen examined there are two small teeth on one side, one on the other (fig. 9cZ). The mandible has four strong teeth, the fifth tooth small, united with the blunt lower point (fig. 96). The maxilla has a straight edge and 14 large spines; those below the upper large pair are in two series (fig. 9c). The cirri i to iii are shorter than in other groups of the genus. Cirrus i has rami about 5 mm. long, of 17 and 15 segments, those of THE SESSILE BARNACLES. 57 the posterior ramus protuberant. Besides the usual long spines, the distal borders of the segments bear minute multifid scales. Cirrus ii has 15 and 12 protuberant segments, posterior ramus shorter by 5 segments. Cirrus iii is about one-third longer than ii, with rami of 14 and 13 somewhat protuberant segments, the posterior ramus shorter by 4 segments. They have series of short, erect spinules along the distal borders of the segments. Cirri iv to vi are nearly similar, composed of a gieat number of short segments, which bear three pairs of long and a fourth of short spines. There are tufts of small spines on the anterior edge, between the spines of the pairs. A regular row of erect spinules borders each segment distally, wanting on some of the ill-defined basal segments. The anterior distal angles of the pedicel are also spinulose. The median segments of cirrus vi are about twice as wide as long (fig. 9o ). Cirrus vi is about 23 mm. long. Balanus tintinndbulum tintinnabulum (Linnaeus) is known in North American waters only as a frequent immigrant on ships. I do not know that it has anywhere established itself in our fauna, but we have no knowledge of the barnacles of the Gulf ports, where such introduction would be expected to occur, if anywhere. The natural habitat of the race remains to be defined, and the inquiry is difficult, because specimens from ports all over the world find their way into museums, without data showing whether they are part of the local fauna or from ship's bottoms; moreover, it is likely that some forms recorded as var. corn-munis will prove to be separable races. It has not been found in any Antillean or North American Tertiary or Pleistocene deposits. Figures 1 — le and the above description were drawn from speci- mens taken from a ship which arrived at Philadelphia from Hongkong and Java. They were associated with B. t. zebra and B. t. occator, but no intermediate or transitional forms were seen. The cylindric form with larger orifice, is prevalent in other lots, particularly those standing crowded. The United States National Museum contains numerous specimens referred to B. t. tintinnabulum, chiefly collected from ships in English and American ports; others from tropical localities and New Zealand are without opercular valves, and therefore of uncertain subspecific identity. BALANUS TINTINNABULUM ZEBRA Darwin. Plate 10, figs. 2 to 3. 1851. Balanus tintinnabulum, var. zebra DARWIN, Monograph, etc., p. 195, pi. 1, fig-<7- Form conical or somewhat tubular ; livid purple or dark livid purple, with snow-white ribs ; radii wide, colored ; sheath madder Irown. Sum- 58 BULLETIN 93, UNITED STATES NATIONAL MUSEUM. mits of the alas oblique. Opercular valves as in B. t. tintinnabulum, the adductor ridge of the scutum often very low, a mere convexity of the median part of the valve, but more emphatic in young individuals. Typical examples from ship bottoms are symmetrically conic and very conspicuously striped. Diameter 50 mm. ; height 30 mm., more or less (pi. 10, figs. 2a, 21, from a ship arriving in Philadelphia from Hongkong and Java). A series collected at Zamboanga, Mindanao, by Dr. E. A. Mearns, show the features assumed in then1 natural habitat, on a rough sup- port. These clustered specimens are more cylindrical than those from ships, with larger aperture and less regular ribs, and in some the base is deep, as usual with crowded barnacles. The color stripes are usually less regular and often the color spreads over the whole parietes toward their bases. The sheath has the remarkable rich madder-brown color characteristic of the subspecies (pi. 10, figs. 3). W.eltncr (Verzeichnis, p. 260) reports this variety from Walfisch Bay, southwest Africa. Various lots in the United States National Museum are without locality or are from ships, like No. 41169, from Dublin Bay (W. H. Dall), and other specimens on a ship from Hongkong and Java. This form is very closely related to the typical form of tintinnab- ulum. BALANUS TINTINNABULUM SPINOSUS (Gmelin). 1791. Lepas spinosa GMELIN, Systema Naturae, ed. 13, p. 3213. 1798. Lepas echinata BOLTEN, Museum Boltenianum, p. 197. 1854. Balanus tintinnabulum, var. spinosus Gmelin, DARWIN, Monograph, p. 196, pi. 1, fig. i. Convexly conical; rather thin, the parietes somewhat ribbed, the ribs terminating in very long, slender, up-curved tubular spines. White or violet-tinted toward the summit, tho spines usually colored. Ac- cording to Darwin the scuta "externally were smooth; the adductor ridge was rather more distinct from the articular ridge than in any other variety, and the terg'a more plainly beaked." The opercular valves are wanting in the speci- men figured, from an unknown locality. In size, this form is one of the smallest, diameter 15 to about 20 mm. (fig. 10). From its frequent occurrence on ships' bottoms associated with B. t. tintinna- bulum, it may be presumed to be from China or India, but it is certainly west African also, possibly colonized by vessels from India by the Cape route. Weltner gives the localities Siam, East Indies, and St. Helena for specimens in the Berlin Museum, and Hoek reports small specimens, up to 7 mm. diameter, taken FIG. 10. — BALANUS TINTINNABULUM SPINOSUS X 2. THE SESSILE BARNACLES. 59 from tho screw of the Challenger when at St. Vincent, Cape Vordes, on the return voyage. Specimens in the United States National Museum and those in the Academy of Natural Sciences have no locality data. BALANUS TINTINNABULUM OCCATOR Darwin. Plate 11, figs. 1 to le. 1854. Balanus tintinnabulum, var. occator DARWIN, Monograph, etc., p. 19G, pi. 1, fig. *; pi. 2, fig. 15. 1900. Balanus tintinnabulum (Linnaeus), var. occator Darwin, BORRADAILE, Proc. Zool. Soc. London, p. 799 (Fiji). Type. — In the British Museum; locality unknown. Distribution. — Indo-Pacific Province: Zamboanga, Mindanao, E. A. Mearns. Radii with their summits slightly oblique; parietes smooth, or ribbed, or spinose; very pale bluish-purple, with narrow darker lon- gitudinal lines; sheath, with the internal surface of the rostrum and lateral compartments, dull blue, whilst the corresponding parts of the carina and carinolateral compartments are white. Scuta, with small, sliarp, hood-formed points, arranged in straiglit radiating lines. Terga with the spur placed at either its own width, or less than its own width, from the basiscutal angle. Darwin. Italics of the foregoing description are mine. The color varies from pale purple to cream color, with white radii, the summit more or less tinged with purple. The deflected tergal area of the scutum is rather narrow and is bent very abruptly, the angle between that area and the face of the valve being but little greater than a right angle. The whole valve is narrower than in B. t. tintinnabulum. The inner face of the scutum is similar to that of B. t. tintinnabulum, the adductor ridge being very weakly developed, obsolete in tho lower half of tho valve. Tho longitudinal furrow of the tergum is more or less open, and the spur varies in proximity to the basiscutal angle, though always nearer than in B. t. tintinnabulum. The habitat Fiji has been given for this race, but most specimens in collections were from ships. A single specimen was in a lot of B. t. zebra collected by Dr. E. A. Mearns at Zamboanga. It has the violaceous coloring on a whitish ground and the narrow ribs of the occa- tor from ships, but no spines are developed. The orifice is broad and triangular. Valves typical, the spur of the tergum inserted at half its own width from the basiscutal angle. Figures I, la, le to \e of Plate 11 represent specimens from the bot- tom of a ship reaching Philadelphia, 120 days from Sudders Bay, Java. Other examples (pi. 11, fig. 1&) are from a ship arriving in Philadelphia from Hongkong and Java, via India, and associated with B. t. tintinnabulum and B. t. zebra. 60 BULLETIN 93, UNITED STATES NATIONAL MUSEUM. It seems rather likely that B. t. occator was the original Lepas crispata of Schroter, but as he gave no description or figure of the tergum, I do not see that his form can be identified with certainty. BALANUS TINTINNABULUM VOLCANO, new subspecies. Plate 11, figs. 2 to 2e. ? Balanus tintinnabulum, var. cr-lspatus Schroter, DARWIN, Monograph, pp. 195, 201, pi. 1, fig. h. Not Lepas crispata Schroter. Type.— Cat. No. 43488, U.S.N.M. Japan, collected by H. Loomis. A large barnacle with the conic shape of typical B. tintinnabulum, nearly smooth except for minute, irregularly scattered and downwardly projecting acute points or very short spines on the parietes, most numerous on the rostral and lateral compartments. Purplish lilac, in places deep slate-violet, where worn becoming pale smoke-gray. Radii wide, transversely striate, with level summits. Sheath whitish or pale flesh tinted. Carinorostral diameter 58 mm.; height 47 mm. Scutum flatter than in B. t. tintinnabulum, with the basi-tergal corner but little cut off, the deflected tergal segment very small; exterior finely but strongly ribbed longitudinally, the ribs prominent on the growth-ridges, which are deeply scalloped by them. The adductor ridge is high and rather massive. The torgum is similar to that of typical tintinnabulum, white with a buff cuticle when unworn, having narrow growth ridges and rather faint traces of fine longitudinal striae. Spur about twice its own width from the basiscutal angle. This subspecies is well characterized by the flat scutum, its tergal segment much less deflected than in B. t. occator, its surface radially costulate over the growth-ridges. The parietes are rather sparsely armed with minute spines; size large, colors dull. B. t. occator is paler, white or violaceous, the size smaller, and the tergurn quite different. It is often profusely spinose, the spines larger than in B. t. volcano. Probably the latter will be found sometimes without spines. In two rather large and strong specimens in the collection of the Academy of Natural Sciences, which I refer to B. t. volcano, the parietes are somewhat rugose, and all the compartments have minute spines. The adductor ridge of the scutum is moderately developed in one, low and rounded as in typical tintinnabulum in the other. They grew on wood, probably ships. B. t. volcano is probably equivalent to part of Darwin's B. tin- tinnabulum var. crispatus Schroter. I do not believe that it can be the Lepas crispata of Schroter. This species, as denned by Schroter,1 1 Lepas crispata Schroter, Einleitung in die Conehylienkenntniss nacb Linne, vol. 3, 1786, p. 534, pi. 9, fig. 21. THE SESSILE BARNACLES. 61 is a medium-sized barnacle; diameter 1£, height 1 inch; radii shaded bluish and white; parietes vertically striate, lighter than the radii, of a reddish color, thickly beset with spines for halfway up from the base. Smaller opercular plates are white, the larger (scuta) are dark blue with sculpture of serpentine (gesclilangelteii) transverse striae. Schroter's figure represents a profusely spinose barnacle very similar to well-developed B. t. occator. The blue radii and scuta also favor this variety, which is usually marked with violet. The form of the terga and color of the sheath, characteristic marks of occator, are not mentioned or figured by Schroter, so that I do not think we would be justified in substituting the name crispatus for occator. Unless the type can be found, crispatus would better be dropped as not certainly identifiable. Darwin states of the form (or forms) which he included under var. crispatus Schroter, that they have "scuta with their exterior surface either plain or with radiating lines formed of hoodlike projecting points;" and on page 201 he adds that the scutum is "broader and flatter than in var. communis, and the adductor ridge is very feebly developed." This last character does not agree with the type lot of B. t. volcano, which has scuta with the adductor ridge rather strongly developed and massive, but some specimens before me from ships' bottoms have it only moderately developed. It seems likely that Darwin's specimens with "plain" scuta (that is, with growth -ridges only) belong to another race. Under the circumstances, it seems best to describe the Japanese form as a new subspecies, in view of the suspicion that at least two and perhaps three races have been known as crispatus, and the practical certainty that the form now called volcano is not the original Lepas crispata of Schroter. I may add that the specimens of Schrotcr and Darwin were off of ships, and no locality is known for them, though they may be presumed to be of East Indian origin. Another obscure spinose barnacle is Lepas ecM?uiia Spongier.1 While I have not been able to match the figure of this form, it seems rather characteristic, and may prove recognizable when the exact race is encountered again. BALANUS TINTINNABULUM ROSA, new subspecies. Type.—C&t. No. 43494, U.S.N.M., from Azabu, Japan. The barnacle is conic or subcylindric, with a rather large, broadly and acutely ovate aperture; roseate (between pomegranate-purple and Indian-lake of Ridgway's Color Standards), the parietes of rostrum and lateral compartments paler than the carina, the radii a deeper shade of the same color. Parietes smooth. Radii with horizontal summits. Sheath a duller shade of the external color. J Skrivter af Naturhistorie Selskabet, vol. 1, 1790, p. 177. 62 BULLETIN UNITED STATES NATIONAL MUSEUM. Scutum with simple growth-ridges, at least in young individuals; adductor ridge very weakly developed. Tergum rather long, with relatively sliort spur, separated by nearly twice its own width from the basoscutal angle, the basal margin sloping to it on both sides. Carinorostral diameter 27 mm.; height 20 mm. (type). Carinorostral diameter 21 mm.; height 25 mm. (cylindric speci- men). Carinorostral diameter 41 mm.; height 49 mm. More brilliant than other oriental forms of the species; by its beautiful color and smoothness resembling B. t. coccopoma, and readily distinguishable from other Indo-Pacific races of B. tintinnabu- lum. Unfortunately, the large individuals had lost their opercular valves, which were described from one of the small individuals of a group of over 20, from Wakanoura. Large specimens become quite heavy and strong, and I had, at one time, some suspicion that the race might be referable to B. ajax Darwin; but a comparison with Darwin's description and a specimen of that species from Mariveles, Luzon, assures me of their specific difference. The very large rostrum, dark-colored sheath, small orifice, and remarkably thick walls of B. ajax are conspicuous dif- ferential characters. Museum No. Locality. Donor. 43494 Azabu, Japan . Imperial University of Tokyo. Wakaiioura, Japan Do. 43495 Kishiu Japan Do 11390 J:ip:in or Ronin Islands, . Jon Uchimura. 43 197 Japan Yedo Bay, Japan Uev. H. Loomis. BALANUS TINTINNABULUM AZORICUS, new subspecies. Plate 12, figs. 2, 2a, 21. Type— -Cat. No. 4S126, U.S.N.M., from Crace, Terciera, Azores, growing on Patella ccerulea; taken in 1894; collector not recorded. The barnacle is cylindric in general shape, the orifice rather large, ovate-trigonal. Parietes roughened by numerous small, irregular riblets. Summits of the radii level. Color dull blue- violet or dark hyssop-violet, clouded with white; terga pale yellow externally; scuta marked with the darker shade down the middle and internally. The sheath is pale violaceous with dirty whitish also; carinolateral compartments sometimes paler than the others. Height 40 mm.; diameter 29 mm. Scutum rather flat, the tergal segment but slightly deflected; growth-ridges narrow and prominent, conspicuously crimped, intervals deeply striate. Adductor ridge strong and acute, much as in B. t. concinnus. THE SESSILE BARNACLES. 63 Tergum rather narrow, with the spur normal in position, but rather short; furrow nearly or quite closed; growth-ridges much more prominent than in B. t. tintinnabulum; radial strise rather weak or wanting. The cirri are generally similar to those of B. t. tintinnabulum, except that the last three pairs have not nearly so many segments, with compensating far greater length of the individual segments. There are fewer distal spinules on the segments, but the same number (four) of anterior pairs of spines. (See p. 52, fig. 8; p. 67, fig. lie.) The penis is as long as the posterior cirri. There are a few sparse hairs near the end, but no basi-dorsal point was seen. A general view of the cirri and penis is given in figure 8. The opercular valves of this race are most like those of B. t. con- cinnus, but the slight deflection of the tergal segment of the scutum is a conspicuous differential character. The acute adductor ridge and the conspicuously crimped growth ridges of the scutum serve to separate the Terciera form from B. t. tintinnabulum. The rather sharp, irregular ridges of the parietes and especially the smaller number and mucli longer segments of the posterior cirri, are also unlike that race. The color of the sheath is such as one often sees in tintin- nabulum, and not darkened as in B. t. zebra, or specially colored, as in some other races described by Darwin. The specimens were much overgrown with seaweed and incrusted with lime. BALANUS TINTINNABULUM ANTILLENSIS, new sttbspecies. Plate 13, figs. 1 to 2e. Type.— No. 2083, A. N. S. P., St. Thomas, R. Swift. Distribution. — West Indies to Rio Janeiro. The barnacle is small, somewhat tubular, with irregularly ribbed parietes; white or whitish, with reddish purple lines on the parietes, or the latter may be Indian lake throughout. Radii wide, whitish. Insides of parietes dusky, sheath elsewhere pale. Diameter. 18 mm.; length 28 mm. Diameter 21 mm.; length 25 mm. Diameter 26 mm. ; length 33 mm. The opercular valves are formed substantially as in typical tintin- nabulum; but the spur is somewhat shorter, twice its own width from the basi-scutal angle; the terga are white or nearly so, and are about as wide as the scuta. The adductor ridge of the scutum is better developed, long and narrow, especially in the smaller examples. The type of this race is in a group (pi. 13, fig. le) which grew upon an oyster shell. The largest measurement given above is from the largest individual of the group, evidently an old one. A few Tctra- clita radiata grew upon the same group. So far as I know, this is 64 BULLETIN 93, UNITED STATES NATIONAL MUSEUM. the chief if not the only form of the species found in the West Indies, but collections are very meager, and it would occasion no surprise if the large oriental races were found established around ports fre- quented by deep-sea vessels. The specimens from Jamaica have waved, transverse, colored bands crossing the stripes on the parietes, and one of them has a deep, pockethke base and cylindric walls, 47 mm. long, with a greatest diameter of 20 mm. Those from Rio Janeiro are imperfect, and referred to this race with some doubt. Mr. S. Raymond Roberts collected specimens near Havana, Cuba. A large series from a whaler, Cape Cod, September 3, 1879, col- lected by Prof. A. E. Verrill, is interesting for its associates and coloration (pi. 13, figs. 2 to 2e). In all probability the vessel was a Provincetown schooner whaling in the West Indies, and the bar- nacles were gathered in course of the usual short (six months) voy- age. The wooden bottom was first rather copiously covered with Balanus trigonus up to about 8 mm. diameter. These were then mostly covered by flat, thin oysters (Ostrea folium Linnseus), mainly under 25 mm. in length, and by the Balanus tintinnabulum antil- lensis, which seem to have settled down at the same time. Upon these oysters and barnacles Tetraclita radiata sits, the specimens reaching a diameter of about 8 mm. There are also a few extremely young Balanus eburneus, 1 to 2 mm. diameter, which were clearly the last settlers, after the vessel returned to Massachusetts. The B. tintinnabulum antillensis of this lot measure 15 to 20 mm. diameter, with a height up to 25 mm., and may, perhaps, fall short of their full growth. The parietes are moderately ribbed, rose-pink to Indian lake, nearly uniform or in longitudinal stripes. The very wide radii are white or nearly so, very smooth and glossy. Sheath very pale. The base is roughened by the projecting edges of the concentric slips composing it (fig. 2a). Scuta and terga as in B. tintinnabulum tintinnabulum, the growth-ridges of the scuta somewhat crimped by the fine longitudinal striae. The scuta are rose tinted; terga white. Museum No. Locality. Collector. Jamaica C. B. Adams. Cape Cod on whaler from West Indies A. E. Verrill. 43499 . Rio Janeiro Balanus tintinnabulum, var. vesiculosus Darwin * was based upon extremely small individuals, scutum about 4 mm. long, and is scarcely comparable with the other forms. Indeed, it seems to have been regarded as a young stage rather than a true variety by Darwin. Monograph, etc., p. 195, pi. 2, fig. Hi. No locality. THE SESSILE BAENACLES. 65 There is a single specimen of unknown origin in the United States National Museum collection (Cat. No. 43496), which agrees with Darwin's too brief description. The scutum is 8.5 mm. long, the upper 4 mm. more coarsely ridged than usual in this part of the valve; the intervals between ridges are deepened to form a series of shallow pits between the tergal edge and a low rounded ridge or convexity which radiates from the apex, nearer to the occludent than to the scutal margin. The lower half of the valve is ridged as in typical tintinnabulum, without pits. The adductor ridge is acute and rather prominent, about as in B. t. antillensis. The other scutum of the same individual does not show the pits between growth ridges. The tergum is decidedly broader than the scutum, with narrow spur, remote from the basiscutal angle. The orifice is rather large and triangular; parietes weakly striate, the intervals between strias marked with dark violet lines. The wide radii are pale violet. Carinorostral diameter 16 mm., height 13.6 mm. This barnacle has a young specimen of Balanus improvisus assimilis Dai-win embedded in the base, suggesting a West Indian or South American habitat. It may prove to be a form of B. t. antillensis, but in the long series of that race I have examined none have pitted scuta. BALANUS TINTINNABULUM CALIFORNICUS, ne\» subspecies. Plate 14, figs. 1-3; plate 15, fig. 4. Type. — Cat. No. 9434a, U.S.N.M., from San Diego, California. Distribution. — Santa Barbara to San Diego, California. Conic, or sometimes tubular, with diamond-shaped or angularly ovate orifice. Parietes rather finely striate, the striae, white on a red (Indian-lake) ground, or some tint of that color; radii similar or paler, sometimes transversely striate near the level summits. Summits of the alse subhorizontal. Scutum similar to that of B. t. tintinnabulum, except that the depressor muscle impression is smaller and deeper; adductor impres- sion deep. The external growth ridges show more or less distinct traces of longitudinal striaB, and the outside is largely roseate, not distinctly bicolored as in B. t. coccopoma. Tergum rose or partly white, with faint longitudinal striae between the growth-ridges, the spur broad, about its own width from the basiscutal angle. The parietal tubes are extremely narrow and numerous (pi. 15, fig. 4, part of the rostrum, with attached vesicular basis on the right) , the septa being very thin and delicate, thereby differing from other forms of B. tintinnabulum. Greatest diameter 57 mm.; height 34 mm. The mouth parts and cirri are unknown, the specimens being preserved dry. 66 BULLETIN 93, UNITED STATES NATIONAL MUSEUM. When growing unhampered on a smooth object, this is a handsome barnacle, quite distinct in appearance from B. t. coccopoma, by the raised white strise of the parietes, as well as by the somewhat different opercular valves. The basi-tergal corner of the scutum is less cut off, and the tergal segment is less broadly deflected and less con- trasted in color. The tergum has a broader spur. When crowded, and sometimes under other circumstances, the shape becomes cylin- dric, with deep basis, such a shape as is often assumed by forms of B. tintinnabulum. Plate 14, figure 3, represents such a specimen from near Santa Barbara. The coloration, the crowded, narrow parietal tubes, the shorter, broader spur of the tergum, and the somewhat smaller size distinguish it from B. t. tintinndbulum. Unfortunately, only dry specimens, from which the body had been removed, are at hand. It appears to be a common barnacle from Santa Barbara to San Diego, at low- water mark, on rocks, oysters, shells, the carapaces of crabs, and on other barnacles, having about the same distribution as B. aquila. It will probably be found as far north as Monterey Bay, and may be expected southward along the ocean coast of the peninsula. So far as is known, this is the only form of B. tintinnabulum inhab- iting the Californian coast, though no doubt various oriental forms are constantly brought into the deep-water ports. Museum No. Locality. Collector. Notes. 91340 San Diego, Cal R. E. C. Stearns Type; figured. 9435 do ... C. R. Orcutt On Ostrea; figured 9434 do R. E. C. Stearns On jB. aquila. 11144 Santa Rosa Island P. Schumacher.. Do. 9179 San Miguel Island W.H. Ball 43484 Santa Barbara On rocks; figured (No label) On crab. BALANUS TINTINNABULUM PENINSULARIS, new subspecies. Plate 15, figs. 1 to 2d. Type.—C&t. No. 43486, U.S.N.M. Type-locality. — Cape St. Lucas, Lower California, growing on shells, etc., collected by John Xantus. No other locality is known. The barnacle is cylindric or conic, with an ovate-triangular orifice. Parietes cinereus, densely covered with lighter spines projecting toward the base; radii from light grayish-olive to fuscous-black, paler toward the rostrad edge, wide, deeply striate transversely, the sum- mits level, parallel to the base. Basal edges of the septa rather thick; basal pores about 18 to 21 in the rostrum. Sheath usually long, with the insides of the parietes dark, the strongly oblique alse pale. Greatest diameter 20 mm.; height 28 mm. (type). Greatest diameter 22 mm; height 17 mm. (conic specimen). THE SESSILE BARNACLES. 67 Scutum dull purple, with smooth growth-ridges. Adductor ridge strongly developed, rather acute. Terga white, shaped as in B. t. tintinnabulum, with a rather short, acute beak; the external furrow closed; spur narrow; scutal margin smooth. The labruni has a small median notch and no teeth on the shortly hairy edge. Mandible with five well-developed teeth, the last united with the lower point (fig. lla). Maxilla has 13 large spines, about as in B. t. tintinnabulum. Cirri about as in B. t. tintinnabulu7n} except that the segments of the three posterior cirri are not so short, and the lower pair of spines on each segment is smaller (lig. lib}. The above description applies to solitary specimens (figs. 2 to 2d) not encrusted by nullipore, algao, or other marine growths. In the FIG. 11.— a, MANDIBLE, AND b, MEDIAN SEGMENT OF CIRKUS vi, OF BAI/ANUS T. PENINSTJLAEIS. C, MEDIAN SEGMENT, CIRRUS VI, OF B. T. AZORICUS. large series comprised in Cat. No. 43487, U.S.N.M., the barnacles grow in clusters (figs. 1, la), and are overgrown with algae, etc. The spines in this lot are less fully developed, usually appearing only on some of the compartments, the others being irregularly ribbed, plicate, or nearly smooth. Some individuals lack spines altogether. The radii are often smooth, rarely striate throughout. The color may be soiled white throughout, or like the type, or lineate and clouded with livid purple, the radii being livid purple, shading into white along one side. The opercular valves are similar to the typical form. I worked over this race a long time in an attempt to identify it with one or other of Darwin's named forms of B. tintinnabulum, finally deciding to give it subspecific rank. Darwin's account of B. t. dorbignyi Chenu, and Chenu's figure, resemble peninsularis rather closely, yet differ by the oblique summits of the radii. Chenu gives no figure of the opercular valves, and Darwin says that the tergum 68 BULLETIN 93, UNITED STATES NATIONAL MUSEUM. is like that of occator. This does not apply to peninsularis, which has the tergum like B. t. tintinnabulum. According to Darwin, B. t. dorbignyi was taken from a ship from Java. B. t. spinosus and B. t. occator are oriental forms, certainly distinct from the present subspecies. B. t. crispatus Schroter, as figured by Schroter, agrees better with our specimens, but it is from an oriental locality, just where being uncertain, as all known examples are from ship's bottoms. There are various discrepancies between our speci- mens and Darwin's account and figures, which cause me to hesitate to assume their identity. Moreover, it is not at all likely that an oriental form was imported to such an out-of-the-way place as Cape St. Lucas, where it seems to be abundant, growing on native shells, etc. It is equally unlikely that the ship furnishing Schroter's specimens could have picked them up in Lower California prior to 1786. Nonspinose individuals of B. t. peninsularis are a good deal like the Antillean B. t. antillensis in color, size, and opercular valves, but the eastern form seems never to become spinose in the lot of several hundred I have seen. BALANUS TINTINNABULUM COCCOPOMA Darwin. Plate 16, figs. 1, la, 2, 2a. 1854. Balanus tintinnabulum, var. coccopoma DARWIN, Monograph, etc., p. 196, pi. 1, fig. d; pi. 2, figs. I/, II, lo. Type. — British Museum, from Panama. Distribution. — Panama to Mazatlan. Coiivexly conic, with small rounded orifice, or sometimes cylindric, with the orifice large,, Walls smooth or weakly striate, the parietes roseate (spinal red or hellebore red of Bidgway), radii vinaceous purple or rarely white. Greatest diameter 30 mm.; height 26 mm.; specimens with a long, cylindric basis up to 50 mm. long. Scutum vinaceous purple, fading toward the lower margin, the deflected tergal segment broad, cream white; adductor ridge promi- nent, slightly overhanging the deep pit of the depressor muscle; a.rticular rib terminating in a broad free point; basiscutal angle usually much cut off, but sometimes shaped as in typical tintinna- bulum; external growth-ridges close, smooth. Tergum as in B. t. tintinnabulum [or "sometimes with a broader spur placed nearer to the basiscutal corner of the valve"]. This small, deep rose-colored race is restricted to the Panamic faunal Province,1 and appears to be rather a common littoral barnacle. It has a very distinct appearance, but no doubt Darwin was right in 1 Darwin mentions specimens resembling this variety sent him as "from a ship direct from China;" but such data are open to doubt. Possibly he had B. t. rosa. The types were on a pearl oyster from Panama "as Mr. Cuming believes;" and I have seen a good many from that place. M. Gruvel has reported it from "California," but if the locality of his specimens is correct, they will probably be found to be B. t. calif ornicus. THE SESSILE BARNACLES. 69 giving it the same rank as the other races subordinated to B. tintin- nabulum. Some specimens in the collection of the Academy of Natural Sciences of Philadelphia, received from Frederick Stearns, are labeled "West coast of Lower California." Part of them are cylindric, with lengthened bases. Darwin mentions a form of B. tintinnabulum from the coast of Mexico and California which is "rugged and of a dull bluish-purple" color, with "opercular valves exactly like those of var. coccopoma. I have not seen it. 11 Locality. Collector Museum. Panama, on oysters . Panama Salinas Bay. Costa Rica Bottom of U. S. S. Portsmouth after leaving Guayinas, Mexico. Mazatlan, Mexico Dr. W. S. W. Ruschenberger, United States Navy. Samuel N. Rhoads Anastasio Alfaro Dr. W. II. Jones, United States Navy. Dr. Paul Bartsch Academy of Natural Sciences, Philadelphia. Do. Do. United States National Museum. Do. BALANUS TINTINNABULUM CONCINNUS Darwin. Plate 16, fig. 3; plate 17, figs. 5-8. 1854. Balanus tintinnabulum, var. concinnus DARWIN, Monograph, etc., p. 196, pi. 1, fig. e; pi. 2, fig. Ig. 1903. Balanus tintinnabulum, var. concinnus GRUVEL, Nouv. Archives du Muse'um 4ser., vol. 5, p. 126. 1909. Balanus tintinnabulum Linnseus, PILSBRY, Proc. U. S. Nat. Mus., vol. 37, p. 65, pi. 16, fig. 3; pi. 18, figs. 5-8. Type. — British Museum. Distribution.— Straits of Magellan to Peru. The barnacle is large, cylindric, or somewhat conic, the orifice usually large. The parietes are nearly smooth or a little roughened, sometimes striate, sometimes weakly plicate; with many longitudinal lines and waved, transverse, narrow streaks of livid purple and livid violet on a whitish ground, producing a finely speckled pattern. Radii broad, with horizontal summits; violet-plumbeous. Alae with nearly horizontal summits. Sheath livid purplish with paler al&3. The scutum (pi. 15, fig. 3; pi. 17, figs. 6, 8) has the basi-tergal corner a good deal cut off, the deflected tergal segment broad; external growth-ridges rather coarse and prominent; longitudinal strise usually conspicuous. Adductor ridge acute and prominent, broadly overhanging the deep and large pit for tlie lateral depressor muscle. The rostral depressor pit is often bounded by a small rib. The tergum is substantially as in B. t. tintinnabulum, except that it is conspicuously striated longitudinally between the narrow growth- ridges, the stria3 coarse on- the scutal side of the closed furrow, fine on the broader side. Spur separated from the basiscutal angle by twice its own width. 4729°— Bull. 93—16—6 70 BULLETIN 93, UNITED STATES NATIONAL MUSEUM. According to Darwin, the segments of the sixth pair of cirri bear six pairs of spines. The conic form is often not large: diameter 33 mm., height 38 mm. (Pacasmayo). The cylindric forms are larger; diameter 40 mm., height 50 mm. (Payta). The largest individual seen in which the base is flattened measures about 67 mm. in greatest diameter, 85 mm. height. It is from the coast of Peru. Some individuals have a very long base, as in B. psittacus. One taken from a wreck at Payta is 150 mm. long, of which the parietes occupy hardly 40 mm.; greatest diameter 42 mm. In these examples the vertical sides of the base are longitudinally plicate, and clouded with white and livid purple. The pocket-like cavity runs down to a point. B. t. concinnus is well defined by the speckled coloration of the parietes, the sculpture of tergum and scutum, and the acute, over- hanging adductor ridge of the latter. According to Darwin, the joints of the last cirrus bear six pairs of spines instead of four. Like B. t. californicus it is a strongly individualized form. Possibly both may deserve specific rank. Darwin gives the locality west coast of South America. Gruvel records it from the Straits of Magellan, on B. psittacus, also Aden and French-Congo. The last two records, if really pertaining to concinnus, must have been based on specimens taken to those places on ships. The records of B. tintinnabulum communis from the west coast of South America may possibly be based on specimens of concinnus. Museum No. Locality. Collector. Notes. Bay of Sechura, Peru Dr. R. E.Coker In 5 to 6 fathoms. 9223 Facasmayo, Peru Dr. W. H.Jones... On beach 43491 ... . .. .do do Chain on pier. 43490 Coast of Peru W. E. Curtis 43492 Payta, Peru Lieut. W. C. Babcock On a wreck BALANUS TINTINNABULUM GALAPAGANUS, new subspecies. Plate 12, figs. 1, la, 16. Type.— Cat. No. 48003, U.S.N.M., from Hood Island, Galapagos, on a rock, Albatross, April 7, 1888. The barnacle is conic with a rather small orifice and smooth or weakly ribbed parietes ; white or pink, with red lines on the parietes ; radii whitish, usually grooved transversely, their summits level; summits of the alse very oblique. Height 10 mm. ; diameter 15 mm. Height 10 mm.; diameter 13 mm. Scutum pale grayish-pink, flat, the tergal border not noticeably deflected. Sculpture of close, sigmoid growth-ridges, no longitudinal stride. Adductor ridge very small, merely an acute ledge alongside the depressor muscle-impression. THE SESSILE BARNACLES. 71 Tergum whitish, striate on the carinal area, with growth-ridges on the scutal area; furrow closed or almost closed; spur narrow, fully double its own width, or more, from the basiscutal angle. This form differs from B. t. concinnus of the mainland by the flat scutum. I have compared scuta of concinnus of the same size and smaller, and in all of them the tergal segment is broadly deflected, as in the adult stage. The external color reminds one of B. concavus. B. t. coccopoma also has a wide deflected tergal border of the scutum, and the external form and color are different. In specimens of B. t. tintinnabulum a little larger than the Gala- pagos form, the tergal edge of the scutum is noticeably -inflected. Otherwise there seems little difference between them. Possibly the Galapagos specimens may be the descendants of imported examples of this oriental subspecies, though it seems to me rather unlikely? Dar- win mentions tintinnabulum from the Galapagos, without comment. As- he treats rather fully of the West American forms, it would seem likely that if he found "var. communis3' there he would have made note of it. Over 60 individuals are grouped on a volcanic rock about 8 inches long. From the nearly equal size of the larger ones, of the bases left by their departed brethren, and the nearly closed furrow of the tergum, it may be inferred that they are nearly or quite adult; yet I feel some doubt on account of the fact that the parietes below the sheath are ribbed. In the fully adult stage, B. tintinnabulum has a smoother interior. Some individuals of the smaller subspecies, such as occator and spinosus I have examined are strongly ribbed within, though doubtless of full size; others, probably older, though not larger, have the interior smooth, except near the base. However this may be, it appears that the Galapagos form differs from other known races of the west coast of the Americas and should be readily recognizable, even if it proves to attain a size greater than the type lot. There is another West American form of tintinnabulum apparently differing from those described above. It was taken by Dr. L. Plate at Cavanche, near Iquique, to a depth of 50 meters, and has been described by Weltner.1 The shell is white, and rather strongly ribbed, "like porcatus" the sheath uncolored or pale rose; radii are very oblique. The scutum has sculpture like occator. The size is up to 30 mm. in height. In color it cartainly resemblos B. psittacus. Other named oriental forms of B. tintinnabulum may be men- tioned here. Variety intermedius Darwin, locality unknown, and var. dorlignyii Chenu, which Darwin reports from a ship from Java, are not represented in the United Statss National Museum collection. 1 Archiv fur Naturgeschichte, 61 Jakrg., 1895, p. 291. 72 BULLETIN 93, UNITED STATES NATIONAL MUSEUM. Hoek lias described two new varieties: var. costatus and var. pli- catus,1 both taken from the bottom of the Siboga and therefore from some part of the Malay Archipelago. Var. costatus was based upon one specimen 14 mm. in diameter; var. plicatus upon two, the larger of 10 mm. diameter. The open furrow of the tergum probably means that both were young barnacles. Quite possibly both may be the young of var. zebra Darwin. In any case, the very great difficulty of reaching a satisfactory understanding of the forms of B, tintinndbulum can not be lightened by the description of scanty, immature, and imperfectly localized material. BALANUS ALGICOLA, new species. Plate 12, figs. 3 to 3y. Type. — Cat. No. 15063, U.S.N.M., from Cape Town, growing on algse, collected by Win. Harvey Brown, United States eclipse expe- dition, 1889. Distribution. — South Africa. D FIG. 12.— BALANUS ALGICOLA a, b, TEKGA OF TWO AND d, e,f, SCUTA or THREE INDIVIDUALS, c, PART OF TUB EDGE OF A RADIUS, SHOWING DENTICULATE SEPTA AND OPEN ENDS OF THE EADIAL PORES. Very small, conic or cylindric, usually growing in crowded clus- ters; white, or sometimes with faint violet stains, chiefly on the radii ; smooth or somewhat ribbed. Diameter 7 mm.; height 9 mm. (typical, cylindric form). Diameter 11 mm.; height 6 mm. (solitary, conic form). Scutum very broad, having widely spaced growth-ridges, alternate ones forming teeth along the occludent margin; no radial striation. A broad, shallow depression runs down the middle of the valve. The tergal border is rather narrowly deflected. Tho basitergal angle is cut off in varying degree, as shown in figure 12 d, e,f. The articular ridge is moderately high, reflexed, with its lower end trun- 1 Both of these names are preoccupied in Balanus. THE SESSILE BARNACLES. 73 cated or slightly overhanging. A ridge runs downward from it, bordering the deep pit of the lateral depressor muscle, but there is no adductor ridge. Pit for the adductor muscle is well marked. The tergum has the longitudinal furrow more or less open. Spur rather short, with rounded end, situated about its own width, more or less, from the basiscutal angle. Articular ridge strong. There are no crests for the depressor muscle. Compartments. — The parietes are typically smooth, but in some conic, solitary individuals they have rather numerous ribs. The radii are wide, with level summits. The lateral edges of the radii and the opposed sutural edges are rather coarsely septate, but the septa are either not distinctly denticulate, merely a little irregular, or there may be a few coarse denticbs on on3 side (fig. 12c). The hoiizontal pores of the radii are well developed. FIG. 13.— BALANUS ALGICOLA. a, MAXILLA. 6, UTII SEGMENT OP CIRRUS vi. c, MANDIBLE, d, MORE ENLARGED THIRD TOOTH AND LOWER POINT OF THE MANDIBLE. The basis is not very thick. It is radially porous, without a cel- lular under-layer, so far as seen. The labrum has three minute teeth on each side. The mandible has three strong teeth, the fourth and fifth being quite small and short (fig. 13c, fZ). The maxilla has 8 to 10 large spines. The margin protrudes some- what toward the lower border (fig. 13o). The cirri are purple. The first three pairs are quite short, as in tintinnabulum; the later ones are not very long, and have segments a little wider than long. The sixth pair has rarni of about 22 segments with from six to eight pairs of spines on the middle segments (fig. 136). I could find no spinules along the distal borders of the segments, such as other races of B. tintinnabulum have. 74 BULLETIN 93, UNITED STATES NATIONAL MUSEUM. The penis is more than twice as long as the last cirri, and has a conspicuous, acute, basidorsal point. Several hundred specimens in the United States National Museum show this to be a distinct species of the tintinnabulum group. They have the form and appearance of mature barnacles. Nearly all of those I opened contained large masses of eggs, of the usual elliptical shape, and from 0.12 to 0.14 mm. long, much smaller than the eggs of tintinnabulum. While we know that Balanus reproduces long before attaining its maximum size, yet the eggs produced by small individuals equal in size those of the larger. The great number of spines on the later cirri is also a feature of maturity. Very young barnacles have fewer spines than old ones. I am therefore convinced that these pygmy barnacles are mature. I believe that Darwin had the same race before him, but mistook it for young B. tintinnabulum, when he stated that ' ' in some young specimens from the Cape of Good Hope * * * I found six pairs of spines on the segments of the posterior cirri." (Monograph, p. 200.) While this barnacle is certainly related to B. tintinnabulum by the shape of the terga, it differs in so many characters that I can not rank it as a subspecies. Except the small size, these characters are not directly correlated with its peculiar station. The structure of the walls is that common to species of Megabalanus, but special differen- tial features of B. algicola are: The small size and pale color; simpli- fied sutural septa (those of B. tintinnabulum being denticulate on both sides); the broad scuta; the short lower teeth of the mandible; the numerous spines of the posterior cirri, and the absence of spinules along the distal borders of the segments. B. algicola grows on alga?, usually in masses mounted upon one another, and is apparently a very abundant form. BALANUS AJAX Darwin. 1854. Balanus ajax DARWIN, Monograph, etc., p. 214, pi. 3, figs, la-lc?. (Philip- pine Archipelago.) 1884. Balanus ajax Darwin, FISCHER, Bull. Soc. Zool. de France, vol. 9, p. 357. 1907. Balanus ajax Darwin, GRUVEL, Bull. Soc. Zool. de France, vol. 32, p. 164. Locality.— Mariveles, Luzon, Paul Bartsch. Cat. No. 43498, U.S.N.M. I do not find that any definite locality in the Philippines has been given for this barnacle, which, though related to B. tintinnabulum, is characterized by its "excessively strong, massive, and heavy" walls, dark sheath, and large rostral compartment. According to Dr. Paul Fischer, it has been collected by Lambert from reefs south of the Isle of Pines, New Caledonia. Professor Gruvel adds the localities Salomon Island, in the Chagos Archipelago, and Seychelles. THE SESSILE BARNACLES. 75 BALANUS PSITTACUS (Molina). Plate 17, figa. 1 to 4; plate 18, figs. 1 to 3. 1782. Lepas psittacus MOLINA, Saggio sulla storia naturale del Chili.1 1818. Balanus tintinnabulum, var. c. RANZANI, Opuscoli Sci., vol. 4, p. 69, pi. 3, figs. 1-4. 1831. Balanus picos LESSON, Voyage autour du Monde de la Coquille, Zoologie, vol. 2, pt. 1, p. 445 (Concepcion, Talcahuano, S. Vincent, Chili). 1854. Balanus psittacus DARWIN, Monograph on the Cirripedia, Balanidse, p. 206, pi. 2, figs. 3a-d (Arica to Chiloe I., Chili). 1904. Balanus psittacus Molina, GRUVEL, Nouvelles Archives du Muse'um d'Hist. Nat., se"r. 4, vol. 6, p. 103, fig. 9. 1905. Balanus psittacus VAYSSIERE, Annales de la Faculty des Sciences de Mar- seille, vol. 15, fasc. 5, p. 161, pi. 1, figs. 1-4 ("Taleahuana," Chili). 1909. Balanus psittacus (Molina) PILSBRY, Proc. U. S. Nat. 'Mug., vol. 37, p. 66, pi. 16, figs. 1, 4; pi. 18, figs. 1-4. Distribution. — Strait of Magellan to Pacasmayo, Peru. The barnacle is pale pink or sometimes soiled white, conio when young, often becoming subcylindric with age, sometimes very large, with a very long tapering basis. The scutum (pi. 17, figs. 3, 4) is trapezoidal, the basitergal corner being cut off, forming an oblique edge parallel to the occludent margin, and about as long as the rest of the base; tergal third of the valve deflected. Sculpture of rather strong growth-ridges crossed by fine but deeply engraved longitudinal strise. Articular furrow nar- row. Articular ridge high and thin, continuous with the high, oblique adductor ridge, which arches over the space between the ridges, leaving a cavity wliicli penetrates nearly to the apex. The tergum is very narrow and long, terminating in a long IteaTc of a pink or purplish color. The spur is long, narrow, and less than its own width from the basiscutal angle, usually very close to it. Groove to the spur closed. External sculpture of growth-ridges and radial striae, but both are often very weak. Inside, the articular ridge stands upon that running to the spur. Between this ridge and the carinal border there is a short, narrow, longitudinal ridge; these ridges and an oblong space between them being purple or deep pink. There are no crests for the depressor muscles. Compartments. — The tubes in the parietes are rather large, not. filled up above, and not transversely septate. The inside below the sheath is ribbed in young, usually becoming smooth in large indi- viduals. The radii are very wide, with level summits, and permeated by unusually large pores. Their distal edges are wide, with rather coarse, branching laminsB, which are deeply denticulate on then- lower sides only. Alse have oblique summits. Laminse of the sutural edges denticulate on the upper side. 1 See Proc. U. S. Nat. Mus., vol. 37, p. 6(3, footnote a, for some account of the various editions of the Abbe Molina's Natural History of Chile. 76 BULLETIN 93, UNITED STATES NATIONAL MUSEUM. The basis, in the small form, is flat, porous, often with an under- lying multicellular layer. In the large form, the basis is lengthened, forming half or three-fourths of the walls, and the cavity usually tapers downward. According to Gravel, it consists of two portions, the true basis and an intermediate segment which he terms the false wall ("pseudo-muraille"), wherein the porous hypodermic layer is reduced to a minimum, the greater part being solid and secreted by the mantle. The littoral form of B. psittacus, which is what the Abbe Molina described, is not a very large barnacle, in shape from conic to cylin- dric. In a series from Valparaiso the diameter is 35 to 40 mm. ; height 40 to 45 mm. The basis is flat or but little built up. The walls are thin or moderately thick; and the parietes are usually ribbed near the summits, but sometimes part or all of them are nearly smooth. A series of varying sizes, down to 2.5 mm. diameter shows that in the early stage, up to about 6. mm. in diameter and height, the parietes are quite smooth. In some individuals a ribbed stage then ensues, to be followed by another smooth stage. In individuals 6 mm. in diameter the opercular valves are exactly as in adults, except that the furrow of the terguni is not closed. At this stage the radii are very narrow. Some of the specimens from Arica show the best development of the ribs (pi. 18, fig. 3). The inside, below the sheath, is strongly ribbed. Examples from Chincha Islands, "abundant on the shore rocks," and others from the Pescadores Islands, collected by Dr. R. E. Coker, are small, though clearly adult. They measure 35 to 45 mm. high, 25 to 35 mm. in basal diameter. The shape is conic or vertical-sided; parietes irregularly ribbed, radii rather wide. The orifice is ovate, or angular at the sides and truncate at the rostral end. The color is dull whitish gray, sometimes partly dull pink. The parietes are ribbed lengthwise inside below the sheath. The basis is as flat as circumstances permit, and either forms no part of the side walls or is but slightly excavated. A group from the Chincha Islands, No. 38692 U.S.N.M., is figured1 of the natural size in plate 16, figure 4, of my paper on Peruvian barnacles. A very large and massive form of B. psittacus is found on the Chilean coast. The lengthened basis forms about one-half of the total height of the side walls. It is irregularly plicate longitudinally, the folds rounded; compartments usually worn, and giving foothold to numerous young of its own kind, B. Isevis nitidus and Verruca Isevigata. Orifice nearly as large as the tube. They grow in groups, diverging from the base. The largest in a group from Conception » Proc. U. S. Nat. Mus., vol. 37. THE SESSILE BARNACLES. 77 Bay measures 20 cm. long, 8.3 cm. in greatest diameter. One from Talcahuano Bay measures 18 cm. long, 8.5 cm. diameter. A specimen from Pacasmayo, Peru,1 differs from these by being much thinner, and the basis is longer, forming about two-thirds of Length 16 cm.; greatest diameter 6.2 cm. the height. Museum No. Locality. Collector or donor. 3SG92 ChinrVha Islands, Peru, shore. R. E. Coker. Pescadores Islands, Peru Do. 15474 Pacasmayo, Peru W. H. Jones United States 48124 Arica, Peru Navy. I. Lea collection. 434S3 Talcahuano Bay, Chile R. E. C. Steams collection. 48125 Valparaiso. Chile. Chile 4S123 Port Churruca, Strait of Magellan A IbatTosn. BALANUS MAXILLARIS Gronovius. 1763. Balanus maxillaris GRONOVIUS, Zoophylacii Gronoviani, IconograpMa sive Tabularum Explicatio, vol. 5. pi. 19, figs. 3, 4. 1790. Lepas cylindrica GMELIN, Systema Naturae, p. 3213. 1854. Balanus capensis Ellis, DARWIN, Monograph, p. 209, pi. 2, figs. 4a, 46. Distribution. — Cape of Good Hope (Algoa Bay and Lagulhas Bank). Cat. No. 3596, Cape Town, U. S. Expl. Exped.; young specimens only. Ellis, who is usually given as the authority for the species capensis, did not make the slightest attempt to use the Linnaean system of nomenclature and certainly can not be quoted for specific names. BALANUS DECORUS Darwin. 1854. Balanus decorus DARWIN, Monograph, p. 212, p. 2, figs. Ga, 66. Type. — British Museum, from New Zealand. Wanganui, New Zealand. S. H. Drew, Chatham Islands, New Zealand, Dr. E. Kershner. As the opercular valves are wanting, the identification is not positive. Subgenus BALANUS Da Costa. = Balanus + Tamiosoma CONRAD, 1856 + Ortho-Balanus HOEK, Siboga-Expe- ditie, Monographie, 316, 1913, p. 158, B. amphitrite here selected as type. Balani in which the parietes but not the radii are porous; basis calcareous, either solid or porous; cirrus iii (and sometimes iv-vi) armed with teeth or spmules. At one time I thought that Hoek's subgerms Oriho-Balanus could be maintained for the species with porous basis, Darwin's Section C; but it is clear that B. nubilis and B. flos, which have the basis incom- Figured in Proc. U. S. Nat. Mus., vol. 37 pi. 16, fig. 1. 78 BULLETIN 93, UNITED STATES NATIONAL MUSEUM. pletely porous, are more related to B. balanus (with a solid basis) by the characters of the maxillse and terga. A division founded upon the character of the basis would not be natural. The armature of the cirri, the sculpture of the scuta and the shape of the terga are diversified so much, and in combinations so various, that unless the group is to be divided into at least six sections, it had better be left intact. In this opinion I find myself in agreement with Doctor Hoek. The interrelations of the species may be shown by a grouping into eight series, of which the first three may be bracketed together, and similarly the last four. [Series of B. ampTiitrite. I Series of B. trigonus. (Series of B. perforatus. Series of B. gregarius. Series of B. aguila. Series of B. nubilis. Series of B. balanus. Series of B. crenatus. The following species, not contained in the United States National Museum, belong to this subgenus, part of them being doubtfully distinct from B. amphitrite. Some notes on their characters and affinities are appended. Balanus poecilus Darwin. See p. 110. Balanus minutus Hoek. Siboga-Expeditie, Cirripedia (p. 177). Entrance of Kwangdang Bay, 80 meters. One specimen on a crinoid pinnule, diameter about 3.7 mm. Pink with reddish stripes. This and B. alatus are similar externally to B. amphitrite, but differ by wanting an adductor ridge in the scutum. From the color,, both may be expected to occur also in shallower water, as the truly deep-sea species are usually white. B. poecilus, alatus, and minutus are alike in having no adductor ridge. Balanus Jiystrix Hoek. /Si&o^a-Expeditie, Cirripedia (p. 218). Ambon anchorage, reef. Diameter 5 mm. Third to fifth pairs of cirri armed with recurved teeth on the anterior borders of the seg- ments. It probably stands near B. perforatus. Balanus wolaceus Gruvel. Nouv. Arch, du Mus. (ser. 4, vol. 5, 1903, p. 133). Locality unknown; type in British Museum. Near B. ampliitrite. It is not Lepas violacea Gmelin, also a Balanus. Balanus dybowskii Gruvel. Nouv. Arch, du Mus. (ser. 4, vol. 5, 1903, p. 143). Congo. Diameter 6 mm.; no radii. The absence of radii may be due to their removal by the very deep erosion of the surface, which also gives the opercular valves a peculiar shape. It will probably turn out to be closely related to B. ampliitrite or a variety thereof. THE SESSILE BARNACLES. 79 Balanus miraMlis Krtiger. Abh. math-pliys. Klasse der K. Bayer. Akad. der Wissensch. (vol. 2, Suppl.-Bd., 8 Abhandlg., 1912, p. 11). Japan. Diameter 20.5 mm.; the walls and opercular valves are very deeply eroded, and therefore no radii are visible. The peculiarly hollowed out tergal border of the scutum is due to erosion of the outer layer of the valve, and will not be present when unworn specimens are found. Affinities uncertain, but I fancy that it will turn out to be a form of B. amphitrite. It is not Balanus perforatus, var. mirabilis Darwin. Balanus patdlaris Spengler, Darwin, Monograph (p. 259). KEY TO RECENT AMERICAN SPECIES. a1. Scutum having one to three longitudinal furrows; tergum with a spur-furrow. B. Isevis, p. 120. a2. Scutum having one or several longitudinal rows of pits, and without a distinct adductor ridge; tergum without spur-furrow, the spur broad, short, and truncate. B. trigonus, p. 111. a3. Scutum distinctly striate longitudinally. 61. Ribs at inner base of the parietes more numerous than the septa in the wall (pi. 35); basis not porous. c1. Tubes in the parietes without transverse septa. Northern. . B. balanus, p. 149. c2. Tubes in the parietes having transverse septa, in the upper half or throughout. Northern Pacific B. rostratus, p. 138. b2. Ribs of the parietes within all continuous with septa in the wall (pi. 40, fig. 4a). c1. Adductor ridge of the scutum well developed; tergum with a spur-furrow, sometimes closed by infolding of the sides. dl. Tergum purple-beaked, with long, narrow spur; pit of the lateral depressor muscle of scutum not bounded by a ridge. A large white, ribbed bar- nacle, often with yellow epidermis; basis nearly solid. California. B. aquila, p. 127. d2. Tergum not beaked; lateral depressor pit of scutum having a raised edge; wall usually pink-striped; basis porous. California to Peru. B. concavus pacificus, p. 104. c2. Adductor ridge of scutum well developed; tergum without spur-furrow, its basal margin hollowed out on the carinal side of the spur; wall white, smooth, with yellow epidermis, the radii wide. Atlantic and Gulf of Mexico. B. eburneus, p. 80. c3. Adductor ridge of the scutum weak; tergum without a spur-furrow, the spur short, truncate distally. d1. Wall smooth; scutum very strongly striate, latticed; basal margin of tergum not forming an angle with the carinal side of the spur. B. spongicola, p. 115. (P. Wall ribbed; scutum less strongly sculptured; basal margin of tergum form- ing an angle with the carinal side of the spur. Antilles, Gulf of Mexico. B. calidus, p. 118. a4. Scutum not striate longitudinally, or very indistinctly so. b1. Ribs at base of parietes inside more numerous than septa in the wall (pi. 35); basis not porous; beaks of terga project upward far beyond the scuta. c1. Tubes in the parietea withotit transverse septa B. balanus, p. 149. c2. Tubes in the parietes having transverse septa in upper part or throughout. B. rostratus, p. 138. 80 BULLETIN 93, UNITED STATES NATIONAL MUSEUM. 62. Ribs of the parietes within all continuous with septa in the wall (pi. 40, fig. 4a). c1. Spur short, near the basi-scutal angle of tergxim. dl. Adductor ridge of scutum strongly developed, remote from the pit of the lateral depressor muscle. e1. Radii narrow, with smooth, oblique summits; walls smooth, white under a yellowish epidermis; spur of tergum one-fourth the width of the basal margin or less B. improvisus, p. 84. e2. Radii rather wide; walls white or colored; spur wider. /'. Spur of tergum about one-third the width of the basal margin; basis conspicuously porous; diameter up to about 25 mm., usually much less B. arnphitrite, p. 89. f2. Spur nearly one-half the basal width; basis with but few pores; sheath dark colored; diameter up to about 30 mm. Peru. B. peruvianus, p. 97. d2. Adductor ridge of scutum short, a pit below it (pi. 43, figs. 4, 6, 7); spur of tergum very short, broad, and truncate; basis not porous. West coast of North America B. glandula, p. 178. d3. No adductor ridge in the scutum. e1. Basis porous; walls smooth, fragile, dull red, freckled with white. West coast of South America B. pcecilus, p. 110. e2. Basis not porous; walls smooth or ribbed, white; opercular valves with strong articular ridges. Northern seas B. crenatus, p. 165. c2. Spur wide at the base, tapering distally, rather remote from the basiscutal angle, and near the middle of the basal margin. Adductor ridge of scutum close to the pit for the lateral depressor muscle. d1. Opercular valves white, thin; adductor ridge of scutum weakly developed. California B. flos, p. 135. d2. Opercular valves buff, solid; adductor ridge of scutum strong. West Coast. B. nubilis, p. 131. NOTE. — B regalis, p. 108, is not included in the above key, as its opercular valves are unknown. SERIES OP B. AMPHITRITE. BALANUS EBURNEUS Gould. Plate 24, figs. 1-lc, 2. 1841. Balanus eburneus GOULD, Invertebrata of Massachusetts, p. 15, pi. 1, fig. 6. 1854. Balanus eburneus Gould, DARWIN, Monograph, p. 248, pi. 5, figs. 4a-4d. 1874. Balanus eburneus Gould, VERRILL, Invertebrate Animals of Vineyard Sound, p. 285, in Report of Commissioner of Fish and Fisheries, p. 579. 1897. Balanus eburneus A. Gould, WELTNER, Verzeichnia recenter Cirripedien- arten, p. 2G6. 1911. Balanus eburneus Gould, SUMNER, Bull. Bur. of Fisheries, vol. 31, p. 129, 302, 645, chart 84. Type-locality. — Boston Bay, Massachusetts. Distribution. — Massachusetts to the Caribbean coast of South Amer- ica, low water to about 20 fathoms. The barnacle is obliquely conic or sometimes shortly cylindric, smooth, with a very acutely ovate orifice. Parietes and opercular valves white, covered with light yellow epidermis, the radii white, without epidermis. THE SESSILE BARNACLES. 81 The scutum has rather fine, ripplelike growth-ridges crossed by clearly cut radial grooves. The articular ridge is very high and termi- nates in a free point. Adductor ridge high but short; there is a small ridge running parallel to it, near the depressor muscle insertion. The upper part of the valve is thickened and rough. The tergum is broad, without an external furrow. The carinal margin is highly arched, having a sort of low appendage built upon it. Spur long, truncate at the end, and separated from the basiscutal angle by about half its own width. There is a deep or shallow bay in the basal margin on the carinal side of the spur, which, when fully developed, gives the valve a thre&-pronged outline, very characteristic of the species in its adult stage. The articular rib is moderately developed, the crests for the depressor muscles usually weak. m FIG. 14.— BALANUS EBURNEUS. a, PALPUS. 5, MANDIBLE, c, LABKUM. d, MAXILLA. SMITH'S CREEK, POTOMAC RIVER. The radii are wide, with oblique, somewhat crenulated and irregular summits. (See p. 85, fig. 16&.) The parietes have strong, regular internal ribs, the sides of which are usually minutely striated longi- tudinally. The parietal tubes are copiously provided with transverse septa, down to the base. There are usually 16 to 20 tubes in the rostrum. Hollows behind the sheath are very shallow. The carina stands steeper than the rostrum, and is sometimes recurved. The basis is very porous, pores large near the periphery and having trans- verse septa. Labrum armed with numerous teeth, with series of smaller teeth running down the sides of the notch (fig. 14c). Palpi densely hairy in 82 BULLETIN 93, UNITED STATES NATIONAL MUSEUM. a broad band along the upper and distal borders, and having a series of long spines at the distal fourth (fig. 14«). Mandible with three acute, widely spaced teeth, with three short, blunt teeth below (fig. 14&). Maxilla has 17 spines, the smaller ones between the upper and lower larger pairs being pectinated. The lower pair stands on a long prominence, below which the margin is densely hairy (fig. 14^). A young specimen from Betterton, Maryland, 7 mm. diameter, has only 10 spines. Cirrus i has very unequal rami of 31 and 19 segments, those of the shorter ramus very protuberant. Cirrus ii has unequal rami of 21 and 16 segments, all protuberant. Cirrus iii has 23 and 20 segments, the anterior ramus longer by six segments. All the segments of the outer ramus are protuberant, the FIG. 15.— BALANUS EBURNEUS. a, 27TH SEGMENT OF CIRRUS vi. b, PROTUBERANT PORTION OF THE 13TH SEGMENT OF ANTERIOR RAMUS, CIRRUS III. SMITH'S CREEK, POTOMAC RIVER. protuberance armed with a distal row of erect, spike-like spinules, a rather large anterior area set with many short, conic spinules (fig. 156). The posterior rarnus has long spines in place of the anterior patch of spinules, and a double subsutural row of erect spinules. Cirrus iv has the anterior ramus armed like that of cirrus iii; posterior ramus without spinules. Cirri v and vi have no spinules. The segments bear 7 to 9 pairs of spines, which as usual are pectinated near the end (fig. 15a). This is one of the common species along the Atlantic seaboard, to be found wherever suitable situations offer standing room. Probably the scarcity of records from the West Indies and Gulf of Mexico is due to the small amount of shore collecting in those areas. The smooth, neat contour, rather wide radii with jagged summits (but often broken) , the longitudinally striate scutum and pronged tergum are such easy recognition marks that no one need mistake the adult THE SESSILE BARNACLES. 83 barnacle for any other. Young specimens in which the sculpture of the scutum and the emargination of the base of the tergurn have not been developed, are perhaps most easily recognized by examination of the cirri, which differ from those of improvisus, amphitrite and crenatus, species inhabiting the same waters. B. eburneus and B. improvisus never develop ribs, and are never colored. B. eburneus has some superficial resemblance to small specimens of B. Jiameri. It is closely related to B. improvisus, and small or young individuals in which the tergum has not assumed the bird's-foot shape, and the stria? of the scutum have not yet appeared, are often extremely hard to distinguish from that species. Darwin writes: I for some time mistook the var. assimilis of B. improvisus for the young of B. eburneus. But I found in the latter that the rami of the first pair of cirri are always, even in the earliest youth, more unequal in length, and that each segment of the posterior cirri bears a greater number of pairs of spines, there being, even in very minute specimens, seven pairs. Moreover, after having examined scores of speci- mens, I found I could almost always distinguish the two species by the smoothness and curvature of the summits of the radii of B. improvisus; I entertain no doubt whatever about the distinctness of the two species; indeed, when both are mature, besides the greater size, striated scuta, etc., of B. eburneus, their general aspect is veiy different. B. eburneus varies but little. The basal margin of the scutum is not always so hollowed out as in the individual figured ; and of course in quite young individuals it is not at all hollowed out. Pleistocene examples from the Panama Canal Zone are quite similar to recent ones from Massachusetts. B. eburneus often lives in brackish water. I found small ones on the piles at Betterton, near the head of Chesapeake Bay, where the water is but slightly brackish, the fresh-water snails Goniobasis and Amnicola living in it. "Professor Wyman found it living about 50 miles up the St. Johns River, Florida, where the water was fresh enough to drink, and the specimens lived well when transferred to a vessel of perfectly fresh water." B. eburneus often attaches to ships' bottoms. No doubt the ex- amples in the Jeffreys collection, taken by A. d'Orbigny at Rochelle, were so transported. It has been reported by Herr Weltner from Venice and Manila, but these records must have been based upon ship-carried individuals. It does not often form crowded or superposed masses, as many species do, and is far of tener found on wood and oyster shells than on rocks. Mr. Win. J. Fox gave me examples taken from the screw of his launch, in frequent use. Dr. Benjamin Sharp took specimens 23£ mm. diameter from a Nan tucket boat which had been in the water 98 days, from June 13 to September 21. In a lot in the Museum, from a boat which had 84 BULLETIN 93, UNITED STATES NATIONAL MUSEUM. been in water (Quissett Harbor) some 80 days (about July 1 to Sep- tember 18), the largest are 20 mm. in diameter. Dr. F. B. Sumner has recorded specimens from 20 to 26 mm. in diameter, on the bottom of a whaleboat which had been moored within the inclosure of the pier at Woods Hole from May until November or December, 1908. It appears., therefore, to attain full size in a little over three months. Locality. Collector. Notes. Rochelle Franco D'Orbigny Jeffreys coll Lynn M.i :s . .............. - Dr. Prescott R. E. Griffith A N S. P. coll Off Chatham Ma«s (13-20 fathoms) . Fish Hawk Nantucket Mass Dr. B. Sharp... Do "St George Island" M. C. M Do. "Waquoit .Bay Mass U. S. Fish Commission Woods Hole, Mass . --- do Many lots Quissett Harbor, Mass do Vineyard Sound Mass .. do Do Off Marthas Vineyard Mass do Buzzards Bay Mass do Off Newport R I . do Noank Conn ..do Long Island Sound do Savin Rock New Haven Conn . . . R Rathbun Seaside Park, N J H. L. Viereck A. N. S. P. coll. Near Port Republic, N. J H. A. Pilsbry Do. Ocean City N J H W. Fowler Do Sea Isle City, N J Wm J. Fox Do. Beasleys Point N J Dr Benj Sharp Do Highland Beach, N j H W Fowler1 Do Cape May N J Isaac Lea Betterton Md near head of Chesapeake Day H A Pilsbry Do St Georges Island Md M C M Ocean Citv, Md H. W. Fowler Do. Smiths Creek Potomac River Md R D Evans ... Very large Chesapeake Beach Va 11 D Hance On drift log Ocean View, Va Helen Winchester A. N. S. P. coll. Fort Macon N C Dr H C Yarrow Charleston, S C I Lea coll Mayport ,Fla . . - M A Mitchell Do. Near mouth St. Johns River, Fla Hon. F. E. Spinner Indian River, Fla . ... Dr E Palmer. Tarpon Springs, Fla Wm. M. Beekley Do. Pass Christian Miss E M Price Cuba Isaac Lea coll Jamaica C. B. Adams Near New Hopo, Canal Zone (Pleistocene) Dr. A. P. Brown Do. BALANU3 IMPROVISUS Darwin. Plate 24, figs. 3-36, 5-5nrk<3 nf two or three (fig. 22, eighth segment of outer ramus, inner face; showing the short teeth of the outside by transparence). Locality. Collector. Notes. Off Falmouth Mass Fish Hdiiik . . Woods Hole Mass U. S. Fish Commission . 7-13 fathoms. Do F B Sumner Vineyard Sound Mass U. S Fish Commission Several lots. Stations 2250, 22tiO, ofl Marthas Vinavard . Albatross Do. Station 1177 east of Marthas Vineyard fish Hawk 3-7 fathoms Off Newport 11. 1. (12-13 fathoms) U. S. Fish Commission Several lots. Newport, R.I Sam Powel . . On Crepidula. Loc 850 Narragansett Bay R.I Fish Hawk 14 j fathoms. Noank, Conn U S. Fish Commission On Crepidula. Capo May, N.J C. Le Roy Wheeler On Fulgur, etc. Smiths Island, Northampton County, Va... Chas. W. Richmond Beaufort Harbor, N. C Wm. Stimpson Station 2284-5-6. 2277 2290, off Capo Hat- A Ibatross On shells. teras (10-16 fathoms). W^m Stimpson On Fulgur Stations 2274, off St. Johns River, Fla Albatross 16 fathoms. Pass-a-Grille reef, Pine Key, Fla H Hemphill On Fasciolaria. Pine Key, Fla do On Strombus. Marco, Fla do On Fasciolaria, Crepidula Sarasota Bay. Fla . do and Fulgur perversum. On Fasciolaria auc{ Fulgur. Tampa Bay Fla Fish Hawk On PoTtunus gibbtsii* f Itarwater Harbor Fla H. A Pilsbry A. N. S. P. coll. Cedar ICoy s, Fla H. Heinphill Do ... Str Bache Station 2369-74, Gulf of Mexico, off Cape San A Ibatross 25-27 fathoms. Bias, west Florida. Fergusons Pass. Fla Near Havana, Cuba S. R. Roberts . Coll. A. N. S. P. Honduras T W Stanton 10 miles east of north end of Patros Island, Norseman 34 fathoms. Brazil. THE SESSILE BARNACLES. 97 BALANUS AMPHITRITE INEXPECTATUS, new subspecies, Plato 20, figs. 5 to 5e. A scries of about 40 specimens from the Gulf of California, Cat. No. 12398., U.S.N.M.j the largest 15 mm. in diameter, was collected by Dr. E. Palmer. They grew on oyster shells. The shape is low- conic, with diamond-shaped orifice, with an even margin. The smooth parietes are of a dull purplish-blue (Ranier blue) color, with many indistinct, whitish, radial lines, the radii white and drab, with sum- mits parallel to the base. The interior is strongly costate. Basis porous throughout, radially grooved inside. Scutum with the basal margin longer than the tergal; dull dark- pui'plish, with a white band along the tergal margin, and an irregular whitish ray near the occludent margin. There are minute growth- strijB and faint longitudinal scratches. The articular rib is very high and prominent, terminating downward in a point. Adductor ridge long and strong; below it is a deep oblong pit, as if for a muscle- insertion. There is a very small pit for the lateral depressor muscle. The upper part of the valve is conspicuously roughened. Tergum white, flat externally, the rather broad spur-fasciole defined by grooves. Spur wide, over one-third the widtli of the valve, short, either rounded or truncate distally, separated from the basi- scutal angle by less than half its own width. Crests for the depressor muscles are strong and project below the margin. The inner face of the valve is roughened. Articular ridge high, articular furrow wide and rather deep. Scutal border rather broadly inflected. Possibly referable to the very inadequately described var. obscurus Darwin, which, from the alleged distribution, I suspect to be merely a color-form and not a race ; yet as Darwin records no specimens of ampMtrite from the west coast of the Americas, it is not likely that he had the present race. BALANUS AMPHITRITE PERUVIANUS Pilsory. Plate 24, fig. 4; plate 37, figs. 2-2c. 1909. Balanus peruvianm PILSBRY, Proc. TJ. S. Nat. Mus., vol. 37, p. 69, fig. 1, pi. 19, figs. 1-4 (October 18). Cotypes.—GsA,. Nos. 38691 and 38692, U.S.N.M. Distribution. — Salt creeks at La Palasada, near Tumbez, Peru, growing on mangroves. General form conic, with flat or concave base and rather small aperture; dirty purplish white or pale dull purple, radii usually darker; very solid and strong. The parietes are snioothish, without ribs, and only minutely roughened. The aperture is pentagonal, with a strongly notched margin. Traces of a thin, pale straw-colored 98 BULLETIN 93, UNITED STATES NATIONAL MUSEUM. epidermis are visible near the base. The parietes have small pores near the base, and the basis, in large part solid, has some rounded pores near and at the periphery. The scutum is nearly half as wide as long, dirty white externally, suffused with dark quaker drab toward the apex, with a ray of the same near the tergal margin; sculpture of narrow, shallow grooves, with wider flat intervals, which in the lower part bear membranous borders from former opercular membranes. The articular ridge is very high and oblique, abruptly truncated below, its inner face striate. An acute ridge defining the lateral depressor muscle insertion runs down- ward from it. Adductor ridge very strong but short, nearer to the occludent than to the tergal margin, confluent above with the articular rib. Adductor muscle insertion deep. Articular furrow deep. The tergum is bicolored, the carinal half deep quaker drab, scutal half white. Sin-face marked with superficial grooves of growth and the faintest traces of radial stride. There is no furrow to the spur, but the flat f asciole is defined by impressed lines. The scutal border is a little turned up. The spur is short, truncated distally, over one- third the width of the basal margin, and sepa- rated from the basi-scutal angle by about half its width. The articular rib is rather strong and runs toward the spur, leaving a FIG. 23— BALANUS AMPHTTEITE broad articular furrow. The scutal margin PSKUVIANUS, LATERAL VIEW. » ,1 -i • -i 1-1 • n -i r^-i • -i of the valve is broadly mllexed. Ihe carinal half of the interior is granose-striate. Crests for the depressor mus- cles are strongly developed, terminating in little teeth projecting at the basal margin. Compartments: The radii have strongly oblique summits and are thick to the edge, which has fine, nearly straight, long, parallel, weakly denticulate septa. The aloe are thin, with oblique summits; sutural edges finely septate, the septa very regular, minutely dentic- ulate. The parietal pores are small, circular, and filled up solidly in the upper part. A transverse section midway of a compartment shows them partially filled, reduced to very small tubes. The inner faces of the parietes below the sheath have strong, rounded, smooth ribs, terminating below in minutely denticulate basal lamina. The number of internal ribs is smaller than usual, 12 in a rostrum exam- ined, 5 in a carinolateral compartment. The sheath, is purplish gray, with a darker lower border, strongly ridged transversely, the ridges bearing minute fringes of bristles. Its lower edge overhangs shallow cavities. The basis clings very f.rmly to the walls, and can not be parted from, them without breaking the interlocking laminae. It has some THE SESSILE BARNACLES. 99 pores near the periphery, at least in places, but is in great part pore- less. Central portion is thin. Carinorostral length of the base 31 nun,; width 28.5 mm.; height 23 mm. 'Length of the scutum 10.5 mm.; width 5 mm. Length of the terguni S mm. ; width 5 mm. The labrum has two teeth on each side of the median cleft. Palpi having a distal group of long spines externally. Inside there is a FIG. 24.— BALANUS AMPHITKITE PERUVIANUS. a, LABRUM. 6, ANTERIOR PART OF STH SEGMENT OK CIRRUS III. C, ANTERIOR PART OF AN INTERMEDIATE SEGMENT OFCIRRUS VI. d, OUTSIDE OFPALPUS. e, MAXILLA. /, MANDIBLE. long area of short spines, part of them curved or hooked, and a distal tuft of longer spines. It is similar to B. ampMtrite niveus (fig. 2 la) in arrangement of the spines (fig. 24a, d). The mandible has blunt teeth, the fourth and fifth very short and obtuse (fig. 24/). The maxilla has 12 spines and scarcely any notch below the upper pair of large spines. The lower two spines are longer (fig. 24e). The first cirrus has rami of 26 and 14 segments, those of the pos- terior ramus strongly protuberant. The posterior ramus is about two-thirds as long as the anterior. 100 BULLETIN 93, UNITED STATES NATIONAL MUSEUM. The second cirrus has 23 and 16 segments, protuberant on both rami. The anterior ramus is about 5 segments longer. The third cirrus has rami of 20 and 17 segments. The anterior ramus has recurved teeth on the anterior side of the first $ine seg- ments, and there are some erect spinules near the anterior distal angle on most of the segments. The posterior ramus has very few straight teeth on a few of the lower segments (fig. 24&). Cirrus iv has 110 teeth or spinules on the segments. Cirrus vi has five pairs of spines on the median segments, with a few small spines springing between the large spines of the upper four pairs (fig. 24c). Lowest pair is much smaller than the others. The penis is about equal to the posterior cirri in length. I at first described this form as a distinct species, but a larger acquaintance with this group of Balanus induces me to reduce it to subspecific rank, although it is as distinct from amphitrite as several East Indian forms described as species. At present we know very little about west American forms of the amphitrite group — only what is contained in this work — -and the final status of the several forms existing from Lower California and Peru can not be foreseen. B. a. peruvianus is closely related to B. am.pliitritc, but it differs in the following characters: (1) It is a much stronger barnacle, with the parietal tubes filled up solidly, except close to the base. (2) The basis clings strongly to the walls and has very few pores. (3) The sheath is dark colored. (4) The tergum is flat outside, and has a wider spur. Finally, it reaches a larger sir/.c. The opercular valves are variegated with dark rays or areas, as in dark forms of B. amphitrite. The mouth parts and cirri do not differ materially from those of B. amphitrite. The pores of the parietes are filled up except close to the base, and might readily be overlooked. The basis is not solid, as I stated in the original descrip- tion. It has distinct pores, near the periphery only, which did not appear in the sections I made at first. They may be seen in plate 24, figure 4, which shows part of the basis adhering to the rostrum. BALAKUS CONCAVUS Bronn. Plate 21, figs. 1-lc. • 1831. Balanus concavus BRONN, Italiens Tertiar Gebilde und deren organische Einschliisse, p. 127. 1838. Balanus concavus BRONN, Lethsea Geognostica, vol. 2, p. 1155, pi. 36, fig. I2a-e. 1854. Balanus concavus Bronn, DARWIN, Monograph, p. 235, pi. 4, figs. 4a-e. Monograph on the Fossil Balanidse and Verrucidse of Great Britain, p. 17, pi. 1, figs. 4a-p. 1904. Balanus concavus Bronn, G. C. MARTIN, Maryland Geological Survey, Miocene, p. 94, pis. 33, 34 (=#. c. chesapeakensis). THE SESSILE BARNACLES. 101 1906. 'Balanus concavus Bronn, DE ALESSANDRI, Palseontographia Italica, vol. 12, p. 295, pi. 16, figs. 21-25; pi. 17, figs. 1-4. Type-locality. — Andona Valley, near Asti, Piedmont. Pliocene. Distribution. — Oligocene to Pleistocene of Italy. Pliocene of Eng- land and Portugal. Various races or subspecies in the Miocene and Pliocene of the United States. Other races recent from California to Peru and in the Philippines. Balanus concavus, in the broad sense, was an abundant barnacle throughout the Neocene in both hemispheres. In the Miocene, when our definite information begins, there were several strongly individualized races, possibly species, but here ranked as subspecies. These continued, in their several areas, into the Pliocene with more or less change; in the Mediterranean basin they endured into the Pleistocene. The total disappearance of the group from Recent Atlantic faunas does not seem explicable at present. The typical form of B. concavus, as figured by Bronn and recently treated in detail by De Alessandri, is conic or convexly conic, with the orifice more or less contracted, or often cylindric with large orifice. The summits of the radii are very oblique, and the parietes are usually ribbed, not very strongly, or variously roughened. Sometimes it is smooth. The Pliocene examples often show color-stripes. De Alessandri, who studied Italian specimens from Oligocene (Tongrian of Sardinia) to Pleistocene, does not record any change throughout the duration of the species in that area — a remarkable constancy if really the fact. I believe, however, that he had not seen the opercu- lar valves of the Oligocene form. The British Red Crag examples (pi. 21, figs. 1, Ic, from the Jeffreys collection, Cat. No. 12058, U.S.N.M.) are practically typical, but they perhaps vary somewhat from the Italian by having the tergum sometimes narrower, with a longer spur. My plate 21, figure 1&, is very similar to one of De Alessandri's figures (pi. 4 , fig. 21) of a topotype. The scutum has rather coarsely latticed sculpture, the longitudinal strise often divided, and obsolete on the roundly inflected tergal margin. The basitergal angle is cut off. The adductor ridge is quite short and not very prominent. The inner border of the rather deeply sunken depressor muscle pit is slightly prominent, but not raised into a ridge. This European form was an abundant Pliocene barnacle of that area, where it seems to have existed almost to the present time. It has not been found in America, where various other races of the species existed, and is noticed here merely for comparison with the latter. Our definite knowledge of East American barnacles of the concavus type begins with the Miocene, continuing to the Pliocene, when the 4729°— Bull. 93—16 8 102 BULLETIN 93, UNITED STATES NATIONAL MUSEUM. species became extinct in this area.1 It appears that two phyletic series are represented, strongly differentiated from their first appear- ance, and both differing from any European forms known to me. In the glyptopoma series the scutum is narrower, more strongly sculp- tured than European concavus. In the proteus series it is wider, more delicately sculptured. The sequence of known forms is about as follows: Europe. Eastern America. West America. Recent. ?regalis pacificua pacificus ? coosensis Pleistocene Pliocene concavus concavus concavus concavus Alligator Creek form glyptc proteua glyptc [ chesapeakensis >poma >poma Miocene Oligocene BALANUS CONCAVUS GLYPTOPOMA, new subspecies. Plate 21, figs. 2, 3; plate 22, figs. 2-2c. In the Yorktown, Virginia, Miocene there is a rugged, small-ribbed form (pi. 21, fig. 3) resembling the typical B. balanus superficially, and reaching a diameter of about 25 mm. There are fully 20 pores in the rostrum. The opercular valves resemble those of the following form, which may fairly be considered a direct descendant. The typical B. c. glyptopoma of the Caloosahatchie Pliocene (pi. 21, fig. 2 ; pi. 22, figs. 2-2c) has rather numerous small ribs on the parie- tes, sometimes weak or nearly obsolete, and not stronger toward the apices. The orifice is large, the summits of the radii not very oblique. Carinorostral diameter 20 to 37 mm. The scutum is sculptured with strong growth-ridges cut into high, erect nodes by the rather deep longitudinal striae. This sculpture is coarser than in other subspecies of B. concavus. The tergal side is abruptly bent nearly at right angles with the rest of the valve, is deeply grooved, but without nodes. The adductor ridge is strong but rather short. The tergum has a short, obliquely truncate spur. 1 1 have seen some American Oligocene barnacles probably belonging to the concavus stock, but without opercular valves. Prof. Gravel has recorded E. concavus as recent from Rio Janeiro, on the evidence of specimens in the Paris Museum, collected by Delalande 1817. As there is no other Atlantic record, this requires confirma- tion. See Nouv. Arch, du Mus., ser. 4, vol. 5, p. 130. THE SESSILE BARNACLES. 103 BALANUS CONCAVUS PROTEUS Conrad. Plate 22, figg. 3-3c. 1834. Balanus proteus CONRAD, Journal of the Academy of Natural Sciences of Philadelphia, vol. 7, p. 134 (Jamea River, Suffolk; Yorktown, Virginia). 1845. Balanus proteus CONRAD, Fossils of the Medial Tertiary of the United States, No. 3, p. 77, pi. 44, fig. 1 (Prince George Co., Virginia). A large, solid, conic form, with small, angular, and deeply toothed orifice, and very strong, unequal ribs, resembling the geniculatus form of B. balanus. The summits of the radii slope steeply. The opercular valves are thin and frail for so solid a barnacle. Scutum with much filler, more delicate external sculpture than Crag concavus, the longi- tudinal grooves shallower; tergal marginal inflection narrower; artic- ular ridge delicate. Adductor ridge usually somewhat better devel- oped than in Crag concavus; and there is a slightly raised edge to the depressor muscle pit. The tergum is wider than that of typical concavus. It commonly grows on oysters or the large Pectens, often in very fine groups. B. c. proteus seems to have persisted to the Pliocene in a somewhat changed form. A barnacle from the Floridian Pliocene of Alligator Creek is very solid and strong ; aperture contracted, but less than in B. c. proteus; parietes ribbed throughout or near the apices only. Oper- cular valves not seen. Diameter 50 to 60 mm., height somewhat greater. BALANUS CONCAVUS CHESAPEAKENSIS, new subspecies. Plate 22, figs. 1-lc. 1890. Balanus convexus, American Naturalist, p. 771 (presumably an error for concavus; no description). 1904. Balanus concavus Bronn, MARTIN, Maryland Geological Survey, Miocene, p. 94, pi. 33, figs. 1-6; pi. 34, figs. 1-7. Type.— No. 1143, A.N.S.P. Distribution. — St. Marys and Choptank formations, Miocene of Maryland. A large, solid barnacle, with small orifice, the parietes having few, strong ribs near their apices, becoming broader and lower downward until they disappear, and with a peculiar fine sculpture as if shriveled ; radii sunken, slitlike in the lower part. Diameter 57 mm., height 44 mm. Scutum having fine, unequal, longitudinal striae over the rather low and wide growth-ridges, about as hi B. c. proteus. Ridges of the inner face more developed than in B. concavus or proteus; adductor ridge long, high in the middle. The large and deep pit for the lateral depressor muscle has a strongly raised bordering ridge, which is parallel to the adductor ridge, and nearer it than to the tergal margin. 104 BULLETIN 93, UNITED STATES NATIONAL MUSEUM. Tergum triangular, with a long spur more than its own width from the basiscutal angle. The spur is continued as a rounded ridge on the inner face of the valve; borders of the external furrow folded closely together. This appears to be a lateral branch of the B. c. proteus stock. Balanus finchii Lea, from St. Marys, Maryland),1 may be a very young specimen of this race, but it is smooth, and the opercular valves are unknown. The young of chesapeakensis should be strongly cos- tate. There are probably one or more races of the concavus group in the Atlantic slope Miocene, in addition to those already mentioned. Darwin's figures, 4h, 4i, 4Jc, represent a Maryland form unlike any I have seen. The subject deserves further investigation with much more material than I can command. BALANUS CONCAVUS PACIFICUS, new subspecies. Plate 23, figs. l-2c. Type.—C&t. 32953, U.S.N.M., from San Diego, California. Distribution. — Northern California to Callao, Peru; Pliocene and Pleistocene of California.2 The barnacle is conical (or cylindric), with a diamond-shaped orifice with the peritreme but slightly toothed; smooth, the wide radii but slightly sunken; striped with vinaceous or deep vinaceous on a much paler or white ground, the radii and sheath vinaceous or white. Epidermis thin and transparent, usually persistent on the parietes. The opercular valves have more or less vinaceous coloring, chiefly inside and near the apices. Greatest diameter 34 mm.; height 20|- mm. (type, pi. 23, fig. 1). Greatest diameter 25 mm.; height 55 mm. (cylindric; San Pedro). Greatest diameter 22 mm.; height 26^ mm. (cylindric; Crescent City). Greatest diameter 18 mm.; height 9 mm. (conic; Crescent City). The scutum has rather low growth-ridges and close, unequal, radial strix throughout. The articular ridge is small, reflexed and not much over half as long as the tergal margin. Adductor ridge high and long, approaching the basal margin. A thin but high ridge bounds the lateral depressor muscle insertion, its crest usually curving toward it, to form an imperfect tube. The tergum is broad, triangular, with a nearly closed furrow to the spur. Spur rather long, separated by its own width or less from the basiscutal angle. The scutal border is but slightly inflected. Crests for the depressor muscles are moderately developed, weakening near the basal margin. Articular ridge is low. » Contr. to Geol., p. 211, pi. 6, fig. 222. 2 See Arnold, Mem. Cal. Acad. Sci., vol. 3, 1903, p. 344. THE SESSILE BARNACLES. 105 Compartments. — The radii arc wide, with the summits making angles of about 45 degrees with the base in young or small individuals, large ones having nearly horizontal summits ; sutural edge with the laminae denticulate below. Interior of parietes ribbed. Parietal tubes very numerous, about 20 in the rostrum, without transverse septa, but filled up near the apices. The basis clings very firmly to the walls. It is porous throughout, and in large specimens the lower part is somewhat vesicular, though it is nowhere very thick. The labrum of B. concavus has three teeth on each side of the notch, according to Darwin; but in that from Long Beach (fig. 25c) there FIG. 25.— BALANUS CONCAVUS PACIFICUS, LONG BEACH, CALIFORNIA, a, SECOND CIERUS OF LEFT SIDE. 6, MAXILLA. C, LABRUM. d, llTH SEGMENT OF THE ANTERIOR EAMUS OF CIRRUS HI. €, MANDIBLE. are none on one side and the outer one on the other side is bifid or twinned. Such asymmetry in the labrum is so frequent as to be hardly anomalous. In a specimen from Albatross station 2939 there were two excessively minute teeth on one side, none on the other. The mandible has four teeth, the fifth united with the lower point. The bifid tip of the second tooth in figure 25e is similar in both man- dibles of the individual figured. In a specimen from station 2939 (fig. 266) the second tooth is minutely bifid on one side, simple on the other, and the third and fourth teeth are very obtuse. This tooth is often more or less noticeably bifid in other species of the group. 106 BULLETIN 93, UNITED STATES NATIONAL MUSEUM. Maxilla (fig. 256) with, nine spines between the upper and lower large pairs, the lower pair standing on a projection, in a Long Beach individual, but this is scarcely noticeable in that from station 2939. The first cirrus in a specimen from Long Beach has 18 and 16 segments, the anterior ramus slightly longer, the posterior having extremely protuberant segments. Cirrus ii has subequal rami of 15 and 14 extremely protuberant segments (fig. 25a). Cirrus iii, anterior ramus, has a few long "teeth" or rather short, spikelike spines on the outer face of each segment near its anterior border. Those farther from the anterior border are often twinned. By focusing down, some excessively small spines, in groups of three or four, may be seen close to the distal suture. The posterior ramus has no such armature. The FIG. 26.— BALANUS CONCAVUS PACIFICUS, STATION 2939. a, ANTERIOR PART OF THE 13TH SEGMENT OF THE FORWARD RAMUS OF CIRRUS HI. b,. MANDIBLE. C, ANTERIOR AND POSTERIOR PARTS OF THE 8TH SEGMENT. inner faces of the segments of both rami bear long spines. The fourth cirri have no teeth. Later cirri have segments with four pairs of spines. In a larger example, from Albatross station 2939, the third cirrus has its outer face set with curved, conic teeth on the anterior ramus (fig. 26a), and with similar teeth mingled with bifid, trifid, or comb- like teeth (fig. 26c) on the posterior ramus, the teeth grouped near the anterior and posterior distal angles of each segment. The fourth cirrus has a few small erect spinelike teeth on the anterior distal part of the lower segments of the anterior ramus. One of the large specimens from station 2939 has rather strong rounded ribs in the lower half of the parietes, the upper half being ribless and pink striped. Others of the same lot are typical in sculpture (pi. 23, figs. 2-2c). THE SESSILE BARNACLES. 107 Its wide terga and the nearly, level summits of the radii give this west coast barnacle the appearance of B. tintinndbulum. In these characters it certainly differs widely from the original B. con- cavus, which had a very deeply toothed orifice and narrow terga. No estimate of the relation it bears to the very large barnacle of the Oregon Miocene (coosensis Dall) can be formed until the opercular valves of the latter are found. Darwin's plate 4, figures 4a-4c, from Panama, belongs, I believe, to the Californian race, but I have not seen any Panamic or Peruvian specimens. B. concavus pacificus attains a size much greater than B. ampJii- trite; the scuta differ by their longitudinal striation, the terga by the longer spur and the well-developed, more or less infolded furrow of the exterior. The rami of the first cirrus are but slightly unequal in length, while in B. ampJiitrite they are very unequal. Finally, the armature of the third cirri is less developed in concavus. Of the variations of B. concavus pacificus in California it need only be said that when crowded the cylindric form is assumed. The details of the mouth parts and cirri are from a specimen of 15 mm. diameter from Long Beach, one of a group on Trophon triangu- laris. Specimens from Santa Maria Bay, on the western coast of Lower California, are more solid than the type, deep hellebore red with coral pink radii, having some resemblance to B. tintinndbulum coccopoma. The opercular valves are wanting. In the specimens from Albatross Station 2939, near Newport, Cal- ifornia (pi. 23, figs. 2-2c), both scutum and tergum are narrower than in the type. The adductor ridge is more united with the articu- lar ridge above, and the articular furrow is deep, bridging over the pit of the depressor muscle, which thus becomes tubular. While the actual structure has not changed much, the appearance is quite unlike the ordinary form. See page 337. Darwin has noticed the same tubular structure of the depressor muscle pit in Panamic examples. The tergum in the specimens from station 2939 has a much shorter spur than in the type of pacificus, but varies in different examples; its external furrow is not quite closed. The armature of the cirri varies; the larger individuals from sta- tion 2939 examined having more "teeth" on the third cirrus than the smaller one from Long Beach, and also having a few on the fourth cirrus, where I found none in the smaller specimen. The oriental form or forms of B. concavus are unknown to me. As it was not obtained by the Siboga or the Albatross expeditions, I presume that it is either rare or local. 108 BULLETIN 93, UNITED STATES NATIONAL MUSEUM. U.S.F.C. Station. Locality. Depth (fath- oms). Collector. Notes. Crescent City, Cal. 1 Unknown Cat No 13111 4492 Monterey Bay, Cal 20 AlbatToss San Pedro, Cal W. M. Gabb Coll A N S P Long Beach, Cal Mrs Oldroyd On TTophon 2939 Near Newport, Cal 27 A IbatToss 4420 Near San Nicolas Island 33 do. San Dipgo. Cal Dr Palmer 4303-4 Near San Diego, Cal 21-25 Albatross Santa Maria Bay, Lower Cal. . . do.. . i This locality, if authentic, carries JB. c. pacificus well north of the greater part of its faunal associates in southern California. The distribution of the species on the coast above Monterey needs further investigation. BALANUS CONCAVUS COOSENSIS Dall. 1909. Balanus tintinndbulum coosensis DALL, The Miocene of Astoria and Coos Bay, Oregon, U. S. Geol. Survey, Professional Paper No. 59, p. 138, pi. 19, figs. 1, 6. This is a very large form from the Miocene of Coos Bay, Oregon, the greatest diameter 50 mm. Parietes smooth; radii with oblique summits, thereby agreeing with most forms of concavus, but differing from B. tintinnalulum and B. concavus pacificus. The parietal tubes of one of the type lot have no transverse septa. There are about 39 tubes in the rostrum. The radii are not porous. It is therefore not related to B. tintinnabulum, which has not been found fossil in America, and is represented in the recent fauna by quite different forms. The opercular valves of B. c. coosensis have not been found, so that the reference to B. concavus, though probable, is provisional. A rather strongly ribbed barnacle from the Lower Miocene or Upper Oligocene of Ventura County, California, has been referred to B. concavus by Kalph Arnold.1 It resembles B. c. glyptopoma exter- nally, but the opercular valves and structure of the wall are unknown. BALANUS REGALIS, new species. Plate 21, figs. 4, 4a. Type. — Cat. No. 43485, U.S.N.M., from Point Abreojos, west coast of Lower California. Albatross, March 14 , 1911. A large, strong barnacle. The walls form a cone strongly bent toward the rostrum. Parietes rather finely, irregularly ribbed and with large folds near the base. Color, from old rose to Vandyke red and dahlia carmine, clouded with white, the sheath and ulterior pale flesh-tinted. Aperture broadly ovate. The carina and carinal latera are closely united by linear sutures, externally visible with difficulty. The other sutures are deep, narrow clefts. Radii are extremely narrow, almost wanting, or represented by irregular, roughened ledges, their summits very oblique, their edges very irregularly crenulated, and not in contact with the broad, » U. S. Geol. Surv. Bull. 309, pi. 32, fig. 5. THE SESSILE BARNACLES. 109 flat, opposed sutural edges, which have fine, irregular, denticulate crenulation. The alse are narrow, with very oblique summits. The rostrum is short and broad ; lateral compartments very broad ; carino- laterals very narrow. There are deep, rather roomy hollows behind the lower edge of the sheath. The interior surface is rather strongly ribbed near the base, becom- ing smooth above. Each rib is continuous with a septum in the wall, as usual. The parietal pores are large, square, separated by thin septa, which at their junction with the inner plate of the wall are thicker and denticulated, as usual. There are a few small, incomplete septa arising from the outer plate of the wall. The parietal pores are not filled up in the upper part, but transverse septa are rather numerous, from the base up. The basis is strong, flat, rather well provided with round pores, but there is no underlying cellular layer. It clings very firmly to the walls. Carino- rostral diameter. Lateral diameter. Height. a... GO 62 38mm. b 59 65 46 mm. This large and handsome barnacle is known by two individuals calcified together, which grew on some nearly flat object. The opercular plates and body were not collected. It is remarkable for the absence of radii, which are represented only by irregularly rough- ened white thickenings along the carinad borders of the lateral com- partments; also for the intimate union of the carina and carino- lateral compartments, the sutures being merely linear or wholly obliterated, although the surface is not eroded. The color and the very short rostrum (if the latter is not the result of some unusual situation or position of the individuals), are also notable. The species should be readily recognizable, since there is no west coast barnacle which could be confused with it, to my knowledge. The affinities of this form can not be worked out until complete specimens come to hand, but the walls suggest relationship with B. concavus and possibly B. nubilis; at all events, it belongs to the same division of the genus, group C of Darwin's classification. The transverse septa of the parietal tubes serve to further distinguish B. regalis from both B. nubilis and B. concavus pacificus. Among the forms of B. concavus, it has some superficial resemblance to B. c. proteus, of the Virginian Miocene. It should be noted also that there is a rare ribbed form of B. c. pacificus, shown in plate 23, figure 2c. As this is one of the largest and handsomest west coast barnacles, it is hoped that living specimens will be looked for, in order to com- plete its description. 110 BULLETIN 93, UNITED STATES NATIONAL MUSEUM. BALANUS POECILUS Darwin. 1854. Balanus poecilus DARWIN, Monograph, p. 246, pi. 5, figs. 3a, 36. Type. — British Museum. Distribution. — West coast of South America, attached to an Avicula (Cuming) . Shell fragile, tubulo-conical ; fine dark-rose color, freckled with transverse, sharply pointed, fine, zigzag white lines, and obscurely striped longitudinally. Basal diameter one-half inch. Scuta dull red with a white band along the tergal margin, externally smooth ; articular ridge moderately developed, slightly refiexed . There is no adductor ridge. There is a distinct pit for the lateral depressor muscle. Tergum with the scutal margin unusually prominent, toothed; longitudinal furrow shallow, the edges not folded in. Spur short, barely one-third the width of valve, with the lower end sharply truncated, parallel to the basal margin. Walls very fragile; radii fragile, broad, their summits moderately oblique. Basis with an underlying cancellated layer. Cirri, first pair with one ramus longer by about four segments, the shorter ramus with protuberant segments. Sixth pair with segments much elongated, but bearing only four pairs of spines. This species is not contained in the United States National Museum, and seems to be known by only one group of specimens, with the indefinite locality recorded above. The above details are abbre- viated from Darwin's description. It does not differ much in essen- tial characters from B. amphitrite, but the absence of an adductor ridge of the scutum and the sharply truncated spur of the tergum are sufficient to distinguish it. BALANUS ALATUS Hoek. 1913. Ealanus alatus HOEK, *Si6o<7a-Expeditie, Monographic 306, p. 175, pi. 15, figs. 1-8. Type. — Siboga station 97, latitude 5° 49' .7" north, longitude 119° 49' .6" east, northeast of the Sulu Archipelago, 564 meters. B. alatus was founded on two specimens, having a diameter of about 3.25 mm. A few specimens which I refer to this species were taken at Albatross station 5163, in the Tawi Tawi group of the Sulu Archipelago, off Observation Island, in 28 fathoms. The basal margin of the scutum is shorter than the tergal margin; maximum diameter of the base about 9 mm. BALANUS POECILOTHECA Kriiger. 1911. Balanus poecilotheca KRUGER, Beitrage zur Cirripedienfauna Ostasiens, Abh. der Math.-Phys. Klasse der K. Bayer. Akad. der Wissenschaften, vol. 2, Suppl.-Bd., 6 Abh., p. 48, pi. 1, figs. 2c-e; pi. 3, fig. 32. THE SESSILE BARNACLES. Ill Type-locality. — Okinose bank, Sagarni Bay, Japan. Numerous examples from three Albatross stations seem referable to this species, agreeing well with the description, except in having the lower teeth of the mandible blunt. D. 5134. Sulu Archipelago, near Balukbaluk Island, 25 fathoms. D. 5135. Sulu Archipelago, vicinity of Jolo, 161 fathoms. D. 5146. Sulu Archipelago, vicinity of Siasi, 24 fathoms. BALANUS TRIGONUS Darwin. Plate 26, figs. 1 to 13e. 1854. Balanus trigonus DARWIN, Monograph, etc., p. 223, pi. 3, figs. 7a-7/("Java; East Indian Archipelago; Peru; West Colombia; California; Sydney; New Zealand"). 1867. Balanus armatus MULLER, Archiv fur Naturgeschichte, Jahrg. 1867, vol. 1, pp. 329-356, pi. 7, figs. 1-21, 23-28; pi. 8, figs. 44, 46-48; pi. 9, fig. 56. 1868. Balanus armatus MULLER, Ann. Mag. Nat. Hist., vol. 1, p. 392. 1897. Balanus trigonus Darwin, WELTNER, Verzeichnis, p. 262. 1911. Balanus trigonus Darwin, KRUGER, Beitrage zur Cirripedienfauna Ostasiens, in Abh. Math.-Phys. Klasseder K. Bayer. Akad. Wissensch., vol. 2, Suppl.- Band, p. 49, figs. 98-100, pi. 1, fig. 6; pi. 3, fig. 33. Type. — British Museum. Distribution. — Pacific, from Tokyo Bay, Japan, through the East Indies to Sydney, New South Wales, and New Zealand; Red Sea; West America from Peru to southern California. Atlantic, West In- dies to southern Brazil; Madeira and Azores to South Africa.1 According to Darwin, it is described as follows : Parietea ribbed, mottled purplish-red; orifice broad, trigonal, hardly toothed. Scutum thick, with from one to six longitudinal rows of little pits. Tergum without a longitudinal furrow, spur truncated, full one-third the width of valve. General appearance: Shell conical, generally depressed; orifice broad, triangular, almost equilateral; walls colored or only mottled with purplish-pink, having either irregularly branching, or regular, longitudinal ribs, which are generally white. The radii are pale pink or nearly white; the opercular valves have either their upper parts, or nearly their whole surface, clouded with pinkish-purple. The epidermis is not persistent; the walls are moderately strong. The largest specimen was one inch, but generally full-grown specimens are about half an inch in basal diameter. The opercular valves have their lower growth-ridges minutely fringed with bristles when unworn. The membrane lining them is dark purple. When cleaned both valves are in part of a pink color internally. The scutum has prominent, narrow growth-ridges which cross several deep longitudinal furrows, producing rows of small, deep pits. There may be from two to six such rows in San Diego individuals of one group. Very rarely there are individuals without pits, according to Darwin. The articular ridge is rather long; articular furrow deep 1 The locality "Delaware," given by Weltner (Verzeichnis, p. 262), could refer only to imported speci- mens, as B. trigonus is certainly not found living there. 112 BULLETIN 93, UNITED STATES NATIONAL MUSEUM. and narrow. There is a short adductor ridge, not united with the articular, and not extending upon the lower fourth or third of the valve. The lateral depressor muscle lodges in a deep cleft. The width of the scutum varies rather widely, and the tergal side is abruptly deflected. The tergum is relatively large, wider than the scutum, and a trifle shorter. It is flat, with slight growth-lines and no furrow to the spur; the latter stands close to the basiscutal angle, is very short, truncate, and broad, one-half to one-third the width of the valve. Inside there is a moderate articular ridge, defining a broadly open articular furrow; the scutal border is not inflexed. Crests for the depressor muscles are sharp and numerous. The labrum (fig. 276) has three rather strong teeth on each side. Palpi substantially as in B. ampliitrite (See p. 93, fig. FIG. 27.— B. TEIGOKUS, WEST INDIES, a, MANDIBLE, b, LABRUM. c, MAXILLA. Mandible (fig. 27a) with four teeth and an irregular lower point. Maxilla (fig. 27c) with seven or eight spines between the upper and lower large pairs, which stand upon very slight projections. Cirrus i has rami of 20 and 9 segments, the posterior ramus half as long as tlie anterior, its segments moderately protuberant. Cirrus ii with 10 and 8 segments (West Indies), or 13 and 9 segments (Cape St. Lucas, Lower California). Cirrus iii having 15 and 12 segments, the anterior ramus 4 segments longer. The lower segment of the pedicel is very broad. The segments of both rami are convex an- teriorly, and armed with thorn-shaped teeth. Smaller teeth, grad- ing down to minute tubercles, are on the adjacent outer face of the segment. These may be numerous, as in the West Indian individ- ual figured (fig. 28a), or few, as in that from Cape St. Lucas (fig. 28d). The distal two segments of the anterior ramus, and four of the pos- terior, have no teeth. The inner faces of the toothed segments of the anterior ramus are smooth, but those of the posterior ramus have some or many long spines. Cirrus iv is long, like the following cirri, but about six segments near the middle of the outer ramus have small THE SESSILE BARNACLES. 113 teeth on the anterior margin (fig. 286). The later cirri have four or at most five pah's of spines (fig. 28e). The second joint of the pedicel of cirrus vi has an upwardly directed tooth near the proximal posterior part, usually with a few minute ones above it (fig. 28c.) B. trigonus may usually be readily recognized by the triangular orifice, the ribbed and colored walls, the rows of little pits in the scutum (which, however, may rarely be wanting, or in very old specimens they may be obscured or removed by erosion), and the thin, flat tergum with a broad spur. The shape of the orifice varies, two angles FIG. 28.— BALANUS TRIGONUS. a, SEVENTH SEGMENT OF ANTERIOR KAMUS, CIERUS in. &, EIGHTH SEGMENT OF CIRRUS IV. C, SECOND SEGMENT OF THE PEDICEL OF CIRRUS VI, "WITH PART OF THE LOWER SEGMENT AND BASES OF THE KAMI, d, SEVENTH SEGMENT OF AN- TERIOR RAMUS, CIRRUS HI, CAPE ST. LUCAS. €, A MEDIAN SEGMENT OF CIRRUS VI. ALL FIGURES EXCEPT d FROM WEST INDIAN SPECIMEN. THE RIGHT SIDE IS ANTERIOR. of the triangle often being cut off, forming two short facets, changing the triangle to a pentagon with two very long sides. It is very frequently associated with other barnacles, and is one of the forms often found on ships' bottoms. Sometimes it forms masses on shells, which may be completely covered excepting the aperture. Doctor Kriiger, who has given an excellent account, with figures, found it on crabs from Jap§n, where it is a common species. He also records a group of small individuals embedded Acasta-like in a sponge. He independently reached Fritz Miiller's idea that the spines on the third cirrus were evolved to break away sponge-spicules from the orifice. 114 BULLETIN 93, UNITED STATES NATIONAL MUSEUM. The size and the sculpture of the scutum are variable among indi- viduals, and especially in different colonies, even in the same general region. Thus, a lot of small trigonus from Misaki, Sagami, Japan, growing on Fusus, has but one row of pits in the scutum, though they were apparently adult. Another Japanese lot from Kagoshima, at the southern extreme of Kyushu, has long, narrow scuta, with several rows of pits. Detailed faunistic studies are needed to determine the significance of such variations. It is quite possible that the Atlantic form of B. trigonus (pi. 26, figs.l- 12a) can be separated from the Pacific form (pi. 26, figs. 13-13e) as a race or subspecies. The typical Pacific form of trigonus, as figured by Kriiger (Japan) and shown in figure 28d, Cape St. Lucas, has the anterior margin of the segments of cirrus iii more protuberant and more coarsely toothed than in Atlantic examples examined (fig. 28a). The tergum is somewhat wider. If these differences prove constant, when a large series is examined, the Atlantic race may be called B. trigonus armatus. As most of the specimens at my command are dry, I have been unable to satisfy myself that the differences are sufficiently con- stant to have racial value. Balanus armatus Fritz Muller, from Santa Catharina Island, Brazil, has been accepted by subsequent authors as a valid species. It is merely a variety of B. trigonus, due to station. It lives on sponges, PapiUina or Reniera, on the polyp Carijoa, or rarely on Purpura, or on rocks, in that case assuming the ordinary ribbed exterior of B. trigonus. According to Muller, who has given a full and beautifully illustrated description, the orifice is pentagonal. The projecting apices of the compartments make the peritreme toothed ; surface generally smooth, more rarely having indistinct ribs. Those seated on rocks have stronger ribs. There are sometimes traces of epidermis on the lower parts of the parietes. Muller states of the terga, " Diese stimmen ganz mit der von Darwin f tir Balanus trigonus gegebenen Beschreibung uberein," but he figures the spur with a more rounded distal end, quite possibly an oversight in drawing. The narrowness of the tergum, as figured, agrees with Antillean specimens. On the west coast the tergum is broader. The scuta are exactly as in a common Pacific form of trigonus. The mouth parts and cirri, as figured by Muller, agree well with those organs in West Indian trigonus, even in the small details, which vary more or less in specimens from differeni localities. Part of Muller' s figures of armatus are copied photographically in plate 26, figures 1 to 11. THE SESSILE BARNACLES. 115 Locality. Donor or collector. Notes. San Diego, California Hagdalena Bay, Lower California Head of Conception Bay, Gulf of California . Manzanillo , Colima, Mexico Panama lyo, Japan Japan Hayama, near Kamakura, Sagami Misaki, Sagami Hirado, Hizen, Japan . . . Kagoshima Bay, Japan . Kagoshima, Japan Philippines Cape Cod, on whaler from West Indies. St. Michael, Azores R. E. C. Stearns C. R. Orcutt Paul Bartsch C. R. Orcutt Dr. W.S. W.Ruschenberger Y. Hirase Imperial University, Tokyo A. C. Hartshorne Imperial University of To- kyo. Y.Hirase North Pacific exploring expedition. Imperial University of To- kyo. Walter Hough A. E. Verrill.. On Tcgula. On drifted pile. Coll. A. N. S. P. Do. Coll. A. N.S. P. On Fusus. Coll. A. N. S. P. No opercular valves. On Charonia lampas ( Tritonnodiferus). BALANUS SPONGICOLA Brown. Plate 25, figs. 2, 3, 4-4c. 1827. Balanus spongicula Leach MS., BROWN, x Illustrations of the Conchology of Great Britain and Ireland, pi. 7, figs. 6, 14, 15. 1844. Balanus spongicola BROWN, Illustrations of the Recent Conchology of Great Britain and Ireland, ed. 2, p. 121, pi. 53, figs. 14, 15, 16. 1854. Balanus spongicola Brown, DARWIN, Monograph, p. 225, pi. 4, figs, la-lc. 1907. Balanus spongicola Brown, GRUVEL, Bull. Soc. Zool. de France, vol. 32, p. 164. Type. — Present location unknown; from Weymouth, Devon. Distribution. — Southern England, Wales, and Ireland to the Med- iterranean; Lagulhas Bank, Cape of Good Hope; off Patros Island, Brazil (Rathbun); La Guayra and Caracas (Weltner); Chagos Archi- pelago, and Seychelles (Gruvel). The barnacle is conic or conic- tubular; pompeian red, deep helle- bore red, or varying in tint to nearly white on the rostral side; radii red or white; walls smooth, the orifice toothed. Scutum with unequal radial grooves, part of them deeply engraved, cutting the strongly developed growth-ridges into small beads. Articular ridge small; adductor ridge small and short, merely forming a raised border of the adductor pit. There is a rather deep and narrow pit for the lateral depressor muscle. The tergum has the apex tinted, produced into an acute beak project- ing above the scuta; exterior nearly flat, band running to the spur being but very slightly sunken. Spur is about one-third the width of the valve, obliquely truncate at the end, the basal margin on the carinal side sloping into it in a nearly straight or slightly concave line (fig. 30a, &, Exmouth.) Crests for the depressor muscles are rather weakly developed. 1 The original spelling spongicula was corrected by Captain Brown in the later edition of his work. We may assume that it was a typographical error. 116 BULLETIN 93, UNITED STATES NATIONAL MUSEUM. The radii vary in width, but have oblique summits, so that the orifice, especially in the more tubular examples, is toothed. The parietal tubes are very numerous, 29 in the rostrum, and are pro- vided with many transverse septa throughout their length. The interior is ribbed only very close to the base. The sheath is colored like the outside. The base is porous, but often irregularly, large parts of it being poreless. Darwin states that there are no pores in a South African specimen he examined. Greatest diameter 20 mm.; height 10 mm. (conic). Greatest diameter 17 mm.; height 15 mm. (conic). Greatest diameter 16 mm.; height 18 mm. (tubular). The labrum has three teeth on each side (fig. 29a). FIG. 29.— BALANUS SPONGICOLA, EXMOUTH. a, LABRUM. 6, HTH SEGMENT OF CIRRUS vi. C, ANTERIOR PART OF AN INTERMEDIATE SEGMENT OF CIRRUS in. d, MAXILLA. The mandible is like that of B. concavus, figured on p. 106, fig. 26&. The maxillaB (fig. 29d) has eight spines between the upper and lower large pairs. There is also an inserted spine between those of the lower pair, and another below them. The edge is rather even. Cirrus i has rami of 19 and 12 segments. The posterior ramus is about three-fifths as long as the anterior and has moderately pro- tuberant segments not nearly so long as in B. concavus. Cirrus ii has 14 and 15 segments, but the anterior ramus is a trifle longer. Cirrus iii has rami of 15 and 13 segments. On the anterior ramus the third to thirteenth segments are armed as shown in fig. 29c, but vary in the number of " teeth." The posterior ramus has the fourth to eighth segments similarly armed. I see no teeth on cirrus iv. Cirri v and vi have most of the segments with three pairs of spines, but there are four pairs, the lower very small, on a few segments. The penis is extremely long, as in other species of this group. THE SESSILE BARNACLES. 117 The description, figs. 29, 30a, ~b, and pi. 25, figs. 2, 3, are from south coast of England (Exmouth) specimens, and represent the typical form of the species. Several specimens taken in 34 fathoms, 10 miles east of the north end of Patros Island, Brazil,1 presented to the United States National FIG. 30.— TERGA OF BALAOTS SPONGICOLA. a, 6, EXMOTJTH. c, OFF PATROS ISLAND, BRAZIL; ALL DRAWN TO SAME SCALE, d, BALANTJS CALEDUS. Museum by Dr. R. Rathbun, taken by the steamer Norseman, Cat. No. 14144 U.S.N.M., grew with B. ampJiitrite niveus. Externally they do not differ from pale examples of the English B. spongicola, but the scuta are somewhat narrower, and the terga (fig. 30c) have the basal margin a little more hol- lowed out on both sides of the spur, which is noticeably narrower. The basal diameter is 13 mm. in the largest example -(pi. 25, figs. 4-4c). The dried bodies of these specimens were much broken, but I note that the mandible is very similar to that of B. calidus. It has the fourth tooth conic though short, the fifth very small, and largely united with the ob tuse lower point. The maxilla has an even edge, and nine spines between the upper and lower large pairs. The third cirrus has minute bifid and trifi d spines near the distal borders of the lower five segments, which alone were preserved. The fourth cirrus 1 Unable to locate Patros Island, I applied to Dr. R. Rathbun, who replied as follows: "We exhausted every resource at the Museum in an effort to locate Patros Island, and then I appealed to the Hydrographic Office of the Navy, but they have not met with better success. The facts are these: When I was in Brazil between 1875 and 1878, with headquarters at Rio de Janeiro, I came in contact with the officers of the British steamer Norseman, which was the repair steamer for the cable along the Brazilian coast. Small specimens used to be brought up attached to the cable or loose in the apparatus they employed. The doctor of the steamer always brought these to me, and I labeled them in accordance with his information. I do not recall anything from the steamer Norseman that did not come from at least moderate depths of water on the coastal platform, and where the name of an island is given, I imagine it simply indicates the approxi- mate locality. I was not the collector of any of the specimens from the Norseman, and my name was put on the labels only to show that they came through me." 4729°— Bull. 93—16 9 ANTERIOR-DISTAL PART OF THE 12TH SEGMENT OF CIRRUS IV. 118 BULLETIN 93, UNITED STATES NATIONAL MUSEUM. has a double row of simple, conic, erect spinules near the distal sutures of the sixth to thirteenth segments, where it is broken off (fig. 31, twelfth segment.) B. spongicola is related to B. trigonus, but differs conspicuously by the longitudinally striate and not pitted scuta, and by lacking pro- jecting teeth on the anterior margins of the segments of the third pair of cirri. There are also many other differences. The walls are smooth in the large series examined, except for some specimens grow- ing on Pecten, which show traces of sculpture acquired from the shell. U.S.N.M. Cat. No. Locality. Collector. Notes. 12145 Dublin Bay J. Gwyn Jeffreys coll On Pecten. 12078 Exmouth, South Devon ..do. . On sandstone. 12097 Exmouth . ............ do On sandstone and Pec- 12088 (No locality) do ten. 14144 10 miles east of north end Patros Is- Steamer Norseman 34 fathoms. 9198 land, Brazil. Farralones ' Watkins i This can hardly mean the well-known islets off. San Francisco Bay, since there is no other Pacific record for the species. The specimen is small, but quite typical spongicola, except that the number of pores in the rostrum (14) is smaller than usual. BALANUS CALIDUS, new species. Plate 25, figs. 1-lc. 1854. Balanus spongicola, var. with the walls slightly folded longitudinally.— DARWIN, Monograph, p. 225, pi. 4, fig. Id. Type.—C&t. No. 48193, U.S.N.M., from Albatross station 2372, lati- tude 23° 15 ' 30" north; longitude 85° 29' 30" west, 27 fathoms, surface temperature, 64° F., in the Gulf of Mexico southwest of Cape San Bias, western Florida. Distribution. — West Indies, from St. Vincent to the northern coast of the Gulf of Mexico, 8 to 88 fathoms. The barnacle is conic, the parietes rather strongly ribbed; purplish- pink with paler ribs, or sometimes pure white. Radii rather narrow, their summits less oblique than in B. spongicola. Sheath purplish in colored individuals. Interior strongly ribbed near the base, smooth above. Pores in the bases of parietes rather small, numerous, about 22 in the rostrum. Carinorostral diameter 8 mm.; height, 4.8 mm. Scutum thick, sculptured externally with crowded growth-ridges and radial striae, but the latter are weaker than in B. spongicola. The articular ridge is larger than in spongicola, and ends below in a free point. The adductor ridge is rather strong but short. There is a little pit between its lower end and the tergal margin, as in B. glan- dula. Pit for the depressor muscle is deep and small. THE SESSILE BARNACLES. 119 The terguin (fig. 30cZ) is broader than that of B. spongicola, with a shorter beak and broader spur. The basal margin is straight on both sides of the spur, which makes angles with it on both sides. In B. spongicola the basal margin slopes imperceptibly into the spur on the carinal side. Crests for the depressor muscles well developed. The labrum has three teeth on each side (fig. 32/"). Labial palpi having a fringe of short spines along the upper margin, a distal patch of long bristles, and an oblique row of long bristles on the outer face (fig. 32d). The inner or labral face has a sigmoid hue FIG. 32.— BALANUS CALIDUS. a, MEDIAN SEGMENT OF CIEEUS vi. &, MANDIBLE, c, MAXILLA. d, OUTER FACE OF PALPUS, e, SIXTH SEGMENT OF CIERUS HI. /, LABRUM AND PALPUS. of short bristles, with larger ones, directed downward, above it (fig. 32/). The mandible has four distinct teeth, the fifth concrescent with the blunt lower point (fig. 32&). The maxilla has six spines between the upper and lower pairs. Cirrus i has rami of 20 and 10 segments, the posterior ramus half as long as the anterior, with moderately protuberant segments. Cirrus ii has rami of 11 segments, the anterior ramus longer by about three segments, though having the same number. Cirrus iii has rami of 11 and 10 segments, the anterior ramus longer by about three seg- ments. The third to sixth segments of the anterior ramus have teeth on the anterior border, with others, mainly trifid or multifid, grouped in the anterior distal part of the segments (fig. 32e, sixth segment) ; the eighth and ninth segments have very minute multifid 120 BULLETIN 93, UNITED STATES NATIONAL MUSEUM. spines near the distal border, but no teeth. The posterior rarnus has teeth on six segments. Cirrus iv has a few minute teeth near the distal borders of some segments of the anterior (outer) ramus. Cirri v and vi have two pairs of spines on most of the segments, but on a few there are three pairs, the lower ones small (fig. 32a.) The penis is extremely long. No point seen on its dorsal base. This common Antillean form was briefly described but not named by Darwin, who hesitated between describing it as a species and placing it under B. spongicola as a variety. His specimens were from St. Vincent, on coral, and others on an Avicula without definite locality. Having studied a long series of B. spongicola and several hundred B. calidus, I do not hesitate to give the latter specific rank. The ribbed wall, the finer and shallower longitudinal striation of the scutum, and the broader tergurn, with wider spur, its carinal margin making an angle with the basal margin, are all characteristic. The opercular valves are not only actually but also relatively smaller than in B. spongicola. By the distinct ' ' teeth ' ' of the segments of the third cirrus it approaches B. trigonus. So far as I know, B. spongicola does not have the armature so strongly developed. The spines of the posterior cirri are slightly more reduced than in B. spongicola, or in fact than in any Balanus I have dissected. The other characters of the barnacle are about as hi B. spongicola. B. calidus lives in populous colonies on shells of all kinds, dead echinoderms, and even on the spines of echini (Cidaris tribuloides} , an unusual station for Balanus, though a favorite one for Verruca. The largest specimen seen has a diameter of 10 mm., height 8 mm. It is from Albatross station 2365. U.S.F. C. station. Locality. Depth (fathoms) Collector. 2372 2405 2407 2403 2365 2362 2360 2363 6075 Latitude 29° 15' 30" north; longitude 85° 29' 30' Latitude 28° 45' 00" north; longitude 85° 02' 00' Latitude 28° 47' 30" north; longitude 84° 37' 00' Latitude 28° 42' 30" north; longitude 85° 29' 00' Latitude 22° 18' 00" north; longitude 87° 04' 00' Latitude 22° 08' 30" north; longitude 86° 53' 30' Latitude 22° 08' 30" north; longitude 86° 49' 00' Latitude 22" 07' 30" north; longitude 87° 06' 00' Off Boca Prieta, Porto Rico west, west. west, west, west. west, west, west. 27 30 24 88 24 25 26 21 81 A Ibatross. Do. Do. Do. Do. Do. Do. Do. Fish Hawk. NOTE.— Station 2372 is in the vicinity of Cape San Bias, or Appalachicola, western Florida. Stations 2405, 2407, 2403 are further offshore in the same region. Stations 2360-2365 are on the Yucatan Bank, north of the northeastern extremity of Yucatan. SERIES OF B. PERFORATUS. BALANUS L^VIS Bruguiere. Plate 27, figs. 1, la, 3-36. 1789. Balanus Isevis BRUGUIERE, Encyclopedic Methodique, p. 164, pi. 164, fig. 1. 1818. Balanus discors RANZANI, Opuscoli Scientific!, vol. 1, p. 77, pi. 3, figs. 9-13. 1854. Balanus Isevis Bruguiere, DARWIN, Monograph, p. 227, pi. 4, figs. 2-2gr, with var. nitidus, fig. 2, and var. coquimbensis, fig. 2a. THE SESSILE BARNACLES. 121 1897. Balamis Ixvis Bruguiere, WELTNER, Verzeichnis, p. 263. 1909. Balanus Isevis nitidus Darwin, PILSBY, Proc. U. S. Nat. Mua., vol. 37, p. 68, pi. 17; pi. 19, figs. 5-9. Type-Locality. — Cape Horn, on Mytilus magellanicus, collected by Dombey. Distribution. — Cape Horn north to the Rio Negro on the east coast, and to Peru on the west. Shore to 20 fathoms.1 The barnacle is white or pale purple, covered with a brown epi- dermis (or nude in var. nitidus). Radii very narrow. Scutum having growth-ridges and one to three longitudinal fur- rows, varying hi width. Inside there is a rather narrow articular rib, terminating below in a free point, and a high adductor ridge wholly free from the articular. Pit for the lateral depressor muscle is small but deep. The terguni has a longitudinal furrow with the edges somewhat folded in. Spur moderately long, wide, with the end obliquely cut off and convex; basicarinal angle very thin; crests well developed. According to Darwin, "in the cirri none of the segments are very protuberant. In the first pair, one ramus is nearly twice as long as the other. In the posterior pairs the segments are not much elongated, but each supports seven pairs of spines." The more minute struc- tures of the cirri have not been investigated. Darwin distinguished three varieties, or, as we would now say, sub- species of B. Isevis, characterized as follows: a1. Basis simply porose. 61. Walls covered with yellow or brownish epidermis; scutum usually with one wide external furrow. Southern Chile, including the Straits of Magellan. B. Isevis Bruguiere 62. "Walls nude and smooth; scutum usually with two longitudinal furrows or one narrow furrow. Concepcion, Chile, to Peru B. I. nitidus Darwin a2. Basis much lengthened, its cavity partially filled with a mass of irregular, super- posed septa of papery thinness, forming an openly cellular mass. B. I. coquimbensis Sowerby The distinctive characters of Isevis and nitidus are those of a great majority of the specimens, but subject to exceptions, as Darwin has noted. Some large groups from Gregory Bay, Magellan Strait, though taken alive, had no epidermis. Over 50 individuals examined had one wide furrow on the scuta (pi. 27, fig. 1), and one specimen had an additional small furrow (pi. 27, fig. la). Numerous specimens from other localities hi the same region agree hi having one wide scutal furrow. Two individuals labeled Cape Horn, collector un- known, have the normal yellow cuticle, but the scuta have two small grooves, as hi B. I. nitidus. A series from Valparaiso is similar, with the epidermis of Isevis, the scuta of nitidus. 'The Ijcality "California," given by Darwin, was based upon incorrectly localized specimens. The species is confined to the cold water area of South America. Weltner reports specimens without sulci on the scuta from Rio Grande do Sul, Brazil. 122 BULLETIN 93, UNITED STATES NATIONAL MUSEUM. BALANUS L.EVIS NITIDUS Darwin. Plate 27, figs. 2-2d; 4,5. Among the very numerous specimens examined from northern Chile (Arica) and Peru, none have the broad scutal furrow of Magellanic Isevis and the epidermis is wholly or largely wanting. The number of scutal furrows in the two largest series examined is as follows : One furrow. Two furrows. Three furrows. Arica, Chile 3 16 1 PI. 27, figs. 2-2, TWENTY-EIGHTH, AND C, SEVENTEENTH SEGMENTS OF CIRRUS IV, ANTERIOR RAMUS. The type-specimen, from Monterey Bay in 10 fathoms, was seated upon a rock. The surface is abraded and perforated in places.1 The xThe worn condition, together with the peculiar tergum, led me into the error of placing the species in Darwin's Section A in my original account. The examination of additional perfectly preserved examples and a careful reexamination of the type shows that the radii are not in the least porous. It belongs, therefore, to Darwin's Section C. 130 BULLETIN 93, UNITED STATES NATIONAL MUSEUM. external ribs are rude, rounded, and very irregular (pi. 31, fig. Their irregularity is probably in part due to the extremely irregular surface of the stone upon which the barnacle grew. The cone leans toward the rostrum, which is much shorter than the carina. Where the parieties are worn externally the very narrow tubes are laid open. They closely resemble those of B. nubilis, but have no transverse septa where exposed. The number of tubes is somewhat increased down- ward by new septa dividing the tubes. The basis is nearly flat. Its substance fills several cavities in the supporting rock, and in only two places a few irregular pores are visible in the section exposed by breaking it across. Elsewhere it is quite solid. The other examples recorded above, from more southern localities, grew on nearly smooth, flat surfaces, perhaps planks. The cone leans toward the carina, which is not much higher than the rostrum. The exterior is perfectly preserved, the ribs stronger and more regular than in the type. The proportions and external sculpture of the compartments are very much as in a large Balanus balanus Linnaeus (B. porcatus Da Costa). The parietal tubes have transverse septa close to the base, whether farther up was not ascertained. The basis is well provided with rounded or oblong pores in the Santa Bar- bara specimen, but in places toward the periphery they are solidly filled up. The Santa Eosa Island specimen also is well provided with basal pores. It is not much more than half grown. In the San Diego example (pi. 31, fig. 2) I found regular, rounded pores in one small area of the basis; the rest of the exposure (a section across the base and another near and parallel to the periphery) is quite impervious. It is obvious that in this species there is a good deal of variation in the degree of porosity of the basis ; and in some old individuals pores are few and very local, therefore easily overlooked. The opercular valves are identical in the Monterey and Santa Barbara examples, except that in the latter they are less worn externally. The other individuals examined lack opercular valves. Small examples of Balanus tintinnabulum calif ornicus grew on the individuals from San Diego and Santa Eosa Island. This species and Balanus nubilis are the largest shallow-water Balani of North America. When in good condition, B. aquila looks like a very large, strongly ribbed B. ~balanus; but it differs from that by the bifid sutural edges of the alse and by the opercular valves, which — especially the tergum — have a remarkable resemblance to those of B. psittacus. The inner structure of the walls is very similar in B. aquila and B. nubilis, but in the former the compartments cohere far less firmly and the sheath is longer. B. nubilis will break through the compartments rather than part at the sutures. The internal or- gans, so far as I examined them, are remarkably similar, particularly the cirri, but it may be noted that the maxillae differ. In B. aquila THE SESSILE BAENACLES. 131 there is no distinct notch below the upper pair of spines, and there is an enlarged spine (as in B. balanus) on the lower prominence of the edge. The very narrow, purple-beaked tergum, the whiteness of the very strong walls, and the bifid ala? readily separate B. aquila from all varieties of the Protean B. concavus. It is a very distinct species. Besides the specimens recorded below, there is one labeled " Ore- gon," without definite locality or record of collector. Its occurrence so far north needs further evidence. Locality. Collector. Number of speci- mens. Remarks. Monterey Bay (10 fathoms) A Ibntross 1 Type. Santa Barbara Cal R. E. C. Stearns 1 Santa Rosa Island P. Schumacher 1 Rostrum and lateral San Diego Cal R. E.G. Stearns 1 plates only. SERIES OF B. NUBILIS. BALANUS NUBILIS Darwin. Plate 30, figs. 1-4 ; plate 31, figs. 3, So, 4, 5. 1854. Balanus nubilis DARWIN, Monograph, etc., p. 253, pi. 6, figs. 2o-2e. Type. — British Museum, from Monterey Bay, California. Distribution. — Southern boundary of Alaska to Santa Cruz, California. Darwin's original description is as follows : General appearance. — Shell conical, rugged, sometimes furnished with sharp longitudinal ribs ; dirty white. Orifice not large, oval, toothed. Radii rather narrow, with their summits oblique, much jagged. Basal diameter of largest specimen 2.1 ; height only 1.3 of an inch. Scuta broad, with the lines of growth prominent ; internally, articular ridge very little prominent, sometimes hardly developed, but thick, ending down- wards in a small free point. Adductor ridge prominent, blunt, produced straight downward, making a deep longitudinal cavity for the lateral depressor muscle ; in some specimens this cavity is almost arched over, so as to tend to be tubular, with a short ridge in the middle ; in other specimens there is no trace of this tubular structure. Terga, with the apex beaked, beak triangular, dull purple ; the longitudinal furrow is so shallow as hardly to exist. The basal margin slopes down on both sides, with a nearly equable curvature toward the spur ; hence the spur is broad in its upper part and narrow at its obliquely truncated lower end. Internally, there is an elongated dark purple patch. The shallow articular furrow is of quite remarkable breadth. The articular ridge is medial, and the inflected scutal margin is not wide. The internal surface of the spur is formed into a ridge, which runs a little way up the valve, and is sometimes partially separated from the spur itself, making the basal extremity toothed or double. The crests for the depressors are pretty well developed. 132 BULLETIN 93, UNITED STATES NATIONAL MUSEUM. Walls moderately strong; inner lamina slightly ribbed; the denticuli on the bases of the parietal longitudinal septa are sharp. I could not see any trans- verse septa in the parietal tubes. The radii are rather narrow, their summits are remarkably jagged and very oblique ; the septa are plainly denticulated on both sides, but chiefly on the lower side; each septum itself, toward the inner lamina of the radius, branches and divides ; the interspaces are filled up nearly solidly. The alse have apparently their summits less oblique than those of the radii, their sutural edges are finely crenated. The lower edge of the sheath is hollow underneath. The basis is flat ; it is rather thin, and imperfectly porose ; in parts it is not at all porose, in others it is traversed only by very minute pores ; there is, nevertheless, in some parts, even where the upper layer is not porose, an underlying, cancellated layer. The labrum is deeply notched, with the edge almost plain, but show- ing one very minute tooth in the specimen dissected (fig. 36alanus. Their most obvious characters are as follows : a\ Transverse septa of parietal tubes extending nearly or quite to the base. bl. Radii conspicuously sunken ; about 14 tubes in the rostrum B. rostratus b\ Radii but slightly sunken; about 18 or more tubes in the rostrum. c1. Large Alaskan form, diam. GO-TO mm.; four or five pairs of spines on each segment of the posterior cirri B. r. alaskensis c3. Smaller Puget Sound form, diam. about 18 mm.; at most four pairs of spines on segments of posterior cirri B. r. heteropiis a*. Transverse septa confined to the upper half of the parietal tubes ; usually about 18 tubes in the rostrum. ft1. Radii but slightly sunken. c\ Rather thin, wall spinose or somewhat rugose; basis typically concave; usually on sponges, sometimes on shells B. r. apertus cz. Large and solid, walls smooth B. r. dalli b\ Radii conspicuously sunken, walls thick B. r. suttiralis BALANUS ROSTRATUS ALASKENSIS, new subspecies. Plate 38, figs. 4, 4a, 5. Type.— Cut No. 3415, U.S.KM., from Kodiak, Alaska, 50 feet, collected by W. H. Dall. The barnacle is white, conic, very solid, with narrow radii; outer lamina of the wall smooth where preserved, but extensively eroded, exposing the large parietal tubes, which are crossed by many trans- verse septa, down to the base. Between the septa, several longi- tudinal threads are seen on the inner lamina. The rostrum has 18 tubes. Interseptal ribs on the inside numerous, sometimes 6 or 9 in one interval. Adductor ridge of the scutum prominent. Both tergum and scutum have a faint pink tint toward their apices. Carinorostral diameter, 61 mm.; height, 53 mm. (Kodiak). Carinorostral diameter, 70 mm.; height, 4G mm. (Unalaska). The labrum in the type-specimen is toothless on one side, with one tooth on the other. Mandibles as usual in the species. Maxilla} (fig. 40. /». apertus were taken from a "hermit crab sponge," Captains Bay, Unalaska (pi. 36, fig. G). The base is very concave, and the spines remind one of spinose varieties of B. tintinabulum. Opercular valves, pink-tinted. The sponge which these barnacles grow in is a very close-grained, soft and friable species. The typical form of apertus is almost al- ways on sponge, but sometimes on shells. One from Pccten (Cap- tains Bay, Unalaska, 10 fathoms, Dall) reproduces the ribs of the shell and has no spines (pi. 36, fig. 4). Another, growing on TerebratyMna (pi. 36, figs. 3, 5), Albatross Station 2849, is unusually thin, with smooth walls and very large orifice. A ground specimen is figured to show the transverse septa of the upper half of the parietal tubes, and their absence in the lower half. A rostrum of one of this lot has 18 tubes ; there is a single accessory rib in each inter- septal interval. In the specimens growing on shells the base is less concave than when growing on sponges, conforming, of course, to the contour of the shell. When growing on a sponge, it appears that the pressure of the growing basal edges of the Avail tends to cut into the sponge, so that the periphery penetrates deeper than the initial point of fixation, causing the base to be dome or cone shaped. In Acasta the exactly opposite condition obtains; the growing periphery of the barnacle yields to the pressure of the living sponge and is forced upward, the base becoming an inverted cone, or bowl-shaped. U.S. F.C. Sta. No. Locality. Depth (fath- oms). Bottom temper- ature °F. Collector. 3232 4777 4778 2849 2856 10 miles west of Franklin Point, Arctic Ocean, Alaska. Latitude 60° 12' 00" north; longitude H)S°M'00"west. Latitude 58° 31' 30" north; longitude 157° 34' 15" west. Constantine Harbor, Amchitka Island 13J Point Barrow expedition. Lieut. Geo. M. Stoney. A Ibatross, W. H. Dall. Albatross. Do. W. H. Dall. Do. Do. Do. Albatross. Do. W. H. Dall. WJ 47 Near Sotnisopochnoi Island . 52 43 10 5-15 Latitude 52° 12' 00" north; longitude 179° 52' 00" east. Captains Ilarbor, Unalaska Unalaska (several lots) Popoff Strait, Shuinagin Island East coast Nague, Shumagiu Island. Latitude 56° 16' 00" north; longitude 160° 28' 00" west. Latitude 58° 07' 00" north; longitude 151° 36' 00" west. Middleton Island, Alaska 69 68 Low tide. 43 44 BALANUS ROSTRATUS DALLI, new subspecies. Plate 38, figs. 1-lc, 2. This form attains a large size and is quite solid; external surface smooth; radii very little sunken, moderately wide. Parietal tubes large and square, with one or two interseptal ribs on the inner lamina; 148 BULLETIN 93, UNITED STATES NATIONAL MUSEUM. these tubes having transverse septa about half way down, the lower half being open. Inside of the parietes sharply ribbed to the sheath (or in some old individuals, becoming nearly smooth above). Carinorostral diameter, 55 mm.; meight, 43 mm. (type). Greatest basal diameter, 47 mm.; height, 62 mm. (No. 48023). The tj7pe of this variety was taken by Dall at Unalaska (Cat. No. 9202, U.S.N.M.). It is on a very large valve of Placunanomia. It differs from B. r. alaskensis by having septa in the upper part of the parietal tubes only, as in B, r. apcrtus, which is a much thin- ner, smaller, and generally rougher barnacle. There are 21 tubes in, the rostrum of this specimen. The mouth-parts of the largest specimen in group No. 38670 (figured in my former paper, pi. 12, fig. 4), agree with B. r. apertus No. 38667. The third cirrus has no spinules, but there are some minute fimbriuted flat spines and slender sutural bristles as in B. balanus. Some of the flat spines were seen on cirrus v, but none on vi. The largest individual in this group of seven on the shell of a Pecten measures 55 mm. high, 45 mm. in greatest diameter of the base. Cat. No. Locality. Collector. Notes. 9202 W. H. Dall Type. PI. 38, figs. 1-lc. 48023 do. .do PI. 38, fig. 2. Plover Bay, Siberia do In 23 fathoms. 38670 AlbatToss Station 4779, near Semiso- A Ibatross BullU. 8. Bureau of Fisher- 91S7 pochuoi Island, Aleutians (54 fath- oms). iCyska llartxT . W. H. Uall. . ies, vol. 29, pi. 12 , fig. 4. Form suturalis (pi. 38, fig. 3). The Cor win took a peculiar form in Alaska, exact locality not noted, in 1884. It is externally a good deal like typical B. rostratus, as the shape is conic, with small orifice, radii are sunken, parietes with angular edges. Otherwise it is more like dcdli. The Avail is thick, with large square tubes, 17 in one rostrum examined. Interseptal ribs, usually one or two. The tubes are open a long way up ; no septa visible from below. The labrum (fig. 41e) has no teeth. The teeth of the mandibles are unusually acute, but typical in arrangement (fig. 416?). Cirri and penis are substantially as in B. r. apertus, the posterior cirri having segments with seven pairs of spines (fig. 41c). The type is Cat. No. 48025, U.S.N.M. I have some doubt whether this form will prove separable from B. r. dalli Avhen large series are obtained. A specimen of dalli from Kyska Harbor and one from Plover Bay have very narrow radii, but they are not sunken as in suturalis. THE SESSILE BAENACLES. 149 BALANUS BALANUS (Linnaeus). Plates 33, 34, 35. 17."S. Lcp'ts luldiiny LI.\N.KI\S, Systema Nature, ed. 10, p. 667 ("ad littora ocean I Eitropaci") ; see HANLKY, Ipsa Linnan OmchyHa, 1855, p. 18. 1778. Jilfiftiiina] ptjrcufiis D\ COSTA, Historia Naturalis Testaceoruiu Bri- tannia?, p. 249. 1780. Lrpus ixila-nus Linnaeus, BORN, Testacea Musei Caesarei, p. 8, pi. 1, fig. 4 (good). 1789. Balanus sulcatus BKUGTJIERE, Encyclopedie Methodique, p. 163, pi. 164, fig. 1. 1803. Lci>as costatus MONTAGU, Testacea Britannica, p. 11. 1804. Lcpas balanus Linnaeus, DONOVAN, Natural History of British Shells, pi. 30, fig. 1. 1804. Lcpas costata DONOVAN, Natural History of British Shells, pi. 30, - fig- 2. 1815. Lcpas scotica WOOD, General Conchology, p. 40, pi. 6, fig. 3. 1818. Balanus tessellatus SOWEKBY, Mineral Conchology, pi. 84. 1830. Balanus ycuiculatus CONKAD, Journal of the Academy of Natural Sciences of Philadelphia, vol 6, p. 265, pi. 11, fig. 16. 1844. Balanus communis BROWN, Illustrations of the Recent Conchology of Great Britain and Ireland, p. 120, pi. 53, fig. 23. 1844. Balanus costatus Montagu, BKOWN, Illustrations of the Recent Con- chology of Great Britain and Ireland, p. 120, pi. 54, figs. 2, 3. 1S54. Balanus porcatus E. da Costa, DAEWIN, Monograph, p. 256, pi. 6, figs. 4a-4e; Monograph on Fossil Balanidre, p. 21, pi. 1, figs. 5a-5ff. 1878. Balanus porcatus Da Costa, MIEES, Narrative of a Voyage to the Polar Sea, by Capt. S'r G. S. Nares, vol. 2, p. 247 (Cape Louis Napoleon, lat. 79° 38' N., 50 fathoms; Richardson Bay, lat 80° 2' N., 70 fathoms). 1897. Balanus porcatus Da Costa, WELTNEE, Verzeichnis der bisher be- schriebeneu receuten Cirripedienarten, Archiv f. Naturg., Jahrg. 1897, p. 267 (exclusive of Japanese records). 1900. Balanus porcatus Da Costa. WELTNEE, Fauna Arctica, vol. 1, pp. 292-297, 303, pi. 8, figs. 1-12 (distribution and variation). 1911. Balanus porcatus Costa, SUMNEE, Biol. Survey Woods Hole and Vicinity, Bull. Bur. Fisheries, vol. 31, p. 646. Type. — Collection of the Linnean Society of London. Distribution. — Arctic and Xorth Atlantic Oceans, from 80° North latitude, Franz Josef Archipelago to the English Channel, and in America south to Long Island Sound. Bering Sea ; a variety in Puget Sound. From low tide (in northern localities) to about 90 fathoms. English Pliocene ; Pleistocene of Sweden, Canada, and Maine.1 According to Darwin its characters are as follows : Shell white, generally sharply ribbed longitudinally ; radii with their summits almost parallel to the basis. Scutum longitudinally striated ; tergum with the apex produced and [usually] purple. 1 The records of this species from Campbell and Stewart Islands, New Zealand, were undoubtedly based upon erroneous identifications. Weltner states that it does not exist in the Mediterranean. 4729°— Bull. 93— 1( 150 BULLETIN 93, UNITED STATES NATIONAL MUSEUM. General appearance. — Shell conical, somewhat convex ; white, sometimes tinted yellowish, from the thin investing membrane ; the produced tips of the terga are purple ; the parietes of each compartment have from two to four strong, prominent, sharp, straight, longitudinal ribs ; these are sometimes irreg- ular, and rarely, as will presently be described, they are absent. The radii are smooth and of considerable breadth ; their summits are nearly parallel to the basis or only slightly oblique ; hence the orifice is entire ; it is rather small and ovate, being broad at the rostral end and very sharp and narrow at the carinal end. The scutum is more or less concave from end to end, with sculpture of narrow, prominent growth-ridges, crossed by fine longitudinal strice which crenulate the ridges. The articular ridge is low, rather abruptly terminated below. Usually there is no distinct adductor ridge, but the callous occupying its place has a slightly raised, acute border, bounding the very deep pit for the lateral depressor muscle, and the border of the adductor muscle pit is slightly prominent and angular. Sometimes these prominences stand in line and are weakly connected, forming thus a rather ill-defined adductor ridge. The tergum is very much narrower than the scutum, its length nearly twice the width. Its pointed beak, of a purplish or pale-pink tint, or sometimes white, projects wett above the scutum. Exter- nally it is marked with somewhat coarse growth-lines. There is no longitudinal furrow, but a wide spur-fasciole is defined by impressed lines. Spur close to the basiscutal angle, truncate distally, the basal margin sloping to it on both sides. The articular ridge is rather low; scutal margin is sharply inflexed in the lowTer part. Crests for the depressor muscles are irregular, not very strong. Darwin says: The parietes have large, square parietal tubes ; in the upper part these are filled up solidly without transverse septa; the longitudinal septa are finely denticulated at their bases, and the denticuli extend unusually close to the outer lamina. In very young specimens the inner lamina of the parietes is ribbed in lines corresponding with the longitudinal septa, as is the case with most species of the genus; but in medium and large-sized specimens there are between the ribs, thus produced, from one to four smaller ribs, which do not correspond with any longitudinal septa ; they are finely denticulated at their bases and may be considered as the representatives of longitudinal septa which have not been developed and reached the outer lamina. I have seen no other instance of this structure, namely, the presence of a greater number of ribs, on the inner lamina of the walls, than there are longitudinal septa. [B. rostratus is similar in this respect.] The radii have their summits generally parallel to the surface of attachment, as is usual in the first section of the genus, but sometimes they are slightly oblique; the septa sometimes rudely branch a little, but they exhibit scarcely a trace of denticuli ; the interspaces are filled up quite solidly. The alse have their summits very oblique ; their sutural edges are finely crenated. Basis rather thin, translucent, not permeated by pores ; obscurely furrowed in lines radiating from the center ; the circumference is marked in a peculiar manner by the longitudinal septa and by the tips of those intermediate den- ticulated ribs which occur on the inner lamina of the parietes. THE SESSILE BAEISTACLES. 151 Mouth. — Labrum with six teeth; mandibles with the fourth and fifth teeth small and rudimentary. Maxilhe, with a small notch under the upper pair of spines; in the lower part there is a single large spine. Cirri, dark brownish purple, making a singular contrast with the white operculum and shell; first pair, with one ramus having 26 segments, and about twice as long as the shorter ramus having 12 or 13 segments, with their front surfaces protuberant. In the second pair of cirri the segments are but little protuberant; third pair about one-third longer than the second pair; sixth pair elongated, having in the same individual 46 segments ; these segments have shield-shaped fronts bearing 5 pairs of spines, with some minute intermediate bristles. There is the usual point at the dorsal base of the penis.1 ( See p. 152, fig. 43. ) The third (fig. 43nieri and B. crenatus. It is rather common in from 20 to 90 fathoms, but seems to drop out of the fauna rather abruptly at the latter depth, as it would surely have been taken if present at some of the very numerous Albatross stations in deeper water. South of Cape Cod it seems exceptional above 18 or 20 fathoms, where B. eburneus and B. amphitrite niveus are the prevalent species. Far- ther north, on the Maine coast and northward, B. balanus is some- times taken at depths of only a few fathoms. On Coffin Island, Mag- dalen Islands, in the Gulf of St. Lawrence, Mr. Bayard Long found it at low water, on Mytilus edulis. Variations in the structure of the wall. — The figures on plate 35 show the chief variations in the basal septa of the walls. Figure 5, from Georges Bank, is the normal and most frequent condition. There are from one to four ribs on the inner lamina between the com- plete septa; outer lamina has several or many very short lamellae within the margin. The rostrum here figured has 11 tubes. Plate 35, figure 3, represents portions of two rostra from Eastport, Maine; strongly ribbed form. Here the inner and outer laminae of 154 BULLETIN 93, UNITED STATES NATIONAL MUSEUM. the wall are more separated and the septa are irregularly spaced, the internal ribs are more numerous, and the lamellae within the outer lamina are stronger. Rostrum has 13 tubes. There is an extraor- dinary development of the interseptal lamelloe within the outer lamina of the wall in a specimen from Portland, Maine (pi. 35, fig. 6). In one example from Cork, Ireland, the interseptal lamella? within the outer lamina of the wall are similar!}'- lengthened (pi. 35, fig. 7, Cat. No. 12092). These lamella) are minutely crenulate; many of them almost reach the inner lamina. Plate 35, figures 2, 2 a, Albatross Station 2079, Georges Bank, in 75 fathoms. Wall thin, the tubes compressed. Inner lamina of wall with one to four ribs terminating in strong, denticulate teeth. Outer lamina bordered with crowded, short lamella?. The rostrum has 13 tubes. Plate 35, figure la, Aberdare Channel, Franz Josef Land, above north latitude 80°. Very few interseptal ribs or lamella?; 14 tubes in the rostrum, which is very narrow. It appears that the number of tubes (about 14 in the rostrum) is rather constant, but their shape and the development of interseptal ribs and lamella? depend upon the thickness of the walls and the shape of the compartment, whether spreading, as in conical individuals, or narrow, as in cylindric forms of the species. There are never any transverse septa in the tubes. Individuals growing on Pecten are often beautifully fluted, in harmony with the ribs of the shell (pi. 33, fig. 2a;), while others in the same group may be unaffected. Often the Pecten specimens have only traces of ribs, the surface being minutely shagreened, as though the conflict between the ribs of the barnacle and those induced by the Pecten had resulted in a general flattening of sculpture (pi. 35, fig. 2). The scutum is thick, often strongly curved; pit for the depressor muscle narrow, deep, almost tubular from the prominence of the tergal border and the adductor callous. In the single British specimen of the typical form I was able to dissect, the six teeth of the labrum (fig. 43a) are exceedingly small. The sixth cirrus has four pairs of spines on the segments (fig. 43&) instead of five, as stated by Darwin, but it is likely that more distad segments would show another pair. In the dry example examined, the cirri were broken at the eighteenth segment. The mandibles and maxilloe are substan- tially alike in the numerous forms of B. l)alanus and B. restrains examined, merely differing a little in the proportions and number of the spines of the maxilla?. Regional distribution and variation. — European specimens (pi. 33, figs. 1-65) rarely attain 30 mm. in diameter, and are more frequently 20 to 25 mm., judging by a considerable series in the museum, brought together by the conchologist J. Gwyn Jeffreys. THE SESSILE BARNACLES. 155 There seem to be two chief races among the British specimens. The typical form (pi. 33, figs. l-2«, G-Gfr) is rather high with steep walls, which have the ribs only moderately prominent and usually irregular; radii wide. The external sculpture is readily modified by the irregularities of the supporting object. The type-specimen x is represented in plate 33, figures 1, 1«. The surface is irregularly roughened by the laminae of the Pecten, and the ribs are irregular. The other European race or "form" (pi. 33, figs 4, 5) is conic, spreading and very rugged; rostrum with four strong ribs, laterals and carina, three or four, carinolaterals with one strong rib; radii rather narrow. Opercular valves as in typical B. balanus. The ribs in this race seem very little affected by the irregularities of the sup- port. Examples from Belfast Bay, growing on Pec-ten opercularis (fig. 5), are similar to those growing on the smooth mussel Modiolus modiolus (fig. 4). Donovan's Lcpas balanus is this form. His Lepas costata seems to be the young stage of a similar form which I have seen from Scarborough (fig. 4), and which differs only by having more ribs; in a specimen 19 mm. in diameter there are seven ribs on the rostrum, five on the lateral compartments. Northward B. balanus becomes larger than in England and Ire- land. Darwin records a specimen 2.1 inches in diameter from the Shetland Islands, and others equally large from glacial deposits of the Isle of Bute. Arctic Ocean. — The highest latitude for B. Ixdanus, or so far as I know, for any cirripede, is Aberdare Channel, east of Alger Island, latitude 80° 21' 21" north, longitude 56° OS' east, in the Franz Josef Land Archipelago. Here the Baldwin-Ziegler Expedition obtained a series of rather peculiar specimens, Cat. No. 48195, U.S.N.M., illustrated on plate 35, figures 1, la, 15. The form is cylindric or barrel shaped, the orifice as large as the base. The parietes usually show weak ribs in the upper part, and sometimes they persist irregularly to the base. Radii very broad. Interior strongly striate, the septa between outer and inner laminae about as numerous as in the typical form, but with fewer interstitial points than in typical Ixdanus. The scutum is thin, with even less trace of an adductor ridge than usual. The tergum is remarkably nar- row, its carinobasal angle rounded off, and the long, free apex is not tinted (fig. 44). The mouth parts are normal, but the posterior cirri have an addi- tional pair of spines. First cirrus with 23 and 10 segments, second with 17 and 13. The third cirrus has many spinules on the segments 1 1 owe the photographs of this typo to the courtesy of the authorities of the Linnean Society of London. They were obtained by the kind intervention of Mr. T. H. Withers, of the British Museum. 156 BULLETIN 93, UNITED STATES NATIONAL MUSEUM. of the anterior ramus, as far as the twelfth segment. On the pos- terior ramus there are fewer spinules, and fewer segments. On the fourth cirrus there are a few spinules, chiefly of the flat multifid form, in a row near the distal sutures of the segments. There D FIG. 44. — BALANUS BALANUS FROM ABERDARE CHANNEL, a, SCUTUM AND 6, c, d, TERGA OF THREE INDIVIDUALS. X 2J. are many erect, mainly simple spinules on the second segment of the pedicel. Cirrus iv has minute, flat multifid spinules on the distal parts of the segments of both rami. In cirrus vi the segments of the pedicel have many minute, multifid spinules, but there are none on the segments of the rami. These have 46 segments, bear- ing six pairs of spines. The fourth and part of the segments of the fifth cirri have five pairs of spines. The penis is typical except that I can find no trace of the point near the lose, char- acteristic of B. lalanus. The individual dissected is certainly adult, the largest of a consider- able series (fig. 45). The habit of this colony is to grow in branching groups, un- like the usual colonies of B. balanus. Greenland (Upernavik) speci- mens attain a good size, 44 mm. in diameter and height. Eibs as in typical B. balanus but weaker, often hardly noticeable. Tubes of the parietes large. Beak of the tergum white. Darwin also has noted that in Arctic specimens the terga have white beaks. Labrador specimens from 60 fathoms are deficient in ribs, with the aperture as large as the base. The terga and sometimes the FIG. 45.— BALANUS BALANUS, ABERDARE CHANNEL. O, BASE OF CIRRUS VI WITH PENIS. 6, PAET OF 7TH SEGMENT OF ANTERIOR RAMUS OF RIGHT CIRRUS III. C, 32D SEGMENT OF CIRRUS VI. THE SESSILE BARNACLES. 157 scuta are faintly pink tinted. Others from 7 and 45 fathoms have the usual ribs. All are rather small. A lot taken by Mr. O. Bryant 20 miles south of Nain, Labrador, have the terga hardly beaked, and white. The longitudinal striation of the scutum is very faint. They are small, measuring 8 mm. in diameter. Specimens externally similar to typical B. balanus, but frequently larger, are common on the American coast, and on Georges Bank (pi. 35, figs. 2, 2#.) A usually larger form from Bar Harbor, Maine (pi. 34, figs. 1, la, 6), has six ribs on the rostrum, four and five on the latera. Others may have as many as eight ribs on the rostrum. The ribs are not nearly so strong as in the form called B. genicuhdus by Conrad. The individual figured has the posterior ramus of the first cirrus two-thirds as long as the anterior, segments 25 and 13 (fig. 43^). Kami of second cirrus somewhat unequal, of 18 and 14 segments. The anterior ramus of cirrus iii has a few spinules, most numerous about the tenth segment (p. 152, fig. 43e). There are also some delicate spines near the distal sutures of the segments. Most of the segments of this cirrus have no spinules. Cirrus iv has a few spinules on some of the median segments (p. 152, fig. 43, BOTH sinus OF A PALPUS, c, 22o SEGMENT OF CIRRUS VI. d, LAERUM. In a specimen from St. Pauls Island, Bering Sea, the labrum has two small teeth on each side, mouth parts otherwise typical. First cirrus with rami of 24 and 12 segments. The third and fourth cirri have very few small spinules, not so many as in the Bar Harbor form. The sixth cirrus has six to seven pairs of spines, as in the preceding form, from which this differs by having teeth on the labrum. The penis has the usual point near the base, and is less than half as long as the sixth cirrus (fig. 47). By the numerous spines of the cirri the Bering Sea B. balanus resemble B. re-stratus, yet the characters of the opercular valves, the absence of septa in the parietal tubes, and the more ribbed external wall are characters which surely indicate that they belong to the Atlantic species. THE SESSILE BARNACLES. 101 Herr "Weltner1 records B. porcatus (=balanus) from various points in Japan — Hakodate, Enoshima, and Yokohama — but on the following page he inserts B. rostratus, without locality record, as one of the species not contained in the Berlin collection. In Fauna Arctica (p. 296) these specimens are discussed and one of them is figured. It is, without doubt, B. rostratus. It may be surmised that all of his Japanese records for porcatus really pertain to B. rostratus. This mistake on the part of a zoologist expert in the determination of barnacles is readily understood, for the really diagnostic character of B. rostratus — the presence of transverse septa in the parietal tubes- was not mentioned in Hoek's description and can be seen only by filing the wall or looking into the pores at the base. EUROPEAN. Locality. Collector. Notes. Aberdare Channel, east of Alger Island, ' Franz Josef Land. Spitzbergen Baldwin-Ziegler Polar Ex- pedition. Ernest Williamson, U. S. N. 1901. 1882 Shetland. Islands ... . ... J. Gwyn Jeffreys . Loch Shielda? West Ross. Scotland do Oban, Scotland do On Ast&Ttc Pectcn and TCTC- Northumbrian coast ..do bratulina. Scarborough, England do On Pectcn Mouth of the Thames do... Sandwich do Swansea Bav , Wales do On ]\fytilus Rosilly Down do Exmouth, south Devon do Langland Bay . ..do On Buccinum Bridlington Crag do Pliocene North of Ireland do Bantry Bay, Ireland do Cork Harbor, Ireland ... do On Pectcn and Pinna Kiel Bay Karl Mobius EAST AMERICAN. TJ.S.F.C. Station. Locality. Depth (fath- oms). Bottom tempera- ture. Collector. Barden Bay, Ingleueld Gulf . . 10-10 0 F. Princeton Expedition Upernavik Greenland Latitude, 70° 20' north; longitude, 56° west, oil 90 C. S. McClain. Hare Island, Greenland. Arctic Ocean Capt. Rogers. Greenland N. P. Scudder. Rittenbank, Greenland H. G. Drexel. Davis Strait 40 N. P. Scudder. Labrador Storer. Off Hebron, Labrador GO O. Bryant. Egg Harbor. Labrador . . 7 Do. 20 miles south of Nain, Labrador Do. Anticosti Island J. Schmitt. Off Halifax, Nova Scotia U. S. F.C. 14 miles south of Cape Sable, Nova Scotia 45 O. Bryant. Bay of Fundy . .*. U.S. F.C. 2500 Latitude, 44° 28' north; longitude, 60° 1.3' 1~>" 36 Albatross. west. Between La Have and western banks . . . J. Allen. G rand Manau W. Stimpson. Eastport, Me Rathbun. Casco Bay, Me Do. Portland, Me.. J. W. Mishels. Verzeichnis, p. 268. 162 BULLETIN 93, UNITED STATES NATIONAL MUSEUM. EAST AMERICAN.! U.S.F.C. Station. Locality. Depth (fath- oms). Bottom tempera- ture. Collector. 32 2520 2066 2525 2079 2081 2082 2057 21B 2260 2253 158 216 135 219 23,28-32 22 348 322 321 269 981 1084 370 240 972 983 984 1222-26 Gulf of Maine 90 °F. U.S.F.C. Schooner Otis P. Lord. A Ibatross. Do. Do. Do. Do. Do. Do. Bache. Albatross. Do. E. P. Wonson. Speedwell. Do. Do. Do. Do. Do. Dr. Pretscott. Speedwell. Do. Do. Do. Fish Hawk. Do. Speedwell. Do. Fish Hawk. Do. Do. Do. U. S. F. C. Do. J. E. Benedict. Brunswick, Me., pleistocene Northeast edge Georges Bank 50 62 65 72 75 50 49 86 52-90 46 32 Latitude, 42° 41' 00" north; longitude, 64° 55' 30" west. Latitude, 42° 19' 40" north; longitude, 65° 49' 30" west. Latitude, 41° 49' 00" north; longitude, 65° 49' 30" west. Latitude, 41° 13' 00" north; longitude, 66° 19' 50" west. Latitude, 41° 10' 20" north; longitude, 06° 30' 20" west. Latitude, 41° 09' 50" north; longitude, 66° 31' 50" west. Latitude, 42° 01' 00" north; longitude, 68° 00' 30" west. Latitude, 42° 49' 00" north; longitude, 68° 50' 00" west. Latitude, 40° 13' 15" north; longitude, 69° 29' 15" west. Latitude, 40° 34' 30" north; longitude, 69° 50' 45" west. West part of Georges Bank 40. G 43.5 43.6 45 46 46.5 •13 50.2 52.9 Off Cape Ann, Mass 38 35 25 32 35-48 North Thatchers Island, Massachusetts Bay.. do 40.5 55.5 Massachusetts Bay ... do Off Salem, Mass Lynn, Mass OS Cape Cod. Massachusetts Bay iei 67" 29J- 53 43 37J 18 18 16 36 33 11J-13 46 40.5 44.5 39.5 49 38 Off Cape Cod do.. do Off Chatham, Cape Cod Off Cape Cod Off Chatham, Cape Cod Off Cape Cod 64.5 52 42 41.5 68-69 Off Chatham, Cape Cod do Vineyard Sound, off Chatham, Mass Vineyard Sound off Nobska Light... Noarik, Conn Fishers Island Round, Crrnn 9-11 Long Island Sound...' WEST AMERICAN AND ASIATIC. Capo Prince nf Wains Alaska , E M Kindle. St. Paul Island, Pribiloff Islands Beach . H. W. Elliott. do Wm. Palmer. 3482 3558 3289 Latitude, 57° 18' 00" north; longitude, 170° 42' 00" west. Latitude, 56° 58' 00" north; longitude, 170° 09' 00" west. Latitude, 56° 44' 30" north; longitude, 159° 42 25 16 38.9 42.9 Albatross. Do. Do. 3600 16' 00" west. Latitude, 55° 06' 00" north; longitude, 163° 28' 00" west. Unalaska 9 40 Do. W. H. Ball. Iliuliuk Harbor, Unalaska 10 Do. Kyska Harbor 10 Do. Bering Island L Stejneger Ochotsk Sea Capt. Stevens. i Records of many specimens from Georges Bank, donated by fishermen who catch the barnacles on cod lines, are omitted, as that region is well covered by the more exact Albatross records. Most of the Maine and Massachusetts localities are represented by several or many lots, from as many collectors, only one from each place being cited here, unless details of temperature or depth are given. All of the specimens from Bering and Ochotsk Seas, except a few. detached ones, grew upon Buccinum^ Chrysodomus, and Placun- anomia. THE SESSILE BARNACLES. 163 BALANUS BALANUS PUGETENSIS, new subspecies. Tlate 36, figs. 9, 10-10&. Type. — Cat. No. 2040, A. N. S. P., San Juan Islands, Puget Sound, between 10 and 50 fathoms, on Pecten, collected by Homer Wheeler, 1910. The barnacle is rather small and thin, with steep walls and a large orifice, not ribbed, dirty whitish, the parietes dull, more or less roughened, radii usually glossy, with the summits slightly oblique and jagged, level in the rostrum. Parietes have rather large tubes, FIG. 48. — BALANOS BALANUS PUGETENSIS. a, 15TH SEGMENT OF THE ANTERIOR RAMUS OF CIRRUS IV. 6, 9TH SEGMENT OF ANTERIOR RAMUS OF CIRRUS III. C, 21ST AND 22D SEG- MENTS OF CIRRUS VI. (1, LABRUM ; ALL OF THE TYPE. €, LAERUM OF SPECIMEN FROM STATION 2864. not septate, and filled up solidly in the upper part (pi. 30, fig. 9). Rostrum with 11 to 16 tubes. Carinorostral diameter of base 21 mm.; height, 18 mm. Opercular valves as in the typical form, except that the longitu- dinal striae of the scutum are delicate and weak, and the growth ridges have an appearance of imbricating, like shingles. The valve is curved between apex and base, and has a rather deep, narrow pit for the depressor muscle. The labrum has two and three small teeth in the type-specimen (fig. 4:8d). In one from Albatross station 2861 there are three very 164 BULLETIN 93, UNITED STATES NATIONAL MUSEUM. minute but acute denticles on one side, one barely perceptible prominence bearing several minute points and short hairs on the other (fig. 4Se). Mandibles and maxillae as usual in B. ~balanus. Cirri. — Cirrus i with rami of 19 and 12 segments; ii with 14 and 13 segments in the type. In a specimen from Albutross Station 2864 there are : Cirrus i, 21 and 12 ; cirrus ii, 15 and 12 segments. Cirrus iii has both rami provided with numerous spinules (fig. 4S&) want- ing on the distal segments. Cirrus iv has many spinules near the distal sutures of the segments (fig. 48a). Cirrus v has similar but fewer spinules. Cirrus vi has four pairs of spines, the third pair small, fourth pair minute, wanting on part of the segments. There are a few minute accessory spines at the bases of the pairs, and some small ones near the distal sutures (fig. 48c). The penis is longer than in B. lialanus, but not so long as in B. rostratus. It has the usual point near the base. By the small number of spines on the posterior cirri, this form approaches some British specimens of typical B. balanus.1 It has decidedly shorter spines on the posterior sutural angles of the seg- ments, and the penis is longer. The parietes are not ribbed, in con- siderable numbers seen. In the series of B. ~balanus from Bering Sea, the parietes are rugose or ribbed, and the cirri are conspicuously more spinose. A long series growing on Pectens, from which the type lot was selected, was submitted by Dr. Homer Wheeler. A small lot, prob- ably from the same localitv, is in the United States National Museum «/ »/ / collection, received from the University of Kansas; and a lot was taken by the Albatross at station 2864, latitude 48° 22' north, longi- tude 122° 51' west, in 48 fathoms, bottom temperature 47.7° F. (Cat. No. 48021, etc., U.S.N.M.) It lives mingled with B. rostratus heteropus, and the two can not be discriminated externally. The easiest and most reliable way to tell them apart is to file the parietal face enough to expose the tubes, which are large and unobstructed in B. b. pugetensis, much smaller and transversely septate in B. r. heteropus. SERIES OF B. CRENATTJS. White Balani, with the basis poreless; terga not beaked, not pro- jecting conspicuously above the scuta, arid without a furrow to the spur; scuta without longitudinal striation. Maxilla with one longer or larger spine near the lower angle. Near the group of B. balanus, differing chiefly by the opercular valves and by the absence of spinules on the segments of the peduncles 1 On the segments of B. r. pugctensis corresponding to those I have figured for B. "balanws there are only three pairs of spines. Another pair appears nearer the distal end, as usual in Balanus. THE SESSILE BAENACLES.- 165 of the cirri. As in the B. balanus group, there is one larger spine near the lower angle of the maxilla, instead of a pair, such as the B. amphitrite group has. It is a boreal group, extending into the Temperate Zone. Three of the commonest west American species, B. crenatus, B. glandula, and B. hesperius, agree in the rather small size, the dirty white ribbed or smooth wall with ribbed interior, the calcareous, pore- less base, and the short spur of the tergum. The parietes have tubes in B. crenatus, none in B. hesperms, while B. glandula has tubes in some specimens, but wholly filled up in others. They are most easily distinguished by the scuta. In B. crenatus there is no adductor ridge, the upper part of the valve being calloused, smooth or roughened. In B. glandula a short adductor ridge branches downward from the articular ridge, and there is a pit below their confluence. In B. hesperius the thick callous between adductor scar and articu- lar ridge is cut into sharp little ridges. B. balanoides is distinguished from these species by its membranous basis, but detached, fragmentary or fossil specimens may be known by the scuta. There is a convexity or rounded callus down the middle of the valve (pi. 45) ; moreover, the parietes are not longitudinally ribbed inside, but have some low anastomosing ridges near the basal edge. BALANUS CRENATUS Bruguiere. Plates 39, 40. 1789. Balanus crenatus BRUGUIEKE, Encyclopedic Methodique, p. 168. 1790. Lepas plicata SPENGLER, Skrivter af Naturhistorie Selskabet, vol. 1, p. 167. 1790. Lcpas fistula SPENGLEK, Skrivter af Naturhistorie Selskabet, vol. 1, p. 176. 1791. Lcpas clongata GMELIN, Syst. Nat., ed. 13, p. 3213.1 1799. Balanus ruyosus PULTENEY, Catalogue of the Birds, Shells, etc., of Dorsetshire, p. 25 (tubular form). 1819. fBalanus glacialis GRAY, Suppl. to Parry's Voyage, p. ccxlvi. 1841. Balanus ruyosus Pulteney, GOULD, Invertebrata of Massachusetts, p. 16, fig. 10. 1854. Balanus crenatus Bruguiere, DARWIN, Monograph, etc., p. 261, pi. 6, figs. 6f?-6f/. 1913. Balanus arcnatus Bruguiere, STEPIIENSEN, Meddelelsor om Greenland, vol. 51, p. 71 (North Stroemfjord). Type-locality. — Coast of England. Distribution. — Arctic Ocean; North Atlantic south to Long Island Sound; Bering Sea and North Pacific, south to Santa Bar- 1 1 am. not sure that L. clongata and L. fistula belong to this species. They may ba Balanus balanoides. 4729°— Bull. 93— 1( 166 BULLETIN 93, UNITED STATES NATIONAL MUSEUM. bara, California, and Northern Japan.1 British Pliocene; Pleisto- cene of Norway, Canada, Maine, and Alaska. Darwin's description is as follows : General appearance. — White, usually of a dirty tint, from the yellowish or brownish persistent epidermis ; conical, generally with the parietes rugged and irregularly folded longitudinally, but sometimes much depressed and extremely smooth ; often cylindrical and very rugged ; occasionally club shaped, the upper part being much wider than the lower ; specimens in this latter condition sometimes have extremely narrow parietes, like mere ribs, and wide radii. The orifice in the cylindrical varieties is often most deeply toothed. The radii are generally narrow, and have jagged, oblique summits, but not in- frequently they are so narrow as to form mere linear border,s, to the compart- ments. The orifice is rhomboidal, passing into oval, either very deeply or very slightly toothed. Scuta : The lines of growth are but little prominent ; the surface is generally covered by disintegrating membrane. The upper ends are usually a little re- flexed, so that the tips project freely as small flattened points. Internally the articular ridge is highly prominent and somewhat reflexed ; there is no ad- ductor ridge, but a very distinct impression for the adductor muscle ; the de- pression for the lateral depressor muscle is small but variable. The terga are rather small, the spur is short and placed at rather less than its own width from the basiscutal angle, the basal margin slopes a little toward the spur of which the lower end is rounded or bluntly pointed in a variable degree. There is no longitudinal furrow, hardly even a depression. Internally the articular ridge is very prominent in the upper part; the crests for the tergal depressors are well developed but variable. Compartments. — The internal carinal margin of each compartment from the sheath to the basis, generally, but not invariably, projects a little inward be- yond the general internal surface of the shell in a manner not common with the other species of the genus; the basal edge of this projecting margin rests on the calcareous basis and is crenated like the basal edges of the longitudinal parietal septa. The whole internal surface of the shell is ribbed, but the ribs are not very prominent. The parietal tubes are large and are crossed in the upper part and often low down by transverse thin septa ; the longitudinal parietal septa are only slightly denticulated at their bases ; occasionally they divide at the basis close to the outer lamina of the parietes, making some short outer subordinate pores. In the circular furrow beneath the lower edge of the sheath there are sometimes little ridges dividing it into small cells; some- times, however, this furrow is filled up by irregular knobs of calcareous matter. The radii are always rather narrow, and often they form mere linear ribbons of nearly uniform width along the edges of the compartments. Their summits or edges are always more or less irregular and jagged, they form an angle with the horizon of generally above 40°. Their septa are fine, and barely or 1 1 do not know the southern limit of D. crenatus in the eastern Atlantic. Darwin gives the localities Mediterranean; Algoa Bay, South Africa; also Jamaica. Gruvel states that specimens ia the Paris Museum are labeled lie King (an island in Bass Strait) and Perou (Nouv. Arch, du Mus. (4), vol. 5, p. l'!9) ; and he has also recorded it from Wasin, British East Africa (Bull. Soc. Zool. Franco, vol. 32, p. 164 K I hesitate to accept these exten- sions of the range of crenatus into and past the Tropics until confirmed by fresh material. There seems a possibility that ballast or ship-carried specimens have been picked up, or there may have been a mixture of material in some of the old museum specimens. For the details of the range of B. crenatus in European and Arctic Seas, Weltner's Ver- zeichnis and his article on cirripedes in Fauna Arctioa (vol. 1, p. 30".) may be consulted. THE SESSILE BARNACLES. 167 not at all denticulated. Tlir al:r> h;ivo onliiiuc summits; tlieir sutural edges are rather thick and distinctly crenated. Basis flat, calcareous, very thin, with the surface slightly marked by radiating furrows, which furrows answer to the radiating pores that occur in the bases of most species. FIG. 4!>. — BALANUS CRENATUS, INGLEFIELD GULF, GREENLAND, a, LABRDM. 6, MAXILLA. C, MANDIBLE. According to Darwin : Mouth: Labi-urn with six teeth. Mandibles with the fourth tooth minute or rudimentary, and the fifth generally confluent with the inferior angle. Maxillte with generally, but not invariably, a small notch under the upper pair of great spines. Cirri, first pair with the raroi very unequal in length, one FIG. 50. — B. CRENATUS, INGLEFIELD GULF, GREENLAND, a, ANTERIOR PART OF THE FIF- TEENTH SEGMENT OF OUTER RAMUS OF CIRRUS IV. ft, MEDIAN SEGMENT OF CIRRUS VI. C, TENTH SEGMENT OF OUTER RAMUS OF CIRRUS III. ramus being nearly twice the length of the other ; in a large specimen having a cylindrical shell the proportional numbers of the segments in the two rami of the first cirrus were 10 to 23 ; in a small conical specimen the members were only 8 to 13. The second cirrus has only two or three more segments than the shorter ramus of the first pair. The third cirrus has one or two more segments than the second ; but it is nevertheless decidedly longer than the second. On the dorsal surfaces of both segments of the pedicel of the third cirrus, there 168 BULLETIN 93, UNITED STATES NATIONAL MUSEUM. Is a tuft of fine spines. The segments of these three pairs of cirri are not much protuberant in front. The segments of the posterior cirri have four, or five, or six pairs of spines. Penis, with a straight, sharp, short point on the dorsal basis. It may be added to Darwin's description of the cirri, quoted above, that there is a small area of short spinules on part of the segments of the third pair of cirri, and in some large forms there are a few on the fourth cirri also. The peduncle of the third cirrus is very broad. There is a group of small slender spines below the upper great pair of the maxilla, and another group of small spines just above the lower angle. These are characteristic of all forms of the species examined (fig. 50). Bruguiere describes this barnacle as depressed-conic, smooth, crenulated or sometimes plicate toward the base. This is a common English form, figured on plate 39, figure 1 from specimens on a potsherd, mouth of the Exe River. The diameter is usually up to 16 or 18 mm. The opercular valves of one of these patelliform speci- mens are draAvn in figure 51, «, b. D FIG. 51. — BALANUS CRENATUS. a, l>, SCUTUM AND TEUGUM OF AN UNWORN PATELLIFORM INDIVIDUAL FROM EXMOUTH, SOUTH I)KVON. c, (I, SCUTUM AND TERGUM OF A RUGGED, DEEPLY CORRODED INDIVIDUAL FROM EXMOUTH. A rugged, deeply- worn individual, in which the articular ridges are more broadly reflexed, supplied the valves drawn in figure 51 } SCUTUM AND TERGUM OF A GREENLAND SPECIMEN, CAT. NO. 24911. C, TERGUM OF A SPECIMEN FROM THE GRAND BANK, ALBATROSS STATION' 2462, WALL SIMILAR TO PLATE 40, FIGURE 6. at the posterior distal angles are about as long as the segments. Penis is longer than the posterior cirri. The maxilla (fig. 49&) has no notch under the superior pair of large spines; below them there are nine subequal spines, with two brushes of bristles at and below the rounded lower angle. The labrum (fig. 49«) has two exceedingly small teeth on each side. The form from the Grand Banks of Newfoundland (pi. 40, fig. 1) is characteristic. The walls taper but little upward, leaving a large orifice, which is deeply toothed in the young, but in old specimens the points are often broken or worn oft'. The parietes have massive, irregular, rounded ribs. There are generally three or four ribs on rostrum and lateral compartments, one on the carinolateral, two to four on the carina, in the half -grown stage (pi. 40, fig. G, Cat. No. 9215) ; but in old ones the number is increased by division of the ribs. The tergum is broader than in English crenatus, with its carinal margin longer. It is broader than the scutum. Often the spur is shorter than in Greenland crenatus. There are also columnar (pi. 40, fig. 2) and tubular forms, flaring toward the orifice (pi. 40, figs. 5-5&), quite like those from Greenland. Two specimens of the col- umnar form out of the lot from Albatross station 2462, Grand Banks, 170 BULLETIN 93, UNITED STATES NATIONAL MUSEUM. 39 fathoms, measure: length 58 mm., diameter 12 mm., and length 40 mm., diameter 17 mm. The radii are narrow. In a few specimens from Albatross station 2462 the spur of the tergum is quite narrow (fig. 52) . The common forms from shallow water on the New England coast are not distinguishable from English examples. A group from Vineyard Sound is figured (pi. 39, figs. 2-2e, 3, 5, Cat. No. 48027-8, U.S.N.M.) showing the columnar form, growing on a pebble, and the conic form, on Mytilus edulls. The opercular valves of the columnar form do not differ materially from those of the smooth form figured, except that they are larger and thicker, the interior of the tergum (fig. 3) being extensively granulated. Specimens, growing on Mytilus, from an iron buoy, Gay Head, Marthas Vine- yard (pi. 39, figs. 2~2c), are beautifully smooth and white, with thin walls and regular, square tubes, 12 in the rostrum of one counted. The opercular valves are rather thin, and the spur of the tergum is farther from the basiscutal angle and narrower than is usual in European crenatus. The scutum is concave externally, with a broadly reflexed articular ridge. On the Newfoundland Banks, this species is most abundant on Buccinwn humphreysianum, donovani, etc., but also occurs in GJiry- sodomus, Tritonifusus, Pecten islandicus, Cyrtodama, .Sempes, on crabs (Hyas}, and on bowlders. It has been found in the THE SESSILE BARNACLES. 171 stomachs of cod. On Georges Bank it is common on Pecten magel- lanicus and Bucclnum undatum; and in the shallow waters of Vine- yard Sound it occurs commonly on Balanus hameri, Cyprina islandica Fulgur, Polinices, Pecten, Cytherea, Mytilus edulis, on bark, etc., Darwin notes that B. crenatus sometimes incrusts vessels, and that it never occurs above low-water mark, while B. Icdanoides is strict!}7 limited to the intertidal zone, and does not extend into the zone of B. crenatus. Sometimes the two are found growing together where their zones meet. Most of the American records are from low tide to 50 fathoms, but in some cases it has been taken in deeper water, up to 98 fathoms. The absence of B. crenatus from the great number of dredgings off our coast in 100 fathoms and over is good evidence that its vertical range is limited rather sharply. The temperature records show a wide range from 30° F., on the Grand Banks, to 67° F. in Vineyard Sound, 9 fathoms, in July, but no doubt individuals from low-tide stations experience greater ex- tremes of temperature in the course of a year. In the estuary of the Exe Elver, Channel coast of Devon, B. crenatus lives where there is some admixture of fresh water, below low tide, according to the labels in the Jeffreys collection. Speci- mens on potsherds (pi. 39, fig. 1) are patelliform, also those on Mytilus, where it occurs with similarly shaped B. balanoides. On Pecten, doubtless in deeper water, the usual steeply conic form is found. In Alaska and on the Pacific coast B. crenatvs seems to be re- stricted to much shallower water than in the Atlantic. Nearly all the records are from collections made on shore or in shallow water, while it is conspicuously absent from most of the Albatross hauls in deeper water. Pacific and Bering Sea forms. The occidental forms of crenatus do not differ materially from those of the North Atlantic. There is the same range in size. The smooth form (pi. 41, figs. 2, 2«, 26, Tacoma, Washington, Cat. No. 48033) and the rudely plicate form (pi. 41, figs. 3, 3«, Bering Sea, and pi. 41, fig. 5, Alaska, Corwin, Cat. No. 48035), with various in- termediate stages are of common occurrence. The opercular valves resemble those of Newfoundland and Vineyard Sound specimens. The articular ridges of both valves vary in the degree of reflection; that of the tergum sometimes stands vertical to the plane of the valve, or sometimes is reflexed or hooked in varying degree over the articular furrow. The articular ridge of the scutum is usually shorter in Pacific forms. A smooth, conic form with rather wide radii was taken by the Albatross in Union Bay, Bayne Sound, British Columbia, on shore, 172 BULLETIN 93, UNITED STATES NATIONAL MUSEUM. the specimen figured having a basal diameter of 14 mm. The labirmi has a wide notch, with three teeth on each side ; only the upper one marginal (fig. 54). In the elongated and club-shaped forms the radii become wide, especially those of the rostrum. This is also the case in many Atlantic specimens. Plate 41, figures 6 to 6e, are from Albatross station 2851, near the Shumagin Islands, in 35 fathoms. The scutum is long, its tergal margin decidedly longer than the basal margin. The callus between the adductor pit and the articular ridge is but slightly roughened, the interior being unusually smooth. The articular ridge of the tergum is moderately recurved. On the borders of the crowded colonies there are often transitions to the normal conic form shown in figure Ga. The labrum has two teeth on each side, larger than those of the Greenland specimen figured. Maxilla with a very slight notch and FIG. 54. — B. CRENATUS, UNION BAT, BAYNE SOUND. Top AND LATERAL VIEWS x3, AND TERQDM. seven subequal spines below the upper great pair, otherwise as in the Greenland form. First cirrus has rami of 17 and 8 segments, the posterior ramus half the length of the anterior. Second cirrus with slightly unequal rami of 13 segments. Third cirrus with 15 and 13 segments, the posterior ramus two-thirds as long as the an- terior. Sixth cirrus having segments with six pairs of spines and sometimes a minute seventh pair. Penis exceedingly long, with an acute point dorsally near its base, the end with a pencil of short bristles. Similar but much smaller examples were taken by the U. S. R. S. Corwin in the Arctic Ocean, on Chrysodomus heros, the contour varying from conic and short to columnar. Southward on the Pacific coast we know little of the range of B. crenatus, as the smaller barnacles of California have been neglected by collectors. At Point Richmond, San Franciso Bay, numerous specimens were taken on Thais plicata septentrionalis (Reeve) by Mr. THE SESSILE BAE1STACLES. 173 C. H. Townsend in 1890. The avails are smooth; radii rather nar- row; parietes having an unusually large number of tubes, 13 to 17 in the rostrum. Spur of the tergum short. The scutum is about typical. The largest examples have a basal diameter of 8 mm. It has the external appearance of B. improvisus. The farthest south known for B. crenatus in the Pacific is Santa Barbara, California. A few opercular valves and detached compart- ments were found in debris washed from-Balamts tintinnabulum cal'i- fornicus and the rock it grew upon. The valves seem nearly typical, but the compartments are thin with smooth outer surface. Complete specimens are needed to show the characters of the race. Pleistocene specimens of this species are in the United States Na- tional Museum from Lawlors Lake, St. John County, New Bruns- wick, Brunswick, Maine, and Douglas Island, near Juneau, Alaska, where they were collected by Dr. Wm. H. Dall " 200 feet above tide- water, in a trench of the pipe line near old mill in bowlder clay." The specimens do not differ from recent forms found in neighboring waters. EUROPEAN. Locality. Collector. Notes. Iceland Shetland Islands J. G. Jeffreys Oban, Scotland do . . ... On Pecten Cork Harbor, Ireland J. G. Jeffreys (Geo. Barlee ). 1S4G. Atran Isles, west coast of Ireland.. . J. G. Jeffreys Bantry Bay, Ireland do Irish Channel do On _B. 7iawi£7*2and Fit sits con* Scarborough, England J. G. Jeffreys (Turton) ... . trarius. Swansea Bay, Wales J. G. Jeffreys Milfurd, South Wale^ \V Stinipson English Channel near Guernsey Jeffreys collection On Pcctcn Exmouth, south Devon do Langland Bay do Portsmouth do.. Sandwich do Off Caswell Bay do On A.poTT'h&i's etc Helgoland. North Sea Royal Biological Station EAST AMERICAN. U. S. F. C. Station. Locality. Depth (fath- oms). Bottom tempera- ture. Collector. Barden Bav, Inglefield Gulf, Greenland 10-40 "F. Princeton expedition. Godthaab, Greenland Greenland J N P Scudder Cornell Near Egg Harbor, Labrador expedition. O. Brvant. St. Michael, Labrador Turner. Northeast part Grand Bank of Newfoundland - 45 Schooner Henry Wil- North part Grand Bank of Newfoundland son. Gloucester fisheries. 2449 2443 2447 Grand Bank of Newfoundland: latitude, 46° 37' 00" north; longitude, 49° 50' 30" west. Latitude, 40° 2S' 00" north; longitude, 49° 39' 30" west. Latitude, 40° 20' 00" north; longitude. 49° 42' 00" west. 39 40 39 33 33.9 34.8 Albatross. Do. Do. 1 Greenland specimens without nearer indication of locality are in the museum from the J. G. Jeffreys and Isaac Lea collections, with others from unknown source. " Many specimens, some very fine groups, the gifts of Gloucester fishermen, are in the United States National Museum from the Grand Bank of Newfoundland, the Banquereau and Georges Banks. As these areas are fairly covered by the exactly located stations of the Fish Commission, the lots designated by banks only are not entered here. 174 BULLETIN 93, UNITED STATES NATIONAL MUSEUM. EAST AMERICAN. U. S. F. C. Station. Locality. Depth (fath- oms). Bottom tempera- ture. Collector. 2445 2444 2441 2462 24G3 24G5 24GS 2467 2443 2440 2438 2439 2430 2437 2493 2498 Grand Bank of Newfoundland— Continued. Latitude, 40° 09' 30" north; longitude, 40° 48' 30" west. Latitude 45°, 59' 00" north; longitude, 49" 45' 30" west. Latitude, 45° 27' 00" north; longitude, 49° 42' 00" west. Latitude, 45° 45' 30" north; longitude, 54° 20' 30" west. Latitude, 45° 44' 00" north; longitude, 54° 27' 00" west. Latitude, 45° 35' 00" north; longitude, 55° 01' 00" west. Latitude, 45° 11' 30" north; longitude, 55° 51' 30" west. Latitude, 45° 23' 00" north; longitude, 55° 41' 00" west. Latitude, 45° 44' 00" north; longitude, 49° 45' 00" west. Latitude, 43° 38' 00" north; longitude, 49° 49' 30" west. Latitude, 43° 36' 00" north; longitude, 50° 03' 30" west. Latitude, 43° 37' 50" north; longitude, 49° 56' 30" west. Latitude, 43° 36' 00" north; longitude, 50° 06' 30" west. Latitude, 43° 36' 00" north; longitude, 50° 05' 00" west. Misiane Bank: Latitude, 45° 19' 00" north; longitude, 58° 51' 15" west. Latitude, 44° 54' 00" north; longitude, 59° 39 39 34 41 45 67 42 38 35 33 37 36 36 37 45 65 °F. 33.5 34.4 33 30 30 30 33 35.8 34.9 38.3 36.8 37.8 34 35.8 32.3 A Ibatross. Do. Do. Do. Do. Do. Do. Do. Do. Do. Do. Do. Do. Do. Do Do. 2500 46' 45 west. Latitude, 44° 28' 00" north; longitude, 60° 36 Do. 15' 15" west. Banquereau Bank 2 75 Capt. McKimmon. Banquereau Bank oil Nova Scotia 50 Do Banquereau Bank, northwest part Gloucester fisheries. Latitude, 44° 28' north; longitude 59° 20' west.. Wm. Hutchings. Sable Island Nova Scotia Willis. Bay of Fundy U. S. F. C. East of Georges Bank 50 Bache. 2079 2080 2244 2245 2250 2580 2251 2256 Georges Bank: Latitude, 41° 13' 00" north; longitude, 66° 19' 50" west. Latitude, 41° 13' 00" north; longitude, 66° 21' 50" west. Latitude, 40° 05' 15" north; longitude, 70° 23' 00" west. Latitude, 40° 01' 15" north; longitude, 70° 22' 00" west. Latitude, 40° 17' 15" north; longitude, 69° 51' 45' 'west. Latitude, 41° 25' 30" north; longitude, 69° 01' 00" west. Latitude, 40° 22' 17" north; longitude, 69° 51' 30" west. Latitude, 40° 38' 30" north; longitude, 69° 29' 00" west. Georges Ban''-' northwest part 75 55 67 98 47 83 43 30 45 46 52.9 50.9 51.4 42.4 50.9 52.9 A Ibatross. Do. Do. Do. Do. Do. Do. Do. Schooner Clytie. Lawlor's Lake St J ohns County, New Bruns- Matthews. wick. G rand Manan W. Stimpson. Gulf of Maine U. S. F. C. Eastport, Me R. Rathbun Casco Bay, Me Brunswick Me (in Lcda clay) Nantucket U. S. F.C. 972 Off Chatham Capo Cod 16 52 Fish Hawk. • 983 . do 17 51 Do. 370 do 18 Speed it'dl. Vineyard Sound Shore 861 do 17 61 Fish Hawk. 984 Vineyard Sound olf Chatham Mass 33 41.5 Do. "Woods Hole Mass U. S. F.C. O fl: Marthas Vineyard Do. Gay Head Marthas Vineyard Buoy Buzzards Bay .Mass Do. 856 OG Newport, R.I 11 67 Fish Jlau'k. Saybrook, Conn . . Shore. THE SESSILE BARNACLES. 175 NORTH PACIFIC, BERING SEA, AND ARCTIC OCEAN. U. S. F. C. StatiouNo. Locality. Depth (fathoms). Collector. Point Barrow, Alaska . . E. A. Mcllhenny. Art-tic Ocean U. S. R. S. Conrin. L'ltilude lid0 12' nortlr longitude 108° 64' wost Lt. Geo. M. Ktoney. Bering Strait Dr. Robert White. 1 atitude 63° 37' north" longitude 165° W west • . . Liout. Geo. M. Stonoy. Latitude' CO" 16' north' longitude 107° 41' west, off Do. Monroe Island. Plover Bay, Siberia 8-20 W. H. Dall. Ochotsk Sea. Capt. Stevens, North Pacific Bering Island exploring expedition. L. Stojneger. Adak Island Aleutians W. H. Dall. Unalaska . Do. Iliuliuk, Unalaska. . Do. 3232 2851 Latitude, 58° 31' 30" north; longitude, 15V° 34' 15" west. Latitude, 54° 55' north; longitude, 159° 52' west Belkofski Alaska 10J 35 2J-4 Albatross. Do. W. H. Dall. Cold Bay, Shelikof Strait T. W. Stanton. Alaska U. S. R. S. Corwin. Douglas Island near Juneau (Pleistocene) W. H. Dall. Loring Eevillagigedo Island, Alexander Archi- AlbatToss. pelago. Quarantine Station Port Townsend Wash Do. Tacoma, Wash Mrs. W. B. Hare. Point Richmond, San Francisco Bay. C. H. Townseud. Santa. Barbara, Cal Not recorded. BALANUS CRENATUS CURVISCUTUM, new subspecies. Plate 41, figs. 1, 4 ; plate 42, figs. 1-16, 2-2alanoides, have terga of the same general appearance, and the mouth parts and cirri do not differ very conspic- uously. V The pores in the basal edges of the parietes are irregular, not devel- oped between all of the ribs of the interior; when developed the inner lamina of the wall does not reach quite to the base. In full- grown barnacles a few narrow pores may usually be found deep between some of the basal ends of the ribs, which are crenulated and unequal; but in some specimens they are wholly filled up, as in B. bdlanoides. I take San Diego to be the type-locality. Plate 43, figures 1 to 3«, represent specimens from there. The shape is conic or convexly conic, and the aperture is small in all the specimens seen. At La Jolla, California, I found B. glandula on rocks near high- tide mark, with Mitella polymerus and Chthamalus fissus. In a group of nine individuals from San Francisco the shape is more cylindric, and the walls are much more weakly ribbed, or in some not at all ribbed. Aperture larger. A Puget Sound series, on valves of Mytilus, contains strongly ribbed, typical individuals, with others of a more cylindric shape, with very weak ribs and large orifice. One is 13 mm. in basal diam- eter, 12 mm. high. At Union Bay, Bajaie Sound, British Columbia, elongated columnar individuals occur with a shorter, obliquely conic form, growing upon the large ones. In some of the shorter individuals the opercular valves are unusually long, the tergal margin of the scutum decid- edly surpassing the basal margin, as in figure 57#. The radii are rather wide in some of this lot, but the compartments are thin and weak (fig. 57). At Sitka the strongly ribbed conic and the smoother, short, cylin- clric forms occur. The largest individual measures 16 mm. in basal diameter, 13 mm. high. Cirri and mouth parts as described by Darwin. See plate 43, figs. 5, 7, 7a. THE SESSILE BARNACLKS. 181 Unalaska specimens are strongly ribbed, with decidedly wider radii than those of southern California. The bases of the parietes show no pores, but traces of them may be seen externally in some compart- ments. Opercnlar valves (pi. 43, figs. G, Get-) like Sitka specimens. Atka specimens are similar to those of Unalaska in the Avails, but the opercular valves are peculiar, unlike any other lot examined. The scutum is very wide and short, the tergum is unusually narrow in contour, but this is largely due to corrosion (pi. 43, figs. -± to FIG. 57. — BALANUS GLANDULA FROM UNION BAT, BAYNE SOUND, BRITISH COLUMBIA, a, 6, c, SCUTAL, INTERNAL AND EXTERNAL ASPECTS OF THE TERGUM, AND d, C, INTERNAL AND EX- TERNAL ASPECTS OF SCUTUM OF THE LONG INDIVIDUAL IN THE GROUP /. J/, SCUTUM OF A SHORT INDIVIDUAL IN THE SAME LOT. The individual I dissected from Atka has the first cirri quite un- equal, posterior ramus of 10 segments not quite two-thirds as long as the anterior of 1C. Second pair subequal, of 10 and 11 segments. The posterior cirri have six pairs of spines on a segment. Penis long, with a dorsal point near the base. Balanus glandula has been reported from the " southern Pacific Ocean attached to Pollidpes polymerus" (Darwin, Monograph, p. 266), on the evidence of specimens in the British Museum labeled as having been collected by Sir James Eoss in course of his Antarctic Expedition. Such distribution seems highly improbable. Until confirmed by new records it may be put in the doubtful list. 4720° —Bull. 93—16 13 182 BULLETIN" 93, UNITED STATES NATIONAL MUSEUM. U.S.N.M. Cat. No. Locality. Collector. Notes. 11151 San Diego, Cal O. N. Sanford On indurated sand do C. R. Orcutt Do. do H. Hemphill On jetty. do . . E. A. Mearns On Mytilus San Francisco, Cal U. S. Exploring Ex- 12333 Puget Sound, Wash . pedition. R. E. C. Stearns Do. Gordon Head, 7 miles from Victoria, Brit- J. E. Benedict 3SG72 ish Columbia. Union Bay Bayne Sound British Columbia A-lbutross Shore 12:516 Sitka, Alaska J. J. Mcljeaii On Mytilus. 32934 Naha Bay Rovilla^i^edo Island, Alex- Allen, 1904 "In mouth of starfish." ander Archipelago, Alaska. TJualaska Alaska Dr. B. Sharp Cull. A. N. S. P. Nazaii Bav Atka, Alaska Albntross Shore. Chasina Bay 1'rince of Wales Island, T. H. Street Alaska. Adak Alaska Win. H. Dall SEMIBALANUS, new submenus. The basis is membranous; parietes porous, or with the pores filled up; 'ulterior not longitudinally ribbed, but usually having small anastomosing wrinkles near the basal edge; rostrum not prolonged downward below the other compartments. No spinules or "teeth" on the cirri. Type. — Bui an us cariosus. I do not regard B. balanoides and B. glandula as transitional be- tween the Balani with solid and those with porous walls. They are porous forms which have filled up the pores more or less com- pletely, in some individuals. While related to the typical group of Balanus^ this subgenus is strongly individualized. The membran- ous basis and the profusely bristly third cirri, without spinules on the outer faces of the segments, are primitive characters, but the closing of the parietal pores in B. balanoides and their multiplica- tion in B. cariosus are relatively more evolved features than the ordinary types of porous wall. KEY TO SPECIES. Parietes copiously ribbed externally with several rows of unequal pores ; tergum very narrow, with long, narrow spur and a more or less closed external furrow . B. cariosus. Parietes coarsely folded or smooth, the pores normal or obsolete ; tergum with short spur and no trace of an external furrow B. balanoiiles. BJ^LANUS BAL.ANOIDES (Linnaeus). Plate 44. 1766. LCIJOS balanoides LINN-^US, Systema Naturae, ed. 12, p. 1108. 1789. Balanus fislulosus BRUGXTIEKE, Encyclopedic Methodique, p. 166. 1790. fLepas elongata Gmelin, Syst. Nat, ed. 13, p. 3213. 1799. Balanus clavatus PULTENEY, Catalogue of the birds, shells, and some of the more rare plants of Dorsetshire, p. 25. 1818. Balanus palmulatus LAMAKCK, Anim. sans Vert., vol. 5, p. 394. THE SESSILE BARNACLES. 183 1839. Balanus fissits ANTON, Ycrzeicliniss meiJier Conchyliensammluag, p. 108, No. 32!>L>. 1841. Bahtniis palinnlalKS Lamarck, DELESSERT, Receuil de Coquilles de- crites par Lamarck, pi. 1, fig. 12. 1841. Balanus orularis Lamarck, GOULU, Invertebrata of Massachusetts, p. 17, 1st pi., fig. 7. 1841. Balanus clonyalus Limueus, GOULD, luvertebrata of Massachusetts, p. 18, 1st pi., fig. 8. 1844. Balanus interrupt us DE KAY, Zool. of New York, Mollusca, p. 252 (Long Island Sound, on rocks). 1847. Chtlia mains ycrmanns and (". pJiilippii FRKY and LEUKART, Beitrh'ge zur Kenntniss Wirlu'l loser Thiere, p. 1G7 (Heligoland). 1854. Ba fan us lalanoidcs Linnceus, DARWIN, Monograph, p. 2G7, pi. 7, fig. 2rt~2(7. 1SG3. Balanus balanoidcs Darwin, STIMPSON, Proc. Acad. Nat. Sci. Phila., p. 140 (Port Foulke). 1882. Balanus balanoidcs Linnreus, LEIDY, Proc. Acad. Nat. Sci. Phila., p. 224 (variation at Bass Rocks, Mass.). 1897. Balanus balanoidcs Linn:cn.s, WELTNER, Verzeichnis, p. 269. 1892. Chthainalns europa'iis PHILIPPI, MS., according to WELTWEE, Zoolo- gischer Jahrbiicher, vol. 6, p. 454. Type. — Lost ; from the coast of Sweden. Distribution. — From latitude 66° 34' north, in the Arctic Ocean, to the ocean coast of France, and to Delaware Bay ; x in the Pacific from Unalaska to Sitka. Station, between tides, chiefly on stones, wood, and shells (Mytilidce}. The barnacle varies in form from a rather low cone with small orifice, and more or less ribbed or folded walls, to cylindric or club- shaped and much lengthened; dirty white. Conic forms are rather solid, but the lengthened varieties are often fragile. The opercular valves are sunken very little below the peritreme. The opercular valves are very similar to those of B. crenatus, but in the scutum there is a callus running downward from the lower end of the articular ridge. The tergum has a very strong triangular articular ridge, and the inflection of the scutal margin is unusually broad. The spur is short, rounded distally, and about half its own width from the basiscutal angle. The inner faces of the parietes are smoothish, or have low, irreg- ular, or branching ridges, but no ribs, and there is never any denticu- lation at the base. The parietal pores are small, rounded, or irreg- ular; the septa between them sometimes branching near the outer lamina of the wall ; or sometimes they are entirely filled up, the wall appearing to be solid when viewed from the base. If the outer lamina is eroded or ground down, it will be seen that there are numerous parietal tubes, transversely septate, or sometimes in part filled up i Darwin gives the locality Delaware. I have not myself taken it south of Ocean City, New Jersey. Northward the United States National Museum has specimens from Cumberland Gulf or Sound, a little short of the high latitude given by Darwin and quoted above. 184 BULLETIN 93, UNITED STATES NATIONAL MUSEUM. solidly. In much worn individuals the tubular layer may be entirely removed. The sheath is very short. Radii narrow or almost obsolete. The basis is wholly membranous. Darwin further describes it as follows : Mouth : Labrum with the teeth on each side of the central notch un- usually variable in number ; I have seen specimens with only two on each side, with four on each side, with five on one side and four on the other, with five on one side and none on the other, and with six on both sides; hence the total number ranges from four to twelve. Mandibles, with the fourth and fifth teeth small, or quite rudimentary. Maxilla, with scarcely even a trace of a notch under the upper pair of spines. Cirri : First pair, with one ramus one-third or one-fourth longer than the other ; in one speci- men the number of segments were 9 and 16 in the two rami ; second and D FIG. 58. — BALANUS BALANOIDES, NEW HAVEN, a, LABRUM. b, MAXILLA, c, MANDIBLE, d, IN- TERMEDIATE SEGMENT FROM CIRRUS VI. FIGURES 0, &, (I FROM A CONIC SPECIMEN, NO. 329-46. FIG. c FROM A TUBULAR SPECIMEN, No. 32947. third rami short, very nearly equal in length, having in the first-mentioned specimen respectively 10 and 11 segments. The sixth cirrus in this same speci- men had 25 segments, each segment being about as long as broad and support- ing six pairs of spines. In the singular variety (a) the posterior cirri are more elongated, and each segment supports 7 or 8, and in one case even 10 pairs of spines. The third pair is also in this variety proportionally rather longer ; at the base of the third pair there is a tuft of fine spines. The penis has not, as in B. crenatus, a point at its dorsal basis. The membranous basis amply distinguishes B. lalanoides from species of the region otherwise similar. When the barnacle is de- tached, it may be known by the wall which is not ribbed 'Witldn., thus differing from B. crenatus. Conic, depressed forms have not the well-developed tubes and septa of most other species, and in most of the lengthened, cylindric, or club-shaped forms the tubes are mainly closed at the basal edge. I believe that the scuta may be recognized THE SESSILE BARNACLES. 185 by the callus below the articular ridge. The callus between the adductor pit and the articular ridge is sometimes grooved, somewhat as in B. hesperius, but much less strongly. The tips of the opercular valves do not diverge as they frequently do in B. crenatus. When the surface has been at all disintegrated, the tips of the scuta form a square projection locked into the terga. The first and third cirri differ from those of B. crenatus. In the walls, but not the opercular valves, B. balanoides often has very much the appearance of Chthamalus stelJatus. The name Chthamalus europceus Philippi seems to have been applied to Helgo- land specimens by some authors. In patellif orm and tubular specimens from New Haven and a high conic specimen from Nahant, I found six pairs of spines on the seg- ments of the later cirri, and rarely a seventh minute pair. In a patelliform individual cirrus i has 13 and 9 segments, cirrus ii 10, cirrus iii 12 and 10, and cirrus vi 30 segments. There are no spinvlcs or " teeth " on elm Hi and iv, such as are found in B. crenatus. The bristles at the posterior distal angles of the segments are always very short. In a tubular specimen the labrum has four teeth on each side. In a conical one from the same place there are four teeth on one side, five on the other. In all, the mandibles and maxilla? could not be dis- tinguished from some B. crenatus; but there is never a- notch below the upper pair of spines of the maxillre in B. balanoides (fig. 58). The elongated, tubular, or trumpet-shaped form (fistulosus Bru- guiere) is in no sense a race, as it is commonly found in the same group with patelliform individuals, as in the group figured from Savin Rock, New Haven, Connecticut. Usually the shape may be attributed to crowding, but, as both Gould and Darwin have noted, extremely lengthened, club-shaped individuals are often found growing soli- tary, under such circumstances that neither crowding nor the nature of the supporting object can be responsible for the shape of the barnacle. Plate 44, figure 4, represents such a solitary specimen from Loch Fyne, Scotland, Gl mm. long, 11 mm. in greatest diameter, the tube smallest (5.5 mm. diameter) near the base. Small cylindric crowded specimens from sandstone rocks near Exmouth, England, measure 8 to 18 mm. long, the tube near the base 2 to 5 mm. in diameter. Figures 1-1&, plate 44, represent the rostrum, interior and exterior of a conic specimen from a buoy at Exmouth, channel coast of Devon, diameter 22 mm., height 8.5 mm. A series from Arctic Island, Cumberland Gulf, consists of patelli- form individuals only. Another from Cumberland Gulf contains transitions from the patelliform to cylindric, the latter solitary and mainly of large caliber, height 21 mm., diameter 12 mm. (pi. 44, figs. 3, 186 BULLETIN" 93, UNITED STATES NATIONAL MUSEUM. Labrador specimens seen are rather small, all of the patelliform shape, and like those of New England. In New England B. balanoides is an exceedingly abundant bar- nacle, on rocks between tides, on piles and buoys, and on the mussels growing there ; in such places they often become larger than those on shore rocks in the same vicinity. The low-conic form may be either sharply, strongly ribbed, as in plate 44, figure 5, from New Haven, Connecticut, on Mytilus edulis, or it may be moderately folded as in plate 44, figure 2, on bark of a pile, New Haven, Connecticut. The less-ribbed form is the common- est and closely resembles European specimens. When they stand crowded the walls become subvertical and higher than the conic form, yet often with no tendency toward the tubular form. Another lot from the same locality, growing on oyster shells, vary from shortly cylindric to hourglass shaped. The tubular form, growing in crowded masses (pi. 44, figs. 2, 7-7^7, Savin Eock, New Haven, Connecticut), is excessively variable in shape. The individuals cohere rather weakly, and may usually be separated without breaking. The compartments are often calcified together in the lower part. Parietal tubes square, the septa thin, but usually they are closed at the basal edge. Two very slender indi- viduals measure : Length 46 mm. ; greatest diameter 8.3 mm. ; least 3.3 mm. Length 2G mm. ; greatest diameter 4 mm. ; least 1.5 mm. In the Savin Rock colony the tergum is slightly narrower than usual, but it is identical in shape in the patelliform and the tubular (pi. 44, fig. 6) forms. I have noted above that the mouth parts and cirri are practically identical in patelliform and tubular individuals. In some groups one may trace all transitions of contour from the low-conic to the tubular. Plate 45, figures 2, 2«, represent tergum and scutum of a small, deeply corroded form of balanoides, growing in the vicinity of the following form. Variety with a narrow spur and numerous spines on the later cirri. — This form, figured on plate 45, figures 1 to !, MANDIBLE, c, LABRDM AND PALPUS. <7, BALANUS BALANOIDES, MIDDLE SEGMENT OF GTH CIRRUS (SEE p. 186). • ridge on the inside of the valve. Crests for the depressor muscles are strongly developed. The basis is wholly membranous. The size is rather variable. Unalaska specimens measure : Diameter, 56 mm.; height, 32 mm. (largest conic example). Diameter, 57 mm. ; height, 37 mm. Diameter, 30 mm. ; height, 24 mm. (conic). Diameter, 35-40 mm.; height, 50 mm. (cylindric). Diameter, 35 mm.; height, 100 mm. (cylindric, longest seen). The first measurement is very close to that of Pallas's figures of the type. The third measurement is a more usual size. The labrum has two teeth on each side of the median notch ; outer angles are more abrupt than usual. Palpi nearly covered with short THE SESSILE BAEKA.CLES. 191 hairs. The mandible has three strong conic teeth and a short fourth one, the fifth tooth very low and obtuse, united with the lower point. The maxilla is notched below the upper spines. Margin advancing below the notch, bearing about 8 spines, the lower two larger. Lower angle and upper margin are profusely hairy. The cirri are nearly black. First three of nearly equal length, not half as long as the following three. Posterior ramus of cirrus i, of 17 segments, about three-fourths as long as the anterior, of 21, and having extremely protuberant segments. Rami of cirrus ii subcqual, of about 15 rather strongly protuberant segments. Cirrus iii having nearly equal rami of about 15 segments; both rami very densely hairy. Cirrus vi has about 40 segments, the median ones bearing 7 pairs of spines (fig. 59). Penis is nearly as long as cirrus vi, sparsely hairy near the end. The young of about 5 or G mm. diameter are beautiful, starlike barnacles, with two or three ribs on the carina, one on the carino- lateral, and three or four on the lateral and rostral compartments. The number of ribs soon increases by intercalation in the intervals. The pores of the parietes are much less numerous in young than in old individuals, but they are already somewhat subdivided and irregular at the 5 mm. stage. I have seen old specimens from a nar- row support in which the membranous basis is reduced to very small area, and the pores are closed at the basal edge. Balanus cariosus has a superficial resemblance to Tetraclita due to its membranous basis and porous wall. It is related to B. ~bda- noifles, but not closely, as the opercular valves are very different. Darwin has called attention to points of resemblance (not, I think, relationship) between the present species B. flosculus and B. niibilis, but there are also important differences; altogether it is an isolated species. B. cariosus is a shallow-water and shore species, commonly grow- ing on pebbles, shells, such as living MytiliPs, Pecten, and other cast- up shells. The single example from a deep-water station (Albatross station 2871) has evidently been dead a long time and probably drifted into deep water from the shore. All of the rest of the series was taken by collectors from the shore. Plate 4G, figures 1, 2, 2<7, 4, 6, 8, are from Unalaska specimens; figures 3 and 7 are from Nazan Bay, Atka ; figure 5 from Neah Bay, Washington. Figures 1 and 8 are slightly enlarged, the others natural size. Rarely B. cariosus grows on sponges which almost bury the bar- nacle. The group shown partly cleared of the sponge in plate 4G, figure 9, is from Sanborn Harbor, Nagai Island, Shumagins. The parietes are narrow, radii wide in the lower part, narrow above, the alee forming the greater part of the walls between the parietes. The 192 BULLETIN 93, UNITED STATES NATIONAL MUSEUM. compartments are thin and part very easily. Without the opercular monly harbors Balanus rostratus apertus. The sponge is the same friable species of soft texture which com- monly harbors Balanus rostratus apertus. The United States National Museum collection is rich in specimens from the Aleutian Islands, and as far south as Puget Sound, but the southern limit of the species remains to be ascertained. Darwin records it from the Columbia Kiver. It probably occurs in northern California. The locality " Golf e de Georgie" (Paris Museum, Gru- vel) also quoted by Kriiger, evidently means the Gulf, or more prop- erly Strait of Georgia, east of Vancouver Island, British Columbia, where Dr. A. Agassiz collected many years ago. On the west, it ex- tends as far south as Hakodate in southern Yesso (Hokkaido), and probably farther south, as it was taken by Mr. II. Loomis, whose material is chiefly from Jedo Bay, in middle Japan. The record Cochin China, in the Paris Museum, can hardly be accepted without confirmation. It seems most improbable. U.S.N.M. Cat. No. Locality. Collector. Notes. St Pinl Island Priliilof Islands William Palmer 1 In'ing Island \j. Sl.iMiie.ger 3507 Nazau Bay, Atka '•Attu \\MLDall do On shore. 3509 9178 Parana Bay Attu ... ... do Dutcli Harbor Uiialaslca A Ibalrosa 823, 9172 9174-9170 9180-91S1 TTnalaska ....... W.H.Dall Very fine series. 9200, 9226 3501, 3505 31S9 Amakiiak Islands Unalaslca do Beach. Nikolski Bay Umnak Island A Ws 3511 Sauborn Harbor Shunia^ins W. Il.J)all In sponge. Coal Harbor Shumagins do Cold Bay Shelikof Strait T. W. Stanion J?ort Wrungell Alexander Archi- W. II. Ball pelago. Kioosta village, Parry Passage, Graham. Islands, British Columbia- Jas. G. Swan Port Townsend Wash Fort Steilacoom Puget Sound Dr. Goo. Buckley, U. S. A... Ncah Bay W^asli J. G . Swan Pu(ret Sound Wash do On stone. Station 2871 oil northwestern Wash- Albatross Long dead; 559 fathoms ington. Oregon Japan . . II. Loomis KESFEEIBALANTTS, new subgenus. Balani with poreless walls and basis, the radii with thick, septate edges; opercular valves as in the Balanus crcnatus group. Mandible with the fourth and fifth teeth short and broad, lower edge shortly hairy. Maxilla with few spines. Type. — B. hesperius. TTTP. SF.SSTT.F. RARNAfH.ES. 1 9 ERRATUM. Page 192, strike out second line from top and insert "valves the species would hardly be recognized ill these individuals." 4729°— 16 BALANUS HESPERIUS, new species. Plate 49, figs. !-!, 1<~, Id) is shaped like that of B. crcnatus; tergal border slightly inflected, longer than the basal ; the occludent border often slightly convex, tMck. Sculpture of close, sharp growth-ridges, every alternate one more prolonged and higher on the occludent edge ; over the ridges there is a very minute longi- tudinal striation. The articular ridge is very high, reflexed, and usually ends in a point ; adductor ridge very short, passing upward into a heavy callus between the articular ridge and the deep pit of the adductor muscle, this callus being cut into several sharp ridges, which typically terminate downward in teeth. Articular furrow deep. Pit for the lateral depressor muscles very small but sunken. The tergum (pi. 49, fig. la) has a rather short carinal margin. Articular ridge well developed, triangularly overhanging the upper part of the broad articular furrow. Spur short, one-fourth the width of the valve or less, rounded or subtruncate, and standing very close to the basiscutal angle. The external face is flat, with a very slight depression running to the spur. Growth-ridges delicate, mainly epidermal, stronger on the scutal side. There are some weak radial striae near the carinal margin. Compartments. — The parietes have no pores 'or tubes whatever. Their inner faces are very strongty and deeply ribbed, the ribs more or less crenulated at the base, and generally unequal. The sheath is extremely short, the opercular valves, therefore, lodged high in the orifice. Radii broad- their summits making angles of about 45° with California. The locality " Golfe de Georgie" (Paris Museum, Gru- vel) also quoted by Kriiger, evidently means the Gulf, or more prop- erty Strait of Georgia, east of Vancouver Island, British Columbia, where Dr. A. Agassiz collected many years ago. On the west, it ex- tends as far south as Hakodate in southern Yesso (Hokkaido), and probably farther south, as it was taken by Mr. IT. Loomis, whose material is chiefly from Jedo Bay, in middle Japan. The record Cochin China, in the Paris Museum, can hardly be accepted without confirmation. It seems most improbable. U.S.N.M. Cat. No. Locality. Collector. Notes. St Paul Island Pribilof Islands Yv'illiain Palmer Ij Steineger Nazan Bay, Atka W. II. Ball On shore. 3507 \Attu do 3509 9178 Sarana Bay, Attu do Dutcli Harbor Umilaska A Ibalross 823,9172 9174-917G 91SO-91S1 Unalaska . W. 11. Dall Very fine series. 9200, 9226 3501,3505 3489 Amaloiak Islands Unalaska .. . do Beach Nikolski Bay, Umnak Island A Ibatross 3511 Sanborn Harbor, Shumaghis W. II. Ball.. In sponge. Coal Harbor, Shumagins do Cold Bay, Shelikof Strait T. W. Stan ton Fort Wrangell Alexander Archi- W. H. Dall pelago. Kioosta village, Parry Passage, Jas. O. Swan. . Graham Islands, British Columbia. Port Towiisend, Wash Fort Steilacoom, Puget Sound. Dr. Goo. Ruckley, U. S. A Neah Bay, Wash J. G. Swan Puget Sound, Wash .. ..do On stone. Station 2871 off northwestern Wash- Albatross Long dead* 559 fathoms ington. Oregon Japan TT. 1, norm's KESPERIBALANUS, new subgenus. Balani with poreless walls and basis, the radii with thick, septate edges; opercular valves as in the Balanus crenatus group. Mandible with the fourth and fifth teeth short and broad, lower edge shortly hairy. Maxilla with few spines. Type. — B. hesperius. THE SESSILE BARNACLES. 193 The single Avest American species composing this group resembles Solidobalanus in the hard parts, but has the mandibles and maxilla) formed as in the typical r>ul, '27 Til SEGMENT OF CIRRUS VI. Maxilla (fig. 61&, c) is slightly notched under the two great spines, there are nine spines below the upper pair in the type, seven in another specimen, one of them stouter, as in B. Ixdanus. Cirri, first and second pairs injured in the type-specimen. The posterior ramus of cirrus i has 9 or 10 segments; anterior segment had been decidedly longer. Cirrus iii with the pedicel expanded as in B. crenatus; posterior ramus of 12 segments two-thirds the length of the anterior of 15 segments. The segments are densely bristly, with- out any spinules or teeth. The posterior cirri have segments wTith three or four pairs of spines, the lower pair minute; the posterior THE SESSILE BARNACLES. 195 distal angle of each segment has a group of spines at least as long as the segment; both rami of cirrus vi have 34 segments (fig. GOZ>). The penis is longer than the cirri, with very few hairs, and so far as I can see, no point at its dorsal base. Examples from other lots examined vary in the armature of the labrum and maxilla, and relative length of the rami of cirrus i, but all are practically alike in other respects. As in other ribbed species, the early stages are smooth; the ribs appear Avhen it is 3 or 4 mm. in diameter, sometimes later, up to 7 mm. The type is one of a very strongly ribbed lot. The ribs are not quite so deeply cut in most lots, and they vary, as in all ribbed Balani. It seems never to become elongated, club shaped, or columnar, as in B crenatius, B. balanoides, and rarely B. glandula. The small FIG. 61. — BALANBS HESPEUIUS, STATION 3483. a, MANDIBLE. &., MAXILLA, c, MAXILLA OF SPECIMEN FROM STATION 3540. d, B. H. NIPPONENSIS, MANDIBLE. number of spines on the posterior cirri distinguishes B. hesperius from all of these species. B. glandula occasionally has almost or quite poreless parietes, but the scutum is unlike that of B. hesperius. It is almost exclusively seated on shells, especially gastropods, in the collections at hand, but this may be because stones are less likely to be taken by the collector. Plate 49, figure 8, represents a large typical specimen growing on the anterior part of a Chrysodomus. Diameter 18 mm. This seems to be the maximum size. In specimens from Albatross station 3540 the wall resembles that shown in plate 49, figure 3. The labrum has one tooth on one side, three on the other. Mandible and maxilla about as in the specimen dissected from Station 5003, except that there is no notch below the upper pair of spines of the maxilla. Cirrus i has 12 and 8 segments, 196 BULLETIN 08, UNITED STATES NATIONAL MUSEUM. the posterior ramus over three-fourths the length of the anterior. Cirrus ii has slightly unequal rami of 9 segments. Posterior cirri with three pairs of spines on the segments. By the proportions of the rami of the first cirrus, this form differs strongly from B. h. nip- •poiwnsis (station 5003), but otherwise is much like it. U. S. N. M. Cat. No. U.S.F.C. Sta.No. Locality. Depth (fath- oms). Bottom tempera- ture. 7 ' Collector. 10038 Latitude, 60° 16' north; longitude, °F. Lieut Geo M Stonoy 107° 41' west, of! Monroe Island. Cape Prince of Wales, Alaska E. M. Kindle. 32942 32944 32935 32940 3302 3482 34S7 3483 3540 3281 Bering Sea: Latitude, 57° 45' 46" north; longitude, 160° 12' 15" west. Latitude, 57° 18' 00" north; longitude, 170° 42' 00" west- Latitude, 57° 10' 00" north; longitude, 173° 45' 00" west- Latitude, 57° 18' 09" north; longitude, 171° 18' 00" west- Latitude, 56° 27' 00" north; longitude, 1(30° 08' 00" west. Latitude, 56° 14' 00" north; 30 42 81 56 51 36 40.2 38.9 37.6 36.8 36 Albatross. Do. Do. Do. Do. Do. 32937 3293S 3542 3537 354S longitude, 161° 41' 15" west- Latitude, 56° 10' 00" north; longitude, 103° 26' 00" west. Latitude, 54° 45' 00" north; longitude, 169° 06' 00" west- Latitude, 54° 44' 00" north: longitude, 165° -11!' 00" west. St. Paul Island, PribilofE Islands. 49 49 91 Beach. 39.2 38 39.5 Do. Do. Do. H. W. Elliott. 3508 Attu, Aleut ian Islands W. H. Dall. 32939 3D74 (Rr>nnrr| mi.=sino-)_ ...... Albatross. 32936 3(175 ."....do "'. Do. A.N.S.P. Mary Island, Alexander Archi- J. G. Malone. 32945 pelago. Kioosta village, Graham Island, Parry Passage,British Columbia. Several other lots are labeled Alaska, without nearer indication of locality. BALANUS HESPERIUS form L^VIDOMUS, new form. Plate 50, figs, l-l/; 2-26. Type. — Cat. N"o. 2106, Acad. Nat. Sci. Phila., from San Juan Islands, Puget Soimd, collected by Homer Wheeler. Distribution. — Monterey, California, to Alaska. The shape varies from broadly conic to shortly cylindric. The external walls are smooth in the typical form of the subspecies; the ribs on the inner faces of the parietes are regular. The scutum has feAver, more widely spaced growth-ridges than in Jiesperius ; they are often low, or very weak. The basal margin of the scutum is usually longer. I segregate this form with some hesitation, yet after going over the material repeatedly there seems to be a constant difference in the external sculpture of the scuta, which it would be a fault to ignore. As the geographic ranges of the two forms overlap in the north and there are some transitional specimens, I do not call it a sub- species. THE SESSILE BARNACLES. 197 The greater number of lots having widely spaced growth-ridges on the scuta also have smooth parietes; yet this association is not inva- riable. A lot from Port Townsencl, growing on Pecten caurinus^ is as strongly ribbed externally as most hcspcrlus, but in the lower part only, the upper part of the cone being smooth. They reach a basal length of 17 mm. (pi. 49, fig. 2). In another lot from Albatross station 28G9, off northern Washington, there are faint traces of ribs close to the base, thus connecting the strongly ribbed and smooth forms. Some fine groups, growing on Natica, at Albatross station 3675, are also transitional in external sculpture (pi. 49, figs. 3, 3) are still smaller, the largest 6 mm. in diam- eter; shape conic with large orifice, or cylindric, the orifice as large as the base ; radii inore oblique than in the usual B. hesperius. Scutum having very low, widely spaced growth-ridges, and internally sim- pler than ordinary hesperius • the callus between articular ridge and adductor pit smooth, raised into an acute ridge along the pit. Most of the characters are those of young hesperius., but the appear- ance of the specimens, which are very numerous, is that of adult barnacles. Possibly a small race inhabits the coast from Oregon to Monterey Bay, but further shore collections are needed to demon- strate this. Both lots grew on twigs. In Alaska the smooth form with convexly conic shape has been taken at Sitka ; diameter 15.5 mm., height 7 mm., growing on Tegula, pulligo (pi. 49, fig. 4). Further north, in the waters where typical B. hesperius is abundant, the variety Iwvidomus seems to be rare. There are a few specimens up to diameter 6 mm., from Chag- afka Cove, Kodiak, and from the mouth of Port Clarence, which, by the smooth exterior and low, widely spaced growth-ridges of the scuta, seem to belong here. Both grew on small gastropods. Smooth individuals seen from other Alaskan localities may be, at least in part, immature stages of the ribbed B. hesperius. 4729°— Bull. 93—16 14 198 BULLETIN 93, UNITED STATES NATIONAL MUSEUM. The form Icevidomus often has a strong superficial resemblance to Balanus wneas Lanchester,1 from the Malay Peninsula, but the following differences may be noted : In B. hesperius the spur of the tergum is wider and very much closer to the basiscutal angle. The articular and adductor ridges of the scutum are shorter and differ in shape. Finally the radii are much better developed. U. S. F.C. station. Locality. Depth (fath- oms). Bottom tempera- ture. Collector. 4561 4457 3096 Monterey Bay, Cal 15 46 33 0 F. 60 Albatross. Do. Do. Kennerley. Homer Wheeler; coll. A.N. S. P. John Allen, coll. A. N. S. P. F. Bischofl. W. H. Dall. Do. do Off Oregon, latitude, 42° 45' north; longitude, 124° 36' 15" west. Puget Sound, Wash. . 46.7 San Juan Island, Puget Sound, Wash. Raft Island, Puget Sound , Wash Sitka, Alaska .. .. Chagafka Cove, Kodiak Island 15-20 7-12 Mouth of Port Clarence, Alaska Somewhat doubtful records are Albatross stations 2869, 2872, 3508, and 3282. These may be the young of either hesperius or Icevi- domus. Ribbed forms of B. hesperius, from the Asiatic coast. A series from Albatross station 3780, attached to egg-capsules of Chrysodo- mus, taken off Kamchatka in 12 fathoms, is externally of the typical ribbed form; basal diameter 9 to 11 mm. (pi. 49, figs. 7-7&). The scuta differ by having growth-ridges decidedly more widely spaced, as in Puget Sound hesperius. In most individuals the valve has the shape of a right-angled triangle with basal and tergal margins sub- equal ; but sometimes the angle is slightly greater, and the tergal mar- gin longer. The spur of the tergum is longer than usual. A similar form was taken at Albatross Station 5003, off southwest- ern Saghalin Island, growing on a Turritella, in 35 fathoms, bottom temperature 42.4° F. In this lot the labrum (fig. 62\ .Scutum not striate longitudinally; its articular ridge very low and broad, not angular. Radii rather narrow ; within the base the crests of the parietal ribs are flattened, and their tapering lower ends are smooth B. crcnnanni a2. Tropical group (StriatoMlanus). Substance of walls either pink or white; compartments strongly united witli the basis; sutural edges of radii feebly crenulated or smooth; basis solid or porous. First pair of cirri with de- cidedlit unequal raml, tJie segments of the shorter ramns protuberant. Spinules, when present on the later cirri, are not numerous. Maxttlce IKI re an- enlarged lower pair of spines. 1>1. Spur of the tcrguni very short and broad, half the width of the valve; scutum strongly striate longitudinally, with a strong adductor ridge. Entirely white; basis not porose B. kriigcri. c1. Scutum strongly striate longitudinally ; walls usiially more or less roseate. tl\ Radii rather wide. Basis porose. Scutum with a distinct adductor ridge; tergum with a longitudinal furrow; median segments of cirri vi wider than long, with 2 pairs of spines B. amaryllis d\ Radii extremely narrow. Adductor ridge of scutum rather small, in the upper part of valve only ; lerguni without a furrow to the spur; median segments of cirri vi longer than broad. c1. Median segments of cirrus vi with three parts of spines B. Mmce. c2. Median segments with four pairs of spines B. maculatns. c2. Scutum finely or delicately striate longitudinally; tergum with a spur fasciole but no furrow. Walls and valves entirely white. Deep water species. (I1. Radii narrow ; adductor ridge of scutum only feebly developed. B. albiis. , MANDIBLE, c, LABRUM. ridge is wholly confluent with the articular rib above, running straight to the basal margin, where it defines a rather large de- pressor muscle pit. It is often weak or almost obsolete in American specimens. The tergum has less coarse growth-ridges than the scutum, and there are a few longitudinal strise near the carinal border. A furrow leads to the spur, its sides more or less folded in in old specimens. The spur is rounded at the end, moderately long, typically separated by its own width from the basiscutal angle, but more distant in most American specimens, in which it is sometimes separated from the basiscutal angle by nearly double its own width. Articular ridge short, sharp, and moderately high. Crests for the depressor muscle sharp and numerous. The labrum has a very shallow notch and two teeth on each side (fig. 65*). The mandible has four primary acute teeth, with smaller ones be- tween the third and fourth and below the fourth (fig. 655). The maxilla has a notch below the upper large spines, and many crowded spines on the edge below it. The upper edge is bearded for a long distance (fig. 65#). Cirrus i has subequal rami of 16 and 14 segments. Cirrus ii with 17 and 19 segments, the rami subequal. Cirrus iii with 15 and 14 segments, the anterior ramus slightly longer. The external anterior faces of the segments have many long THE SESSILE BARNACLES. 207 spines, and there are some short, slender spines near the distal sut- ures. Cirri iv-vi are similar, the segments wider than long, each with three pairs of large spines and one small pair. There is a dense tuft of small spines between the first and third pairs. The posterior distal angles of the segments have groups of three or four unequal spines, the longest as long as the segment. On cirrus iv the segments of the pedicel have narrow areas of minute, erect spinules on the distal an- terior part (fig. G6«). Following segments have increasingly more extensive spinulose areas anteriorly and along the distal margin (fig. 66e). The inner ramus has fewer spinules. The fifth and Fin. 66. — BALANUS HAMERI. a, SECOND SEGMENT OF THE PEDUNCLE AND TWO LOWER SEG- MENTS OF ONE RAMOS OF CIRRUS IV ; ONLY THE ANTERIOR MARGIN SHOWN. It, TWENTY- FOURTH SEGMENT OF CIRRUS VI. C, NINETEENTH SEGMENT OF CIRRUS IV, OUTER RAMCS. sixth pairs of cirri have fewer spinules than the fourth. The fifth, pair has spinules on the pedicel. The sixth pair has densely spinulose areas on the posterior proximal parts of the segments (fig. 66£>, twenty-fourth segment of cirrus vi), but none on the pedicel. The penis is as long as the posterior cirri.1 B. hameri is easily known from other Atlantic barnacles by its readily separable, thin, externally smooth compartments, poreless 1 The above details and figures of mouth parts and cirri are from a specimen 43 mm. in basal diameter, from Georges Bank. A young one 13 mm. in diameter is very similar, but with fewer segments— 10 and 9 in the raini of cirrus i — and with the spiuules far less developed. 208 BULLETIN 93, UNITED STATES NATIONAL MUSEUM. when broken across or viewed from the base; by the poreless, cal- careous basis, the longitudinally striate scutum, and the narrow spur of the tergum. It is closely related to the north Pacific B. evermanni, but differs by the distinct longitudinal striation of the scutum, which invariably, in a vast number of specimens I have particularly examined, has a thin, well-raised articular ridge, culminating below in an obtuse but very distinct angle, below which it tapers downward. In B. evermanni the exterior of the scutum is flat, without longitudi- nal striation, and the articular ridge is extremely low, rounded, and not angular. The spur of the tergum is narrower in B. evermanni. There are also important differences in the compartments. The wall is thinner than in B. evermanni, its inner surface more ribbed; the basal edge has fewer septa, which are subequal, more spaced and different in shape. The size and shape are variable. The following measurements of American specimens give the maximum and the usual size attained in our waters. Greatest Altitude. basal Local! ly and notes. diameter. mm. mm. 35 50 Ofl Cape Cod, 33J fathoms; truncate-conic; solitary. 00 50 Woods Hole; tulipiform; growing on one another. 35 45 Woods Hole; maximum si/.e in ordinary colonies. 63 50 New England, on Pectin magellanicus. 53 56 Do. 67 68 New England, on Pcctcn magellanicus; scuta 37.3 l>y 17.3 mm. 62 58 Speedwell Station 41, off Nova Scotia, 82 fathoms. 75 fil Do. 64 61 Off Chatham, Cape Cod. Darwin mentions specimens from Scarborough 2 inches in diam- eter, If inches high, and l.G inches diameter, 3 inches high. The usual dimensions are therefore about the same in northern European and American waters. Pleistocene specimens from Uddevalla, Sweden, are said to be nearly 4 inches long, therefore about equal to the largest American individuals. They grow upon any available object, usually on shells and upon one another. The commonest situs in our waters is on Chrysodomus decemcostatus, Buccinum undatum, Pecten magellanicus, Modiolus modiolus. More rarely I have seen them on Terebratulina septentri- onalis, the carapax of Ilyas, and on stones. By far the greatest number of specimens in the museum are from between 30 and 55 fathoms. It is abundant on the fishing banks, and is frequently brought up on cod lines. Like B. balanws, it is wanting on the Newfoundland Bank, and none have been obtained in a greater depth than 1G7 fathoms. The recorded temperatures are from about 39° to 58°. THE SESSILE BARNACLES. 209 Whether the American area of the species is continuous in the north with the European is not positively known, but from what we know of the limitations of the species, such continuity at the present time does not seem likely. In the Pleistocene this was an abundant barnacle in northern Europe and Canada, New Brunswick, and Bangor, Maine. LinnEeus was the first to notice the species. He found it in the pleistocene deposits of Uddevalla, but in the text of his work (p. 198) he seems to have taken it for the Uddevalla form of B. balanus, and not a distinct species. EUROPEAN. Locality. Collector. Remarks. Faroe Islands Isaac Lea collection Shetland Islands J. Gwyu Jeffreys Larno, Ireland do Dublin Bav, Ireland ....do Irish Channel ..do.. On Chrysodoinus dntlou'Us Ban try Bay , Ireland do.. Swansea Bay, Wales do Scarborough, England do Mouth of Thames England . do Oil Margate England do Sandwich, England do AMERICAN. U.S.F.C. Station No. Locality. Depth (fath- oms). Bottom temper- ature. Collector. La Have Bank 45 °F. Gloucester fisheries 41 Latitude,42° 49'north;longitude,66° 19' 82 Speedwell. west. Sable Island, Nova Scotia Unknown. Off Nova Scotia 55 Gloucester fisheries 2518 40 Latitude, 43°05' north; longitude, 64°40' 30" west. Latitude, 42° 46' north ; longitude, 66° 27' 60 75 38.7 Albatross. Speedwell. 2063 2522 2067 2000 2059 west. Latitmle,42°23' north; longitude,66°23' west. Latitude, 42°20' north; longitude, 65 °07' 3D" west. Latitude, 42° 15' 25" north; longitude, 65" 4 8' 40" west. Latitude,42° 10' north; longitude, 66° 4 6' 15" west. Latitude, 42°05' north ;lougitude,66° 46' 141 104 122 123 41 46 46.7 46 55 Albajross. Do. Do. Do. Do. 2057 15" west. Latitude, 42°01' north; longitude, 68°00' 86 Do. 30" west. Lawlors Lake, St. Johns County, New Pleistocene. Brunswick. Off Grand Manan Fishermen. New England coast .... Steamer Spray. Jeffreys B ank Schooner Paul Revere. East of Georges Bank Schooner A lice O. Wonson. 82B Latitude 41° 25' north; longitude 65° 58' 03" west. Northeast edge Georges Bank 60 50 58 Bachc. Schooner Otis P. Lord. Georges Bank (many lots) Fishermen. Northwest part of Georges Bank Schooner Clytie. West part of Georges Bank Schooner E. P. TPbnson. 2525 2580 Latitude, 41°49' north; longitude, 65° 49' 30" west. Latitude, 41° 25' 30" north; longitude, 69° 01' west. 72 S3 43.6 42.4 Albatross. Do. 210 BULLETIN" 93, UNITED STATES NATIONAL MUSEUM. AMERICAN-Continued. U.S.F.C. Station No. Locality. Depth (fath- oms). Bottom temper- ature. Collector. 2579 Latitude, 41°23' north; longitude, 68" 47' 83 42.2 Albatross. west. 2080 Latitude,41° 13' north; longitude, 66°21' 55 46 Do. 50" west. 2079 Latitude, 4 1 ° 13' north ; longitude , 66 ° 19' 75 45 Do. 50" west. 2081 Latitude,41° 10' 20" north; longitude,66° 50 46 Do. 30' 20" west. 2082 Latitude, 41° 09' 50" north; longitude, 49 46.5 Do. 66° 31' 50" west. 2256 Latitude, 40° 38' 30" north; longitude, 30 52.9 Do. 69° 29' west. 2253 Latitude, 40° 34' 30" north; longitude, 32 52.9 Do. 69° 50' 45" west. 2251 Latitude, 40° 22' 17" north; longitude, 43 52.9 Do. 69° 51' 30" west. 2250 Latitude, 40° 17' 15" north; longitude, 47 51.4 Do. 69° 51'45" west. 2249 Latitude,40°ll'north;longitude,69°52' 53 51.4 Do. west. 326 Off Cape Cod F. C., 1879. 984 Off Chatham, Cape Cod 33 41.5 Fish Hawk. 964-983 Vineyard Sound to Cape Cod Do. 269 Off Cape Cod 53 39.5 Speedivcll. 1081 do 33', 39 F. C., 1882. 972 Off Chatham Cape Cod 16 52 F. C. 983 do 36 42 Do. 981 Southwest of Chatham Light 43 Fish Hawk. 991 Latitude, 40°39' north; longitude, 70" 46' 34 47.5 F. C. west. Off Marthas Vineyard Albatross. Woods Hole F. C., 1888. 519 Off Block Island 11 55 F. C. 2016 Latitude, 37 ° 31' north; longitude, 74 ° 52' 19 54.5 Albatross. 36" west. 2264 Latitude, 37° 07' 50" north, longitude, 167 46.8 Do. 74° 20" west. BALANUS EVERMANNI Pilsbry. Plate 54. 1907. Balanus evermanni PILSBRY, Bulletin of the Bureau of Fisheries, vol. 26, p. 203, fig. 4, pi. 7, figs. 7-14 ; pi. 8, figs. 1-4 ; pi. 10, fig. 1 ; pi. 11, fig. 1 (June 29). 1911. Balanus eversmanni Pilsbry, KRUGER, Zoologischer Anzeiger, vol. 38, TA, B. (Feb. 17). 1911. Balanus eversmanni Pilsbry, KRUGEB, Zoologischer Anzeiger, vol. 38, pp. 460, 463. Type—Cat. No. 41840, U.S.N.M., from Albatross station 4239, at the junction of Clarence Strait and Behm Canal, Alaska. Distribution. — Southern Alaska through Bering Sea to the Kuril Islands, in 72 to 248 fathoms, bottom temperature 37°.l to 48°.8 F. The barnacle is tubular, tulip-shaped, enlarging upward, usually with the summits of the compartments, except the carina, curving inward at the aperture, which is large, quadrangular and very deeply toothed. White, with traces of a thin, pale primrose-yellow epider- mis, which is deciduous in large part, often wholly lost, and more persistent on the radii than on the parietes. The opercular valves are white under a similar epidermis. The parietes have low, transverse, well-spaced growth-ridges or merely some irregular rugre, and usually show fine, irregular, longitudinal strise ; next to the radii and THE SESSILE BAENACLES. 211 especially along the ake, there is often an acute ridge, sometimes over- hanging, or a strong longitudinal rib. The strong, calcareous basis is flat or irregular, and never forms part of the wall. The scutum is flat, with well-developed growth-ridges; faint, ir- regular and rather close longitudinal scratches may be seen between the ridges. The articular ridge is very low, narrowly reflexed, its contour gently rounded from end to end; it is confluent with the adductor ridge, which is represented by a low callous, rounded or angular along the depressor muscle scar. The tergum is more delicately ridged than the scutum, and there may be a few weak longitudinal striae near the sides. The furrow is B . (57. — BALANUS EVERMANNL, ONE-HALF NATURAL SIZE, a, NEAR BERING ISLAND, b, NEAR SIMUSHIR ISLAND, No. 38G62. deep and narrow, the sides partly folded in. The spur is narrow, separated from the basiscutal angle by twice its own width. Articu- lar ridge moderate. There are small crests for the lateral depressor muscles. The compartments are strong, rather thick, but very weakly ce- mented together. The carina is recurved, but the other compartments usually curve inward at the orifice. The parietes of the carinolaterals are always very narrow — less than half as wide as those of the laterals. The radii are wide or moderate, with very long, steeply sloping, smooth summits; sutural edges not denticulate. The ala? are extremely wide, summits strongly oblique ; their surfaces are smooth and nude, except for the distal triangles, which often retain the epidermis; edge without septa or denticles. The sheath is glossy above, its lower edge hanging close to the wall, leaving narrow cavities. Be- low it the parietes are almost smooth, except close to the base, where they become very closely and acutely ribbed, the ribs flattened and 212 BULLETIN 93, UNITED STATES NATIONAL MUSEUM. striate (somewhat T-shaped in section), but not in the least denticu- late at the basal edge. There are many accessory short lamella) on the inner edge of the outer lamina of the wall. The basis is strong, white, poreless, with only very weak, obtuse traces of peripheral denticles. Greatest carinorostral diameter 67 mm. ; lateral diameter 66 mm. ; height 150 mm. (station 4253). Height 88 mm. ; length of scutum 41 mm., breadth 18.7 mm. ; length of tergum 33 mm., breadth 13 mm. FIG. 68. RALANUS EVERMANNI. a, LABRUM. 1), MORE MAGNIFIED CENTRAL PART OF SAME. C, MANDIBLE. d, MAXILLA. C, INTERMEDIATE SEGMENT OF CIRRUS VI. /, SPINDLES OF THE AREA INDICATED ON FIG. e. The labrum (fig. G8«, b) has a wide, shallow notch, with several unequal teeth and numerous short hairs on each side. Mandible (fig. 68) of another. I have therefore not been able to add any- thing to Mr. Lanchester's account of the walls, basis, or internal anatomy. The scutum has narrow, very little raised and widely spaced growth ridges, much like some forms of B. amphitritc. The articular ridge is prominent and somewhat reflexed. The adductor ridge is very narrow and low, and there is a smaller ridge parallel with it, nearer the articular rib; these two ridges are connected above by a semicircular ledge, bounding the flat, depressed interval between them; and in suitable light they appear to form a narrow inverted U. The pit for the lateral depressor muscle is small but distinct. The tergum has a distinct though quite shallow depression running to the spur, varying in depth in the two individuals. The carinal margin is arched, and shorter in one of the examples, and it bears numerous delicate hairs. The crests are well developed. It will be noted from the above details, together with Mr. Lan- chester's account, that this form agrees veiy closely with B alarms social* s Hoek.2 I can find no tangible differences; and unless the cirri (which are not described in B. a'neas} are shown to differ, I would suggest that B. ceneas be written as a synonym of B. socialis. I may further remark that B. socialis and B. ceneas differ from the other forms of frolldobalanus by having very narrow, smooth radii, with steeply oblique summits, whereas the other species have wide, transversely grooved radii, with summits far less oblique; yet from Doctor Hoek's account of the mouth parts of B. socialis, it appears to belong with the other Solidobalani rather than with the B. ama- ri/ttis group. (r/iff/.s Lanchester, Proc. Zool. Soc., London, 1902, vol. 2, p. 370, pi. 34, figs. 4, 46. Malay Peninsula, on the shells of Strombus and Natica inhabited by the hermit crab Pacninif; JirsKii Miers (Proc. Zool. Soc., London, 1902, vol. 2, p. 3641. Col- lected by the Skeat expedition. " Balanus socialis Hoek, rjiallenr/er Report, Zoology, vol. 8, Report on the Cirripedia, p. 150. pi. 13, figs. 23-28 (1883). Si&o^a-Expeditie, Cirripedia, p. 192, pi. 18, figs. 2-12 (1913). Arafura Sea, type locality; also Malay Archipelago, in 9 to more than 69 meters. 222 BULLETIN" 93, UNITED STATES NATIONAL MUSEUM. BALANUS HAWAIENSIS, new species. Plate 48, figs. 1 to Iff. Type.— Cat. No. 43474, U.S.N.M. Distribution. — Hawaiian Islands, 21 to 222 fathoms, on spines of the sea-urchin Phyllacanthus thomasi Agassiz and Clark; collected by the Albatross Hawaiian Expedition, 1902. A very small, strong, and firmly attached barnacle, with a solid, calcareous basis and rather thick, solid (poreless) walls. Radii pink; parietes white, or sometimes having some pink stains. The form is oval, conical, with strongly ribbed parietes; carinal latera have a single strong rib, the rostrum usually three, and the other compartments two ribs. The radii are rather wide and rather deeply, regularly grooved transversely, their summits strongly oblique. The alee have straight or arched and smooth summits when unbroken, and are nearly level, so that the margin of the aperture is nearly regular. The aperture is ovate, angular at the carinal end. The sheath is very short and its lower border does not overhang. Below it the inner surface of the parietes is smooth, becoming ribbed near the base. Basal edges of the wall plates are thick and crenu- lated. The articulating borders of the radii are finely crenulated, as are the opposed sutural surfaces. The basis is thick. Length of base 3.2 mm., width 2.8 mm., height 1.5 mm. Length 5 mm., width 3.5 mm., height 2.2 mm., largest specimen. The white opercular plates lodge close to the aperture and project above it. The scuta are sculptured with flat, regular growth-ridges, about every second or third one forming a tooth on the occludent margin. These teeth, interlocking in the closed barnacle, produce a crenellated occludent suture. There is a rather prominent, acute, somewhat reflected articular ridge, nearly the whole length of the tergal margin, and a narrow articular groove. There is no trace of an adductor ridge. The scar of the adductor muscle is small and distinct. The terga are nearly twice as long as wide. Externally there are very weak ridges of growth except on the band leading to the spur, where the ridges are stronger and arcuate. This band is not de- pressed, but is separated from the rest of the surface by a slight radial depression. The spur is very short, tapering to a rounded end. Its outline passes imperceptibly into that of the basal margin. Inside there is a moderate articular ridge about one-third the length of the plate. There are about five rather strong crests for the de- pressor muscles. The labrum has three short, conical teeth on each side of the deep, narrow median notch (fig. 70S). Palpi armed with very long hairs (fig. 71c). THE SESSILE BARNACLES. 223 The outer maxilla? are oval, rather densely covered with long hairs. Maxilla (fig. 70# ) has a small notch below the upper pair of large spires, a short spine in the notch. Below it the straight margin bears five principal spines, the lower two largest. The distal fourth of the face and the lower margin have some delicate spines and the upper margin several pairs of hairs. Mandible (fig. 7O) with four teeth above the pointed, bispinose or trispinose lower angle. Lower margin bears a close series of deli- cate regular spines. The distal part of the inner face is hairy, and there are five pairs of long hairs on the upper margin. Cirri. — First pair with very unequal branches of 6 and 11 segments, the shorter branch about two-thirds as long as the longer, with strongly convex segments. Second pair, branches slightly unequal, of 8 segments which pro- trude somewhat, and are densely hairy. FIG. 70. — BALANUS HAWAIENSIS. o, MAXILLA. 6, UPPER EDGE OF LAERUM. c, MANDIBLE. Third pair, branches somewhat unequal, of 8 and 9 segments, which protrude a little and bear fewer hairs than the second pair. Fourth to sixth cirri much longer, of long segments, with four or five pairs of spines on each segment, the proximal one or two pairs short (fig. 71«, fifth segment of cirrus vi). Cirrus vi has rami of 19 and 20 segments. The terminal segments have the distal pair of spines very long (fig. 715). None of the cirri have any "teeth" or spinules on the segments. The penis is extremely long, closety annulate, and very spareeLy hairy. Specimens from six localities indicate that this small barnacle inhabits the entire Hawaiian ridge, in the warm water (60° to 69° F.) of moderate depths, down to 212 fathoms. It is usually seated length- wise on the rough spines of the sea-urchin Phyttacanthiis th&masi, and is very uniform in the size attained, and in other characters, throughout its range of about 1,700 miles. It is sometimes abundant. On one spine 6 cm. long from Station 4064: there are about 108 individuals. 224 BULLETIN 93, UNITED STATES NATIONAL MUSEUM. B. hawaiensis is a species of the snbgenus /Solidolalanus, nearest, I believe, to B. auricoma Hoek, from Ternate. It differs from B. auricoma in the following characters: The wall is strongly ribbed externally. There are no hairs on the opercular plates. The articu- lar ridge of the tcrgum is much shorter, and the tergum is wider to- ward the spur, which is shorter. The teeth of the labrum are more separated. The outer maxillae have a regularly oval shape. The palpi have a row of long spines instead of a patch. The greatest I I V\ " - ' U MM ii/mh FIG. 71. — BALANUS HAWAIENSIS. a, STH SEGMENT OP CIRRUS vi. ~b, THREE TERMINAL SEGMENTS OP INXKK RAMUS OP CIRRUS VI. C, PALPI'S. number of spines on cirrus vi is five pairs, without short hairs at their bases. Albatross J-'tation No. Locality. Depth (fath- oms). Bottom tempera- ture. Museum No. 40G° Off northeast coast of Hawaii 88-113 °F. 43474 4004 do . 63-107 69 43475 3S63 Pailolo Channel between Maui and Alolokai 127-1S4 60-61 43476 3838 South coast of Molokai 92-212 67 43477 3S23 do 78-222 69 43478 4162 Ofl Bird Island (Modu Manu) 21- 24 43479 BALANUS TANTILLUS, new species. Plate 48, figs. 2-'2e. .—Czt. No. 48202, U.S.N.M. Distribution. — Albatross station D5153, near Tocauhi Point, Tawi Tawi group of the Sulu Archipelago, 49 fathoms. The barnacle is minute, oval, tapering slightly to the broad sum- mit, between cartridge buff and white; solid, the walls and base not THE SESSILE BARNACLES. 225 porous; rostrum and lateral compartments usually parted into two or three broad, low, rounded ribs near the base, by one or two shal- low furrows. Eadii broad. Orifice pentagonal, with two long sides; closed by the scuta, which lodge high and project above the lateral compartments. Scutum (pi. 48, h'gs. 2c, d] slightly arched from base to apex, the outer face with a longitudinal flattening or slight depression, marked with low growth-lines but no longitudinal strise; occludent edge crenated; a tergal segment rather deeply deflected. Inside there is a moderately high articular ridge, about three-fourths the length of the tergal border, and a moderate articular furrow. There is no ad- Fn;. 72. — BALANUS TANTILLUS. a, LABRUM. I), 12TH SEGMENT OF CIRRUS vi. c, MANDIBLE. ductor ridge whatever. Pit for the lateral depressor muscle is small, deep, and upon the basal margin. The tergum (pi. 48, figs. 2, 26) is flat externally, with very fine growth-striae. No trace of a band or depression leading to the spur, which is rather narrow and rounded distally, and passes gradually into the basal margin. A basiscutal angle is hardly perceptible, the spur forming a continuation of the scutal margin. Inside there is a high but short articular ridge and a rather broad articular furrow. Crests for the depressor muscle are strongly developed. Compartments. — The walls are thick and massive for so small a barnacle. Inside irregularly ribbed close to the thick base, smooth above. Sheath short, not overhanging, though the wall is somewhat hollowed below it. Radii wide, transversely grooved, with the sum- mits oblique; edges thick and septate, as are the opposed sutural edges. Ala3 wide. Basis rather thin, calcareous, poreless. Greatest diameter, 3.3 mm.; height, 1.6 mm. (largest example). Greatest diameter, 2.5 mm.; height, 1 mm. (usual size; type). 226 BULLETIN 93, UNITED STATES NATIONAL MUSEUM. The labrum has two stout teeth on each side of the median notch (fig. 720). The palpi closely resemble those of B. hawaiensis The mandible has four rather long teeth, and a trifid lower point. There are small teeth above and below the fourth tooth. The lower margin bears a few long spines. There are a few hairs on the upper margin (fig. 72cv — British Museum, East Indies or Philippines. Distribution. — Philippines and Malay Archipelago. Taken by the Albatross at Catbalogan, Samar, growing, associated with small B. amaryllis, 011 a living Euchelus found on the reef. Subgenus MEMBRANOBALANUS Hoek. Mcmbrano-Balanus HOEK, The Cirripedia of the Siboga-Expedition, Siboga- Expeditie, Monographie olb, pp. 159, 205, May, 1913. Walls thin, impervious, the compartments weakly united; sutural edges of the radii not septate; basis membranous; rostrum boat- shaped, about twice as long as the other compartments; spur of the tergum very short and broad. First cirri with very unequal rami. Fourth cirri having teeth on part of the segments. Sixth cirri com- posed of long segments bearing few pairs of spines (-L in known species) . Living embedded in sponges. Type. — Balanus declivis Darwin. This group, as proposed by Hoek, " corresponds to Darwin's Section E and contains the species with a membranous basis." As the only species mentioned are B. longirostrum, new species, and B. declivis Darwin, the latter being a member of Darwin's Section E, I restrict the new section to this aberrant group, selecting B. declivis as its type. The poreless walls and armed cirri of these lorms show that they are not directly related to other species having the basis membranous, and I believe that the tAVo series should be widely separated in a natural classification. Membranobalanus is related to Armatobalanus and to Acasta. KEY TO SPECIES OF HEMBRANOBAiANUS. a1. Small, fragile, rostrum less than 10 mm. long ; radii present ; tergum about as wide as scutum, the spur occupying half the basal margin; scutum with the adductor ridge very weak or wanting. 61. Rostrum convex throughout, its lower half broadly rounded. Fourth cirri with the segments of outer ramus armed with erect distal teeth and with large, recurved teeth on the anterior protuberance. West Indies B. declivis Darwin I3. Rostrum grooved by a median longitudinal furrow ; its lower half narrower, tapering; scutum with two shallow longitudinal depres- sions externally. Fourth cirri armed with erect teeth near the distal margin of the lower 10 segments. East Indies. B. longirostruni Hoek 1 1 Balanus longiratfrum Hoek, Cirripedia of the S;6o^o-Expeditie, Monographie 316, p. 205, pi. 20, figs. S-16, 1913. Off Dongola, Palos Bay, Celebes, 36 meters, arid east of Dangar Besar, Saleh Bay, 30 meters. This species is not represented in the collection of the United States National Museum. It seems to be closely related to B. declivis, but is clearly a distinct species by reason of the marked dilt'erence in the armature of the fourth cirri, the protuberant segments of the shorter ramus of the first cirri, and various minor details of structure. An undetermined form similar to B. declivis has been reported from the Black Sea by Czerniavski. See Zoological Record, 1S70, p. 205. 4729°— Bull. 93—16 16 230 BULLETIN 93, UNITED STATES NATIONAL MUSEUM. a2. Much larger, rostrum about 18 mm. long; radii extremely narrow or want- ing; tergum much wider than scutum, the spur occupying two-thirds of the basal margin ; scutum with a well-developed adductor ridge ; sheath long, two-thirds the length of the lateral compartments. West America. B. orcutti Pilsbry BALANUS DECLIVIS Darwin. Plate 55, figs. 1-lfZ. 1854. Balanus declivis DAKWIN, Monograph, p. 275, pi. 7, figs. 4o-4(Z. 1901. Balanus declivis Darwin var. cuspitlatius YEKKILL, Trans. Connecticut Academy, vol. 11, p. 22. Type. — British Museum. Distribution. — Antillean faunal province, known from the follow- ing localties: Fish Hawk Station 7300, oil Cape Sable, Florida, 11 J feet, in a sponge. Bermuda, Louis Mowbray. It has also been re- ported by Darwin from the West Indies (British Museum) and Jamaica, in a sponge (Cuming collection, now in British Museum). The barnacle is fragile, the compartments being very weakly cemented together; walls thin, not porose, basis membranous; ros- trum boat-shaped, about twice as long as the other compartments. Aperture toothed. Parietes smooth except for faint growth-lines and in places some fine, oblique wrinkles or scalelike tuberculation ; gray or white under a very thin cartridge-bull' epidermis, which also covers the opercular valves. Greatest diameter 6 mm., length of rostrum 9 mm. in the largest specimens.. The scutum is somewhat convex externally, but with a slight lon- gitudinal depression in some examples, with sculpture of close, fine growth-ridges, which are all continued on the occludent edge. The ridges are very finely crenulated by longitudinal striae, sometimes very faint, and in the best-preserved specimens are minutely bristly. There is a narrowty triangular area or radius built out on the apical half of the occludent edge. The articular ridge is rather strong, two-thirds as long as the tergal edge or less, its lower end oblique. There is the mere trace of an adductor ridge, or none, and a small, lather deep depression for the lateral depressor muscle at the lower margin. The tergum is about as wide as the scutum, somewhat beaked, ciliated along the carinal border, which is well arched. Articular ridge moderate, articular furrow wide. The spur is very short, truncate, half as wide as the basal margin or slightly more. It stands very close to the basiscutal angle. Compartments. — The paries of the lateral compartment is wider, sometimes three times as wide, as that of the carinolateral. The radii are usually narrow but sometimes wide, not sunken or conspicuous, but whiter than the parietes by lacking epidermis ; summits oblique. The ala3 are rather wide with oblique summits and smooth edges. THE SESSILE BAENACLES. 231 The sheath is short, about half the length of the carina and sides, one-fourth that of the rostrum, with fine horizontal ridges bearing short fringes of golden bristles. Its lower edge is continuous with the interior of the walls. The parietes are nearly smooth within, but sometimes very weak ribs are visible. The basal edges of the com- partments are smooth and beveled. The base of the rostrum is broadly rounded, the upper end tapering a little. Sides nearly in a plane. The labrum has three teeth and is minutely hairy on each side of the deep notch (fig. 735). The mandible (fig. 73«) has five teeth, the lower two small, lower one united with the lower point. The maxilla (fig. 73c) has a slight notch below the upper pair of spines. There are seven spines below the upper pair, the lower two slightly larger. FIG. 73. — BALANDS DECLIVI^ a, MANDIBLE, b, LABRUM. c, MAXILLA. The first cirrus has rami of 25 and 9 segments, the posterior ramus about one-third as long as the anterior. The segments do not pro- trude. Both rami are very slender. The second cirrus has slightly unequal rami of 13 and 10 seg- ments. The third is somewhat longer, with rami of 18 and 15 seg- ments, the outer slightly longer. There are a few minute spinules near the distal borders of some segments. In the remaining cirri the first joint of the pedicel is very long. Cirrus iv has unequal rami of 18 and 21 segments, the outer ramus shorter, with protuberant seg- ments (fig. 74«). Both segments of the pedicel have series of small, erect spinules at the distal anterior angles (fig. 71&). The lower segments of the outer ramus have a short distal series of erect teeth, and an anterior series of large recurved teeth. The latter appear on the lower 12 segments, but the teeth become fewer above (fig. 7!<7, d). The inner ramus has three pairs of spines on the segments. The sixth cirrus has rami of 36 segments, bearing three pairs of spines, some median segments with a very minute fourth pair (fig. 74:e). The penis is nearly as long as the sixth cirrus, with a few short hairs near the distal end. Near the proximal end there is a minute point on the dorsal side. 232 BULLETIN 93, UNITED STATES NATIONAL MUSEUM. Specimens from Bermuda which I have seen agree with Darwin's description. The irregular, strongly marked ridges of growth on the lower part of the rostrum show that individuals 8 to 9 mm. long are old. The maximum length of rostrum given by Darwin is .3 of an inch, or about 7.5 mm. Professor Verrill's var. cuspidatus, from Bermuda, is described as follows : Our specimens differ as a variety from the typical form described by Darwin, in having the summit of the rostrum divided into four or six acute denticles ; FIG. 74. — BALANUS DECLIVIS. a, CIRRUS iv, THE SPINES OMITTED. Z>, LOWER PART OF THE SAME. C, FIFTH SEGMENT, AND d, TENTH SEGMENT OF CIRRUS IV. e, 22D SEGMENT OF CIRRUS VI. • it is very convex and considerably incurved. The summit of the carina is bilobed by a narrow incision. The base is membranous and very obliquely placed, owing to the downward prolongation of the rostrum, as in the type. Long Bird Island, on the flats, embedded in a blackish massive keratose sponge (Spongia, sp.), which often lives half buried in the calcareous sand at low tide, and which also harbors a small Alplieus and several isopod crustaceans. The denticles at the summit can only be produced by breakage or erosion, and their presence in Professor Verrill's specimens is prob- ably accidental — an individual and not a racial character. Some specimens I have seen show faint gray and white longitudinal stripes near the summit of the rostrum, possibly indicating differences in the THE SESSILE BAKNACLES. 233 i density of the wall, which might sometimes result in apical clenticula- tion, though in all individuals I have seen the summits of rostrum and carina are irregularly worn. In one specimen the rostrum and lateral compartments on one side have been injured when the barnacle was half grown. Perfect repair followed, but the rostrum was stunted, projecting very little below the bases of the other compartments. The opercular valves are normal. B. declivis is described here in some detail because it was known to Darwin by but few examples not containing the soft parts, and ex- cept for Verrill's brief note, its characters have not been noticed by any other author. In view of the description of allied species from west America and the East Indies, it does not seem superfluous to confirm the characters assigned to B. declivis by the description of other specimens. B. declivis is known from the Antillean faunal province only, since it is likely that Weltner's record from Bat j an x pertains to the closely similar East Indian species B. longirostmm Hoek. BALANUS ORCUTTI Pilsbry. Plate 55, figs. 2-2d. 1907. BaJamis orcutti PILSBRY, Proc. Acacl. Nat. Sci. Phila., p. 361, pi. 29, figs. 1-7, September 28, 1907. Type. — ^o. 17S3 A.N.S.P. Topotypes in the United States National Museum. Distribution. — San Ysidro, Lower California, embedded in sponges, collected by C. R. Orcutt. The walls are thin, impervious, the compartments not firmly ce- mented together; basis membranous; rostrum boat-shaped, twice as long as the rest of the wall, strongly arcuate and convex ; the other compartments nearly straight. Aperture small, oblong, toothed. Parietes marked with growth-lines, and minutely, densely wrinkled, the rugae transverse or oblique, in some places interrupted, forming a pattern of long granules. Greatest diameter 11 mm., lateral diameter 9.2 mm., length of rostrum 18 mm. The scutum is decidedly less than half as wide as long. It is sculptured with close, irregular, deeply cut ridges of growth. Articular ridge high and angular, about half as long as the tergal margin, its lower end oblique. Articular furrow is very narrow. The adductor ridge stands free of the much higher articular ridge. It is strong and straight, running to the basal margin, close to and slightly overhanging the pit for the lateral depressor muscle, which is oblong and deep. Adductor scar well marked. 1 Verzeiclmis, p. 270. 234 BULLETIN 93, UNITED STATES NATIONAL MUSEUM. The tergum is triangular, much wider than the scutum-. It is flat externally and sculptured like the scutum. Articular ridge is very short and acute; articular furrow wide. The spur is extremely short, two-thirds as wide as the basal margin, extremely close to and curving into the basiscutal angle. The whole inner face is roughened with lengthened tubercles. There are no crests for the depressor muscle. Compartments. — The carinolateral compartment is about half as wide as the lateral. There are no radii, merely a slight thickening along the radial edges. The alse are wide, with thin, oblique sum- mits. The sheath is about two-thirds the length of the carina and lateral compartments, over one-third the length of the rostrum. It bears many fine horizontal ridges closely set with short, golden bristles. The parietes are not hollowed out below the sheath and are distinctly ridged longitudinally. The basal edges of the com- partments are blunt and nearly smooth. The lower part of the rostrum tapers to a rounded extremity (appearing more obtuse in the foreshortened figure 25). None of the dry specimens examined contained the body and limbs. This species is knowyn by numerous specimens, more or less per- fect, collected by Mr. Orcutt in 1889. It is twice the size of the largest specimens of B. (led iris Darwin and differs from that West Indian species in the following respects: The radii are practically absent. The sheath is much longer. The interior is much more strongly ribbed. The scutum is constantly much narrower relative to its length. Its articular ridge is shorter, and there is a u^ ell- developed adductor ridge. The tergum is much wider, with a wider, shorter spur, and roughened interior. The external sculpture of the parietes is essentially similar in the two species, but the minute wrinkling is more fully developed in B. orcutti. The type-specimen is figured. Fragments of a small, delicate species of Membrano7)alanus were found in a sponge from Cape St. Lucas, Lower California. The rostrum is much narrower than that of B. orcutil; Cat. No. 32933 U.S.N.M. • Subgenus CONOPEA Say. 1822. Conopea SAY, Journal of the Academy of Natural Sciences of Phila- delphia, vol. 2, p. 323. 1825. Conoplea GRAY, Annnls of Philosophy, new ser., vol. 10, pp. 98, 103. 1839. Balaninus O. G. COSTA, Corrispondenza Zoologica, vol. 1, p. 181 ; Fauna del Regno di Napoli, MolHichi, Cirropecli, p. 19, monotype B. galeatus. 1854. Bahmiis, Section B, DARWIN, Monograph, p. 216. 1913. PateUa-Balanus HOEK, /S%o#a-Expeditie, Monographic 316, Cirripedia sessilia, pp. 160, 162, 221 (Type Balanus calceolus Ellis, Darwin). THE SESSILE BARNACLES. 235 'Farietes and basis sometimes permeated by pores, sometimes not; radii not permeated by pores. Sh<'U elongated in its rostrocarinal axis; Lasts boat-shaped [or compressed conic]. Attached to Gor- goniae and Milleponr." (Darwin). Radii well developed. Type. — C. elongata Szy=Balamis gdleatus (Linnaeus) Darwin. Distribution. — Tropical and warm temperate seas in both hemi- spheres, from above low tide to over 200 fathoms. This group was thought by Darwin to have affinities with the subgenus now called Megabalanus, and with Acasta. Hoek places it at the end of Balanus, after the groups with poreless compartments. The characters of the cirri favor this view. The segments of the first and second cirri are not protuberant, and in some species the fourth cirrus bears some short spiimles, reminiscent of those of Acasta. I have been unable to decide whether the species of Conopea writh poreless compartments are secondarily so by reason of the filling up of pores solidly, or whether, like Acasta, parietal pores have never been evolved. It is possible, though it does not appear prob- able, that the group is diphyletic, composed of one series of species related to the poreless Balani and Acasta, and another related to the porous Balani. I have been able to study only B. gdleatus, E. calceolus, and B. scandens. B. cornutus is remarkable for the abortion of the carinolateral compartments. It is the only Balanus having but four compart- ments. Lepas cassis Spengler1 is a Balanus growing on a gorgonian as the Conopeas grow. It can probably be recognized if found again. Conopea contains nine species, enumerated below. They are not well-known barnacles, as excepting B. galeatus, the species are known by but few specimens in museums. The Malay Archipelago is the center of speciation. Only two species are known to occur in the Atlantic. Those represented in the United States National Museum are starred in the following list. B. stultus Darwin, 1854. Singapore. *B. calceolus Darwin, 1854. West coast of Africa; Tuticorin; Malay Archipelago : Coralline Crag of Britain. B. investitus Hoek, 1913. Flores Sea. * B. galeatus Linnaeus. West Indies; Southern California. B. nai-'/rula Darwin, 1854. Tuticorin; Malay Archipelago. B. cornutus Hoek, 1913. Malay Archipelago. B. cymbiformis Darwin, 1854. Tuticorin, near Madras. B. proripiens Hoek, 1913. Malay Archipelago. * B. scandens Pilsbry. Japan. 1 Skrivter af Naturhistorie Selskabet, vol. 1, 1790, p. 184, pi. 6, fig. 3a, I. 236 BULLETIN 93, UNITED STATES NATIONAL MUSEUM. KEY TO SPECIES OF CONOPEA. a1. Parietes • porous. b\ Terguni with an external furrow, closed except on the spur, which is nearly its own width from the basiscutal angle. Scutum with strong growth-ridges and sinuous base, prominent in the middle ; adductor ridge moderately developed B. stultus. b3. Tergum sometimes with a depression but no furrow; spur near the basi- scutal angle. c\ Scutum with the basal margin prominent in the middle, and having a moderate adductor ridge B. investitus. (?. No adductor ridge in the scutum ; spur of tergum \ to 3 width of valve, usually having small teeth or points at the end B. calceolus. a2. Parietes not porous. 61. Carinolateral compartments wanting; laterals bearing hornlike proc- esses B. cornutus. b2. Carinolateral compartments present, as usual. c\ Rostrum produced, its end reaching the supporting stem. d\ Apex of tergum square, by projection of the articular ridge. B. galeatus. d\ Apex of tergum acute; carinal margin forming an acute angle with the scutal margin; scutum longitudinally striate; Carinolateral com- partments very narrow B. nairicula. d\ Carinal margin of tergum at a right angle with the scutal margin. B. cymbiformis. B. proripiens. e2. Rostrum scarcely produced, not extending to the supporting twig, which is clasped by the base only B, scandens. BALANUS GALEATUS (Linnaeus). Plate 56, figs. 1-lrf. 1771. Lepas yaleata LINN^US, Mantissa Plantarum altera, p. 544. 1822. C.[onopea] elongnta SAY, Journal of the Academy of Natural Sciences of Philadelphia, vol. 2, p. 324 (inlets of Charleston Bay). Not Lepas clongata Gme\\n=Balanus crenatiis. 1854. Ba1ani Annals of Philosophy, new ser., vol. 10, 1825, p. 103. THE SESSILE BARNACLES. 239 Lepas calccolus was merely mentioned by Pallas as adhering to Gorgonia verrucosa, and covered by its bark. Since there is no de- scription whatever, and no reference to a figure, or to Ellis, the name is absolutely nude, and does not prejudice Darwin's subsequent use. It may or may not be Darwin's species.1 BALANUS SCAND5NS, uew species. Plate 56, figs. 2-2d. Type.— Cat. No. 48048 U.S.N.M., from Albatross station 3716, off Ose-Zaki, Honshu Island, Japan, in 65 to 125 fathoms. The barnacle has rather thin, impervious compartments and basis and is oval in peripheral contour, the outlines rounded below, ob- liquely conic above the periphery, which is angular at the sides and rostral end, rounded at the carinal end. The surface is smooth. The carina is steep, almost vertical, rostrum sloping, but not produced in a point, and not clasping or approaching the supporting stem, which is clasped only by the bottom of the basal cup. When cleaned, the compartments are lilac tinted with whitish vertical lines, fading to white below, the radii rather narrow and white, basis whitish. The carinolateral compartments have narrow, bandlike parietes, nearly as wide at apex as at the base. Inside, the parietes are ribbed below the sheath ; basis also ribbed very close to the periphery, else- Avhere smooth. The sheath is very long, about three-fourths the length of the compartments, and of a dull lilac tint. The scutum has distinct but not prominent growth-ridges; alter- nate ridges appearing on the inflected occludent margin as prominent, oblique teeth. The articular ridge is rather low, somewhat reflexed, about two-thirds the length of the tergal border and truncate at the end. Articular furrow rather deep but narrow. There is no ad- ductor ridge. Pit for the lateral depressor muscle small and very close to the edge. The tergum is broad, flat, with fine, sinuous growth-ridges exter- nally, the carinal margin much shorter than the scutal, and making with it an angle decidedly less than a right angle. Articular ridge low and close to the scutal margin. Spur short, very close to the scutal border, more than half the width of the valve, its end ob- liquely truncate. The labrum has three teeth on each side of the median notch (fig. 76a). The palpi have an irregular row of long spines on the face and a double or triple series of short ones along the upper margin (fig. 76c). The mandibles have five teeth, the lower one more or less united with the lower point (fig. 7G&). i See P. S. Pallas, Eleuchus Zoophytorum, 1766, p. 198. 240 BULLETIN 93, UNITED STATES NATIONAL MUSEUM. The maxilla has an even edge, armed with eight large spines, below the last a group of short spines. There are unusually long bristles behind the spines (fig. 76d). The first cirrus has strongly unequal rami, the shorter ramus of seven segments (longer ramus broken). The second cirrus has rami of 10 and 7 segments, the anterior ramus longer by about 4 segment. The third cirrus has 12 and 9 segments, unequal as in the second. Fourth to sixth cirri are similar. The sixth has segments with four pairs of spines, lower pair quite small. None of the cirri have any " teeth " or spinules. The penis is decidedly longer than the last cirri, closely annnlated, with a very few short hairs near the end. There is no basi-dorsal point. FIG. 76. — BALANUS SCANDENS. a, LABRUM. Z>, MANDIBLE, c, PALPUS, d, MAXILLA. This species stands near B. cymbiformis Darwin and B. proripiens Hoek. In both of these species the carinal margin of the tergum makes a right angle with the scutal margin. In B. scandens the angle is acute and the valve is narrower. In B. proripiens and presumably in B. cyinbiformis the rostrum is elongated and touches the supporting stem, as usual in Conopea, whereas in B. scandens the rostrum is not especially lengthened and is lifted high above the support. B. proripiens has "teeth" on the third and fourth cirri, but there are none in B. scandens. The cirri of B. cymbiformis are unknown. These characters seem sufficient ground to forbid a refer- ence of the Japanese species to any of the described forms. B. cymbiformis and B. proripiens seem to be very closely related to one another. The latter has a somewhat less broad tergum and the articular ridge of the scutum is better developed. B. proripiens THE SESSILE BARNACLES. 241 and B. scand'ens are known from single specimens, B. cymbiformis by three. Genus ACASTA Leach. 1817. Acasta LEACH, Journal de Physique, vol 85, p. 69. 1854. Acnsta Leach, DARWIN, Monograph, p. 302. Compartments six, thin, not porous, weakly attached together and to the basis; all except the carina provided with radii. Base not porous, calcareous, flat, or cup-shaped; form globose or acorn-shaped, the basal contour rounded or oval, not produced in the carinorostral axis; opercular valves and mouth parts as in Balanus; fourth cirri armed with stout, short, erect spinules or recurved teeth. Living embedded in sponges or crelenterates. Type. — ^-1 cast a, spongites.1 Acasta is to be regarded as a group derived from Armatobalanus, from which it differs by adaptations consequent upon life in sponges. These adaptive features are of quite secondary value, as Darwin rec- ognized ; but they are nevertheless conspicuous, and have secured for it recognition as a genus. So long as we recognize that Acasta is of no greater taxonomic rank than the subgenera of Balanus, I agree with such good authorities as Darwin, Gruvel, and Hoek that it is an advantage to retain it as a genus; the more because Balanus will sooner or later be dismembered to form several genera. The armature of teeth on the fourth cirri was first observed by Darwin, and supposed to be peculiar to Acasta; but it is now known that many Balani are similar in structure. Membranobalanus has entirely homologous structures, and those of Armatobalanus and the Balanus trig onus group are similar, though in some forms it is the third cirrus which is chiefly modified. It would not be amiss to speak of Membranobalanus as an Acasta with membranous basis, just as Semibalanus is a Balanus with membranous basis. Darwin described nine species, of which one is known only as a fossil of the British Crag. Twelve species and one subspecies have been described since his monograph appeared.2 The following 21 species are now known, those represented in the United States National Museum marked with an asterisk : *A. spongites (Poli), 1795. Europe; Mediterranean; South Africa. A. sulcata Lamarck, 1818. Australia. *A. cyathus Darwin, 1854. Madeira ; West Indies. A. undula&a Darwin, 1854. Coralline Crag, Sutton. 1 Leach gave an unmistakable diagnosis of Acasta, but mentioned no type. Subse- quently he described A. montayui (=A. spongites). - Amalthea coxl Sowerby, Proc. Malac. Soc. London, vol. 8, p. 17, pi. 1, figs. 9-11, seems to be the basis of an Acasta. See Hedley, Proc. Linn, Soc. N. S. Wales, vol. 33, 1908, p. 468. 242 BULLETIN 93, UNITED STATES NATIONAL MUSEUM. A. fischeri Locard Miocene, Corsica. A. muricata Seguenza Pliocene, Sicily. A. sarda De Alessandri, 1895. Oligocene, Sardinia. A. fornue De Alessandri, 1897. Miocene, Italy. A. schafferi De Alessandri, 1910. Miocene, Austria. A. glans Lamarck, 1818. Australia. A. Icevigata Gray, 1825. Red Sea; Philippines. A. fenestrata Darwin, 1854. Philippines. A. pui'i>urata Darwin, 1854. East Indies. A. sporlllus Darwin, 1854. Suln Islands. A. scutlcosta Weltner, 1887. Carthagena, Spain. A. striata Gruvel, 1901. Atlantic, 400 meters. A. funiculorum Annandale, 1906. Gulf of Manaar, Ceylon. *A. ja.powca Pilsbry, 1911. Japan. *A. dofleini Kriiger, 1911. (Japan ?) ; Philippines. *A. pectmlpes Pilsbry, 1912. Philippines (+ A. nitida Hoek, 1913. Java Sea). *A. idiopoma Pilsbry, 1912. Philippines. A. conica Hoek, 1913. Macassar. Besides the species starred in the above list, I have been able to study specimens of A. glans,, A. sulcata and A. Icevigata, in the col- lection of the Academy of Natural Sciences. The distribution of the genus Avill probably be much extended when the sponges of some extensive coasts are examined for barn- acles— such as east and west Africa and west America. Most of the species now known inhabit the shores and archipelagos between Japan and South Australia, with the most intense speciation about the middle of this region. ACASTA SPONGITES (Poli). 1795. I.epas spongitcs POLI, Testacea utriusque Siciliee, p. 25, pi. 6, figs. 3-6. 1854. Acasta spongitcs Poli, DARWIN, Monograph, p. 308, pi. 9, figs. la-Id. (See for synonymy.) Distribution, — British Islands to the Mediterranean ; Cape of Good Hope (Darwin). The tergum of a specimen from Exmouth is figured (fig. 77). U. S.N.M. Cat. No. Locality. Collector or donor. West Ross Lou^h Sheildaig, Scotland J. 0. Jeffreys, 1843. 120S6 Exmouth south coast of Devon J G. Jeffreys, 1831. 12074 Cornwall Do. Weymouth Do. 12101 12107 >No locality probably English Do 12135 Sicily I. Lea collection. THE SESSILE BARNACLES. 243 ACASTA JAPONICA Pilsbry. 1911. Acasta spongites japonica PILSBRT, Bull. Bur. of Fisheries, vol. 29 (Document No. 739), p. 80, pi. 16, figs. 1-9. Type.—Q-At. No. 38681, U.S.N.M., from Albatross station 4936, off Kagoshima Gulf, Japan, in 103 fathoms, embedded in a sponge. In the absence of specimens of A. spongites for direct comparison, I described this as a subspecies of that European form. Having now studied a long series of the latter, I have reconsidered the matter and believe that the Japanese form is specifically distinct. It is larger than A. spongites; the shape of the tergum is quite different and it FIG. 77. — ACASTA SPONGITES, EXMOUTH, TERGUM. FIG. 78. — ACASTA JAPONICA, TERGDM OP TYPE. has an external depression or furrow to the spur. In A. spongites there is no furrow, but the flat spur-fasciole is bounded by lines. As there seems to be no figure of the exterior of the tergum of A. spongites I am illustrating it here for comparison with that of A. japonica, both figures being drawn to the same scale. The sculpture of the scutum is stronger in A. spongites, the longitudinal grooves more emphatic. In A. japonica the longitudinal sculpture is of nar- row raised threads. Finally, the proportions of the valves are dif- ferent. In A. spongites the length of the tergum is but slightly more than three-fourths that of the scutum. In A. japonica it is seven- eighths. The breadth of the tergum is less than that of the scutum in A. spongites, but in the Japanese species both valves have the same maximum breadth (fig. 78). 244 BULLETIN 93, UNITED STATES NATIONAL MUSEUM. ACASTA CYATHUS Darwin. • Plate 57, figs. 1-3. 1854. Acasta cyatlins DARWIN, Monograph, p. 312, pi. 9, figs. 3a-3c. 1906. Acasta cyatlius Darwin, ANNANDALE, Supplementary Report No. 31, on the Cirripedia, in Herdnian's Rep. Pearl Oyster Fisheries of the Gulf of Manaar, p. 144. Distribution. — Madeira; West Indies, west coast of Florida, and near Colon. Darwin's description of this species is as follows: Carinolateral parietes about one-fourth of width of lateral parietes ;* radii wider than the parietes ; basis nearly flat, small ; tergum with the spur trun- cated, half as wide as valve. General npixartinrc. — Color pale pink, or that of flesh; basis remarkably flat and rather small, with the walls above bulging out a little. The radii are very wide, being wider than the parietes to which they belong; the orifice is gener- ally rnther large. The parietes of the carinolateral compartments vary from one-third to one-fourth of the width of the parietes of the lateral compart- ments. Basal diameter of largest specimen .35 of an inch. Internally, the parietes are generally more strongly ribbed than A. spongites. The opercular valves are large, owing to the form of the shell. The scuta present no particular character, and are not distinguishable from those of A. sulcata, but the adductor ridge is perhaps rather more developed. The terga [pi. 57, figs. 15, 2o] are nearly as large as the scuta, and this is an unusual cir- cumstance; the spur is more than half as wide as the valve; it is placed not quite close to the basiscutal angle ; on the carinal side the basal margin of the valve slopes a little toward the spur. I may mention that in several specimens from Madeira the scuta and terga, on one side, had grown to a monstrous thickness. Cirri : These resemble in every respect those of A. spongites, with the remark- able exception that on the anterior ramus of the fourth cirrus several segments were furnished with the beautiful downward curved mandiblelike teeth, as in A. sulcata; but differently from in that species, there were none on the upper segment of the pedicel. I should have thought this an excellent specific char- acter had not these teeth been so extremely variable in A. sulcata. Two American specimens which I dissected show considerable varia- tion in the armature of the cirri; one from near Colon (pi. 57, figs. 1 to 16; text figs. 79, 80a to 80rf), the other (pi. 57, fig. 3; text figs. 80e to 80A), from near the Dry Tortugas, Florida. The labrum has two teeth on one side of the median notch, none on the other (fig. 790). The mandible has four teeth and a truncated or denticulate lower point (fig. 795). Maxilla has a straight edge, armed with 10 spines below the upper great pair, three near the lower angle are larger than the others. There is a tuft of small, short spines below the lower large one (fig. 79*). The first cirri have slender rami of 17 and 9 segments, the anterior ramus nearly double the length of the posterior. THE SESSILE BARNACLES. 245 The second cirri have 10 and 7 segments, anterior rainus longer by about three segments. The segments do not protrude. Third cirri similar to the second, with slightly unequal rami of 11 and 10 segments. The fourth cirri are longer (fig. 80d). The pedicel is rather long. The anterior minus has recurved teeth on the anterior margins of the first to tenth segments, varying in number and size as shown in the figures. There are also several smaller, erect spinules near the an- terior distal part of each toothed segment. These segments bear two or three spines, which arise behind the teeth or toward the inner face of the cirrus, except the upper one, which stands on the front margin. FIG. 79. — ACASTA CYATHUS FROM ALBATROSS STATION 2146. a, C, MANDIBLE. LABRCM. b, MAXILLA. Beyond the tenth segment the anterior rainus is similar to the pos- terior, which has no teeth, the segments bearing three to four pairs of spines. The individual from near the Dry Tortugas (figs. 80e to h) differs from the preceding by having the segments of the fourth to sixth cirri longer, about twice as long as wide. The teeth are not so large, and there are three instead of two on part of the segments. There is also some difference in the number of erect spinules, as shown in the figures, although the general arrangement is not very different. The sixteenth and last toothed segment of the anterior ramus is drawn in figure 80e. The largest individuals seen are from St. Thomas, collected by Robert Swift, in the museum of the Academy of National Sciences. Greatest diameter 12 mm., height 11.8 mm. The color is pale pink. The hollow spines are often forked at the end. 4729°— Bull. 93—16 17 246 BULLETIN 93, UNITED STATES NATIONAL MUSEUM. FIG. 80. ACASTA CYATHDS. «, INTERMEDIATE SEGMENT OF CIRRUS VI. I), TENTH SEGMENT OF CIRRUS IV, ANTERIOR RAMUS. C, FIFTH SEGMENT OF SAME. (/, LOWER PART OF CIRRUS IV ; ALL FROM ALBATROSS STATION 2146. C, SIXTEENTH SEGMENT OF CIRRUS IV, ANTERIOR RAMUS. f, LOWER PART OF CIRRUS IV. ). Locality. Station 2414, near the Dry Tortugas, Fla. (26 fathoms). Station 2140, latitude 9° 32' iiorlh, longitude 79° 64' 30" west, near Colon, C. Z. (34 fathoms). St. Croix No locality Collector or donor. ^4 Ibatross. Do. Pr. Griffith, in I. Lea collection. ( Unlabeled specimens.) Doctor Annandale has reported A. cyathus from the Gulf of Manaar, the shell longer and less spheroidal than the one figured by Darwin, and white instead of pink. He does not mention whether his specimen has the characteristic teeth on the fourth cirri. ACASTA DOFLEINI Kriiger. 1911. Acasta dofleini KEUGEK, Beitrage zur Cirripedienfauna Ostasiens, in Abh. K. Bayer, Akad. Wissensch, Suppl.-Bd. 2, 6 Abhandl., p. 56, pi. 4, fig. BQa-d. Doctor Kriiger does not give the locality of his type, but it wras apparently collected by Doctor Doflein, whose chief collecting was in Sagami Bay, Japan. The Albatross obtained numerous examples from sponges at station D5147, in the Sulu Archipelago, near Saisi, in 21 fathoms. ACASTA PECTINIPES Pilsbry. 1912. Acasta pcctinipes PILSBEY, Proc. U. S. Nat Mus., vol. 42, p. 294. 1913. Acasta nitifJa. HOEK, Si&Oflra-Expeditle, Monographic 31fr, p. 237, pi. 24, figs. 17-19 ; pi. 25, figs. 1-3. Type.— Cat. No. 43473, U.S.N.M., from Albatross station 5276, near Malavatuan Island, off southern Luzon, 18 fathoms. ACASTA IDIOPOMA Pilsbry. 1912. Acasta idiopoma PILSBRY, Proc. U. S. Nat. Mus., vol. 42, p. 29-1. Type.— Cat No. 43466, U.S.N.M., from Albatross station 5254, Gulf of Davao, Mindanao, 21 fathoms. This species and the two preceding will be fully illustrated in a report on barnacles of the Albatross Philippine Expedition. 248 BULLETIN 93, UNITED STATES NATIONAL MUSEUM. Genus TETRACLITA Schumacher. 1817. TetracUta SCHUMACHER, Essai d'un nouveau Systeme des Habitations des Vers testaces, p. 91, type T. squamulosa Schumacher=T. squamosa Brugui&re. 1817. Conia LEACH, Journal de Physique, vol. 85, p. 69, monotype C. porosa. (Monolopus Klein stated to be the same.) 1817. Asemus RANZANI, Opuscoli scientific!, vol. 1, p. 275, no species men- tioned; also vol. 2, 1818, p. 64, for A. porosus (=Lepas porosa Gmelin). 1822. Polytrcma FEKUSSAC, Dictionnaire classique d'Histoire Naturelle, vol. 2, p. 144 (Balanus stalactifcrus Lamarck and squam-osus Bruguiere). Balanidse with four compartments, sometimes externally calci- ned together ; parietes permeated by pores, generally forming several irregular rows; radii either developed or obsolete. Basis flat, irreg- ular, calcareous, or thin or membranous. Labrum notched in the middle. Type. — T. squamosa (Bruguiere). Distribution. — All tropical and warm temperate seas, in the lit- toral zone. TetracUta and the allied genera Elminius, Creusia, and Pyrgoma are apparently to be regarded as Balanoid barnacles which have lost the carinolateral compartments. These compartments tend to dis- appear in some hexamerous barnacles. They are very narrow and do not reach the base in some species of Acasta and Conopca, and are wanting in Balanus (Conopea) cornuta. In TetracUta and several other tetramerous genera it appears that a parallel modification has taken, place. There is a striking resemblance between TetracUta and /Semibalanus, possibly indicating some affinity. Both have a tendency to subdivide the parietal pores, and in both the internal lamina of the wall is ribless. When radii are undeveloped there are still vermiculate ridges representing the septa of the radial edges. These are represented in plate 61, figure le. Schumacher, Leach, and Ranzani recognized and gave names to this generic group in the same year. It is not known which actually published first, but the name given by Schumacher has been preferred by all subsequent zoologists mentioning the group. My field experience with TetracUta is limited to southern Florida, Cuba, and California, where it is an intertidal barnacle, living in a zone above any Balanus of the same localities. From its frequent association with Ckthamalus I presume that it is also a surf barnacle elsewhere. TetracUta has its greatest development in the Philippines and Malay Archipelago. The following three forms are not represented in the National Museum collections : T. squamosa, patellaris Darwin (T. porosa var. patellaris Darwin, Monograph, p. 330) . The type was from a ship in Boston Bay. One THE SESSTLE BARNACLES. 249 specimen in the collection of the Academy of Natural Sciences, Phila- delphia, was from a ship from the East Indies. It is volcano-shaped, with very small orifice; scutum thin, with rather weak crests for the lateral depressor muscle; tergum small and extremely narrow. T. mitra (Lepas mitra Spengler, Skrivter af Naturhistorie Selska- bet, vol. 1, 1790, p. 192, pi. G, fig. 5. From " Niquebar''). T. serrata Darwin (Monograph, p. 334) , South Africa. Close to T. squamosa, but the articular and adductor ridges are united above, inclosing a " cavity which runs to the apex of the valve." Weltner and Kriiger state that there are forms intermediate between serrata J5 and squamosa* This species could not be distinguished by the char- acters given in the keys of Hoek and Gruvel. These keys are also otherwise impracticable. T. purpurascens Wood (DarwTin, Monograph, p. 342). Synonyms: Balamis pi hat us Lamarck. Conia depressa. Gray. Australia ; New Zealand. TETRACLITA SQUAMOSA (BruguieTe). 1789. Balanus sqnanwsiis BRUGUIERE, Encyclopedic Methodique, p. 170. 1790. Lrpas fmiyites SPENGLEB, Skrivter af Naturhistorie Selskabet, vol. 1, p. 189. 1791. Lepas porosa GMELIN, Systema Naturae, ed. 13, p. 3212. 1817. Tetraclita sqnamulosa SCHUMACHER, Essai d'un nouv. Syst. Vers Testae., p. 91. 1854. Tetraclita porosa Gmelin, DARWIN, in part, Monograph, p. 329, pi. 10, figs. lrt-lw, with varieties com munis, niarescens, vlridis, nibescens, and p. 330, var. elegans, patcUaris. 1900. Tetraclita porosa (Gmelin) var. viridis Darwin, BORRADAILE, Proc. Zool. Soc., London, p. 799 (Rotuma). Distribution. — World- wide in tropical and subtropical seas; dis- tribution of the typical form, Japan, coast of China, Philippines, and the Malay Archipelago.1 Six varieties of this species were defined by Darwin. As in the cases of Balanus tintinnabulum and B. amphitrite, he at first thought to rank several of them as distinct species, but was deterred by find- ing various forms uniting characters of twro varieties. After study- ing some hundreds of specimens I am much disposed to rank as species T. rubescens and stalactifera in America, and T. squamosa, japonic a^ and rufotincta in the Old World. While they are varia- ble, I have no reason to think that any of these races intergrade. Yet as the forms of India, South Africa, and Australia are unknown to me, such a course might be premature. Moreover, I have not been able to find time for a thorough examination of the cirri and mouth parts of the several races. 1 Doctor Kriigor has reported T. porosa var. viridis from Sagami Bay, Japan, and the Pescadores, and has figured the tergum and six scuta. The form of the tergum is somewhat unlike the Chinese and Phil- ippine specimens I have seen. 250 BULLETIN 93, UNITED STATES NATIONAL MUSEUM. My studies in the group show that the distribution of the races as here defined conforms to that of mollusks and other littoral animals, each of the marine faunal provinces having its race of Tetraclita. They are not scattered haphazard, as one might suppose from the existing literature. We haA'e no direct means of knowing the type-locality of Bruguiere's type of squamosus. His references, so far as they can be localized, pertain to oriental forms. The terms of his description apply to either the Panamic or the Chinese and Philippine forms, not to the West Indian. He states that the orifice is small, that there is no trace of radii, and " 1'epaisseur de ces valves est tres-considerable, elle egale a la base la moitie du diametre inferieur de la coquille." The opercular valves were wanting in his specimen. It seems far more likely that Bruguiere would have an East Indian than a Panamic barnacle, as oriental shells and barnacles were common in Europe long before his time. The type-specimen was probably lost, for the illustrations pub- lished in the Encyclopedic several years later (pi. 165, figs. 9, 10) were copied from Chemnitz. Under these conditions it has seemed best to consider the common form of China and the Philippine Islands as typical T. squamosa. Gmelin's L. porosa\ was also of oriental origin, so far as can be determined. His very brief account was compiled. Lepas fungites and T. squamulosa were also from eastern sources. Darwin did not assign typical localities for the varieties he described, but inciden- tally he mentioned having var. communis from Pernambuco and the Galapagos Archipelago; var. nrbescens from the Philippine Archipelago, and var. elegans from California. The Galapagos form may be what is herein described as milleporosa. The Philippine record for rubescens must have been based upon specimens with an erroneous locality, or upon some oriental form which I have not seen. It may be noted here that some obvious errors among localities given for barnacles by Darwin may be traceable to specimens from Gum- ing's collection, which is known to have been the source of numer- ous erroneous localities in the literature of mollusks. It is well known that Cuming trusted to his memory for localities, instead of recording them on the labels at the time the specimens were collected or received. KEY TO SUBSPECIES OF T. SQUAMOSA. «\ Inflected occludent margin of the scutum having few (one to three) oblique teeth or folds. Tergum narrow, its width not much over one-third its length, the basal margin sloping to, and almost in line with, the carinal border of the spur. California. ft1. External wall eroded, reddish ; sheath and interior of tergum reddish- purple or tinted T. s. riibescens b2. External wall not eroded, whitish T. s. rubescens, form elegans. THE SESSILE BARNACLES. 251 a". Inflected occludent margin of the scutum broad, with four or five very coarse teeth. Scutum white with purplish clouds and stains, the crests at base strongly developed. Spur of the tergum tapering to a narrow end. Sheath somewhat purplish T. s. japonica a3. Inflected occludent margin of scutum having rather small and close oblique teeth (one to every second growth-ridge of the exterior), their number de- pending upon the degree of erosion of the valve. ?>\ Exterior and sheath, pink; scutum, pinkish or white within; tergum with the basocarinal angle very prominent, the basal margin nearly at right angles with the carinal edge of the rather narrow spur T. s.rufotincta b*. Exterior usually dark, the sheath generally of a greenish shade. Scutum dusky bluish-green, with narrow, multidentate, occludent border; crests in the base weak. Tergum narrow T. squamosa squamosa &'. Exterior nearly white, gray, or blackish ; sheath blackish. Scutum wide, violet-black and white, with strong crests for the depressor muscles. c\ Pores of the wall rather coarse and not extremely numerous ; tergum about half as wide as long, with the spur wide at the end, T. s. stalactifera c2. Similar, but tergum narrower T. s. stalactifera form conflnis c3. Pores of the very thick wall small and very numerous. d\ Width of tergum decidedly less than half its length — T. s. panamensis (72. Tergum as in T. s. stalactifera; scutum white with a purple stain on tergal margin T. s. milleporosa TETRACLITA SQUAMOSA SQUAMOSA (Bruguidre). I am using this name as synonymous with T. p'orosa var. viridis Darwin. It is a rather low, spreading, circular barnacle when grow- ing on a flat surface, the orifice small, sutures obliterated or nearly so, the outer lamina of the wall dark colored or gray, eroded, exposing the filling of the parietal tubes, producing fine, more or less interrupted ridges, which are usually beaded finely. The wall is thick, pores very numerous and small. The sheath usually has a decidedly greenish hue. The radii are represented by very irregular or vermiculate crenulations on the flat radial faces. The scutum is dusky bluish- green, fading on the crest of adductor ridge and toward the basitergal border. Articular ridge and furrow small, in comparison with the West Indian subspecies. Adductor ridge very long, extending nearly to the apex and to the base, not con- fluent with the articular ridge. Inflexed occludent border narrow, set with many small teeth. Crests for the lateral depressor muscle simple ; the crests on the occludent side of the base very weak or wanting. Tergum very narrow, the basal margin sloping toward and nearly in line with the carinal border of the spur. Spur narrow and long, with the end rounded or pointed. This seems to be a very distinct form. I have seen a large number without any tendency whatever to grade into either the Japanese or the East African subspecies. Unfortunately, I have not been able to compare the Tetraclitas of the squamosa group inhabiting India or those of Australia. 252 BULLETIN 93, UNITED STATES NATIONAL MUSEUM. The outer lamina of the parietes is pitted internally, as may be seen by looking in the outer row of basal pores. This produces the dis- tinctly beaded riblets of the worn exterior. The same structure is found in some other subspecies of T. squamosa, but much less dis- tinctly developed. Locality. Collector. Notes. Ch ina . ..... Doctor Emerson I. Lea collection. Kowloon China A Ibairoas Philippine Islands . . Dr. E. A. Af earns . . Balayan Bay Luzon A IbatToss Shore Janielo Bay Luzon ... . . . . ..do . .. Tibi and P*ili Hot Sprinas Albay Luzon Dr E A Mearns Port Binauga Subig Bay Albatross Pucot River. Mariveles .. ... . ..do Catbalogan, Samar ....do On reef. Port Cuyo do Damerug Point, Masbate Dr. Paul Bartsch Maricaban Island A Ibatross On shore. Siasi Island, Jolo do Moronga Island, Jolo do Rapatag Island, Tawi Tawi group do Shore. West Africa ' A varietal form. » A form from West Africa in the National Museum , and Capo Palmas in the collection of the Academy of Natural Sciences of Philadelphia, closely resembles the oriental T. s. squamosa. The specimens seen, about 20, are small, the largest 16 mm. in diameter. The radii are generally distinct, though narrow, ana the eroded ribs of the parietes are conspicuously beaded. The pores are coarse, in two or three irregular rows, and the wall is not very thick, thus ditfering from typical squamosa. The sheath is green. The long adductor ridge of the scutum unites with the articular ridge above, but there is no cavity perforating to the apex, such as is described for T. scrrata. TETRACLITA SQUAMOSA JAPONICA, new subspecies. Plate 58, figs. 1 to 3r/, 1911. Tetrad! t a porosa vai'. nigrescens KRUGER, Beitriige zur Cirripedien- fauua Ostasiens, p. 61, pi. 4, fig. 41c. Type.— Cat. No. 580GO, U.S.N.M., from Ayukawa, Japan. The surface is wholly removed in adults, deep or dark purplish- gray or deep mouse-gray; sutures distinct or obliterated; no crenu- lation on the flat radial faces ; pores of medium or small size ; sheath generally of unusual length, but sometimes short, vinaceous slate to dull violet black. Orifice usually rather large in adults. Scutum with rather inconspicuous growth-ridges. Inside varying shades of slate-violet. Articular ridge small and projecting or re- flexed very little. Articular furrow small. The adductor ridge is strong and extends nearly to base and apex ; a deep but narrow fur- row separates it from the articular ridge throughout. The crests for the depressor muscles are strongly developed. The rather broadly inflexed occludent border has four or five strong, oblique teeth (pi. 58, fig. 3«). The tergum is rather narrow, its median width contained two and one-third to two and one-half times in the length. Externally it has a slight depression running to the spur, which is removed a little from the scutal border; growth-ridges narrow and rather conspicu- ous. Inside nearly white, not bicolored. Basal margin oblique, but THE SESSILE BARNACLES. 253 making a wide angle with the spur. The spur is long and tapers to a narrow end. The scutal border is very narrowly inflexed. The compartments may be separated readily in some individuals, but in others the sutures are calcified and the wall will break through the parietes rather than part at the sutures. The sutural edges, in individuals which part there, are flat and smooth without the irregu- lar crenulations representing radii in T. s, squamosa. In this race the articular ridge of the scutum is longer than in T. s. squamosa-, and not united above with the adductor ridge; the crests at the base are much stronger, the teeth of the more broadly inflexed occludent border are larger and less numerous, and the external sculp- ture is more effaced. There are also differences in the terga and walls. The color is toward purple instead of green. The opercular valves are larger relative to the size of the walls than in T. s. squamosa. I have seen a good many specimens. It seems to be the prevalent form of the species in Japan. Doctor Kriiger reports it (as var. nigrescent} from Tokyo and Sagami Bays and the Pescadores. Locality. Collector. Notes. Ayukawa Japan . A Ibatross Type lot. Yokohama Japan H . Loomis Alia Japan .do Wakanoura, Kishiu Imperial University of Tokyo TETRACLITA SQUAMOSA RUFOTINCTA, new species. Plate 58, figs. 5 to Qa. Type.— Cat. No. 48055, U.S.N.M., from Aden. Distribution. — Gulf of Suez to Zanzibar. The surface is eroded, showing fine short ridges or raised lozenges ; pink (hydrangea pink to pinkish vinaceous of Ridgway) ; sutures often scarcely or not visible; sheath colored like the outside. Wall very thick, Avith many rows of small pores. Diameter 30 to 44 mm. Scutum livid brown and whitish within, adductor ridge well de- veloped, but low, and in the upper part it is low, close to and united with the articular ridge by a callous partly filling the groove. In the lower half of the inflected occludent margin there are 6 to 10 or more short, oblique teeth. Tergum with the basocarinal angle very prominent, the basal mar- gin nearly transverse to the adjacent margin of the spur. Scutal margin only narrowly inflected. This race is readily recognized by the pale color of exterior and sheath, the small pores, the shape of the tergum, and the numerous " teeth " of the occludent border of the scutum. 254 BULLETIN 93, UNITED STATES NATIONAL MUSEUM. I have seen two apparently typical specimens, said to be West Indian, one from " St. Crux, Doctor Griffith, I. Lea collection," the other from St. Thomas, R. Swift, in the collection of the Academy of Natural Sciences, Philadelphia. As both were associated in trays with ordinary West Indian stalactifera, it seems possible that there has been a mixture or exchange of specimens in the 50 years or more they have been in collections. Without further evidence I hesi- tate to add West Indies to the range of the subspecies, as its known habitat is the Red Sea and East Africa. A single large example from Prison Island, Zanzibar, collected by Sir Charles Eliot, 1901, is in the collection of the Academy of Natural Sciences. It differs from the Aden examples by having the oper- cular valves white within. The scutum is wider, with a deeper and wider articular furrow. The tergum has the angle between basal margin and spur less deeply entering, and the scutal margin is broadly inflected below (pi. 58, figs. 6, Ga). Locality. Collector. Notes. Aden, Arabia Ward's natviral science Two groups. Do . establishment. L. M. McCormick Gulf of Suez McAndrew " St. Crux'' Doctor Griffith I. Lea collec- tion. TETRACLITA SQUAMOSA STALACTIFERA (Lamarck). Plate 59, figs. 1 to 5&. 1818. Balamis stalactiferus LAMARCK, Animaiix sans Vertebres, vol. 5, p. 394 (Habite les mers de St. Domingue). 1854. Tetraclita porom var. communis DARWIN, Monograph, p. 329, pi. 10, fig. la (? and It, Ifc). 1854. Tetraclita porosa var. nigrescens DARWIN, Monograph, p. 329, pi. 10, fig. 16. Type. — Presumably in Musee d'Histoire Natural de Geneve, from the island of Haiti. Distribution. — West Indies and American mainland, Florida to southern Brazil ; west coast of Mexico. The surface is typically eroded, dull, and variable in color, dirty white, cream, pale olive-buff, or plumbeous-black, the sheath plumbeous-black (never green or pink even in forms externally light colored). Pores larger and fewer, in the average, than in T. s. squamosa or T. s. rufotincta. Usual diameter of adults from 24 to 30 mm. The scutum is dusky slate-violet, dull violet-black, or raisin black or clouded with these colors internally, with paler or whitish bord- THE SESSILE BARNACLES. 255 ers and adductor ridge. The adductor ridge is very strongly de- veloped, deeply undercut, rather well removed from the articular ridge, but sometimes the space between them is partly filled up above. The articular ridge is rather broad. There are usually five or six strong, oblique teeth on the lower part of the occludent margin, those above having been removed by erosion. The tergum is typically about half as wide as long. The carinal half is dark or dark-tinted, like the scutum, the scutal half and spur white within. The basal margin forms an angle with the spur. The spur is moderately wide, with a very obliquely truncate end. The great variation in color led Darwin to define a var. nigres- cens — "Outer lamina of shell almost wholly removed; the portion preserved and the exposed parietal tubes very dark purple or inky black." I have been unable to satisfy myself that this form is racially distinct from the light colored and gray forms. The opercular valves are similar in all. Form floridana: The only deviation of note observed among the specimens seen is in a large lot from the rocks at Lake Worth Inlet, Florida. In these the young individuals, sometimes up to 20 mm. diameter, preserve the surface, which is finely and evenly ribbed. The largest individuals, 25 mm. in diameter, have lost the outer layer. The scuta are pale, only tinted with violet, and the terga, also pale, are decidedly narrower (pi. 59, figs. 6-66). On the Pacific coast there is a form of T. s. stalactifera ranging from Cape St. Lucas, Lower California, to Nicaragua (pi. 59, figs. 5-56, Mazatlan). The color, rather coarse pores, and characters of the opercular valves seem to be the same as in Antillean examples. There is a good deal of variation in the size of the pores, even between individuals of the same group and having the opercular valves practically identical. Plate 59, figure 4, from San Juan del Sur, Nicaragua, illustrates this variation. In an old stock, such as this, which has been separated from its Antillean relatives without much change since the Oligocene or Miocene, it is natural that there should exist a number of collateral varieties, resulting in hetero- geneous colonies. There are also several incipient geographic races. Form confinis: A lot taken by the Albatross at St. Georges Island, in the Gulf of California, (pi. CO, fig. 2), resembles T. s. mitteporosa and the Lake Worth Inlet form floridana by having the terga de- cidedly narrower than in typical stalactifera and the spur projects very shortly below the basiscutal angle. The articular ridge of the scutum is narrower, and the articular furrow makes a shallower bay below it. The eroded exterior is gray or cream. This is probably a local race of the Gulf, which may be called form confiwis (fig. 81). 256 BULLETIN 93, UNITED STATES NATIONAL MUSEUM. Locality. Collector. Notes. Bahamas B A. Bean Lake Worth Inlet Fla H. A. Pilsbry Voriaflofidana. Porto Rico U. S. F.C St Thomas Barbados Lieut. C. L. Fitzgerald. Santa Marta, Colombia R. A. Dr. Ainos P. Brown Coll. A. N. S. Phila. Santa Catherina, Brazil I. Lea collection. Cape St. Lucas, Lower California Do Dr. E. Palmer J. Xantus San Benedicito, Lower California do St. George's Island, Gulf of California A Ibalrosx Form confinis. Mazatlan Mexico P. Bartsch FIG. 81. — TETRACLITA SQUAMOSA STALACTIFERA FORM CONFINIS. a, c, SCUTA AND ft, d, TERGA OF TWO INDIVIDUALS FROM ST. GEORGES ISLAND, GULF OF CALIFORNIA. TETRACLITA SQUAMOSA PANAMENSIS, new subspecies. Plate GO, figs. 3-3&. 1909. Tetradita porosa (Gmelin) PILSBRV, Proc. U. S. Nat. Mus., vol. 37, p. 64, pi. 16, fig. 2. Type.—Cai. No. 58061, U.S.N.M., from Panama. Distribution. — Panama to Peru. Form, thick wall, small orifice and fine pores as in T. s. milleporosa, the external color gray or tea green with light purplish-gray stains, the sheath slate-violet to dusky slate-violet. Diameter 30 to 40 mm. «/ Scutum, very similar to that of T. s. stalactifera; often whitish in the middle. Articular ridge and furrow narrow and small. Ad- ductor ridge strongly developed, arcuate and long. Tergum decidedly narrower than in stalactifera or miNcporosa. I have seen a considerable number from Panama. While related to T. s. milleporosa and T. s. stalactifera, it has a rather distinct aspect, somewhat like typical T. squamosa. Locality. Collector. Notes. Panama C. B. Adams Ecuador or Peru . . . Dr. W. II. Jones, U. S. Navy. Payta, Peru do Figured, Proc. U. S. Nat. Mus., vol. 37, pi. 16, fig. 2. THE SESSILE BARNACLES. 257 TETRACLITA SQUAMOSA MILLEPOROSA, new subspecies. Plate 60, figs. 1 to Id. Type.—G^i. No. 58059, U.S.N.M., from Albemarle Island, Gala- pagos. The form is often lower, more spreading than usual, the orifice very small. External lamina wholly eroded, exposing the fine, short, scalelike upfilled pores ; sutures usually wholly obliterated externally, calcified. Walls very thick, the pores very small and numerous. Ex- ternal color ivory yellow or with a grayish tone, the sheath dark varley's gray or violet-slate. Diameter 46 mm., height 16^ mm. The opercular valves are very small. Scutum short and broad, white within, stained with dull purple on the articular rib and at the base of the occludent margin. Articular rib not so strong as in sta- lactifera. Adductor ridge strong, parallel to the rounded basitergal border, approaching the articular ridge above, and separated from it by a superficial groove only. The tergum is shaped much like that of T. s. xtalactifem, the spur being wide with oblique end; but the carinal side of the valve is somewhat narrower than stalactifera, the scutal side wider. Related to panamensis by the unusually thick wall, which is so calci- fied that it can not be broken along the sutures; but the tergum is shaped like that of stalactifera. TETRACLITA SQUAMOSA RUBESCENS Darwin. Plate 61, figs. 1 to le. 1854. Tetraclita porosa var. rubcscens DARWIN, Monograph, p. 329, pi. 10, fig. 1& (? and I/, 1m). 1854. Tetraclita porosa var. elcgans DARWIN, Monograph, p. 330, pi. 10, fig. Id. Distribution. — Farallones, California, to Cape St. Lucas, Lower California. The surface is dull, eroded, roughened like thatch, varying from deep hellebore red to livid brown, sometimes with a gray-white zone at the base, where it is less deeply eroded in some specimens ; sheath colored like the exterior. The pores are larger than in typical squa- mosa. Scutum but little cut oil at the basitergal angle, and with the adductor ridge strongly developed; white below the adductor ridge, corinthian purple or deep hellebore red above it. The occludent mar- gin has only one to three very long, very oblique teeth. Tergum is extremely narrow, its greatest width but little exceed- ing one-third of the length ; carinal part of the base steeply sloping, nearly in line with the adjacent border of the long spur. Crests for the depressor muscles strongly developed. Corinthian red, fading to white at end of the spur. 258 BULLETIN 93, UNITED STATES NATIONAL MUSEUM. Large specimens reach a diameter of 42 mm. I have seen others, containing eggs, not more than 11 mm. in diameter. Darwin did not give the distribution of rubescens, but his figure and description apply perfectly to the California!! race defined above, for which I use his name in a restricted sense. Reports of rubescens from other regions were doubtless founded on other races of some- what similar color or upon erroneously localized specimens. T. s. rufotincta is paler, with finer pores, producing finer external sculp- ture; it has a differently shaped tergum and numerous short teeth on the occludent border of the scutum. It is not closely related to the Californian race. Form elegans Darwin (pi. 61, fig. 2). Outer layer of the wrall preserved, except sometimes near the summit ; white under a cream- color or cream-buff epidermis, which, when perfectly preserved, bears close concentric fringes of short, delicate hairs; strongly ribbed, the ribs crossed by fine concentric growth-ridges. Sheath reddish in some examples, and these usually show reddish spots where eroded near the orifice, and if filed, a red layer is found under the white, caused by the colored filling of the pores. Some individuals, however, are truly albino, without red in the sheath or pores, and others show only a few small red spots on the sheath. The opercular valves are like those of rubescens. The largest specimens seen are 20 mm. in diameter. The form described as var. elegans by Darwin does not seem to be separable from rubescens, as there are some transitional individuals. It appears to be a form, perhaps an incipient race, in which the cuticle, with the underlying whitish outer layer, are persistent up to a certain size, as in the Lake Worth Inlet form of squam>osa, noticed on p. 255. It is not a stage passed through by all individuals of T. s. rubescens, as I have seen typically eroded and colored specimens only 11 mm. in diameter. The exact status of elegans must be determined by observations by those who have opportunity to study and collect them. Locality. Collector. Notes. Farallone Islands, Cal Pacific ( !rove , Cal J. E. Benedict San Pedro Cal San r)iogo Cal C R. Orcutt. Do Dr. Palmer.. . South end Cerros Island Lower California Albatross With form clcgans. "WestCoast" Catalina Island, Cal Form clcgans. Point Loma San Diego Cal C. R. Orcutt Do. No locality; on Mytilus californianus Conrad Do. Cape St. Lucas, Lower California Do. THE SESSILE BARNACLES. 259 TETRACLITA RADIATA (Blainville). Plate 61, figs. 3-3c, 4. 1854. Tetraclita radiata Blainville, DAKWIN, Monograph, p. 343, pi. 11, figs. 5a-5d. Distribution. — West Indies ( ? also New South Wales and Suma- tra). This was described by Danvin as follows : Shell white, with numerous approximate longitudinal ribs ; radii broad, with their summits slightly oblique, internally porose ; tergum with the articular ridge extraordinarily prominent, with the spur not joined to the basisculal angle. The white color, the narrowly and closely ribbed parietes, and the broad radii give this species an aspect by which it can be easily recognized. The large size of the tergum in comparison with the scutum is a further characteristic mark of this species. Unlike most Tetraclitas, it has often been found on ships. Specimens in the United States National Museum were found grow- ing on Balanus tintinnabulum antillensis, Cat. No. 2031, taken from the bottom of a Cape Cod whaler from the West Indies. There are others in the collection of the Academy of Natural Sciences of Phila- delphia from St. Thomas. TETRACLITA COSTATA Darwin. 1854. Tetraclita costata DARWIN, Monograph, p. 339, pi. 11, figs. 2a-2c. Type. — British Museum, from the Philippine Archipelago. Specimens are in the collection from " East Indies," Isaac Lea col- lection, and Tataan Island, Tawi Tawi group of the Sulu Archipelago, Albatross. TETRACLITA CCERULESCENS (Spengler). 1790. Lepas coerulescens SPENGLEE, Skrivter af Naturhistorie Selskabet, vol. 1, p. 191. 1854. Tetraclita ccerulescens Spengler, DARWIN, Monograph, p. 3 1'J, pi. 11, tigs. Tataan Island, Tawi Tawi group of the Sulu Archipelago, Alba- tross. Zamboanga, Mindanao, E. A. Mearns. TETRACLITA VITIATA Darwin. 1854. Tetraclita vitiata DARWIN, Monograph, p. 340, pi. 11, figs. 3«-3e. Tataan Island, Tawi Tawi group, Sulu Archipelago, Albatross. TESSEROPORA, new submenus. Tetraclita with a single row of parietal pores. Type. — T. rosea Krauss. Darwin has noted that the pores in the walls of Tetraclita^ become more numerous with age, and at a very young stage there is but one row. The recent species for which this subgenus is proposed, is to be 260 BULLETIN 93, UNITED STATES NATIONAL MUSEUM. regarded as an unprogressive form, which retains characters of the ancestral stock of the genus, elsewhere found only in an early stage of development. The Italian Oligocene species, TetracUta isscli De Alessandri,1 be- longs to this group and is closely related to T. rosea. TETRACLITA ROSEA (Krauss). Plate 58, fig. 4. 1848. Conia rosea KRAUSS, Die Siidafrikanischen Mollusken, p. 136, pi. 6, fig. 28. 1854. TetracUta rosca Krauss, DAKYVIN, Monograph, p. 335, pi. 10, figs. 3a-3d. Distribution. — South Africa ; Australia. A single large specimen of this species in the National Museum is labeled " Orange Harbor," no doubt erroneously. No collector given. This specimen is figured (pi. 58, fig. 4) to show the features of the pores. It is 25 mm. in diameter. There is a series in the collection of the Academy of Natural Sciences of Philadelphia from Richmond, near Melbourne, Victoria, collected by Mrs. Agnes F. Kenyon. Genus ELMINIUS Leach. 1825. Elminius LEACH, Zoological Journal, vol. 2, p. 210. 1854. Elminius Leach, DARWIN, Monograph, p. 345. Barnacle conic or cylindric; compartments four; parietes not porous ; basis membranous. Type. — E. kingii Gray. Distribution. — Austral in both hemispheres; littoral. Elminius differs from TetracUta by the absence of pores in the parietal walls. It holds such a relation to TetracUta as CJurona to the typical Balani. TetracUta is a more evolved genus. Leach did not mention a species in his table defining this genus. In fact no species had then been described. I am selecting E. kingii, the first species described, as the genotype. ELMINIUS KINGII Gray. 1831. Elminius kingii GRAY, Zoological Miscellany, p. 13. 1831. Elminius leachii KING and BRODEKIP, Zoological Journal, vol. 5, p. 334. 1854. Elminius kingii Gray, DAKWIN, Monograph, p. 348, pi. 11, figs. Qa-Qe. 1911. Elminius kingii Gray, ORTMANN, Princeton Patagonian expedition, p. 637. 1914. Elminius kingii Gray, STEBBING, Proc. Zool. Soc., London, p. 376. Distribution. — Falkland Islands, Tierra del Fuego, Chiloe (Dar- win). Darwin describes it as follows: Shell smooth, gray, or dirty white ; radii broad, smooth edged. Scutum with- out an adductor ridge. Tergum with the spur distinct from the basiscutal angle. Scutum and tergmn sometimes calcified together. > Palceontographia Italica, vol. 12, 1906, p. 318. THE SESSILE BAKNACLES. 261 The barnacle is thin, the compartments rather easily separated. They are sometimes more or less roughened, but not ribbed or plicate. The thin basal edge is not crenulated, but there are sometimes some fine vertical striae within the edge. " The scuta are remarkable for not having any adductor ridge or crests for the depressor muscles." There is a cylindrical specimen in the United States National Museum from the Isaac Lea collection, without locality. ELMINIUS PLICATUS Gray. 1854. Elm Inins plicalus Gray, DARWIN, Monograph, p. 851, pi. 12, figs. 2«-2/. Distribution. — New Zealand. Two specimens without opercular valves. Also two from " Orange Bay," with Tetraclita rosea; no col- lector given, and locality doubtless erroneous. Two other species of Ehninius have been described from New Zealand, E. xinuatus and E. rugosus Hutton,1 and two from Aus- tralia, E. simplex and E. modestus Darwin. Professor Grtivel has described a very small form from the breakwater at Ponta Delgada, San Miguel, Azores, as E. cristaUinus. This is the only species known in the Northern Hemisphere. Genus CREUSIA Leach. 1854. Creiisia Leach, DARWIN, Monograph, p. 375. Darwin describes this genus as consisting of- Coinpartments four, furnished with radii ; basis cup-forrned ; attached to corals. This genus is represented in the United States National Museum by five small specimens on a bit of coral, I. Lea collection. No locality is recorded. Darwin records the single species recognized by him, Greusia spinulosa Leach, from both the West and East Indies. No definite West Indian locality is given. Genus PYRGOMA Leach. 1854. Pyrgoma Leach, DARWIN, Monograph, p. 354 (see for synonymy, etc.). 1838. Duplocona SCHLUTER, Kurzgefasstes systematisches Verzeichuiss meiner Conchyliensaruinlung, p. 38, for D. UevigaM Schliiter ( =Balanus tl uploconus Lamarck ) . According to Darwin, this genus possesses a "shell formed of a single piece; basis cup-formed or subcylindrical, attached to corals." Pyrgoma is considered a further development of Creusia, in which the four compartments have become wholly concrescent. i Trans. N. Z. Inst., vol. 11, 1879, p. 328. 4729°— Bull. 93—16 18 262 BULLETIN" 93, UNITED STATES NATIONAL MUSEUM. Few of these barnacles are in the National Museum, evidently be- cause the corals and millepores of the collection have not been exam- ined for them. No species is positively known from American seas, but P. stokesii (Gray) Darwin has been found upon Agaricia agaricites, believed to be West Indian, and P. cancettatum Leach was found on a Gemmipora, probably West Indian, but perhaps Pacific. PYRGOMA ANGLICUM Sowerby. Cat. No. 12072. Exmouth, England, from the Jeffreys collection. PYRGOMA CRENATUM Sowerby. Jeffreys collection and I. Lea collection ; one specimen in each ; no locality. Subfamily CHELONIBIIN^FG Pilsbry. BalanidcT, in which the sheath extends to the base and forms the whole inner wall of the body-chamber. The sutures uniting rostral latera and rostrum into a composite rostral compartment are usually discernible. Compartments essentially porose, though often second- arily filled up, always conspicuously lamellate at the basal edge. Basis membranous. The opercular valves are much smaller than the orifice; the articular ridge of the scutum is chitinous. This seems to be a -group of at least as high systematic rank as the Coronulinre. It has a primitive character in the incomplete con- crescence of the elements of the composite rostrum, but in other re- spects is decidedly specialized. The reduced opercular valves resem- ble those of the Coronulina3 superficially, but differ in their articula- tions, so that no direct relationship is to be predicated from them. It appears that this reduction is connected in some unexplained way with their habits, since it occurs in all genera living on vertebrate animals. The specialization of the wall is also adaptive, but the resemblance to the whale barnacles is merely superficial, as Darwin has shown. The retention of a primitive character — the incomplete union of the rostrum and rostral latera — is of much greater systematic value in the highly evolved family Balanidse than the same feature is in the more primitive Chthamalidae. Genus CHELONIBIA Leach. 1817. Chelonibia LEACH, Journal de Physique, vol. 85, p. 68. 1818. Coromda LAMABCK (part), Animaux sans Vertebres, vol. 5, p. 385. 1825. Astrolepas Klein, GKAY, Annals of Philosophy, new ser., vol. 10, p. 105. 1854. Chelonobia DARWIN, Monograph, p. 382. THE SESSILE BAKNACLES. 2G3 Compartments generally extremely thick, six, but the rostrum is composed of three very intimately united compartments, the sutures visible internally and in Avorn specimens also on the outside. Parietes porous (septate), but sometimes filled up solidly nearly to the bases of the septa. Basis flat, membranous; opercular valves narrow, not nearly closing the orifice, the scuta and terga united by a chitinous articular ligament (pi. 62, fig. 6). Labrum having a long row of teeth and a median notch in the margin. Third pair of cirri long, but structurally like the second; later cirri long, having seg- ments with two pairs of spines, with little tufts of fine spines between. Type. — C. testudinaria (Linnaeus). Distribution. — Tropical and temperate seas, on turtles, crabs, and manatees. Pliocene of Grand Canary and Italy. This group retains a primitive character in the incompletely con- crescent rostrum and rostro-lateral compartments. The sutures may be traced on the inside and in worn individuals externally. It is a transition from the octomerous stage to the hexamerous. In other respects it is rather highly specialized. In the least modified species, C. patula, the structure of the Avail reminds one of Balanus, but I venture the opinion that the resemblance is probably due to con- vergence, the structures being homoplastic. The more specialized species are admirably adapted to the rough conditions of existence on the backs of sea turtles, the Avails being enormously thickened and the stature low. They have a superficial resemblance to the whale barnacles, Coronula. C. testudinaria is attached superficially, and when removed the turtle shell is found quite smooth and uninjured. It is the same with C. patula on crabs. In C. caretta the groAving peripheral edge cuts into the turtle shell, Avhich commonly covers or curves up over the edges of the barnacle. DarAvin quite appropriately compares this penetrating POAVCT of the barnacle to that of growing roots. Clielonobla patella (Ranzani)1 is evidently a pen error for C. patula. The f olloAving fossil species have been described : G. hemisp/iccrica Rothpletz and Simonelli,2 Pliocene of Grand Canary; C. emixpha- rica De Alessandri, 1906. C '. dcpressa Seguenza, 1875, Pliocene of Sicily. C. capellinii De Alessandri,3 Miocene and Pliocene, Italy. All of them are of the testudinaria type, and therefore afford no information on the phylogeny of the genus. The recent C. patula is the most primitive of the known species in structure. 1 Zoologischer Anzeiger, vol. 38, p. 461, November, 1011. - Zeitschrift deutsch. Gool. Ges., vol. 42, 1891, p. 724, pi. 36, fig. 2. 3 Palaeontographica Italica, vol. 12, 1906, p. 313. 26-1 BULLETIN 93, UNITED STATES NATIONAL MUSEUM. KEY TO RECENT SPECIliS OF CHELONIBIA. a1. Walls heavy, the compartments thick and strong; radii narrow; septa very numerous ; living on turtles or on the manatee. ft1. Radii rather narrow and well sunken ; cavities in the parietes between the basal septa rather deep. c1. Radii usually notched on the sides, sometimes smooth ; parietes not ribbed or longitudinally folded, the peripheral edge not lobed or in- cised C. testudinarin. c2. Parietes ribbed or folded, at least near the edge ; radii usually quite without notches. d. Parietes with coarse ribs, subdivided near the periphery C. •inanati. d2. Lower part of parietes plicate; periphery lobed C. in. lobatibasis. d3. Parietes plicate at the edge, showing a few small, loop-like incisions in the base C. m. ercnatihnnis. b2. Radii not developed, or narrow; pa rides xolidly filled itp nearly to tlic base, the septa much interrupted. Shell extremely massive and heavy C. carctta. a2. Thin and light, the outer lamina and septa of the wall very thin, cavities between septa not at all lilled up with calcareous matter. Shell steeply conic, the orifice generally exceeding half the basal diameter; radii broad, smooth, only slightly depressed. Usually living on crabs C. patula CHELONIBIA TESTUDINARIA (Linnaeus). Plate 62, figs. 1-4. 1758. Lepas tentudinaria LINN.EUS, Systema Naturae, ed. 10, p. 668. 1778. Balaniis polythalainius BOCK, Der Naturforscher 12tes Stuck, p. 170, pi. 4, figs. 9a, 9&. 1825. Astroh'pas rotund anus J. E. GRAY, Annals of Philosophy, new ser., vol. 10, p. 105. . Coronula tcstitudinaria Lamarck, CHENU, Illustr. Couchyl., pi. 2, fig. 2. 1854. Chelonobia testudinaria Limueus, DAEWIN, Monograph, p. 392, pi. 14, figs. la-Id, 5 ; pi. 15, fig. 1. 1911. Chelonobia teslmlinaria Lhmreus, KKUGER, Die Cirripedien fauna Ostasiens, p. 57, figs. 121-125 (mouth-parts of specimens from Sagami Bay, Japan). Distribution. — All tropical and warm temperate seas. Pliocene of Tuscany. This species is very widely distributed in tropical and temperate seas, probably \vherever its usual host, the loggerhead turtle, occurs. It is common on our Gulf coast and in the Atlantic as far north as Delaware Bay, but is not often taken farther north. The distinct, star-like radii, usually toothed along the edges, and the rather deep excavation of the parietes between the parietal septa will readily separate this species from C. caretta, which must be rare on our eastern coast. The parietes are not folded or ribbed longi- THE SESSILE BAENACLES. 265 tudinally, and there are no incisions or lobes in the periphery, un- less the two varieties placed under C. mftnati belong to this species. There seems to be but little racial differentiation in C'. testudinaria, though very large series might show more than I can see at present. The Atlantic specimens, as a general rule, have fewer and coarser transverse sutural ridges than those of the Pacific. Rarely they are almost obsolete. When old the wall is usually higher, especially the rostrum, which has a more arched profile; but this is not obvious in smaller examples. The basal septa are often, but not always, thicker. The orifice is sometimes longer, but varies from about one-third to nearly one-half the total length. A specimen of about the maximum size reached on our coast measures 48 mm. in carinorostral diameter, height 18 mm. (pi. C2, fig. 2). The only one I have seen from the Galapagos is veiy large and low, 78 mm. long, 19 mm. high. The body-chamber is less than half of the basal diameter (pi. 62, fig. 1). A similar specimen 60 mm. long was taken in San Bartholome Bay, Lower California. In the Gulf of California and at Cape St. Lucas there may be a small race. At all events, in three lots, about 25 specimens, the maxi- mum length is about 28 mm. (pi. 62, fig. 3). In these, and all west American specimens seen, the transverse ridges in the radii are narrower and slightly more numerous than in Atlantic examples. Locality. Collector. Notes. Dr. Edgar A. Mearns On loggerhead. Point Pleasant N J l Witmor Stone Delaware Bay 'N J l H.J.Mitchell On turtle. Beaufort N C ' L. R. Gibbes East Coast of Florida F. E. Spinner Pcnsacola Fla ..... Silas Stoarns Key West Fla A Ibatross Heilprin expedition Point Fatuoa, Honduras W.H.Sligh On loggerhead. Do. Aluemarle Island, Galapagos Stanford University Gulf of CahToniia On turtle; diameter 28 mm.; San Luis Gon/alez Bay Gulf of California A Ibatross largest 29 rum. diameter. Cape St "Lucas Lower California Diameter 27i mm. Magdalona -Bay Lower California C. R. Orcutt San B'irtholome Bay Lower California A Ibdti'oss Hawaiian Islands ..... Win. Alanson Bryan IVarl Il'irhor O'lhn A ibf-itrofis - - - Carolina Island, Central Pacific1 Ana, Japan Do C. D.Voy H. Loomis Up to OS mm. diameter. i Specimens in the collection of the Academy of Natural Sciences of Philadelphia, the records inserted hero to show its occurrence in the Middle States, etc. CHELONIBIA MANATI Gruvel. 1903. ritrlonnltia nninati GRUVEL, Nouvelle Archives elu Museum d'Histoire Naturelle, ser. 4, vol. 5, p. 11G, pi. 2, figs. 14, 17, IS ; pi. 4, figs. 15, 1G. 1905. Clictonobid itxmaU GRUVKL, Monographie ties Cirrhipedes, p. 207, fig. 2976. Tape. — Museum d'Histoire Naturelle de Paris, from the Congo coast, abundant on skin of Manatus senegalensis. 266 BULLETIN 93, UNITED STATES NATIONAL MUSEUM. This species is related to C. testudinaria, from which it differs by having the sides of the well developed radii not dentate, the parietes having salient longitudinal ribs which subdivide toward the base, and the basal septa are fewer. I do not know that typical specimens of this species exist in any American museum, but there are certain barnacles in the series be- fore me which, while possibly referable to C. testud-inaria as varieties, have some characters of the West African species, and may be noticed here. I am giving names to these forms in order to call attention to their characters which might otherwise be overlooked by those having opportunity of seeing large numbers of turtle barnacles. Their status as races can not yet be considered established. C. in. lobatibasis, new variety. A specimen from Osprey, Florida (pi. 62, figs. 7, 7«) , on Caretta, caretta, No. 2107, Academy Natural Sciences, Philadelphia, has a large orifice and steep walls, which are irregularly plicate or ribbed in the lower half, producing an irregularly lobed periphery. The radii are rather wide, without " teeth." The basal septa are less numerous than in C. testudinccria, and there are rather small, deep cavities between them. Base of sheath as in C. teslndnnn-nt, with many breaches, leaving only wide and narrow pillars. Diameter 23 mm., height 9^ mm. C. m. creriatibasis, new variety. A group of three old specimens (pi. 02, figs. 5, 5«, Cat. No. 48196, U.S.N.M.), from the Isaac Lea collection, locality and station unrecorded, have the orifice very large, the radii partly simple, but a few show very weak traces of teeth. Very close to the base there are numerous inconspicuous folds, and the interstices between these, or part of them, form minute loops, projecting into the septate base. (Seen on the right side in fig. 5.) This rather inconspicuous character is not present in any of the large series of ordinary testudinaria, which has passed under my eye. The parietal cavities are particularly large and evenly developed. The parietal septa are distinctly of four lengths — those extending to the inner wall, those extending half across the cavities, others extending to the inner border of the outer wall, and the shortest series at the peripheral margin. Specimens measure, diameter 43 mm., height 18 mm. ; diameter 37 mm., height 13 mm. The battered summits of the compartments testify to a life of hard knocks, such as falls to the lot of most turtle barnacles. Moreover, some thin laminae adhering to the base are probably from the logger- head turtle. THE SESSILE BAKNACLES. 267 CHELONIBIA CARETTA (Spengler). Plate 63, figs. 5, Or/, 1790. Lcpas carclta SPENGLER, Skrifter af Naturhist, Selskabet, vol. 1, p. 185, pi. G, fig. 4. 1825. Astrolepas tcfttudinaria GRAY, Annals of Philosophy, vol. 10, p. 105. 1840. Balanus chclytrypetes HINKS, Annals of Natural History, vol. 5, pp. 333-4. . Coroniila sulcata CHENU, Illustrations Conchyliologiques, pi. 1, fig. 1. 1854. Chelonobia carctta DARWIN, Monograph, p. 394, pi. 14, fig. 2. According to Darwin — The descending sheath and radiating septa are of very variable thickness and have their basal edges finely dentated. The septa are not continuous from the circumference to the sheath in unbroken plates, but are irregularly divided into separate, often short, portions and even occasionally into mere points. The sheath differs from that of the other two specimens in having loopholes for the entrance of ribbons of corium only on the eight lines of suture, and not, with rare exceptions, in the middle of each compartment. This is evidently due to fewer filaments of corium being here sufficient to supply the less deep inter- spaces between the radiating septa, for in this species there are no flattened cavities or tubes running far up the shell. The inner lamina of the walls can not be here distinguished, for a solid, flat calcareous surface extends from the circumference between the radiating septa to the sheath. The sheath, had it not been from the light thrown on this part by the other species, would have cer- tainly been mistaken for the inner lamina of the walls. Tlie absence of tlie flattened cavities or tubes extending up tlie parietes seems to be the least vary- ing character and serves to distinguish this species from those worn and massive specimens of C. testiiiUnaria, which have narrow and not-notched radii. The opercular valves hardly present any essential difference, compared with those of the other species, but the occludent margin of the scutum is apt to be more sinuous and its rostral end blunter and squarer. The carinal end of the tergum is also squarer than in any common variety of C. tcstudinaria, the external furrow or spur near the carinal margin is very indistinct, and even sometimes is quite absent. Distribution. — Darwin had this species from the west coast of Africa and northern Australia. Doctor Weltner reports it from Vene- zuela, Massaua, and Torres Strait. The Paris Museum has speci- mens from Cape of Good Hope and Saigon. Specimens are in the collection of the Academy of Natural Sciences, Philadelphia, from St. Thomas, West Indies, taken by Robert Swift, and from a logger- head turtle from Delaware Bay, New Jersey, taken by myself. These examples are very small and flat, 13 mm. long, and nearly covered by the shell of the turtle. Equally small examples of C. testudinaria on the same turtle were not at all embedded. Those in the United States National Museum are from " East Indies," I. Lea collection, and Cape Frio, Brazil, collector not recorded. It appears to be chiefly tropical. Records from the central and eastern Pacific are lacking. 268 BULLETIN 93, UNITED STATES NATIONAL MUSEUM. CHELONIBIA PATTJLA (Ranzani). Plate 63, figs. 4, 4a. 1818. Coronula patula RANZANI, Opuscoli Scientific!, vol. 2, pi. 3, figs. 25-28. 1822. Coronula flentulata SAY, Journal of the Academy of Natural Sciences of Philadelphia, vol. 2, p. 325. 1825. Coronula, dcnticula Say, GRAY, Annals of Philosophy, new ser., vol. 10, p. 105. 1825. Astrolepas Items GRAY, Annals of Philosophy, new ser., vol. 10, p. 105. 1854. ChclonoUa patula Ranzani, DAKWIN, Monograph, p. 396, pi. 14, figs. 3a, 3b, 4. Distribution. — Mediterranean and both sides of the Atlantic in tropical and subtropical waters; Australia; Japan. The pale buff or nearly white shell is very light and fragile in contrast with the preceding species. The outer lamina of the wall is thin, the radiating septa are thin, with delicately crenulated edges. The interseptal pores are not filled up, but penetrate to the summits of the parietes. The lower edge of the sheath is reduced to mere pillars. The opercular valves are somewhat narrower than in the other species. Greatest diameter 22 mm., height 8 mm. All of the specimens I have seen attached and others bearing data are or were seated on crabs or Limulus. The types of Say's Coronula dentulata, in the collection of the Academy of Natural Sciences of Philadelphia, are labeled Florida. The single specimen seen from Port Townsend (presumably Washington) was without record of the collector. It has been reported by Gruvel from the Hawaiian Islands, specimens collected by M. Bailleu, 187"). Ranzani'S type was from the Adriatic, on a crab. Locality. Collector. Notes. Cedar Keys Fla Steamer Cache Cameron La - . . . . . L. R.Cary On CaUinectessapidtis Rat hb. To Kas . . ... . . J.D. Mitchell On crab. University of Kansas On Callinectes sapidus. Cape Cajon, Cuba Tomas Barrcra expedition. . . Cat. No. 4SS30. Rio Bayamon above Pa!o Seco, Porto Rico. . Port Townseiid U.S.F.C (Not stated) On Callmcctcs. Locality seems doubtful. Subfamily 1825. Corontilaihr LEACH, Zoological Journal, vol. 2, p. 209 (exclusive of Chelonibia). 1854. Kccoinl sec-lion of ihe stilt family Balaninfe, DARWIN, Monograph, p. 397. 1905. Coronulincp and XenolxiJinihifr GRUVEL, Monographic des Cirrhipedes, p. 8. Compartments six. Scutum and tergum, when present, not over- lapping or articulated together; the terga or both scuta and terga THE SESSILE BARNACLES. 269 sometimes wanting and always much smaller than the orifice they protect. Parietal pores, when developed, in the outer layer only. Basis membranous. Each branchia is composed of two plicated folds. Living attached to marine vertebrates. This group of genera was recognized by Leach and Gray, but they included Chelonibia with the whale barnacles. Darwin elimi- nated Chelon'tbia, showing that its resemblance to the others is merely adaptive and superficial. We owe to him a discussion of the morphology of the group so lucid that no subsequent student has been able to add anything of importance. Darwin did not consider the group of enough systematic importance for subfamily rank ; but systematic values throughout zoology have risen, and the group is now generally held to be a subfamily. Professor Gruvel has sep- arated XenolaJanus as another subfamily, Xenobalanince; but while this genus shows great modification, it is essentially Coronulid, with many characters in common with T-ubicinella. It appears to me that its affinities are obscured by segregating it in a separate subfamily. The number of genera of Coronulinse has been doubled since Dar- win's monograph was published. It is somewhat remarkable that with the exceptions of Ooronula, Platylcpas, and possibly Stomatolepas, all of the genera of Coro- nulina? are monotypic. The wall in Coromilinre is essentially poreless; or at least there are no pores homologous with those of the Balaninoe, which arose, as already explained, by the concrescence of lateral processes on internal ribs. In many Coronulinre there are pores in the oiitcr layer of the parietes, which are wholly independent in genesis from those of BaJanus, and apparently were formed by the deepening and closing over of external stria?. The body-chamber of the shell has the conic form of more normal Balanida3 only in the genus Platylepas. In other genera the cham- ber is cylindric or contracted at the base, reducing the size of the membranous basis. A basis of large area would doubtless be pressed inward by the skin of the host. The genera of Coronulinae form two collateral series, indicating an early split in the stock. The differences between the two series, as well as nearly all those characterizing the genera, are adaptive, being directly related to the modes of strengthening the shell to withstand impacts. In the Coronulid series the parietes have no median sulcus or change of sculpture, and there is never any trace of props or midribs projecting into the body chamber; the oral borders of the integu- ment are produced, forming a "hood." The species are singularly conservative in the selection of hosts. They are known only from Cetacea. 270 BULLETIN 93, UNITED STATES NATIONAL MUSEUM. The Platylepadid series is composed of genera having a midrib within each compartment, produced by a median infolding ; or when this is not present there is externally a median longitudinal smooth area, or interruption of the sculpture, which may be regarded as the vestige of a former mesial infolding which has left this permanent mark upon the external sculpture after the fold itself has utterly disappeared. So far as known there is no oral " hood." In the selec- tion of hosts the species show catholic tastes. While chiefly (and probably in the beginning) turtle barnacles, thej also lire on mam- mals (Sirenia), sea-snakes, and fishes, but not one has yet been found on a cetacean. The genera of these two series follow, closely related groups being bracketed together. Coronulid series. . Coronulinse .Xenobalanus. .Tubicinella. fCryptolepas. [Cetopirus. .Coronula. jTlatylepas. .Platylepadid seri J ICylindrolepas. •fStephanolepaa. [Stomatolepas. KEY TO GENERA OF CORONULIN.E. a1. Body lengthened, having the appearance of a naked pedunculate cirripede, not contained in the cavity of the wall, which is minute, star-shaped, and embedded in the skin of the host. Opercular valves wanting. Xcnob. 271 d*. Form cylindric (hexagonal), the orifice and basis of eqnal size; basal edges of compartments having small toclli, (ho median one largest Ci/linHalanus, Tubicvnella, and Cryptolepas. C. (I'nnlema. lives only slightly embedded in the skin, and it very frequently affords support to the stalked barnacle, C onchoderma auri- funi. C. regince is about one-fourth or more covered by the skin, or in other words, the edges of the barnacle cut into and embed themselves in the skin of the host. Coronulre are disliked by whalers because they dull the knives used in " cutting in." C. diadema is a common and long known barnacle, but C. compla- nata, while known since 1705 or earlier, is comparatively rare in col- lections, and we have little information as to its distribution, and none upon its station or soft anatomy. C. ref/inre has been the rarest species, as no author except Darwin seems to have seen it ; but we now know that its station is on the lip of the humpback Avhale, in both the North Atlantic and the North Pacific Oceans. It is probably not very rare, though being inconspicuous it has not often been collected. KEY TO SPECIES OF CORONULA. a1. Body-chamber shaped like a teacup, the orifice much larger than the basal opening; sheath running nearly to the base of the inner wall; branches of the sutural ribs not symmetrically arranged, the ribs sometimes with- out branches ; opposed sides of the terminal flanges of the ribs crenulated ; radii less than half the thickness of the compartments, leaving a cavity between radii and alje. Subgenus Coronula. 61. Crown-shaped, elevated, the parietes convex, with convex ribs. C. diad etna, p. 273. THE SESSILE BARNACLES. 273 I)1. Convexly conic, depressed, the parietal ribs flat, beautifully bonded ; ribs in tbe base having few, not symmetrical branches C. rcitinu; p. 275. a*. Body-chamber very shortly barrel-shaped or cylindric, the basal opening at least as large as the orifice; sheath decidedly shorter than the inner wall, its basal edge not overhanging; ribs along the sutures, in the base, having several symmetrically arranged branches in adult individuals; radii almost as thick as the compartments; opposed edges of the terminal flanges of the ribs roughened but not crenulate ; form depressed. Subgenus Cctopirns. C. complanata, p. 27G. Pliocene species of Coronula. Coronula barbara Darwin (Monograph, p. 421), of the British Red Crag, is related to G. diadema, but the spaces below the radii are solidly filled up. Coi'onula bifid a 1 has not been very clearly distinguished from C. barbara.'2 Diadema diluviana O. G. Costa3 appears from the figures to be either C. bifida or O. barbara. Coronula ficarazzensis De Gregorio, referred to above under the perfectly useless subgenus Fhtbclcorona, is a form very close to C. regime Darwin; whether identical or not requires a comparison of specimens to tell. CORONULA DIADEMA (Linnaeus). Plate 65, figs. 3, 4. 1767. Lcpas diadcina LINNAEUS, Systeuia Naturse, ed. 12, p. 1109 (see Hanley, The Shells of Linmeus, p. 20). 1776. Lcpas balwnaris O. F. MULLEB, Zoologies Danica. 1'rodromus, p. 250, No. 3024. 1778. Balanus bala'na DA COSTA, Hist. Nat. Test. Brit., p. 251. 1780. Lcpas bala-naris O. PABEICIUS, Fauna Grceulandica, p. 425. 1790. Lcpas balanaris GMELIN, Systema Naturse, ed. 13, p. 3208. 1817. Diadcina rulyaris SCHUMACHER, Essai d'un nouveau Syst. Vers Testaces, p. 91. 1818. Diadema eaiididuin HANZANI, Opuscoli Scientific}, vol. 2, p. 88. 1818. Coronula diadcina Linnaeus, LAMARCK, Hist. Nat. Anim. sans Vert., vol. 5, p. 387. 1825. Polylepas (Diadcina) klcinii GKAY, Annals of Philosophy, new ser., vol. 10, p. 105. — . Coronula diadema Lamarck, CHENU, Illustration Conchyliologiques, pi. 1, fig. 3 ; pi. 2, fig. 3 ; pi. 3, fig. 5. 1854. Coronula diadema Linnaeus, DARWIN, Monograph, p. 417, pi. 15, figs. 3, 3ff, b; pi. 16, figs. 1, 2, 7. 1870. Coronula biscayensis VAN BENEDEN, Bull, de 1'Acad. Roy. des Sci. ties Lettres, et des Beaux-Arts de Belgique, ser. 2, vol. 29, p. 349. No description. 1870. ? Diadema japonica VAN BENEDEN, Bull, de 1'Acad. Roy. des Sci. des Lettres, et des Beaux- Arts de Belgique, ser. 2, vol. 29, p. 354. Named, but not described, from a Japanese drawing. 1 Bronn, Italiens Tertilir-Gebilde, 1831, p. 126. 2 de AlessandH, Palwontographica Italica, vol. 12, 1006, p. 315. 3 Di alcuni Balanidi app. al Regno di Napoli, in Atti Accad, Sci. Napoli, vol. 5, pt. 2, 1843, p. 120, pi. 1, fig. 7. 274 BULLETIN 93, UNITED STATES NATIONAL MUSEUM. 1870. Diadema californica VAN BENEDEN, Bull, cle 1'Acad. Roy. des Sci. des Lettres, et des Beaux-Arts de Belgique, ser. 2, vol. 29, p. 355. No description. 1874. Coronula diadema Linnaeus, SCAMMON, The Marine Mammals of the Northwest Coast of North America, p. 47, pi. 10, fig. 5. 1897. Corointlrt diadema, Linimms, WKLTNER, A^erzeichnis, Archiv fiir Natur- geschichte, vol. 1, p. 254 (distribution). 1900. Coronula diadema Linnseus, WELTNER, Fauna Arctica, vol. 1, p. 302 (distribution). 1903. Coronula diadema Linnseus, STEAD, Proc. Linn. Soc. New South Wales, vol. 28, p. 944 (on Balamoptera, off Cavalli I., N. Z.). The barnacle is crown-shaped, or formed like a short cask, having convex ribs, crossed by narrow, minutely beaded rugae, the opposed lateral edges of the ribs not crenated. Radii very broad, and seen to be very much thinner than the compartments, leaving a large space filled by branches of the ovary between the radii and alie, visible only when the compartments are separated. Orifice very much larger than the basal opening. Terga wanting, or rarely present as minute vestiges. Diameter, 86 mm.; height, 67 mm (Tonga Island). Diameter, 75 mm.; height, 59 mm. (Monterey, California). Diameter, 63 mm.; height, 31 mm. (Unalaska). Diameter, 44 mm.; height, 36 mm. (Unalaska). Diameter, 57 mm.; height, 36 mm. (Bering Sea). The lamellar parietal folds or ribs branch much less freely than in C. complanata. Individuals up to 45 mm. in diameter and evidently adult sometimes have all of the ribs simple, though usually some are forked. The branches appear first on the rostral sides of the sutures; they are not symmetrically developed on both sides of the sutures, as in C. complanata; nor are the branches arranged symmetrically on the two sides of the barnacle. As a general rule, the more spreading individuals have more branches, thus keeping the buttresses evenly spaced at the periphery. The elaborately denticulated radii (pi. 65, fig. 3), are much wider than in C. regince, but they leave a far larger cavity than in C. com- planata. Only a small part of the total height of the barnacle is embedded in the skin of the whale. They are often seated upon it about as close as they can stand. One piece of dried whale skin in the United States National Museum, 26 inches long and averaging nearly 5 inches wide, supports 118 individual Coronulas of all sizes. This is the common wThale-barnacle of the Northern Hemisphere. It is the " whale louse " of the humpback whales, Megaptera. I have found no record of it from other genera of whales. In the Arctic and Atlantic I have seen specimens from Spitzbergen and Disco south to St. Bartholomew, but it is certainly much less abundant southward. THE SESSILE BARNACLES. 275 There are no records from the equatorial and southern Atlantic, Antarctic, or Indian Oceans. In the Pacific C. diadema is widely spread from Bering Sea, Japan, and California south to New Zealand, Tonga, and Chili— practically the whole Pacific Ocean.1 Dr. W. H. Dall notes that " this species has been obtained from the Humpback (Jfegaptcra versabilis) from Bering Strait to the Gulf of California. It is especially abundant on the flippers and on the underlip of these animals." Captain Scammon in his interesting book on Marine Mammals has given a figure of the humpback whale showing the areas chiefly infested with barnacles — the underlip and throat, front edges of the fins, and the flukes. The opercular mem- brane in the living barnacle is brown, the "hood" slightly purplish. Locality. Collector. Notes. Godhiven Di^co Islcuid Greenland Shetland Islands . . ... J. O. Jeffreys.. F. W. True. . ... On lip of humpback; alco- Nova Scotia holic. St Bartholomew West Indies L. Steineger Win. H. Pall . Unalaska . do On Mcgaptem versabilis Mrs. E. H. Harriman . .. Cope. Neih Bay Wash J. G. Swan Month of Uinpcnia River Ore1* . . . - Doctor Holhrook In alcohol. Stanford University From whale; in alcohol. Taylor Do Captain Scammon On humpback. Matrdilena Bay Lower California Albnl ross Tonga Island Ward's natural science es- Dry and in alcohol. (No locality) tablishment. Vinal Edwards On whale skin; in alcohol. (No label) On whale skin. CORONULA REGIN^E Darwin. Plate 64. 1854. Coronula regime DARWIN, Monograph, p. 419, pi. 15, fig. 5; pi. 16, fig. 4. Distribution. — Northern Atlantic and Pacific Oceans, on hump- back wales (Megaptera). Shell convexly-conic or depressed-conic, with flattened parietal ribs having crenated edges and beautifully striated and granulated surfaces (pi. 64, figs. 1, 3). Eadii not exceeding one-fifth the thick- ness of a compartment (pi. 64, fig. 1). Body-chamber cup-shaped, the basis much smaller than the orifice. Eibs in the base branching irregularly, as in C. diadema, not symmetrically on both sides of the sutures as in C. complanata. Terga wanting. Diameter 65 mm.; height 19 mm. (Unalaska). 1 Weltner has materially enlarged our knowledge of the southern range of this barnacle, from the rich series in the Berlin Museum. 276 BULLETIN 93, UNITED STATES NATIONAL MUSEUM. Diameter 48 mm. ; height 19 mm. Diameter 53 mm. ; height 13 mm. By its depressed contour and the flattened ribs of the upper sur- face this species has a superficial resemblance to B. complanaiaj but the narrow radii with a large cavity under them, the crenulated edges of the terminal flanges of the ribs, and their irregular branch- ing, and especially the shape of the body chamber, are characters certainly allying it to C '. diadema. The sculpture is remarkably delicate. From one-fourth to one-third of the whole diameter is embedded in the skin of the whale, so that the barnacle projects very little. The oral opening has a " hood " as in B. diadema,. It was supposed by Darwin to be a Pacific species, but the only definite locality he had was Iquique, Peru, on Mr. Cuming's author- ity. Mr. Gruvel gives the locality Chonos Archipelago, Chile, for a single example in the Paris Museum. It occurs on the lip and per- haps other parts of the whale where the skin is thin and light colored. It appears to be perfectly distinct from both of the old species. About 20 specimens seen. Locality. Collector. Notes. Snooks A nn, Newfoundland F. W. True Lip of humpback whale. Unknown Jeffreys collection Do Unalaska Pall and Baker On beach. Do W. H. Dall . ... On humpback Mouth of Umpqua River, Greg Doctor Holbrook On smooth thin spotted whale skin. CORONTJLA COMPLANATA (Morch). Plate 63, figs. 1, 2, 3, 3a. 1790. Lepas balcnaris SPENGLEK, Skrivter af Naturhistorie-Selskabet, vol. 1, p. 187. 1802. ? Coronula balcenaris DUFKESNE, Annales clu Museum Nationale, vol. 1, p. 473, pi. 30, figs. 2-4.1 1818. Cetopirus baJcenaris RANZANI, Opuscoli Scientific!, vol. 2, p. 87. 1818. Coronula balamaris LAMAECK, Hist. Nat. ties Animaux sans Vertebres, vol. 5, p. 387. 1823. ? Lepas quwquevalvis MAWE, The Linnsean System of Conchology, p. 5, pi. 2, fig. 3.2 1824. Coronula balanaruin BLAINVILLE, Dictionaire cles Sciences Naturelles, vol. 32, p. 380 (obvious error for 1 It is quite possible that the figures publisher! by Dufresne as C. balwnaris arc really C. reyince ; but their identity would have no effect upon nomenclature. 2 I have been unable to decide whether Lepas quinquevalvis Mawe is C. complanata or C. regin, figs. 1, 4 ; pi. 3, figs. 1-4. 1852. Cetcopirus conipldnatus Chemnitz, MOKCI-I, Catalogue Conchyliorum, Comes de Yoldi, p. 67. 1854. Coronuln bahrnarin DARWIN, Monograph, p. 415, pi. 15, figs. 2-2b; pi. 16, figs. 3, o. 1910. Coronula danrini STEBBING, Annals of the South African Museum, vol. 6, pi. 4, p. 57l!, based iipon C. bnhrnaris Darwin. Distribution. — Amboina (Rnmphius) ; New South Wales (Dar- win) ; South Africa (Krauss, Darwin) ; West Africa and Valparaiso (U. S. N. M.) ; Coquimbo and coast of Norway (Paris Museum). C. complanata differs from the other recent species by the broad base of the body-chamber and the very thick radii, in which the beau- tifully laminate edge covers almost the whole sectional area of the compartment, while in the others the laminate edge is restricted, and there is a hollow below it occupied by branches of the ovaries. (See pi. 63, figs. 3, 3i,tus to Chemnitz, who had given a description and characteristic figures;2 but Chemnitz was heterodox in his nomenclature, and therefore Morch must be given as sponsor for the name. The type-specimen is that figured by Chem- nitz. The name C. l>alanarum Blainville seems to me to have been merely a careless slip for baZcenams, for we can hardly suppose that so scholarly a naturalist would intentionally coin a false and inappli- cable name to replace an appropriate one which was certainly well known to him. All codes of nomenclature provide for the elimination of such obvious errors. Genus CRYPTOLEPAS Ball. 1872. Cryptolcpas DALL, Proceedings of the California Academy of Sciences, vol. 4, p. 300. Depressed Coronulina? with the body-chamber shortly cylindric, the parietes bearing radial lamellar folds which are irregularly branched in adults, and are not united into a continuous wall at the ends and above; sheath grooved transversely; radii moderately de- veloped; basis membranous. Opercular valves and oral hood as in Coronula. Type. — C. rachianecti Dall. Distribution. — North Pacific, living embedded in the skin of the California gray whale, Rhachianectis glaucus Cope. Cryptolepas is very closely related to Coronula, more especially to Coronula (Cetopirus] complanata, wrhich is similar in the contour of body-chamber and exterior; but the present genus differs by lacking terminal flanges uniting the radial lamella? into a solid outer wall, though there is sometimes a suggestive approach to that struc- ture. The number of radial lamellas or folds is greater than in Coronula,' there are four complete and two (sutural) half folds on each compartment, as a rule, but exceptional individuals have the number reduced by one or two folds. The branches of the lamellae . du Mus., vol. 1, p. 464. ""Lepas complanata polytJialaiiiia. Balanus polythalamius complanatits," CHEMXITZ, Systematisehes Conchylien Cabinet, vol. 8, 1785, p. 325, pi. 99, figs. 845, 846. THE SESSILE BARNACLES. 279 are irregular in occurrence and arrangement, and many of them do not reach the periphery. Finally, the sheath is grooved transversely, as in Tuli/c'tncUa and Xenobalanug. AVith the exception of the grooves of the sheath, nearly all of these differences from Coronula are degenerative changes apparently cor- related with the protected station of the animal embedded in the skin of the host. An outer wall is no longer needed. The branches of the ribs, which in Coronula serve as buttresses, have become short and extremely variable. In fact, the form and size of the ribs them- selves vary remarkably. The increase in number of parietal ribs or folds over that in Coronula complanatn probably took place through the accelerated branching of suturai folds, bringing the lower branches down to the circumbasal border, where they appear as primary folds. The circumstances are similar in many phyletic series of shells, in which external ribs become emarginate, then bifid, and finally separate ribs. It may be concluded, therefore, that Cryptolepas is a derivative of the Cetopirus branch of Coronula, and that its differential charac- ters are mainly due to the degeneration of protective and strengthen- ing structures, now useless because of its deep embedment in the skin of the host. But one species of Cryptolepas is known. Cryptolepas ophiophilus Kriiger is a member of the genus Platylepas. CRYPTOLEPAS RACHIANECTI Dall. Plate 66, figs. l-5a. 1872. Cryptolepas rachianecti DALL, Proc. California Academy of Sciences, vol. 4, p. 300. 1874. Cryptolepas raclnanccti DALL, in SCAMMON, The Marine Mammals of the Northwestern Coast of North America, p. 22, pi. 10, fig. 6. 1903. Cryptolepas rachianectis Dall, GEUVEL, Nouvelles Archives des Muse- um, ser. 4, vol. 5, p. 153, pi. 2, figs. 4-10 ; pi. 3, figs. 10, 11. 1905. Cryptolepas rachianectis Dall, GEUVEL, Monographic des Cirrihipedes, p. 274, fig. 299. Type.—C&t. No. 9192 U.S.N.M., from Monterey, California. Distribution. — Bering Island to Lower California; Hawaiian Islands.1 The barnacle is almost wholly embedded in the whale's skin, " usually on the head and fins," only the opercular membrane and parts of the radii or sometimes the more prominent ribs being ex- posed. When the skin is removed, four to six ribs are seen on each compartment above. These ribs are denticulate along both sides. In basal view the ribs are seen to be loops of the wall, as in Coronula. xThe last locality is given on the authority of Professor Gruvel, who found specimens in the Paris Museum. 280 BULLETIN" 93, UNITED STATES NATIONAL MUSEUM. They are finely striate vertically and crenulated at the basal edges, lilt young specimens the ribs are simple, but in old ones they branch more or less freely, most of the branches not reaching to the periph- ery. Normally there are 30 ribs and 30 lobes of the basal margin of the body-chamber. Rarely an individual may have one or more com- partments with only three or four loops of the inner wall, with branches parallel with and close to the upper side, so that an in- complete outer wall, analogous to that of C'oromda, is formed. In section it is seen that the inner wall is very dense and solid, but has a friable outer layer, which is closely porous, and which forms the greater part of the substance of the ribs. The radii are as thick as the compartments and their edges are intricately sculptured with crimped sutural lamina) (pi. 06, figs. 5, 5«). The sheath is transversely grooved, a little shorter than the body-chamber, and its lower margin is not overhanging or prominent. The scuta are juxtaposed as in Coronula. Their upper layers fcale off. Terga very small. " Color of membranes, when living, sulphur yellow ; hood extremely protrusile." It is excessively variable in size, proportion of diameter to height, and shape of the ribs or lamella, which may be short, W7ith a rounded (semicircular) outline, or long, and triangular in outline. The ribs may have many or very few branches. Apparently adult individuals measure as follows: Greatest diameter, 55 mm. ; height, 15 mm. Greatest diameter, 49 mm. ; height, 16 mm. Greatest diameter, 37 mm. ; height, 18 mm. In young specimens the shape is that of a thick disk with rounded periphery, and the folds are simple. At all stages their free edges are beautifully crenulated. Plate 66, figure 3 represents the usual appearance in the skin of the whale, the hood contracted. In figures 2, 2a the lateral com- partment of a cylindric individual, with very short parietal ribs, is drawn. The usual forms have the wall triangular (fig. 5) or irregularly convex (fig. 5a) in section. Figures 1, 3, 4 are top views, la, 4« basal views. The porous, friable texture of the radial lamella) make this bar- nacle extremely hard to disengage from the skin of the whale. Prob- ably the best way would be to macerate fresh specimens, or have them cleaned by ants or Dermestes. After being in alcohol the whale skin becomes extremely hard and tough, and treatment with caustic soda loosens part of the lamella), besides separating the compartments. Upon the opercular membrane, and especially in the shallow caA7i- ties of the eroded radii, one often finds the little parasite Cyamus clinging. THE SESSILE BAI1NACLES. 281 According to Dr. W. H. Dall : This species is found sessile on the California gray whale, Rhachiti-nrctix glaiicns Cope. I have observed them on specimens of that species hauled up on the beach at Monterey for cutting off the blubber, in the bay whaling of that locality. The superior surfaces of the lateral lamina?, being covered by the black skin of the whale, are not visible ; and the animal removed from its native element — protruding its bright yellow hood in every direction, to a surprising distance, as if gasping for breath — presented a truly singular appearance. U.S.N.M. Cat.No. Locality. • Collector. Notes. 14312 14313 11609 12041) 9192 /Bering Island Grebnitzky On fyray whale. Dry collection. Neah Bay, Wash .... California . Lockington Chas. 11. Townsi-ud.. Wrn. H. Dall Monterey Cj\l Genus TUBICINELLA Lamarck. 1802. Tubicinella LAMAKCK, Annales du Museum Nationale, vol. 1, p. 461. 1854. Tubicinella Lamarck, DAEWIN, Monograph, p. 430. Shell tubular, wider at the top in adults, composed of six equal compartments, belted by several or many rounded ridges, the parietes longitudinally striated, the outer layer porose; radii narrow; sheath nearly as long as the tube, marked with circular grooves ; lower layer of the opercular membrane lining the shell nearly to the base ; oper- cular valves four, rather large. Type. — TubiGinella major Lamarck. Tulticinella may be described as an elongated Coronula without radial ribs. It is also related to Xenolalanus by the very long opercular membrane. It lives embedded nearly to the top in the skin of the whale. With growth the shell and opercular valves wear oil at the top, so that the length of an adult individual represents but a small part of the shell formed during growth. TUBICIIfELLA MAJOR Lamarck. Plate 65, fig. 5. 1802. Tulticinella (major), and Tubicinella (minor) LAMAKCK, Annales du Museum, vol. 1, p. 463, pi. 30, fig. 1. 1806. Lepas trachealis SHAW, Shaw and Nodder's Naturalist's Miscellany, vol. 17, pi. 726. 1815. Lepas tracheceformis WOOD, General Conchology, p. 31, pi. 4, figs. 1-3. 1818. Tubicinella amilata RANZANI, Opuscoli Scientific!, vol. 2, p. 89. 1818. Tubicinella baleen a rum LAMAKCK, Anim. sans Vert., vol. 5, p. 385. 1821. Tulticinella balwnae OKEN, Naturgeschichte fur Schulen, p. 659. 1824. Tubicinella laniarckii LEACH, Encycl. Brit. Suppl., vol. 3, pi. 57 (not seen ) . 1824. Coronula tubicinella Lamarck, BLAINVII.LE, Diet, des Sci. Nat., vol. 32, p. 380, pi. 117, fig. 5. 282 BULLETIN 93, UNITED STATES NATIONAL MUSEUM. 1854. Tubicinclla tracliealis Shaw, DARWIN, Monograph, p. 431, pi. 17, figs. 3a-3c. 1900. Tubicinclla tracliealis MABLOCH, Trans. South African Philos. Soc., pp. 1-6, figs, (mode of growth). 1903. Tubicint'Ua IraclicuUs Shaw, GBUVEL, Deutsch Siidpolar-Expedition, 1901-1903, vol. 11, p. 216. 1910. Tubicinella "slriata Lamarck" STEBBING, Annals of the South African Museum, vol. 6, p. 573.1 Of the three specimens contained in the United States National Museum,, one is labeled Isle of France, Isaac Lea collection. The others, without data, are rather remarkable for the wide spacing of the annuli. That shown in plate 65, figure 5, is 50 mm. long, 17i mm. in greatest diameter. The series in the collection of the Academy of Natural Sciences in Philadelphia is Avithout locality. I do not know that it has been found on any wliale in North American W7aters. Darwin gives the localities: Southern Pacific Ocean, western South America, New South Wales, Cape of Good Hope. Gruvel, Marloch, and Stebbing have given South African localities. It lives on the southern right whale Balcena australis, on the upper jaw, forehead, and over the eye. In the year 1650, specimens of TvMcineUa were observed on the head of a whale found dead on the coast of Syderoe, one of the Faroe Islands, according to Doctor Olao Worm, who gives two character- istic figures in his Museum AVormianum, page 281, published in 1655. This is the only reference I have found to the occurrence of Tubi- cinella in the Northern Hemisphere. Genus XENOBALANUS Steenstrup. 1851. Xenobalanus (ylobicipitis) STEENSTRUP, Yidenskabelige Meddelelser fra den naturhistoriske Foreniug i Kjobenlmvn, pi. 3, figs. 11-15. 1852. A'cuobdlitiiiis STEEM STBUP, Oversigt over det Kongelige danske Vi- denskabernes Selskabs Forhamlliugar, Februar, 1852, pp. 158, 161. 1852. Kiijhonicinella (Darwin), STEENSTKUP, Oversigt over det Kongelige danske Yidenskabernes Selskabs Forhaudlingar, Februar, 1852, p. 160. 1852. Xenobalanus STEENSTEUP, Yidens. Meddel., p. 62. 1852. tiiphonicella DARWIN, Monograph on the Lepadidse, p. 156. 1854. Xetiobalanus DARWIN, Monograph on the Balanidse, p. 438. It is described by Darwin as having " shell almost rudimentary, star-formed, composed of six compartments; with a long peduncle- formed body rising from the middle; opercular valves none." This animal has a striking superficial resemblance to Conclw- derma (Otion) auritum, which is also found on cetacea, though never attached directly to the skin. 1 Mr. SI ebbing has, in my opinion, taken the first word of Lamarck's diagnosis for a specific name. That the words inclosed in parentheses in Lamarck's paragraphs are the real specific names is demonstrated by his following paragraph, where he says that " Le citoyen Faujas * * * m'a dit que le tubicinclla major a ele decouvert dans les mers du sud de 1'Amerique." THE SESSILE BARNACLES. 283 The morphology of Xenobcdutms has been very fully discussed by Darwin, who has demonstrated its relationship to other Coronulinse, and especially to Tubicinella. He writes: In the shell the aflinity is almost equally close to Coronula and Platylepas, but considering the whole animal, the affinity is somewhat closer to Tubicinella. Xcnobalanus may indeed be described as a Tubicinella without opercular valves — with the opercular membrane thickened down to the basis — and with the shell, excepting the few last-formed basal zones of growth, almost wholly removed by the breakage of its upper end ; this remnant of a shell, however, presenting some strong points of resemblance to Coronula. The tendency toward degeneration of the opercular valves, notice- able in Coronula, culminates in Xenobalaanus^ where they are entirely Avanting; but the hoodlike borders of the oral orifice are developed more than in the other genera. XENOBALANUS GLOBICIPITIS Steenstrup. Plate G5, figs. 2, 2a, 2b. Distribution. — Northern Atlantic, near the Azores between Ma- deira and England, and the Faroe Islands; New England, on the fins of the blackfish, GlobiocepJialus. It is described by Darwin as follows : General appearance. — The shell is in an almost rudimentary condition, and appears like a small white irregular star, embedded up to its top in the skin of the porpoise. Out of this thin, star-shaped shell a cylindrical flexible, peduncle-formed body springs, which forms the main part of the animal ; it is narrow where corning out of the central cavity of the star, but soon acquires its full diameter ; at the upper end it has a reflexed hood, and hence is broader, and this has the appearance of forming a capitulum, like that of a pedunculated Cirripede. This pseudo-capitulum is formed by a membranous reflexed collar or hood, whi.-h is very narrow at the lower end of the orifice, close under the mouth, and becomes wider and wider toward the upper and carinal or posterior end of the orifice ; hence the lower reflexed edge of the hood is only slightly oblique or even nearly transverse. The orifice leading into the sack is large and nearly in the same straight line with the peduncle ; it is a little hollowed out in the middle at the upper end, and on each side of this medial hollow there is a small, rounded projection or horn, not perforated, but hollow, as may be seen by turning up the hood and looking at its under side. These two little horns curiously bring to mind the ear-like appendages in Conchoderma aurita (Otion), but these latter are perforated, open into the sack, and point outward. The peduncle-formed body answers, as we shall presently see, to the main part of the shell in Tubicinella, and the hood, as it would appear, to the lips of the sack-aperture, which project between its scuta and terga ; of these valves there is not here a trace. The whole surface is smooth and is formed by rather thin membrane of an orange color; but from the color of the underlying corium the whole appears of a dark chocolate red, the reflexed hood being rather lighter colored. The part forming the hood apparently answers to the protuberant lips of the operculum, and the lower part to the subcylindrical shell of Tubicinella; both shell and peduncle in the two genera being wider at top than at bottom. 284 BULLETIN 93, UNITED STATES NATIONAL MUSEUM. If in imagination we chip away (an action always in progress) the whole tipper part of the shell of TubicineUa, leaving only two or three zones of growth at the base, we shall convert it into a Xenobalanus, with every internal part and organ occupying the same relative position; for it should be borne in mind that the shell of TubicincUa is lined close down to the basis by the opercular membrane, and this is strictly comparable with the outer mem- brane of the pseudo-peduncle of Xenobalanus. The body, as in TubicineUa, is attached in a vertical position, with the longer axis of the thorax and of the much elongated prosoma extending in the direction of the longitudinal axis of the pseudo-peduncle. So far as I can see, the American specimens do not differ from European. The color (in alcohol) is nearly black, and the ordinary length is from 30 t'o 40 mm. The}' grow in close groups. The lo- calities represented in the United States National Museum are North Dennis and Woods Hole, Massachusetts, on the tips of the flippers of Grlobiocephcdus intermedius, and Albatross station 2424, 36° 41' 37" north latitude; 74° 42' 15" west longitude, on porpoise. A form which may be called variety pattidus is represented by a group of similar individuals, No. 2390, from the Fish Commission, 1875, labeled in Professor Verrill's hand " from tips of flippers of GlobiocephaZus intermedium." The locality is doubtless New Eng- land. They are light buff on one side, tinted with russet on the other. Length 43 mm., diameter of shell 5 mm. (pi. G5, fig. 1). PLATYLEPADID SERIES. Oral opening not protected by a hood. Each of the wall compartments has a median longitudinal sulcus or im- prtssion. Genus PLATYLEPAS Gray. 1S2.~>. ridti/lcpas GRAY, Annals of Philosophy, now por., vol. 10, p. 105, monotype P. inih-lira Gray (—!'. bi-ixc.i-lobata Blainville, according to Darwin). 1S32. CoUiincUlna BIVONA, Kffemeridi Sfi. e Lit. Sicilia, type C. bissexlobata, pi. 3, fig. 1 (not seen). 1S54. Platylepas Gray, DARWIN, Monograph, p. 424. Form conic, the base being decidedly larger than the orifice. Com- partments six, each bilobed, at least inwardly, and produced so as to form six midribs, which support the outwardly convex, mem- branous basis. Sheath short. Basal and inner edges of parietes sharply ribbed. Opercular valves occupying the whole length of the orifice, their upper surfaces scaling off with growth. Type. — P. hexastylos (Fabric-ins). Distribution. — Tropical and warm temperate seas, partly embed- ded in turtles, manatees, sea-snakes, and fishes. This genus consists, at present, of four species, of which only one can be considered at all well known. The others are known by single or very few lots. The essential feature of Platylepas is that its membranous basis is supported by proplike midribs formed by THE SESSILE BARNACLES. 285 the infolded median parts of the parietes. These props also sup- port the low dome of the Avail, which without them would easily be stove in by the impacts incident to its station on turtle shells. In other embedded barnacles the base is smaller relative to the sixe of the body-chamber. In some species the outer layer of the parietes is permeated with minute pores, as in many other Coronulince. Ouly P. ht'.riistylos is known, from eastern American waters. The other species described are: Plaiylepas dccorata Darwin,1 Galapagos Islands, etc. Plat ylf pas ophiophilus Lanchester,2 Malay Peninsula, on the sea- snake Enhydris curtus. riatylcpas kriiyeri, new name for Cryptolepas opfiiopMliis Kriiger.3 Bangkok, Siam, on the sea-snake D-istira; Gwadar, Beluchistan, on the tail of Hydro phis. Though rather incompletely described, this species seems to be quite distinct from P. opJiiophilus Lanchester and P. dccorata Darwin. It certainly is not a Cryptolepas. PLATYLEPAS HEXASTYLOS (O. Fabricius). Plate G7, figs. 1-lc, 3. 1708. Lepas hcxastylos O. FABRICIUS, Skrivter af Naturhistorie-Selskabet, vol. 4, Heft 2, p. 35, pi. 10, figs. 1, 2. 1S24. Coronula bisexlobata DE BLAINVXLLE, Dictionaire des Sciences Na- tmvlles, vol. 32, p. 379, pi. 117, fig. 1 (republished in Manuel de Mala- cologie, p. 600, pi. SO, fig. 1). 1825. Platylepas pulclira GRAY, Annals of Philosophy, new ser., vol. 10, p. ID.") (Corsica). 1825. "C. bisexloba Ranz," GRAY (not of Ranzani), Annals of Philosophy, new SIT., vol. 10, p. 105. — . Coronula califomiensis CHENU, Illustrations Conchyliologiques, pi. 1, fig. 4 (sur les Cetaces, Calif ornie). 1854. Platylepas lissexlobata DARWIN, Monograph, p. 42S, pi. 17, figs, la-ltf. ( Mediterranean, on turtles ; River Gambia and Honduras, on manatee ; Moreton Bay, Australia, " apparently attached to the dugong of that coast"). 1884. JUatylcpas Ussexloltata Blainville, P. FISCHER, Bull. Soc. Zool. de France, vol. 9, p. 359 (New Caledonia, on Halicorc dugong). 1903. Plati/h'pas bissexlobata Blainville, GRUVEL, Nouv. Ann du Museum, ser. 4, vol. 5, p. 151, pi. 3, fig. 13 (Sicily; type of Coronula concent rica Valenciennes MS.). 1912. Plniylcpas bissexlobata (de Blainville) KRUGER, Abhandl. K. Bayer. Akad. Wissensch., Suppl.-Bd. 2, 8 Abhandl., p. 13 (Timor Sea, on Chclone im bricata ) . Type. — Probabty lost ; from the Mediterranean. 1 1854, Monograph, p. 429. 2 Troc. Zool. Soc., London, 1902, pt. 2, p. 371 ; pi. 35, figs. 5-56. 3 1912, Abhandlungen der math.-phys. Klasse der K. Bayer, Akademie der Wisseu- schafti-u, Suppl.-Bd. 2, 8 Abhandl., p. 12, figs. 6-10 ; pi. 3, figs. 7, 8. 286 BULLETIN" 93, UNITED STATES NATIONAL MUSEUM. Distribution. — Tropical and subtropical seas, on turtles (Caretta caretta and Thalassochelys imbricatci) ; also on the African and American manatees- the dugong, and a variety on Lepisosteus. The barnacle is much depressed and broadly oval or circular ; orifice oval. Each compartment is divided by a median radial sulcus, which does not reach to the orifice in small individuals. Surface elegantly sculptured with close concentric ridges, and sometimes (especially where worn) showing fine radial stria3. The outer layer is permeated by fine pores. Radii rather narrow, transversely crenulated near and at their edges. Basal and inner margins sharply septate. Sheath not over half the length of the compartments, hollowed out beneath. Each compartment bears an internal buttress or prop, the mem- branous basis being stretched over them. Darwin says of it : Scuta oblong, about twice as long as broad, with the rostral end rounded, rather narrower than the other end, and curled a little inward. Terga of nearly the same shape and nearly as long as the scuta ; the carinal end is rather more pointed than the scutal end of the valve, and when viewed internally, the growing surface of this end is seen to be bluntly pointed. In both valves the upper layers of shell usually scale off. The distribution of this species is wide, as would be expected from the wandering habits of the sea turtles it lives upon. Moreover, it appears to have a variety of hosts. All of the localities I have seen reported are given in the reference paragraphs above. So far as I know, it has not been reported from our west coast except by Chenu, an authority of no great weight. There is a series of the t.ypical form, agreeing well with Fabri- cius's figures, in the collection in the Academy of Natural Sciences from Osprey, Florida, taken from Caretta caretta by Mr. Baker (pi. 67, fig. 3). They measure up to 17 mm. in diameter. In profile view the base is seen to be as convex as the upper surface in most small examples, but less so in the larger. I took a series of smaller specimens from a loggerhead turtle captured in Delaware Bay (pi. 67, figs. 1-le). The form is very much depressed; diameter, 9 to 10T^ mm. The median sulci of the exterior are far less sharply impressed than in the Florida examples, and the sharp septa within the basal edge are longer. Both of these peculiarities, as well as the considerable length of the internal props, may be due to imma- turity, but from the worn condition and nearly uniform size of the largest examples, I imagine that they are full grown, and represent a slightly different race. Of the synonyms cited above, the names hexastylos, ~bisexlobata, calif orniensiS) and concentrica were based upon the depressed form figured in plate 67, figure 3, and are therefore, I believe, exactly synonymous. P. pulchra Gray has not been described, but Darwin, who had seen the type, placed it in the synonymy of U. liisexlobata. THE SESSILE BARNACLES. 287 Darwin seems to have included barnacles varying a good deal in shape in this species, though the existing descriptions and illustra- tions give only an inadequate idea of the forms seen by him. There is a small individual in the Isaac Lea collection, United States National Museum, from Sicily, which probably represents a sub- species (pi. CT, fig. 4). It has steep, convex sides, deep median clefts in the compartments, but the internal midribs are slender and project but little. The septa are very numerous, sharp, and close; greatest diameter, 8.5 mm.; height, 4.8 mm. From the ap- pearance of this barnacle I suspect that it did not live on the shell of a turtle. There is some orange-colored skin adhering in the furrows of the lower part of the parietes. /'. h. irfifJi'/oj'hila, new variety, plate 67, figure 2. Specimens taken by Mr. Joseph Willcox from a Lepisosteus caught in brackish water in Hernando County, Florida, are small, very thin, and delicate, oval or rounded, 7 to 8 mm. in diameter. The rugae of growth are re- duced, and on some compartments absent. Median sulci of the com- partments shallow, probably on account of immaturity. The inter- nal midribs or props are more slender than in P. hexastylos, scarcely sculptured. Internal septa of the edge much less numerous than in hcxa-stylos, and projecting toothlike at the edge. There are four or five principal septa on each side of the midrib in the rostrum (pi. 67, fig. 2). So far as I know this is the only record of a barnacle attached to a fish.' It was identified as Platylepas decorata Darwin by Dr. John A. Ryder.1 CYLINDROLEPAS, new genus. Form cylindric, the orifice and base of equal size; bases of the compartments obtusely dentate, the median tooth of each compart- ment larger, slightly inflected; sheath very long, not quite reaching to the base. Basis and opercular valves as in Platylepas. Living embedded up to the orifice in the skin of turtles. By its deep embedment and small size this barnacle resembles StepTumolepaS) but it differs by the strictly cylindric shape and the denticulation of the bases of the compartments; StepJianolepas being cup-shaped, the base much smaller than the orifice, and the basal edge not dentate. The prominent midribs of the compartments of Platylepas are represented in Cylindrolepas by slight prominences of the basal borders — vestigeal structures, now useless in consequence of the altered shape of the barnacle. Unlike Platylepas, the sheath is nearly as long as the compartments. Type. — G ylindrolepas darwiniana, new species. 1 American Naturalist, vol. 1.°,, July, 1879, p. 453 288 BULLETIN 93, UNITED STATES NATIONAL MUSEUM. CYLINDROLEPAS DARWINIANA, new species. Plate 68, figs. 3-3&. Type.— 'No. 2057 A.N.S.P. Locality. — West Indies? embedded in the skin (not the shell) of sea turtles (Robert Swift). The barnacle is hexagonal, the carinorostral diameter a little larger than the lateral, of about equal diameter from base to summit; whitish, with fine sculpture of close transverse wrinkles, and on the carina and carinolateral compartments a few low, coarse vertical ribs. The compartments when isolated are square. Their summits are beveled and polished, apparently by wear. A median fold or rilled sulcus is indicated on the polished summit by a small depression filled with the softer and dull substance of the outer layer; and on some compartments a slight, mesial sulcus is visible externally. The radii are represented by narrow sulci; their edges are distinctly septate. The lower edges of the compartments have about three short, vertical, blunt teeth on each side of a larger median tooth, which bends slightly inward, and is homologous with the prop or midrib in typical forms of Platylepas. The sheath is delicately striate transversely, and stops a little short of the basal edges of the com- partments. The scuta are in contact with the terga, and together they stretch from end to end of the orifice. Carinorostral diameter, 4 mm. ; lateral diameter, 3.8 mm. ; height, 3 mm. Some individuals are slightly larger, greatest diameter 5.3 mm. These barnacles were in the collection of Robert Swift, one time United States consul in St. Thomas. His collection was almost wholly of West Indian mollusks — few, if any, from any other region. He also collected West Indian barnacles. It is likely therefore that this species, which had no locality, was found in the West Indies. In any case, the species differs so widely from those described that it should be easily recognized. The specimens of Cylindrolepas were embedded in a very hard yellowish substance showing but little structure. Dr. Thomas Bar- bour, of the Museum of Comparative Zoology, to whom I applied, concluded that it is the salt-water cured, sun-dried skin of either a loggerhead or green turtle, probably from between the neck and flippers or around the base of the tail. On account of its small size and deep embedment Cylindrolepas is likely to escape notice. It may turn out to be common and widely distributed. Genus STOMATOLEPAS Pilsbry. 1910. Stomatolepas PILSBRY, American Naturalist, vol. 44, p. 304. Wall bowl-shaped, the orifice far larger than the base; compart- ments six, silicate down the middle, with the outer layer composed of imbricating calcareous scales arranged in chevron pattern ; inner layer projecting above, finger-nail like, beyond the outer, its basal THE SESSILE BARNACLES. 289 edge thin and simple; .sheath very long, transversely grooved, with- out a distinct lower edge. Opercular valves long and narrow, thin, the outer layer not deciduous. Basis membranous. Type. — jStomatofepas prccgustator. Station. — In the mucous membrane of the gullet of sea turtles. Stomatolepas and Stephanolepas form a little division in the group of turtle barnacles, characterized by the simple, thin basal edges of the compartments, which are without teeth, ribs, or laminae. The presence of an external shallow median sulcus in each compart- ment shows that their ancestors were Platylepas-\\\\.Q barnacles, since this sulcus is doubtless the vestige of an infolding of the wall. The elaborate sculpture of the exterior of Stoinatolepas seems to be a development of the sculpture of Plcctylepas, which is formed of con- centric wrinkles cut into beads by radial strise. In Stomatofopas the wrinkles assume an oblique direction and the beads are prolonged to form scalelike processes. STOMATOLEPAS ELEGANS (O. G. Costa). Plate 68, figs. 2, 2«. 1838. Coronuln clcgnns COSTA, Di alcuni Balanidi app. al Regno Napoli, 1838 (p. 17 of separate copy), in Atti Accad. Sci. Napoli, vol. 5, 1843, pt. 2, p. 117, pi. 1, figs. 1, 2, 3. 1839. Cliclonibia elegans COSTA, Fauna del Regno di Napoli, Cirropedi, p. 14. Distribution. — Taranto, Italy, the host unknown. It is described by Costa, as follows : Coromtla with the tube conic-truncate, prominent areas bipartite, elegantly scrobiculate, the scales coriaceous, depressed areas smooth, internal lamina having naillike projections. Opercular valves four, smooth, subequal ; color orange. Breadth 4 lines, altitude 2 lines. I am giving copies of Costa's description and figures in order to direct attention to this lost species, which will probably be found again in the throat of sea turtle. I suspect that it may be identical with S. prcegustator, yet the differences in the color and the external sculpture of the parietes, // not due to careless drawing, may indi- cate a distinct species. STOMATOLEPAS PR^GUSTATOR Pilsbry. Plate 68, figs. 1, la, 15. 1910. Ktoinatolci>fi.s pra'yusiator PILSBKY, American Naturalist, vol. 44, p. 304, fig. 1. Type. — Cat. Xo. 1851 A.N.S.P., from Tortugas, Florida, par- tially embedded in the mucous membrane of the upper end of the gullet of Caretta caretta. Edwin Linton. General form is that of a broad, shallow bowl, the diameter of the base about half that of the oral orifice. The inner layer of the compartments is thin, white and glossy, and projects well above the outer layer, the upper ends of the compartments being smooth, 290 BULLETIN 03, UNITED STATES NATIONAL MUSEUM. sharp, and arched. The outer layer is chamois colored, and scaly. There is a groove down the middle of each compartment, and a tri- angular smooth area, where the outer layer is wanting, at the base. A slight ridge encircles the wall above the middle, marking the limit of the portion of the barnacle embedded. The scaly surface is produced by delicate ribs bearing series of flat lobes or digitations, the ribs being arranged en chevron on each compartment, and the lobes or scales of one rib imbricating upward over the bases of the next. Upon the upper-part, above the encircling ridge, the scales are larger and arranged in nearly horizontal rows. The sheath covers fully two-thirds the height of the compart- ments, is glossy, white, and regularly grooved transversely. Its lower edge is continuous with the smooth inner surface. The basal edges of the wall plates are thin and smooth. The basis is entirely membranous and flat. Rostrocarinal diameter, G.7 mm.; lateral diameter, 6 mm.; height' 3 mm. The opercular valves protect less than half the area of the orifice, but extend nearly its whole length. They are very thin, glossy, white, and smooth both outside and within. They are long and nar- row, the terga in contact with the scuta but not articulated or inter- locking in any way. The scuta are longer than the terga, tapering to a point at the rostral end, obliquely rounded at the tergal end. Costa's paper of 1838, describing and figuring Coronula elcgans, was not contained in our library at the time I described Stomato- lepas, and his species has never been mentioned by any other author so far as I know. While it seems likely that the Mediterranean and American forms are specifically the same, there are certain differ- ences which influenced me to leave them apart until an actual com- parison of Mediterranean examples can be made with our form. Costa describes elegans as orange in color, but this might be on account of the dry tissues of the host adhering to the barnacle. His figure shows the parietes evenly scaled, while in our form the squama - tion of the upper part differs rather conspicuously from the lower portion. This would be an important distinction if confirmed, but it might easily be due to insufficient observation on the part of Costa's artist. Family CHTHAMALIDvE. 1854. ChthamalincB DABWIN, Monograph, p. 446. Sessile barnacles in which the walls are not porous ; the rostrum has alee; or when concrescent with the rostrolateral compartments, the composite plate has radii, or overlaps the lateral compartments. The rostrolateral compartments (when not fused with the rostrum) are without alse on either side. The labrum has a concave, not notched edge, and is often swollen or " bullate " externally. The lower angle THE SESSILE BARNACLES. 291 of the mandible is pectinated. The cirri of the third pair resemble the fourth and later pairs of cirri, or are of intermediate character between the second and fourth. Every Balanoid barnacle in which both rostrum and carina have ala3 belongs to this family; but it includes also one genus — Pachy- lasma, with the satellite or subgeneric groups Ilexelasma. and Bathy- ~balanus — in Avhich some species have the rostrolateral compartments wholly concrescent with the rostrum in the adult stage, thus having a wall like that of Dalanus. This family is more primitive than the Balanidse, and in most of its departures from Balanid organization it approaches or is like the LepadomorpTwt. The labrurn is like that of Verrucida? and the pedunculate groups; also the mandibles and to a less extent the maxilla1. The third pair of cirri is like the succeeding pairs, and not, as in Balanidse, modified to resemble the second pair. Caudal appendages are often present (never in Balanidse). The rostrolateral compartments are often retained as separate plates, but in Balanidse they are always concrescent with the rostrum. The genera differ a good deal in the degree in which old characters, such as the caudal appendages, have been retained. Advance has been in the simplification of the Avail by reduction of the number of compartments. In C atopJiragmus all of the compartments of the ancestral Balanomorpha may be presumed to be present. In Octo- meris the outer whorls have been lost, leaving eight. Two phyletic series lead from this point: (1) Pachylasma &n&Hexelasma, culmi- nating in a hexamerous wall, and (2) Chthamalus and Chamcesipho, the latter tetramerous. There has been parallel and of course totally independent reduc- tion of wall-compartments in the two families Balaniclse and Chtha- malidse, as shown in the following table, in which the leading genera of both families are grouped to show the number of compartments and the relationship within each series: 8 compartments with accessory plates. 8 compartments. 6 compartments. 4 compartments. 4 compart- ments con- crescent into one. Chthamalid series. Catophrag- nius. Pachy 1 Octomeris. Hexelasrna. lasma. Chthamalus. . . Charnwsipho. Balanid series. Chelonibia. 1 Balanus. Poreless Balani. Coronulinae. Tetraclita. Elminius. Creusia Pyrgoma. 292 BULLETIN 93, UNITED STATES NATIONAL MUSEUM. Structurally, the Chthamalidse stand between the Balanidio and the pedunculate cirripedes, but the most primitive members now existing of the two families are as unlike as the highest in essential structure. In fact, the nearest approximation is found in some of the more evolved members of each series, such as Pachylasma and Ba- lanus— forms which have been similarly remodeled. The common ancestor of the two families may be presumed to be a Mesozoic genus approximating Catophragiwts or Octomeris in structure of the wall. Chthamalidic are very rare as fossils, but it is evident that they arose well down in the Mesozoic. Chthamalus darwini Bosquet of the upper cretaceous is a typical species, so far as the walls are concerned, and Ilexelasma appears in a gigantic species in the Miocene. As neither of these can be considered primitive, it is obvious that the family has had a long history. Indeed, it is probably now decadent. Characteristics suggesting this view are the strikingly discontinuous distribution of the species of most of the genera ; the small number of species and their strong differentiation. These peculiarities are most marked in the most primitive and presumably oldest genera. Chtha- malus, a relatively evolved genus, is the only one which is generally distributed. The others have the appearance of disconnected frag- ments lingering like Limulus, the Dipnoi, or the struthious birds, from an earlier time of wider distribution. As yet there is no palaeon- tological evidence for this view. In the stations chiefly occupied by Balanidse — that is, from low- water mark to the edge of the continental shelf, at about 100 fathoms — the Chihamalicbe seem to have been almost crowded out of the race. Chthamalus^ the only prolific and generally distributed genus, mainly inhabits a higher zone on the shore than Balanus. Pachylasma. and the closely related Hexelasma are mainly inhabitants of deep water, where Balanus is rare. Other genera have very few species. Only two species of Octomeris, two of ChamoBsipho^ and two of Catophragmus — all very local and most of them rare — inhabit the shore zone, where they compete with Balanus and, more espe- cially, Tetraclita. We owe the establishment of this family solely to the taxonomic genius of Darwin, who first brought the genera together and dem- onstrated their relationships. I have examined and dissected many more species, I suppose, than anyone else, and I find all of the evi- dence supports Darwin's views. I have not found any facts favoring Professor Gravel's distribution of the genera into the three families Octomeridse, Hexameridse, and Tetrameridae, among Balanid genera. KEY TO GENERA OF CHTHAMALID^E. a\ Four compartments, the carina and rostrum having alse ; sutures more or less obliterated Chamcecipho* genus is not contained in the United States National Museum. THE SESSILE BAENACLES. 293 «a. Six compartments. l>1. Rostrum having nine like the carina, the adjacent rostrolatcral compart- ment without al;i> on either side ChtJi1 il". Radii wanting or not distinctly differentiated from the parietes. Pa ch yhisin a ( p. 327 ) . c3. Basis membranous, at least in the center ; no radii — Hexelasma (p. 329). a3. Eight compartments at least. I)1. Rostrum and rostrolateral compartments closely united by linear su- tures Pachylasma (p. 327). I3. Rostrolateral compartments as distinct as the others ; rostrum with ate. c\ No accessory compartments outside the eight composing the wall. Octomeris (p. 334). c2. Wall surrounded with short accessory compartments outside. Catophragmus (p. 334). Genus CHTHAMAL.US Ranzani. 1S17. ClitJiamalus RANZANI, Opuscoli Scientific!, vol. 1, p. 270 (no species mentioned. ) 1818. Chthamalus RANZANI, Opuscoli Scientific!, vol. 2, p. 83 (for C. tjlabcr and (7. stellatus). 1837. EurapJiia CONRAD, Journ. Acad. Nat. Sci. Philadelphia, vol. 7, p. 261, monotype E. hcinbcJL 1854. Chthamalus Ranzaui, DARWIN, Monograph, p. 447. Compartments six ; rostrum similar to the carina in being provided with alfe; rostrolaterals triangular, without alee, the sheath having a narrow projection. Carinolaterals wanting. Basis membranous or covered with a calcareous layer formed of the inflected basal edges of the compartments. Labrum with the concave or straight edge toothed or hairy. Man- dible with the lower part pectinated. First two pairs of cirri short, densely spinose, the third pair much longer and bearing spines like those of the later pairs. Type- — Chthamalus stellatus (Poli). Distribution. — Nearly world wide, in the littoral zone. Chthamalus is one of the most distinct genera, really forming a subfamily of the Clithamalidae, distinguished by the persistence of the rostrolaterals as distinct compartments and the loss of carino- laterals. It differs essentially, therefore, from other hexamerous Clithamalidae, in which the rostrolaterals are concrescent with the rostrum, and the carinolaterals persist as separate compartments. The shape of the rostrolateral compartments, which have no alse, is extremely characteristic of the genus (pi. 73, fig. 2e; pi. 75, fig. 1). 1 This genus is not contained in the United States National Museum. 4729°— Bull. 93—16 20 294 BULLETIN 93, UNITED STATES NATIONAL MUSEUM. The Chthamali are exclusively littoral barnacles, many of them living higher up the beach than most Balani. They rarely, if ever, live below low tide. They are usually attached to stones, other bar- nacles, and molluscan shells, but I have seen one species on rushes, evidently from some inside bay or passage. Sometimes they occur on other barnacles attached to floating objects. The walls and valves are particularly subject to corrosion, owing partly to their exposure to the buffets of the surf, partly to the unusually large amount of animal matter they contain — chitinous films and pores occupied by filaments from the mantle. This corrosion obscures the external char- acters so much that scarcely any sample can be identified without a deliberate examination of the opercular valves. Even these are sub- ject to great alterations in outline, the effect of erosion of their outer layers. In corroded individuals the sutures of the opercular plates form a figure the shape of the Greek letter 1F. The valves and compartments of alcoholic or fresh specimens may -be isolated and cleaned under the dissecting microscope, but dry sam- ples must be boiled or soaked in caustic potash to free them of the adherent tissues. After that I have found it convenient to mount the opercular valves with glue or mucilage on slips of black card, so that they may be examined under the microscope without risk of loss — nearly all of them being diminutive objects of only a few milli- meters' extent. Taking the characters of the mouth parts and cirri into account, and making due allowance for distortion and corrosion, and the fre- quent tendency to become cylindric, the species are not very hard to determine, after one becomes accustomed to Chthamali, except in the group of forms typified by C. stcllatus, and widely spread in the Atlantic and communicating seas, and in the oriental seas. I believe that the definition and full illustration of a number of subspecies will materially simplify the study of this group, and a partial revi- sion has been attempted. A very large amount of oriental material must still be collected and overhauled before we can claim to have a fairly complete knowledge of the tropical Indo-Pacific species. Thanks to their paltry and insignificant appearance, Chthamali are apt to be overlooked, and our collections would be much poorer than they are were it not that they may often be found on the larger barnacles and shells in museums. The supposed difficulty of the genus has probably deterred natural- ists from undertaking serious study of the group. Only one recent species has been described in more than 60 years since Darwin's monograph appeared. I have not seen C. dentatus Krauss (South Africa), or C. stellatus var. depressa Poli (Mediterranean, etc.). C. antennatus Darwin is in the collection of the Academy of Natural Sciences from Richmond, THE SESSILE BAENACLES. 295 Victoria. C. Ugusticus De Alessandri, of the Italian Pliocene and C. danoini Bosquet, of the upper Cretaceous of Vaels, Belgium, are fossil species not known to me by specimens. All other described species are in the United States National Museum and are noticed below. With the exception of the Hawaiian C. hembeU, all of the species are small, rarely exceeding 12 or 15 mm. in diameter, and more often half that size. They are generally conic or depressed, but sometimes cylindric. The opercular valves are deeply locked or mortised together. The tergum never has a long or distinctly formed spur. In many species of C htliamalus the terminal segments of the second pair of cirri have one or several broad or lanceolate spines with conspicuously serrate edges, as in figures 825, e. I have not dissected enough individuals of any one species to determine the value of these spines as specific characters. They may perhaps vary with the age of the individual. They are somewhat similar to the spines from the first two pairs of cirri of Mitella figured by Kriiger, and supposed by him to have a sensory function. This appears to me doubtful. Throughout the Balanomorph cirripedes one often notices that some of the spines become delicately pinnate toward the end, but I have not noticed such a specialization of this structure in any genus but CJithamalus. In the maxilla the spines are arranged in three groups: An upper group of two or three large and several small spines, followed by a notch; a middle group partly of rather large spines, and a lower group of mainly smaller spines. The species differ among themselves in the number and length of the hairs on the upper and lower borders of the maxilla and in the shape of the spinose edge, but with a few exceptions the maxilla? are a good deal alike throughout the genus. The mouth parts and cirri of Chthamalus deserve a much more ex- tended examination than I have been able to find time for. The modifications of the mandible, etc., may be found to give the best characters for subdivisions of the genus, but its structure is unknown in some of the species, so that I have been unable to use these characters in the key to species. There are two main groups : I. Mandible having four teeth followed by an even, comblike row of narrow spines, below which the lower extremity is trispinose. The upper tooth is much larger than the other three ; the third and fourth are usually bifid at the tips. Spines of the lower extremity are usually unequal. a\ Spines between the fourth tooth and lower point are very numerous, narrow, and crowded. ( See p. 303, fig. 84d. ) 61. Cirrus iii with one ramus far longer and more slender distally than the other C. cirratus. 62. Kami of cirri iii not very unlike: C. stcTlatus, C. s. angusHtergum, C, fragilis, C. dalli, C. anisopoma, C. challenycri, C. scabrosus. 296 BULLETIN 93, UNITED STATES NATIONAL MUSEUM. a'. Spines between the fourth tooth and lower point are fewer, compara- tively coarse, and distinct, easily counted (fig. 90) C. malayensis. II. Mandible having three large teeth and a broad lower extremity set with many spines, which are largest at the end, decreasing above and be- low it. «l. Without caudal appendages. b1. Anterior ruinus of cirrus iii much longer than posterior, with spines in circles on the distal segments (7. antcnnatits.1 b2. Third pair of cirri much longer than second, second pair having coarsely pectinated terminal spines C. dental us* b3. Third pair of cirri having a few basal segments thickly covered with spines, like the second pair C. intcrtcxtus.1 I*. Maxilla and cirri normal C. witlicrsi (fig. 91). b5. Maxilla densely crowded with subequal spines. Posterior ramus of cirrus ii long, like the following cirri ; dense short tufts between the spines of the later cirri C. hembeli (fig. 97). a3. Having long caudal appendages—- C. caurlatus (fig. 92). KEY TO SPECIES OF CHTHAJ1ALUS. The keys for the determination of specimens constructed by Hoek and Gruvel from Darwin's descriptions will not work in actual prac- tice. Gruvel's key is workable with the most perfect specimens, but not with much of the material one encounters, since the characters used are often corroded away. The following key is highly artificial and not very satisfactory : a\ Very large, solid and strong, with zigzag sutures ; base calcareous in adults ; tergal margin of the scutum longer than the basal C. licmbcli (p. 324). a2. Smaller, diameter usually 5 to 15 mm. ; not so strong. bl. Right and left opercular valves very unlike in size and shape. C. anisopoma (p. 317). b-. Opercular valves nearly or quite alike on the two sides in normal specimens. c1. Interior of a uniform very dark (purplish) color. d1. Interior rich violet, the basal margin inflexed ; sutures, when unworn, of interfolded laminae. Tergum very narrow in the lower half, calcified to the scutum C. intcrtc.rtus (p. 324). d'\ Interior blackish violet, without basal ledge ; sutures simple. Tergum narrow, with a short, rounded spur, not calcified to the scutum, which has a very low articular ridge and no pits for the muscle- insertions C. imperatrix (p. 320). c2. Interior not uniformly very dark. d1. Adductor ridge of scutum distinct. c1. Tergum broad in the lower part, its basal margin not distinctly siuuated below the depressor crests. f. Tergum triangular, equilateral; tergal margin of the scutum short, its adductor ridge small C. fissus (p. 317). f. Tergum longer than wide; tergal margin of scutum longer, the adductor ridge long and strong C. dalli (p. 316). 1 1 have not dissected C. scabrosits., C. antennatits, C. dcntatus, or C. interteorttts, in- cluded in the above table, the details being taken from Darwin. As none of the mandibles have been figured, it is possible that some of these species are incorrectly grouped. THE SESSILE BARNACLES. 297 e2. Tergum narrower in the lower half, the basal margin distinctly sinuated or incurved helow the depressor muscle crests. p. Crests of the tergum on a little plate raised from the valve; sutures iuterfolding when perfect C. scabrosus (p. 323). f. Crests of tergum normal ; sutures simple C. challcngeri (p. 307). d3. Scutum without a distinct adductor ridge. e1. Greatest prominence of articular ridge of the scutum helow middle of tergal margin, its lower end ahruptly truncate. /'. Occludent margin of scutum making a right angle with edge of articular ridge; tergum very broad above, triangular, its basal margin not sinuated below the crests C. stellaiiis (p. 301). f. Occludent margin of scutum making less than a right angle with the tergal margin. g1. Tergum triangular, broad above, the basal margin straight. C. anlcnnfilits Darwin. g". Basal margin of tergum distinctly sinuated below the crests. hl Tergum very narrow and thick C. s. (nigustiterguni (p. 305). h2. Tergum moderately narrow, having a long furrow next to the crests f. s. lisinuatus (p. 306). h3. Tergum wide above, narrow at the base. C. s. punctatus (p. 304). 7i4. Tergum wide at the base C. moro (p. 311). e". Greatest prominence of the articular ridge of the scutum about median or above, the lower end gradually sloping. f. Sutures zigzag. g1. Exterior ribbed C. dcntatus (p. 294). (f. Exterior nearly smooth G. caudatus (p. 314). /=. Sutures simple. (f. Tergum broad and rounded at base ; wall usually not corroded, smooth or with rounded ribs C. fragiHs (p. 297). g*. Tergum almost equally wide above and below, with an external furrow ; adductor scar of scutum deep— C. panamensis (p. 319) . g3. Tergum narrow in the lower half. /i1. Scutum slender, its greatest width about half the length, the tergal and basal margins about equal ; articular ridge very small; tergum triangular in section C. withersi (p. 312). 7i2. Tergal margin of scutum decidedly shorter than the basal. C. malaycnsis (p. 310) ; C. cirratus (p. 321). ATLANTIC AND MEDITERRANEAN SPECIES. CHTHAMALUS FRAGILIS Darwin. Plate 70, figs. 1 to 4. 1854. Chthamalus steUatus var. fragilis DARWIN, Monograph, p. 456, pi. IS, fig. Id. 1909. CMhamalus stcUat-us var. fragilis Darwin, STJMNER, Science, vol. 30, pp. 373-374. Type. — British Museum, from Charleston, South Carolina, on oysters. Distribution. — West Indies, and on the mainland north to Woods Hole, Massachusetts. 298 BULLETIN 93, UNITED STATES NATIONAL MUSEUM. The barnacle is conical, rounded or oblong, thin, smooth, or with rounded ribs, not eroded, or but very slightly worn, covered with a thin cuticle; compartment easily separable from one another and from the surface of attachment ; radii developed, narrow. Color very light bluish gray or olive brown. Carinorostral diameter, 5 mm. ; lateral diameter, 3.5 mm. Carino- rostral diameter, 5.5 mm. ; lateral diameter, 3.3 mm. Scutum rather broad, the apical angle less than a right angle; the articular ridge has a rounded outline, gradually tapering down- ward and upward. The adductor muscle pit is smaller than in j but deep; its tergal margin is straight and very slightly FlG. 82. ClITHAMALUS FRAGILIS. a, MAXILLA. 1}, TERMINAL SEGMENT OF SHORTER RAMUS OF CIRUDS II. C, ELEVENTH SEGMENT OF CIRRUS VI. (/, PART OF THE LABKUM, ALL FROM ALBATROSS STATION 2004. e, TERMINAL SEGMENT OF SHORTER it AM us OF CIRRUS ii, OCEAN CITY, N. J. f, CHTHAMALUS STELLATUS, NAPLES, TENTH SEGMENT OF CIRRUS VI. raised, so that there is the trace of an adductor ridge in some speci- mens. The exterior has conspicuous but very low growth-ridges, and usually a fine longitudinal striation. Tergum not varying much from that of typical stellatus, except that on account of the nearly perfectly preserved scutal margin, the articular ridge appears less prominent. There is a short, rounded and broad spur, decidedly more developed and broader than in stellatus. The labrum is strongly concave in the middle, and on both sides the edge is spinose (fig. 82d). The mandibles, palpi, and maxillae do not differ materially from those of C. stellatus, figured on page 303. Cirrus i has slightly unequal rami of 7 and 0 segments, armed with simple spines. Cirrus ii has slightly unequal rami of 7 and 5 THE SESSILE BAKNACLES. 299 segments. In a specimen from station 2004 the terminal tuft of spines on each ramus contains one broad, serrate spine with a pair of large teeth (fig. 8'2&). The specimen dissected from Ocean City has rami of 9 and 6 segments, the terminal tufts having several serrate spines (fig. 82e), and there are others of less characteristic shape on several of the later segments. The cirri iii to vi have segments with four pairs of spines (fig. This species differs from C. stellatus by its smoother wall, usually covered with an epidermis, by the shape of the articular rib of the scutum, and the much broader lower part of the tergum. In the specimen of stellatus I dissected there are no such strongly modified spines on the second cirri, and the later cirri have five pairs of spines, fragilis having four. The specimens growing on rushes (pi. 70, figs. 1-Id, 4). are usually elongated, and sit with the carinorostral axis lengthwise of the rush. In hundreds examined, the parietes are never ribbed. In a group on an oyster (Ostrea parasitica Gmelin) from Varadero Park, near Cardenas, Cuba, collected by Dr. J. W. Ross, the con- tour is usually shorter and the surface is either smooth or furnished with round radial ribs. There are also transitional forms. The scutum has a longer basal and shorter tergal margin than in the Florida examples on rushes, and the opercular valves are beautifully rose colored inside. Exterior dull olive or olive brown, not corroded, length G, width 5 mm. (pi. 70, figs. 3-3). Cirrus i has rami with seven and five densely hairy segments. 1 As noted elsewhere, Darwin applied the name " var. communis " to the typical form of every species having several varieties. THE SESSILE BARNACLES. 303 Cirrus ii has seven and six segments. Among the terminal spines of the shorter (posterior) ramus there is one broader lanceolate spine having two closely toothed edges, but without larger teeth below the serrate portion (fig. 84a). There are three such spines at the distal end of the longer ramus. Cirri of the third to sixth pairs much longer than those preceding, and bearing five pairs of spines on the median segments (p. 298, fig. 82/). FIG. 84. — CHTHAMALUS STELLATUS, NAPLES, a, TERMINAL, SEGMENT OF THE SHORTER KAMI'S OF CIRRUS II, SHOWING ONE LANCEOLATE, SERRATE SPINE. 6, PALPOS. C, MAX- ILLA. (1, MANDIBLE. The penis is much longer than the last cirri. It is slender, closely ringed, and has a delicate pencil of hairs at the end. As this species is the type of the genus, and has been reported from many places all over the world, including our own shores, it has been thought best to give an account of the typical form. Figures 1 to Ib represent topotypes from Naples, which agree fully with Darwin's plate 18, figures la (locality not given) and If (Madeira) ; also with De Alessandri's figures of Italian Pleistocene examples. The opercular valves are highly characteristic. My figure of the entire animal shows only deeply corroded specimens. Small specimens up to 3 mm. diameter, but evidently adult, from Fayal, Azores, growing on Purpura hwma-stoma have 10 to 12 very conspicuous ribs. The opercular valves are thin, but typical in form (pi. 71, figs. 4, 304 BULLETIN 93, UNITED STATES NATIONAL MUSEUM. It appears, then, that this typical form of the species is known from the Mediterranean, Madeira, and the Azores; whether it occurs in northern Europe is still uncertain. Darwin figures (pi. 18, fig. Ik) a peculiar form which I have not seen, from St. lago, Cape Verde Islands. Northern Europe. — Form punctatus Montagu (pi. 71, figs. 2-25, 3, 3#) . In English specimens there is a good deal of variation from the characters given above. The external form is often typical, as in plate 71, figures 3, 3a, from Exmouth ; but when crowded they become cylindric, as in plate 71, figures 2, 2«, 25, exceedingly like the cylindric form of Balanus balano-ides. This tubular form is what Professor Gruvel has called var. fistulosus. There are many transitional specimens between the tubular and the depressed forms, in the same groups. The scutum, in all of the English examples I have closely exam- ined, is longer than in the Mediterranean form, with the apical angle acute, the tergal margin shorter, and the adductor muscle pit smaller. The tergum also differs by having a sinuation in the basal margin near the depressor muscle crests. I have not taken time to compare large series — the cleaning is somewhat tedious — but according to Darwin these characters of the valves vary so much that he included all of them in var. communis. If the form in question proves to be racially distinguishable from typical stellatus it will be called punc- tatus Montagu. Eroded specimens usually have a punctate or pep- pered appearance. M}^ plate 71, figures 2-25, 3, 3, are from British specimens of this race. U.S. Cat. N.M. No. Locality. Collector. Notes. 12006^ 1209S/ 12108 12148 12095 England (?) Clark, in Jeffreys collection . . .Teffrevs _ - (On Patella vulgata \ rocks. Tubular variety. Not typical. On mitelfa. and on Mitella do Exmouth, England ' do Englaud(?) - - do. _ Fayal, Azores Lewis Dexter Port Cuyo, Philippines A Ibatross CHTHAMALUS STELLATUS DEPRESSUS (Poli). 1791. Lcpas flcpressa POLI, Testacea utriusque Sicilite, vol. 1, p. 27, pi. 5, figs. 12-17.1 1818. Chthamalus glaltcr RANZANI, Opuscoli Scientific!, vol. 2, p. 83, based upon Lcpas depressa Poli. 1854. Clitliamalus steUatus var. depresses Poli, DAEWIN, Monograph, pi. 18. fig. Ib (locality not given), ly (Mediterranean). name Lcpas depressa has page priority over L. stcllata, but subsequent authors have preferred the latter, depressa being a far less common and local form. THE SESSILE BARNACLES. 305 This subspecies is described by Darwin as follows: Shell much depressed, surface much corroded, smooth; ;il;c largely exposed, marked by lines of growth ; radii not present ; parietes on the under side often supported by pillars; orifice subhexagonal. Diameter up to three-quarters of an inch. Tergum very narrow. This variety or subspecies is known from the Bay of Naples (type- locality), Straits of Gibraltar, and St. lago, Cape Verde Islands, where it occurs associated with stellatus. It is not present in the museum, and is included here for comparison •with the following form, which is rather similar in the shape of the opercular valves. CHTHAMALUS STELLATUS ANGUSTITERGUM, new subspecies. Plate 71, figs. 5-5 &. Type.— Cat. No. 48199, U.S.N.M., from the Bahamas. The walls are deeply corroded above, irregularly ribbed near the base, as in stellottts; interior roughened, more or less purple-tinted. The scutum has a straight articular rib, truncate at the lower end. The adductor muscle pit is very shallow; no adductor ridge. Pit for the lateral depressor deep. The tergum is very narrow and thick. There is a small but distinctly developed spur, much narrower than in fragilis; basal margin concave; crests very strong. From its thickness the tergum is triangular in transverse section. It is seen rolled toward the right in plate 71, figure 55, showing the broad scutal articulating face. In figure 85 a direct view of the inner face is given. The opercular valves are white or pink inside. The labrum has a concave edge with teeth along the median por- tion (fig. 865). The mandible and maxilla are very similar to those of C. stellatus, shown in figures 84c, d. Cirrus i has rami of 7 and 5 segments, the anterior longer by two segments. Cirrus ii has 6 and 5 segments, the anterior ramus longer by two. There are no large pectinated spines. Cirrus iii has rami of 12 and 14 segments, the lower ones having six pairs of spines, the rest five pairs. FIG. 85. — CHTHAMALUS STELLATUS ANGUSTITEKGUM. SCUTUM AXD TERGUM OF THE TYPE. 306 BULLETIN 93, UNITED STATES NATIONAL MUSEUM. Cirrus vi has rami of 15 segments, most of them bearing five pairs of spines (fig. 86a). FIG. 86. — CHTHAMALUS STELLATUS ANGUSTITERGUM, ABACO. a, INTERMEDIATE SEGMENT OF CIRRUS VI. 6, LABRDM. This is the race of the Bahamas and Florida Keys. It is probably a species distinct from Ch. stellatits. Locality. Collector. Notes. Bahamas B. A. Bean . . Type lot. Abaco, Bahamas Albatross, 1SS8 Boca Cliica Key, Fla H. A. rilsbry. Coll. A.N.S.P. CHTHAMALUS STELLATUS BISINUATUS, new subspecies. Plate 71, figs. 6, 60. Type.— Cat. No. 48085, U.S.N.M., from Santa Catharina Island, Brazil. Articular ridge of the scutum prominent in the middle, hollowed out above and abruptly terminated below; the articulating margin therefore being bisinuate. Pit for the adductor muscle is deeply excavated, as in typical stellatus, and there is no adductor ridge. The tergum is wider than in C. s. angmtitergiim. The scuta 1 margin of the articular ridge is prominent. There is a small spur, as in angustitergum. The crests for the depressor muscle are strong and long, and there is a deep fissure or furrow next to the lower crest, running far up the central part of the valve. This furrow is present in both of the specimens I examined, and has not been found in any other species. Whether it is a constant character of this race re- mains to be determined. The dingy, corroded wall measures about 7.5 mm. in diameter. Darwin has given some notes on specimens from Gorriti Island, Uruguay, probably belonging to this race. The specimens in the United States National Museum are from Brazil; Rio de Janeiro, collector unknown, and Santa Catharina Island, Isaac Lea collection. Both lots are preserved dry. THE SESSILE BARNACLES. 307 ORIENTAL SPECIES. CHTHAMALUS CHALLENGERI Hoek. Plate 72, figs. l-4r/. 18S3. Chth amalus challcngcrl HOEK, Challenger Reports, Zoology, vol. 8, p. 1G5, pi. 13, figs. 35-38. 1911. Chlhanwlus cluillcnyrrl Hoek, KRUGEIJ, Beitriige ziir Cirripedienfauna Ostasiens, p. 46, pi. 3, fig. 30. Distribution. — Japan ; Matsushima. The barnacle has rounded ribs, rather strong, white throughout, rot corroded, and smooth inside. The radii are very narrow. Carino- rostral diameter 7.6 mm. The scutum is lengthened. Articular ridge prominent, its edge bisinuate, being excavated above, tapering below the median promi- FIG. 87.— CHTHAMALUS CHALLENGED, MATSUSHIMA. o, MANDIBLE. 1), MAXILLA, c, TERMI- NAL SEGMENT OF THE SHORTER UAJIUS OF CIRRUS II. (I, SEVENTH SEGMENT OF CIRRUS VI. C, INTERMEDIATE SEGMENT OF CIRRUS VI OF THE VARIETY FROM AYUKAWA, JAPAN. nence. Adductor muscle pit small and rather deep, with a raised rim forming a strong adductor ridge. Lateral depressor muscle pit is very indistinct. The tergum is wide above, narrow below. Upper free portion con- spicuously laminate. Articular ridge strong, the articular furrow wide. There is no real spur, as the basiscutal angle is terminal. The basal margin is deeply sinuated below the depressor muscle crests, the strongly developed crests being borne on a triangular lobe of the valve, as in many other species. The mandible is of the stellatus form, but the three points at the lower extremity are much more strongly developed and the finely pectinated space above them is shorter (fig. 87«). 308 BULLETIN 93, UNITED STATES NATIONAL MUSEUM. The maxilla has three large spines and a group of small ones above the rather deep notch (fig. 87&). Cirrus i has rami of 8 and 6 segments, the posterior ramus three- fourths the length of the anterior. The posterior border of the basal segments of the anterior ramus bears some very short, stout, slightly curved spines, much as figured for C. cirratus, but not noticed in any other species. Cirrus ii has rami of G segments, the posterior ramus shorter by the length of one segment. The terminal segments of both rami have several simply serrate spines and a few broad ones with two coarse teeth below the finely serrate portion, as shown in figure 87 .segments. The spines of the terminal segments are as described and figured for (\ x/ct/t'ttis. There are no large-toothed spines, as in C. challcngcri. Cirrus vi has 16 segments, bearing four pairs of spines, as in the specimens from Ayukawa drawn in figure 87e. I had thought this a race of C. stellatus or C. chattengcri until I examined the mouth parts. The mandible is so different, however, that in the present state of our knowledge I think it best to rank it as a species. In place of the even, fine, comblike pectination of the space below the fourth tooth of the mandible, which many species FIG. 90. — OHTHAMALCS MALAYENSIS. a, MAXILLA, AND &, MANDIBLE. of Chthamalus have, there is a series of coarse teeth. The equality of the three spines at the lower angle of the mandible is a less im- portant difference. The mouth parts of this species and C. chaL- lengeri are drawn to the same scale. The status of this form depends upon the constancy of the features of the mandible, which can be determined only by the examination of a larger series of specimens. CHTHAMALUS MORO, new species. Plato 72, figs. 6, 6«, Gb. Type. — Cat. No. 48197, U.S.N.M., from Zamboanga, Mindanao, on Tcfraclita squamosa, collected by Dr. E. A. Mearns. The barnacle is strongly ribbed, whitish, conic; radii narrow, the ala3 rather wide; sutures distinct, simple. The tergal margin of the scutum is nearly equal to the basal; articular ridge straight, long, obliquely truncate below, not project- ing beyond the tergal border of the valve. Adductor muscle pit not 312 BULLETIN 03, UNITED STATES NATIONAL MUSEUM. deep. There is no adductor ridge. Pit for the lateral depressor muscle deep. Interior white. Tergum with moderately developed articular ridge and narrow articular furrow7. Spur broad, rounded, and short. Carinal lobe, bearing the crests, rather large, making an angle with the rest of the basal margin. This species has valves much like those of the American C. fmg'dis, but the articular ridges of both valves are weaker. It differs from C. challengeri by the much less broadly reflexed articular ridge of the scutum, the absence of an adductor ridge, and the broader lower part of the tergum. It is also unlike the specimen referred to G. stellatus, figured in the Siboya report, but it probably belongs close to steHatus. Besides the type lot from Zamboanga collected by Dr. E. A. Mearns, there is a beautiful group seated together with Tetraclita squamosa upon a mangrove oyster collected by the Albatross in the Philippines, exact locality not noted. The specimens were preserved dry, and I have not worked out the mouth parts and cirri. CHTHAMALUS WITHERSI, new species. Plate 73, figs. 2 to 2e. Type.— Cut. No. 48088, U.S.N.M. Locality. — Reef opposite Cebu, Philippine Islands, in a group of Balanus ampkltrlte. Albatross, April 7, 1908. Specimens not distorted by crowding are depressed with a rather large, wide orifice ; cinnamon brown, becoming bluish where the epi- dermis is worn off; the surface smooth, but little worn, the lower part showing growth-stria?. Alse broad, wuth arched, subhorizontal sum- mits, and sculptured with growth-striae stronger than on the parietes. Interior smooth, without basal rugosity or inwardly growing ledge, dull brown, shading into white; sheath short. Sutures smooth, not plicate or crenulated. Diameter, 9.5 mm. ; height, 3 mm. The scutum is thin, triangular, convex between apex and base, more than twice as long as wide, the basal margin somewhat surpassing the tergal. In the lower part there are fine growth-lines. Inside dull brown and white, smooth. The articular ridge is a very feebly de- veloped median lobe, not extending beyond the scutal border. The articular furrow is shallow but sharply incised. There are no pits for the adductor or depressor muscles. The tergum is very narrow, club-shaped, very thick (not eroded in the specimens seen). The articular ridge is rather high but not much reflexed. Articular furroAv shallow. The loAver half of the valve is narrow., but thick, very convex externally, forming a sort of THE SESSILE BARNACLES. 31,'! spur, which is wholly united with the basiscntal angle. The carinal lobe is narrow, situated high, and shows a few short crests for the depressor muscle. The labrum has a broad, nearly straight edge, the middle fourth having a series of 18 strong teeth (fig. 9ld). The mandible has three large teeth and a pectinated lower point having eight slender teeth (fig. 91a). The maxilla has a pair of large upper spines followed by two smaller spines above the small notch. The median part bears a group of about 8 rather large spines. The lower third protrudes, and bears about 10 large and small spines. There is a group of short spines on the lower edge. The prominence of the lower part is a chief feature (fig. 91liialanus Hoek.1 It is evidently no Balanid barnacle, but closely related to Ilexelasma and Pachylasma, differing from Hexelasma by its distinctly calcareous basis, from Pachyla^ma by the absence of caudal appendages, and from both it differs by having well-developed radii. None of these characters are of very great importance; yet, in the present condition of our knowledge of deep-water barnacles, a union of the groups would be premature. KEY TO THE SPECIES OF PACHYLASMA. a1. Rostrum and rostrolateral compartments completely concrescent in the adult stage (distinct and united by linear sutures for a very brief period after fixation) ; the other compartments having well-developed alse. Scuta having growth ridges cut by a few longitudinal furrows or impressed lines. Mediterranean P. yiganteutn (Philippi). a1. Rostrum and rostrolateral compartments closely united by linear sutures, which are sometimes obliterated externally but visible inside. bl. Lateral and carinolateral compartments closely united by a linear su- ture ; only the carina and the lateral compartments showing alse exter- nally; sheath long; scutum having wrinkled growth-ridges cut by slight radial grooves, its width less than half the length. New South Wales. P. aurantiacum Darwin.2 63. Carinolateral compartments having conspicuous alse. o1. Scuta about twice as long as wide, having sinuous or puckered growth- ridges ; tergum with no spur ; carinolateral compartments much more than half as wide as the lateral. Philippines. P. darwinianum Pilsbry. ra. Scuta having sculpture of smooth, even, transverse growth-ridges, not cut by longitudinal grooves or strife ; carinolateral compartment half as wide as the lateral ; tergum having a very short, wide spur. d\ Scutum convex, its width contained two and one-half times in its length ; tergum with no longitudinal depression externally, its ar- ticular ridge not projecting beyond the scutal border. China Sea. P. chinense Pilsbry. d2. Width of scutum contained twice in its length ; tergum having a lon- gitudinal depression externally, its articular ridge projecting a little beyond the scutal border. Japan P. crinoidophilum Pilsbry. 1 Bathy-Balanus Hoek, Si&oj;a-Expeditie, Monographic 31&, p. 160, monotype Balanus pcntacrini Hoek. 2 P. aurantiacum is not contained in the United States National Museum. THE SESSILE BARNACLES. 329 PACHYLASMA GIGANTEUM (Phllippl). 1854. Pachylasma yujanti'inn, Philippi, DARWIN, Monograph, p. 477, pi. 19, figs. 5a-5d. Cat. No. 12060. Strait of Messina. Seguenza, in Jeffrey's collection. PACHYLASMA DARWINIANUM Pllsbry. 1912. Pachylasma darwinianum PILSBRY, Proc. U. S. Nat. Mus., vol. 42, p. 293. Type.— Cat. No. 43465, U.S.N.M., from Albatross Station 5168, Tawi Tawi group of the Sulu Archipelago, 80 fathoms. PACHYLASMA CHINENSE Pilsbry. 1912. Pacliylasma cMnense PILSBRY, Proc. U. S. Nat. Mus., vol. 42, p. 293. Type.— Cat. No. 43471, U.S.N.M., from Albatross Station 5301, China Sea, near Hongkong, 208 fathoms. PACHYLASMA CRINOIDOPHILUM Pilsbry. 1911. Pacliylasma crinoidophUum PILSBRY, Bull. Bureau of Fisheries, vol. 29, p. 81, fig. 11 ; pi. 17, figs. 1-11. Type.— Cat. No. 38675, U.S.N.M., from Albatross Station 4934, off Kagoshima Gulf, in 152 fathoms. Genus HEXELASMA Hoek. » 1913. Hexelasma HOEK, Stfeo^a-Expeditie, Monographie 31fr, pp. 157, 214. Hoek described this genus as follows : Compartments six ; carina, carinolateral and lateral compartments with alee, but without radii, the rostrum having neither radii nor alre. Parietes not porous and without longitudinal ribs on their inner surfaces. Basis mem- branous. Opercular valves subtriangular. Mouth with the labrum not notched in the middle; mandibles with 4 to 5 sharply pointed teeth; nuixillne with numerous spines beneath the notch. Third pair of cirri resembling more those of the fourth than of the second pair. No caudal appendages. Species living in deep water. By the texture of the compartments and valves, the absence of radii and the absence of an adductor ridge in the scutum, Ilexelasma resembles Pachylasma; but it differs by having no trace whatever of caudal appendages, and in the typical species by having a mem- branous basis. In H. americanum and H. callistoderma the basis is calcareous, but very thin in the center, so that in specimens removed from the support the very thin, filmlike central region adheres partly to the support, so that I formerly described callistoderma as having the central part of the basis membranous. There is an in- flected rim at the bases of the compartments very much thicker than the true basis. 330 BULLETIN 93, UNITED STATES NATIONAL MUSEUM. The absence of terminal appendages is perhaps a more important character, differentiating Hexelasma from Pachylasma; yet these vary a good deal in Pachylasma. In P. crinoidophilum the appen- dages have eight joints; in P. darwinianum only one extremely minute joint, with minute terminal bristles. Since the rostrum of Hexelasma overlaps the adjacent latera, which have alse, it is certainly a composite plate formed of the con- crescent rostrum and rostral latera, exactly as in Pachylasma yigan- teum. Young specimens, when found, should be examined for traces of the sutures. Darwin found them at the apex in a Pachy- lasma slightly over 1 mm. in diameter. The form of the labrum and of the third cirri show at once that Hexelasma, belongs to the Chthamalid(L', and not to the Ba- lanidw. The armature of mandible and maxilla, the form of the lower edge of the sheath, and the texture are also characters pointing in the same direction. Ilexelasma now contains seven species, as follows : H. velutinum Hoek. Malay Archipelago, 204 to 390 meters. II. arafurcc Hoek. Malay Archipelago, 560 meters. H. corolliforme Hoek. Near Kerguelen Island. 270 meters. H. hirsutum Hoek. Faroe Channel, 930 meters. H. aucklandicum Hector.1 New Zealand, Miocene. And the folloAving collected by the Albatross: HEXELASMA AMERICANUM, new species. Plate 69. Type.— Cut. No. 14559, U.S.N.M. Type-locality. — Albatross station 2G63, off South Carolina, lati- tude 29° 39' north ; longitude 79° 49' west; 421 fathoms, bottom tem- perature 42°.7 F., seated on a branch of coral. The barnacle has a membranous basis with narrowly inflected cal- careous borders; strong, solid compartments which are only weakly cemented together, are without pores, and have no radii. Light buff or delicately salmon tinted under a very thin pale corneous cuticle, which extends over the parietes and part of the ala?. The orifice is rather small and deeply notched. The alae are broad, regularly ob- liquely striated, and have very oblique, smooth summits. The parietes have distinct, spaced linear growth-marks, which on some of the plates show an indistinct and minute puckering (possibly indicative of deciduous hairs) ; the surface between growth-marks being minutely rippled and longitudinally a little roughened. The sheath is salmon buff, smoothly grooved transversely, less than half as long as the irT. II. Withers, Proc. Zool. Soc. London, 1913, p. 841, pi. 85. The detached compart- ments of this gigantic species were originally referred to ScalpcUum. Its proper generic reference is due to Mr. Withers. It attained a length of 19 cm. THE SESSILE BARNACLES. 331 wall, its lower margin not in the least overhanging. The interior is not in the least grooved below the sheath, and at the basal edge tho compartments are very narrowly inflexed or have a slight rim around the membranous basis. The carina is longer than the rostrum, longer than wide, triangular in outline. The carinolateral compartments have very narrow, band- like parietes, hardly one-fourth as wide as that of the rostrum. The rostrum is normally about as high as wide, and triangular in shape. The base is modified in shape by the cylindrical coral, which serves as support, and upon which the barnacle is seated with the carino- •u^ FIG. 98. — HEXKLASMA AMERICANUM. a, INTERMEDIATE SEGMENTS OF ciuuus vi. 6, FIRST CIRUUS. C, MANDIBLE. d, MAXILLA. rostral axis transverse to the long axis of the coral-branch in all but one of the specimens seen. Greatest carinorostral diameter, 17 mm.; basal diameter at right angles to preceding, 18 mm. ; height of carina, 21 mm. The scutum is at least two and one-half times as long as wide, sculptured with regular growth-ridges, which unite by pairs to form oblique teeth along the occludent edge. There are no longitudinal strise. Inside there is a very low, rounded, rather massive articular ridge, and a deep, very narrow articular furrow, but no adductor ridge whatever. There is a small pit with a couple of short crests for the lateral depressor muscle. The occludent border of the plate is bent up along its lower half. 332 BULLETIN 93, UNITED STATES NATIONAL MUSEUM. The tergum is nearly flat, weakly striate transversely, the carinal half slightly convex and scored with a few longitudinal lines. A weakly impressed line runs to the carinal base of the spur, which has no furrow. The spur is very short, occupying about one-third of the basal margin. It is close to the basiscutal angle, and its end is obliquely truncate. Inside there is a rather low but long articular ridge, and numerous sharp but short crests for the depressor muscle. The mandible has four rather acute teeth and a spinose lower point. The maxilla has two large spines followed by a notch in which there are several small ones. Median third is armed with long but unequal spines and the lower fourth with shorter spines (fig. 98^). This peculiar barnacle is obviously related to Hexelasma callisto- derma (Pilsbry) of the western Pacific, agreeing with that in the- structure of the walls and opercular plates, the slender teeth of the mandible, the strongly annulate, rather short and hairless penis, and the structure and spines of the cirri. It differs from the Pacific species by having a narrower scutum, while the tergum is somewhat wider, with longer basal and shorter carinal margins; the spur is shorter and scarcely separated from the basiscutal angle of the valve. The external sculpture of the compartments is also less developed in the Atlantic species, which moreover differs by the flattened side walls and various other peculiarities of the wall plates, such as their minute sculpture. The material examined consists of one perfect individual (Cat. No. 14559) from the type-locality, and parts of at least three incomplete ones (detached plates of the wall) from a lot labeled as from Alba- tross stations 2662-3-9, 2671-2 and registered as Cat. No. 48093, U.S.N.M. The remains of two individuals in No. 48093 show carinrc similar to that of the type, except that they are a little less bowed, the roof being flattened (pi. 69, fig. 3). In the third individual (pi. 69, fig. 2) the carina is almost straight, narrow, and nearly parallel-sided, with the roof very convex. From the shape of the basal margin it is clear that this one grew upon a narrow branch of the coral, with its carinorostral axis parallel to that of the branch. The whole contour of the barnacle was doubtless modified by the narrow support. HEXELASMA CALLISTODERMA (Pilsbry). 1911. Balamis callistoderma PILSBET, Bull. Bureau of Fisheries, vol. 29, p. 78, fig. 10, pi. 12, fig. 5 ; pi. 15, figs. 3-7. Type.— Cat No. 38690, U.S.N.M., from Albatross station 5068, Suruga Gulf, Japan, in 77 fathoms. THE SESSILE BARNACLES. 333 To the description of this species may be added that the labrum has a rather deep median concavity but no notch. The edge is densely set with minute spines, and below the edge there are shorter spines set in groups. There are no " teeth " (fig. 99). The palpus has a series of long spines on the face, as usual in Balanus and some Ckthamali, running into a group on the distal end. Upper margin densely covered with much shorter spines. The third cirrus has long rami like the fourth. The lower seg- ments are densely bristly, like those of the second cirri, but the FIG. 99.— HEXELASMA CALLISTODERMA. a, EDGE OF THE LABRUM. 6. SMALL FART OF THE EDGE MAGNIFIED TO SHOW THE SPINES. C, SPINES FROM THE CENTRAL PART OF THE LABRt'M, SOME DISTANCE BELOW THE MARGIN. median and distal segments bear two pairs of long spines as in the later cirri. Dense tufts of hair rise from the inner faces of the median segments. None of the cirri have " teeth " or spinules. The penis is not much more than half as long as the sixth cirri, and has no basi-dorsal point. There is no trace whatever of terminal appendages. The basis is entirely membranous in young individuals, and the compartments are longitudinally ribbed inside and at the basal edges. In the adult stage the basal edges of the compartments grow in- ward, as in some species of Chthamalus, forming a ledge, thick outwardly, but thin at its inner edge, which is often somewhat scalloped or lobed. The true basis is partially calcified, there being an extremely thin calcareous film over large parts of it in old indi- viduals, but, so far as I have seen, not complete. It is not easy to observe, since parts of this calcareous film adhere to the peripheral ledge and the body when the barnacle is removed from its support, and parts of it remain upon the support. The calcification is there- fore less complete than in Pachylasma. Albatross Station. Locality. Depth, fathoms. Bottom tem- perature. Collector. 5068 SuruRa Gulf Japan 77 Albatross. 3741 Ose Zaki Japan.. 63-68 Do 334 BULLETIN 03, UNITED STATES NATIONAL MUSEUM. Genus OCTOMERIS Sowerby. 1S25. Octomeris SOWEEBY, Zoological Journal, vol. 2, p. 244. Monotype, O. angulosa. 1854. Octomeris Sowerby, DARWIN, Monograph, p. 282. Chthamalidce with eight compartments; edges of the radii crenated; basis membranous. Darwin describes two species, O. angulosa Sowerby, from Algoa Bay, South Africa, and O. brunnea Darwin, from the Philippines. No others have been described since his monograph. They inhabit the littoral zone. OCTOMERIS ArGULOSA Sowerby. 1854. Oclomrrift angulosa Sowerby, DARWIN, Monograph, p. 483, pi. 20, figs. 2a, 2b. Locality. Collector. Cape of Good Hope Win Stimpson, North Pacific Exploring Expe- Capo Town dition. U. S. Eclipse Expedition, 18S9. (Not stated) Isaac Lea collection. The Cape Town specimens have deeply cut, continuous ribs, such as are shown in Chenu's figures of "Octomeris augubra" This form may, perhaps, be separable from the typical O. anyulosa-, but my material is not abundant enough for a decision. Chenu's name was probably an error of the engraver and not intended as a new name. Genus CATOPHRAGMUS Sowerby. 1S27. Catophragmus SOWERBY, Genera of Recent and Fossil Shells. 1854. Cato-pJiragmus Sowerby, DARWIN, Monograph, p. 485. Interior compartments eight, provided with alfe but no radii; their bases concealed by one or several exterior whorls of small, supplemental compartments ; basis either membranous or calcareous ; scutum without an adductor ridge, the articular ridges of both valves strongly developed. Caudal appendages present in some species. The three species of this genus are about as widely separated as possible, one littoral species on the eastern coast of Australia, another in the West Indies, and the third in deep water of the Hawaiian Archipelago. They are evidently the remnants of an ancient group. In structure they are rather divergent. I have not seen C. imbricatus, but the other two species differ markedly in texture. C. polymerus has a great deal of chitin in the compartments, and the calcareous material is partly purplish. C. darwini is conspicuously porcellanous and dead white. THE SESSILE BARNACLES. 335 KEY TO SUBGENERA AND SPECIES. a1. Caudal appendages wholly wanting; basis membranous; basal edges of the inner compartments beveled outside, the outer layer not extending to the base ; supplementary compartments numerous, carinate, imbricating over the sutures of each preceding whorl. Subgenus Catomcrus (new subgenus) C. polymcrus Darwin. a'. Caudal appendages present. b1. Basis calcareous ; supplementary compartments not keeled, not very numerous, imbricating over the sutures ; white ; caudal appendages very small. Subgenus Catopliragmus C. imbricatus Sowerby. b\ Basis unknown ; basal edges of the inner compartments not beveled out- side, the outer layer extending to the base; supplementary compart- ments in a single series, not restricted to the sutures of the inner wall, and of several forms, with or without one or two alse ; white and por- cellanous in texture ; caudal appendages well developed. Subgenus Chionelasmns Pilsbry C. darwini Pilsbry. CATOPHRAGMUS IMBRICATUS Sowerby. 1827. CatopJiragmus imbricatus SOWERBY, Genera of Recent and Fossil Shells. 1S54. CatopJiragmus imbricatus Sowerby, DARWIN, Monograph, p. 490. 1901. Catopliragmus imbricatus Sowerby, VERRILL, Trans. Conn. Acad., vol. 11, pt. 1, p. 22, pi. S, figs. 8, 9. Type. — British Museum, from Antigua. Distribution. — Antillean faunal province; Antigua and Bermuda. This species is not contained in the National Museum. It is dis- tinguished from C. polyinerus by the white color, the calcareous basis and the caudal appendages, which, according to Darwin, are short, equaling only the lower segment of the pedicel of the sixth cirrus, and consisting of three joints, in a young specimen 5 mm. in dia- meter. It attains a diameter of three-quarters of an inch, according to Darwin. Professor Verrill remarks of those found by him in Bermuda : Several specimens of this interesting barnacle were found on littoral rocks. They are all young (about 5 to 8 mm. in diameter) and agree well with the young one described by Darwin from Antigua. The eight primary mural plates are pointed and surrounded and partially concealed by about three alternating whorls of smaller, pointed plates; rapidly decreasing in size ex- teriorly. The opercular scuta are strongly concentrically ribbed and have a deep, median radial sulcus. The base is calcareous, but thin. The color is pure white. CATOPHRAGMUS DARWINI Pilsbry. 1907. Catopliragmus darwini PILSBRY, Bulletin of the Bureau of Fisheries, vol. 26, p. 188, fig. 4, pi. 5, figs. 1-8. 1911. Catopliragmus (Chionelastmis) darwini PILSBEY, Bull. Bur. of Fish- eries, vol. 29, p. 82. Type.— Cat. Nos. 32407, 32408, U.S.N.M. Distribution. — Hawaiian Islands: Albatross station 30J)8, vicinity of Kauai, in 228 to 235 fathoms. 336 BULLETIN 93, UNITED STATES NATIONAL MUSEUM. CATOPHRAGMUS POLYMERUS Darwin. 1854. Catophragmus poly merits DARWIN, Monograph, p. 487, pi. 20, figs. Type. — British Museum, from Twofold Bay, New South Wales. Richmond, near Melbourne, Victoria, on shells and stones, collected by Mrs. Agnes Kenyon. The shape of the opercular valves varies a good deal. In low, spreading individuals the scutum is broad, as figured by Darwin, but in high ones with steep walls it is narrower, the basal margin shorter than the tergal, and the articular furrows of both valves are more oblique, so that the articulating borders are much less deeply notched than Darwin's figures show. It appears to be a strictly littoral species, living with Tetraclita, Chthamalus, etc. APPENDIX. Balanus concavus pacificus Pilsbry (p. 104). Specimens from between Venice and Kocky Point, California, collected by the Anton Dohrn for the Venice Marine Biological Station, agree with those from Newport, California (pi. 23, figs. 2-2c), in the form of the opercular valves. This particular race may be denoted as form brevicalcar. See page 107 for description. Balanus eburneus Gould (p. 80). The following synonym should be added : B.[alanus] democraticus DEKAY, Zoology of New York, Mollusca, 1844, p. '2~>'2. 337 EXPLANATION OF PLATES. PLATE 1. FIG. 1. Verruca coraliophila Pilsbry. Top view of type. C., carina ; F. Sc., fixed scutum; F. T., fixed tergum; Us. rostrum. Page 21. la. Verruca coraliophila. Basal view. A. R., adductor ridge. 2, 4. Verruca coraliophila. Carinorostral views of two individuals, the movable plates lacking. 3. Verruca coraliophila. Interior views of fixed tergum and scutum. 5. Verruca coraliophila. Interior views of movable tergum and scutum. PLATE 2. FIGS. 1-1 b. Verruca alba Pilsbry. Pom-tales Plateau, near Key West, Florida. Top, carinorostral and basal views. Page 25. 2. Verruca alba. Basal view of a Blake specimen. 3, 3a. Verruca alba barbailcnsis Pilsbry. Top and rostrocarinal views of the type. Page 28. 4. Verruca alba caribbea Pilsbry. Colony on a sea-urchin spine. Page 28. PLATE 3. FIGS. 1-lc. Verruca nexa, Darwin. Top, scutotergal, and carinorostral walls and base. Page 29. 2. Verruca cuglypta Pilsbry. Interior view of rostrum. 2a. Verruca euglypta Pilsbry. Interior view of fixed and movable scuta and terga. Page 39. PLATE 4. FIGS. 1-lc. Verruca floridana Pilsbry. Top, base, rostrocarinal and scuto- tergal walls. Page 31. 2. Verruca floridana. Movable plates of a more sculptured indi- vidual. 3. Verruca floridana. Carinorostral view of an individual which sat transversely upon an echinoid spine. 4. Verruca crtlothcca Pilsbry. Basal view of type. Page 33. 4c, 4&. Verruca calotheca. Interior of movable scutum and tergura. PLATE 5. FIGS. 1, la. Verruca calotheca hctcropoma Pilsbry. Top and carinorostral walls of the type. Page 35. 2, 2a. Verruca calotheca flavidnla Pilsbry. Carinal and top views of the type. F. T., fixed tergum; If. T., movable tergum. Page 34. 339 340 BULLETIN 93, UNITED STATES NATIONAL MUSEUM. PLATE 6. FIGS. 1-lb. Verruca xanthia Pilsbry. Carinorostral, basal, and top views of the type. Page 36. 2. Verruca xanthia insculpta. Top view of the type. Page 37. 3, 3er, 3&. Verruca entobapia Pilsbry. Basal, rostrocarinal, and top views of the type. Page 38. PLATE 7. FIGS. 1-1&. Verruca bicornuta Pilsbry. Rostrocarinal, tergoscutal, and rostral views of the type . Page 43. lo. Verruca bicornuta. Interior of scutum and tergum. 2-2&. Verruca rathbitniana Pilsbry. Carinorostral, scutotergal, and rostral views of the type. C. carina ; F. Sc., fixed scutum ; F. T., fixed tergum ; M. Sc., movable scutum ; M. T., movable tergum ; R., rostrum. Page 41. PLATE 8. FIGS. 1, la-. Verruca halotheca Pilsbry. Top and Carinorostral views of the type, on a volcanic pebble. Page 46. 2. Verruca hrvifjnta Sowerby. Top view of specimen from Talca- huano Bay, Chile, growing on Balanus psittacus. Page 25. 3-3&. Verruca bicornuta Pilsbry. Second, first, and part of the sixth cirri. Page 43. PLATE 9. FIG. 1. Verruca bicornuta Pilsbry. Base of cirrus vi and terminal append- age. Page 44. 2. Verruca alba. Penis, cirrus vi, and terminal appendage of indi- vidual figured on plate 2, figs. 1-3. Page 27. 3. Verruca cuglypta Pilsbry. Pedicel of cirrus vi and terminal ap- pendage. Page 40. 4. Verruca entobapta Pilsbry. Pedicel of cirrus vi and terminal appendage. Page 38. PLATE 10. FIG. 1. Balanus tintinnabulum tintinnabulum (Linnsens'). Taken from a ship reaching Philadelphia from Hongkong, Java, and India. Lateral view. Page 55. la-Id. Opercular valves of same specimen. le. Basal edge of wall of another specimen of the same lot. 2. Balanus tintinnabulum zebra Darwin. Part of the free edge of radius. Page 57. 2a, 2b. Balanus' tintinnabulum zebra Darwin. Apical views of two indi- viduals from the ship mentioned above. 3. B. t. zebra. Zamboanga, Mindanao. Cat. No. 43489, U.S.N.M. Figs. 1, 2a, 21), 3, 3«, natural size ; the others enlarged. PLATE 11. FIGS. 1-le. Balanus tintinnabulum occator Darwin. Taken from bottom of iron ship reaching Philadelphia from Java. Nos. 469 and 585, A.N.S.P. Page 59. 2-2e. Balanus tintinnabulum volcano Pilsbry. Japan. Lateral view, scuta and terga of the type. Cat. No. 43488, U.S.N.M. Figs. 1, le, 2dt natural size ; the others enlarged. Page 60, THE SESSILE BARNAOLES. 341 PLATE 12. FIGS. 1-1&. Balanus tintinnabulum galapaganus Pilsbry. Hood Island, Gala- pagos. Tergum and scuta of the type. Cat. No. 48003, U.S.N.M. Page 70. 2, 2a, 2b. Balanus tintinnabulum azoricus Pilsbry. Terceira, Azores. Scuta and tergum of the type. Cat No. 48004, U.S.N.M. Page 62. 3-3d. Balanus algicola Pilsbry. Cape Town. Groups and solitary indi- viduals growing on various algae. Cat. No. 15063, U.S.N.M. Page 72. 3e, 3f, 3ff. -Balanus algicola. Terguna and scuta of type, in group 3a. PLATE 13. FIGS. 1-le. Balanus tintinnabulum antillensis Pilsbry. St. Thomas, West Indies. Type and paratype group, with opercular valves. Page 63. 2-2b. B. t. antillensis from bottom of a Cape Cod whaler, from the West Indies. Lateral and basal views. Cat. No. 48005, U.S.N.M. In fig. 2b a small specimen of Tetraclita radiata is seen attached. 2c, 2d, 2e. Tergum and scuta of the same. Figs, le, 2-2&, natural size. PLATE 14. Balanus tintinnabulum californicus Pilsbry. FIG. 1. Type and paratypes, San Diego, California. Cat. No. 9434a, U.S.N.M. Natural size. Page 65. lar-ld. Opercular valves of type. 2. Group on an oyster, San Diego. Cat. No. 9435, U.S.N.M. Natural size. 3. Group showing the form with lengthened basis, near Santa Bar- bara, California. Cat. No. 43484, U.S.N.M. PLATE 15. FIGS. 1, la. Balanus tintinnabulum peninsularis Pilsbry. Groups. Cat. No. 43487, U.S.N.M. Natural size. Page 66. 2-2d. B. t. peninsularis. Cape St. Lucas. Type with its opercular valves, and a smaller specimen. 2b, 2c natural size. Cat. No. 43486, U.S.N.M. 3. Balanus tintinnabulum concinnus Darwin. Inside of scutum. Page 69. 4. Balanus tintinnabulum californicus Pilsbry. Basal edge of the wall of one of the type group. The spongy basis is seen near the left side. Page 65. PLATE 16. FIGS. 1, 10. Balanus tintinnabulum coccopoma Darwin. Tergum and scutum of specimen from Panama. Page 68. 2, 2a. Balanus tintinnabulum coccopoma Darwin. Group and outside of scutum. Bay of Panama. Fig. 2 natural size. 3. Balanus tintinnabulum concinnus Darwin. Payta, Peru. Cat. No. 12417. Natural size. Page 69. 4729°— Bull. 93—16 23 342 BULLETIN 93, UNITED STATES NATIONAL MUSEUM. PLATE 17. FIGS. 1-4. Balanus psittacus (Molina). Talcahuano Bay, Chile. Page 75. 5-8. Balanus tintinnabulum concinnus Darwin. Peru. Page 69. PLATE 18. Balanus psittacus (Molina). Page 75. FIG. 1. Adults from Talcahuano Bay, Chile. Cat. No. 43482. Length of right-hand specimen about 18 cm. Small barnacles growing on the larger ones are Balanus Iccvis nltidus Darwin and Verruca Icevigata Sowerby. 2. Young individual from Valparaiso. Cat. No. 48007. Showing transient ribbed stage. Natural size. 3. Young individuals from Arica. Cat. No. 48006, U.S.N.M. Ribbed form, in lateral and obliquely rostral views. Natural size. PLATE 19. Balanus amphitrite nivcus Darwin. Page 92. FIGS. 1, la, 15, Ic. Vineyard Sound, Massachusetts. Terga and scuta of an indi- vidual of group Ic. Ic. Vineyard Sound, Massachusetts. Cat. No. 38313, U.S.N.M. Group growing on a pebble. Id. Vineyard Sound, Massachusetts. Tergum of another specimen of group Ic, having the spur rounded distally. 2. Marco, Florida. Cat. No. 48008, U.S.N.M. Group growing on the back of a Crepidula. la, 26, 2c. Marco, Florida. Terga of three individuals of same group. 2d, 2e. Marco, Florida. Scuta of individuals of same group. Figs. Ic and 2 natural size. PLATE 20. FIG. 1. Balanus amphitrite albicostatus Pilsbry. Yedo Bay, Japan. Cat. No. 48011, U.S.N.M. Lateral view. Page 90. 2-2b. B. a. albicostatus. Type. Cat. No. 32950, U.S.N.M. Lateral view, tergum and scutum. 3. B. a. albicostatus. Group on a quartz pebble, from the North Pacific Exploring Expedition. Cat. No. 48008, U.S.N.M. 4. B. a. albicostatus. Hirado, Hizen. No. 1518, A.N.S.P. Rugged form. 5-5e. Balanus amphitrite inexpectatus Pilsbry. Gulf of California. Cat. No. 12398, U.S.N.M. Type-specimen, growing on an oyster, with terga and scuta. Page 97. 5c. Tergum of a smaller individual, showing variation in shape of the spur. THE SESSILE BARNACLES. 343 PLATE 21. FIGS. 1-lc. Balanus concavus Bronn. Typical form from British Red Crag (Pliocene). Cat. No. 12058, U.S.N.M. Page 100. 2. Balanus concavus glyptopoma Pilsbry. Caloosahatclne Pliocene. Cotype, Academy Natural Sciences of Philadelphia. Page 102. 3. Balanus concavus glyptopoma Pilsbry. Miocene, Yorktown, Va. 4. Balanus regalis Pilsbry. Interior view of rostrum and part of the basis of a cotype. Page 108. 4a. Balanus regalis Pilsbry. Point Abreogos, Lower California. Co- types. Cat. No. 43485, U.S.N.M. Figs 1ft, 2, 3, 4a about natural size. PLATE 22. FIGS. 1-lc. Balanus concavus chesapeakcnsis Pilsbry. Chesapeake Bay, Mary- land, Miocene. Type, with tergum and scuta. Page 103. 2,2a,2b,2r. Balanus concavus glyptopoma, Pilsbry. Caloosahatchie River, Florida, Pliocene. Scuta and tergum, cotype, Academy Natural Sciences of Philadelphia. Page 102. 3-3c. Balanus concavus proteus Conrad. Virginia, Miocene. Scuta, ter- gum, and apical view of typical examples, collected and labeled by Conrad. Page 103. Figs. 1 and 3c natural size. PLATE 23. FIGS. 1-1(7. Balanus concavus paciflcus Pilsbry. Lateral view, scuta and terga of the type, San Diego, California. Cat. No. 32953, U.S.N.M. Page 104. 2-2c. Balanus c. paciflcus form brevicalcar Pilsbry. Specimens from Albatross station 2939. Page 337. PLATE 24. FIGS. 1-lc. Balanus eburncus Gould. Smith's Creek, Potomac River, Mary- land. Page 80. 2. B. eburneus. Vineyard Sound, Massachusetts, off Martha's Vine- yard. 3, 3«, 3b. Balanus improvises Darwin. South Downs, England. Cat. No. 48009, U.S.N.M. Tergum and apical view. Page 84. 4. Balanus amphitrite peruvianus Pilsbry. Rostrum with part of the basis of a paratype. Page 97. 5-5d. Balanus improvisus Darwin. Quinnipiac River, below Grand Street Bridge. Cat. No. 48010, U.S.N.M. Group on an oyster, and oper- cular valves. Page 84. Figs 1, 2, 36, and 5 natural size. 344 BULLETIN 93, UNITED STATES NATIONAL MUSEUM. PLATE 25. FIGS. 1-lc. Balanus calidus Pilsbry. Albatross station 2372, off western Flor- ida. Opercular valves and lateral view of type-specimen. Cat. No. 10069, U.S.N.M. Page 118. 2. Balanus spongicola Brown. Dublin Bay, Cat. No. 12145, U.S.N.M. Lateral view of specimen seated on Pecten opercularis. Natural size. Page 115. 3. B. spongicola. Exmouth, Devon. Cat. No. 12078, U.S.N.M. Lat- eral view of specimen seated on a sandstone pebble. Natural size. 4-Ac. B. spongicola. Patros Island, Brazil. Cat. No. 14144, U.S.N.M. Lateral view of group, and opercular valves. PLATE 26. Balanus trigonus Darwin. Page 111. FIGS. 1-9. Type figures of Balanus armatus F. Miiller, copied photographically from Miiller's plate, r, carina ; r, rostrum. 10, 10a-. Internal and external views of the tergum, from the same source. 11. External view of the scutum, from the same source. 12, 12a. Lateral view of wall and inside of tergum of a West Indian speci- men, taken from the bottom of a Cape Cod whaler. Cat. No. 21550, U.S.N.M. Length, 8.3 mm. 13-13c. Group covering the shell of a Tegula, and opercular valves. San Diego, California. Cat. No. 11153, U.S.N.M. PLATE 27. FIGS. 1, la. Balanus Iwris Bruguiere. Gregory Bay, Strait of Magellan. Cat. No. 48012, U.S.N.M. Scuta. Page 120. 2-2d. B. I. nitidus Darwin. Arica, Chile. Page 122. 3, 3ffl, 36. B. Iwvis. Albatross station 2773, east coast of Patagonia. Cat. No. 4S013, U.S.N.M. Groups and spongy bases of specimens which grew on pebbles. Page 120. 4. B. I. nitidus. Callao. Cat. No. 9209, U.S.N.M. Specimens forming a ball, wholly concealing the original supporting object. Page 122. 5. B. 1. nitidus. Arica, Chile. Scutum with groove much reduced. Figs. 3-4 about natural size. PLATE 28. FIGS. 1, la. Balanus grcgarius (Conrad). San Pablo formation, Salinas Val- ley, Monterey County, California. Detached basis, upper and basal views, the latter natural size. Page 126. 2. B. gregarius. Lateral view of a biconic example 104 mm. in greatest diameter. 3. B. gregarius. Section about midway of the basis of an elongated example, viewed from above. Natural size. 4. Balanus Iwvis coquimbensis Sowerby. Opened longitudinally to show the septa of the basis. Somewhat enlarged. Page 122. The specimens illustrated in figs. 1-3 are property of the United States Geological Survey. THE SESSILE BARNACLES. 345 PLATE 29. FIGS. 1, Ic. Balanus gregarius (Conrad). San Pablo formation, Salinas Val- ley, Monterey County, California. Median longitudinal section through the carinorostral axis, and external lateral view of the same individual. Length, 198 mm. Property of the United States Geological Survey. Page 126. PLATE 30. Balanus nubilis Darwin. Page 131. FIGS. 1-lc. Straits of Juan de' Fuca, Washington. Cat. No. 4S014, U.S.N.M. 1, Inside of scutum ; la, group, natural size; lb, part of the basal edge of the carina ; Ic, segment of basis, showing spongy struc- ture of the lower layer. 2, 2a. Puget Sound. Cat. No. 48015, U.S.N.M. Tergum and lateral view of wall, the latter natural size. A young specimen. 3, 3«. Admiralty Inlet, near Port Townsend, Washington. Natural size. Valves of the same individual are shown enlarged in plate 31, figs. 3, 3a. 4. Group, Cat. No. 4669, U.S.N.M., the largest individual having partly lost the outer lamina, exposing the parietal tubes. Four- fifths natural size. PLATE 31. FIG. 1. Balanus aquila Pilsbry. Santa Barbara, California. Cat. No. 9432, U.S.N.M. Lateral view of a perfect individual. Page 127. 2. B. aquila. San Diego, California. Cat. No. 9434, U.S.N.M. In- ternal view to show strongly bifid alse of the carina and lateral compartment. 3, 3fl. Balanus nubilis Darwin. Tergum and scutum of very deeply cor- roded specimen from Admiralty Inlet ; 1| natural size. Page 131. 4, 5. Balanus nubilis Darwin. Tergum and scutum of well-preserved individual, Cat. No. 48014, U.S.N.M., from the Straits of Juan de Fuca. 4a. Balanus aquila Pilsbry. Monterey Bay, California. Cat. No. 32403, U.S.N.M. Lateral view of the type, seated upon a rock which is partly concealed by worm-tubes. Page 127. PLATE 32. FIGS. l-l/. Balanus flos Pilsbry. Monterey Bay, California. Cat. No. 32405, U.S.N.M. Lateral and apical views, and opercular valves of the type. Page 135. 2-2c. Balanus aquila Pilsbry. Valves of the type individual figured on plate 31, fig. 5. Reproduced from the Bulletin of the Bureau of Fisheries, vol. 26, plates 8 and 9 ; drawn by Helen Winchester. Page 127. 346 BULLETIN 93, UNITED STATES NATIONAL MUSEUM. PLATE 33. Balanus balanus (Linnaeus). Page 149. FIGS. 1, la. Tablet bearing Linnseus's specimens, and profile view of the type- specimen, from the collection of the Linuean Society of London. 2. Large English specimen of the typical form. Cat No. 12077, U.S.N.M. This individual grew on Pecten opercularis. 2a. Specimen growing on Pecten opercularis and showing its sculpture. Cat. No. 12077, U.S.N.M. England. 4. Strongly ribbed form, growing on a smooth mussel. Scarborough, England. 5. Strongly ribbed form, growing on a smooth mussel. Belfast, Ireland. 6, 6ff, 6ft. Opercular valves of the typical English specimen shown in fig. 2. Gr. Tergum of specimen from Bering Sea, Albatross station 3289. See also plate 35, fig. 4. PLATE 34. Balanus balanus (Linnfeus). Page 149. FIGS. 1-1 c. Bar Harbor, Maine, lateral view of specimen from a smooth shell, with opercular valves. 2. Portland, Maine. Cat. No. 4801G, U.S.N.M. Specimen showing normal development of carina and carinal latera, and broadly spreading latera and rostrum. See also plate 35, fig. 6. 3. Maine. Type-specimen of Balanus {icniculatus Conrad. Coll. A.N.S.P. Page 158. 4. Fish Commission Station 134, off Thatchers Island. Rostral view of specimen growing on a smooth pebble. 5. Georges Bank, in 40 fathoms. Cat. No. 3522, U.S.N.M. Specimens growing on Pecten magellanicus. 6. Bar Harbor, Maine. Specimen growing on a small pebble, collected with fig. 1. 7. Bay of Fundy. Cat. No. 2303, U.S.N.M. Group on a smooth pebble. Figs, lo-lc enlarged, the others reduced. THE SESSILE BARNACLES. 347 PLATE 35. Balanus balanus (Linnreus). Page 149. FIGS. 1-16. Aberdare Channel. Two groups, natural size, and basal view of rostrum. 2, 2ff. Georges Bank, Albatross station 2079. Lateral view of group and basal margin, typically sculptured form with thin wall. 3. Off Eastport, Maine. Basal view of the lateral compartments of two specimens growing together. The exterior is Hke plate 34, fig. 1. 4. Albatross station 3289, Bering Sea. Cat. No. 48017, U.S.N.M. Growing on Chrysodomus. See also plate 33, fig. Gc 5. Georges Bank. Basal view of part of the rostrum. 6. Portland, Maine. Part of the base of specimen figured in plate 34, fig. 2, to show long lamellae depending from outer lamina of the wall. 7. Cork, Ireland. Cat. No. 12092, U.S.N.M. Basal view of lateral compartment to show long lamellae of the outer lamina. 8. Cape Prince of Wales, Alaska. Cat. No. 48018, U.S.N.M. Lateral and carinal views of specimens seated on Chrysodomus. Height of right-hand specimen, 27 mm. Figs. 1, 16, 2, 4, and 8 about natural size, the others enlarged. PLATE 36. FIG. 1. Balanus rostratus Hoek. Tokyo Harbor, Japan, No. 1814 A.N.S.P. 2, 2«. Balanus rostratus Hoek. Japan. Cat. No. 48019, U.S.N.M. Lat- eral view and basal view of part of the rostrum. Page 138. 3. Balanus rostratux apertus Pilsbry. Albatross station 2849. Cat. No. 48020, U.S.N.M. Smooth specimen growing on Tercbratulina. 4. Balanus rostratus apertus Pilsbry. Captains Bay, Unalaska. Cat. No. 9191, U.S.N.M. Growing on Pectcn, and reproducing its sculpture. Page 144. 5. Balanus rostratus apertus. Albatross station 2849, on Terebratu- lina. Cat. No. 48020, U.S.N.M. Outer lamina of the lateral com- partment filed, showing the parietal tubes. ' Page 144. 6. Balanus rostratus apertus Pilsbry. Captains Harbor, Unalaska. Typical spongicolous form, spinose and with deeply concave basis. Cat. No. 9190, U.S.N.M. . Page 144. 7, 7«, 8. Balanus rostratus heteropus Pilsbry. Albatross station 2864. Puget Sound, Washington. Cat. No. 48022 U.S.N.M. Type and paratype. Tergum and lateral view of wall, the lateral compart- ment filed to show the parietal tubes. Page 142. 9. Balanus balanus pugetcnsis Pilsbry. Albatross station 2864. Cat. No. 48021, U.S.N.M. Filed to show parietal tubes. Page 163. 10, 10«, 106. Balanus balanus pugetensis Pilsbry. San Juan Islands, Puget Sound. Type No. 2040 A.N.S.P. Lateral view, filed to show parietal tubes ; tergum, and scutum. Page 163. 348 BULLETIN 93, UNITED STATES NATIONAL MUSEUM. PLATE 37. FIGS. l-lA Balanus rostratiis apertus Pilsbry. Opercular valves of the type. Page 144. 2-2c. Balanus amphitrite peruvianus Pilsbry. Opercular valves of the type. Page 97. Figs. 1-le reproduced from the Bulletin of the Bureau of Fisheries. Figs. 2-2c from the Proceedings of the United States National Museum. Drawn by Helen Winchester. PLATE 38. FIGS. 1-lb. Balanus rostratiis dalli Pilsbry. Unalaska. Cat. No. 9202, U.S.N.M. Type. Lateral view, basis and basal edge of the rostrum. Page 147. Ic, portion of rostrum filed to show parietal tubes. 2. B. r. dalli. Unalaska. Cat. No. 48023, U.S.N.M. 2a. Balanus balanus L. Unalaska. Cat. No. 4S024, U.S.N.M. Grow- ing on B. r. dalli. Cat. No. 48023, U.S.N.M. Page 159. 3. Balanus restrains suturalis Pilsbry. Alaska. Cat. No. 48025, . U.S.N.M. Page 148. 4, 4a. Balanus rostratiis alaskcnsis Pilsbry. Kodiak. Cat. No. 34515, U.S.N.M. Lateral view and scutum. Page 141. 5. Balanus rostratus alaskensis Pilsbry. Cape Douglas, Alaska. Cat. No. 48026, U.S.N.M. Basal edge of the rostrum. Page 141. PLATE 39. Balanus crenatus Bruguiere. Page 165. FIG. 1. Estuary of the Exe River, England. Group on a potsherd. 2, 2a, 2b, 2c. Gay Head, Massachusetts. On Mytilus edulis, growing on an iron buoy. Cat. No. 48027, U.S.N.M. 3. Vineyard Sound, Massachusetts. Tergum of a tubular specimen. Cat. No. 4S028, U.S.N.M. 4, 4a. Davis Strait, Greenland. Scutum and tergum. 5. Vineyard Sound, Massachusetts. Cat. No. 48028, U.S.N.M. Group of the tubular form growing on a pebble. THE SESSILE BARNACLES. 349 PLATE 40. Balanus crenatus Bruguiere. Page 1G5. FIG. 1. Newfoundland Bank, in 35 fathoms. Albatross station 2443. Cat. No. 48029, U.S.N.M. Characteristic group, growing on shell of Buccinum. 2. Newfoundland Bank, 39 fathoms. Albatross station 2449. Soli- tary columnar form. Cat. No. 48030, U.S.N.M. 3. Sable Island, Nova Scotia. Growing on bark. Cat. No. 48031, U.S.N.M. 4, 4a. Inglefield Gulf, Greenland., Cat. No. 24911, U.S.N.M. Lateral com- partment and interior view of rostrum. 5, 5ff, 56. Newfoundland Bank. Cat. No. 4S032, U.S.N.M. Flaring and bell- shaped solitary specimens, one having the lateral compartments removed on one side to show the strong sutural ridges in the cavity. G. Fishing banks. Cat. No. 9215, U.S.N.M. Growing on the shell of Cyrtodaria, which also supports a coral (gift of Gloucester fisherman). All figures except 4 and 4« are natural size. PLATE 41. FIG. 1. Balanus crenatus curviscutum Filsbry. Unalaska. Cat. No. 9201, U.S.N.M. Interior of tergum, showing narrow spur. See fig. 4. Page 175. 2-26. Balanus crenat us Bruguiere. Tacoma, Washington. Cat. No. 48033, U.S.N.M. Nearly smooth specimen on a smooth pebble. Page 171. 3, 3a. Balanus crenatus Bruguiere. Bering Sea. Albatross station 2462. Cat. No. 48034, U.S.N.M. ' Ribbed form, on gastropod. Page 171. 4. B. c. curviscutum Pilsbry. Unalaska. Cat. No. 9201, U.S.N.M. Entire individual and bases of four others, on Mytttus eclulis. See also fig. 1. Page 175. 5. B. crenatus Bruguiere. Alaska. Cat. No. 48035, U.S.N.M. Page 171. G-Ge. B. crenatus Bruguiere. Alaska. Albatross station 851. Cat. No. 48036, U.S.N.M. Smooth cylindric or liliaceous forms, with wide radii when crowded; more conic, with narrow radii when growing alone (tig. 6). Page 172. PLATE 42. FIGS. 1-16. Balanus crenatus curviscutum Pilsbry. Bristol Bay, Alaska. Cat. No. 48037, U.S.N.M. Fig. 1 is 11.5 mm. high. Page 175. 2-2d. B. c. curviscutum. Albatross station 3232, Bristol Bay, Alaska. Cat. No. 32948, U.S.N.M. Crowded, cylindric form. Fig. 2c rep- resents specimen 20 mm. long. Page 175. 3-36. Balanus crenatus delicatus Pilsbry. Humbolt Bar, California. Cat. No. 48039, U.S.N.M. Altitude of fig. 3, 13.25 mm. Page 177. 350 BULLETIN 93, UNITED STATES NATIONAL MUSEUM. PLATE 43. Balanus glandula Darwin. Page 178. FIGS. 1-lb. San Diego, California. Cat. No. 48002, U.S.N.M. 2. San Diego, California. Cat. No. 11151, U.S.N.M. Rostrum. 3, 3o. San Diego, California. Cat. No. 48040, U.S.N.M. Exterior nearly perfectly preserved. 4-4c. Nazan Bay, Atka. Cat. No. 4S001, U.S.N.M. Exterior and oper- cular valves deeply corroded, the outline of the tergum much changed thereby. 5. Sitka, Alaska. Cat. No. 1231G, U.S.N.M. Group on shell of Mytilus. 6, 6a. Unalaska. Opercular valves of crowded examples. 7, 7a. Sitka. PLATE 44. Balanus balanoides (Linnseus). Page 182. FIG. 1. Exmouth, England. Cat. No. 12156, U.S.N.M. Rostrum of a worn specimen showing parietal pores and transverse septa. la, ~Lb. Lower and upper views of a perfect example of the same lot. 2. Savin Rock, New Haven. Cat. No. 4791, U.S.N.M. Group growing on a pile, showing transition from low-conic form (above) to the cylindric form caused by crowding (below). One of the latter is shown detached at A. 3, 3a, Cumberland Gulf. Cat. No. 3294G, U.S.N.M. Cylindric and conic forms. 4. Loch Fyne, Scotland. Cat. No. 12150, U.S.N.M. Tubular, solitary form, supporting several conic individuals. 5-56. New Haven, Connecticut. Cat. No. 48041, U.S.N.M. Patelliform ribbed specimens growing on Mytilus, with scutum and tergum. 6. New Haven, Connecticut. Cat. No. 32947, U.S.N.M. Tergum of a tubular individual. 7-7(7. Savin Rock, New Haven. Cat. No. 32947, U.S.N.M. Individuals and groups taken from a densely crowded colony. Figs. 1, 5d, 5b, G enlarged ; the others about natural size. PLATE 45. FIGS. 1-lc. Balanus balanoides, " var. a." Nahant, Massachusetts. No. 2051, A.N.S.P. Terga and scuta. Page 186. 2, 2«. Balanas balanoides (Linnaeus). Nahant, Massachusetts. No. 2052, A.N.S.P. Tergum and scutum of small, deeply corroded speci- mens. Page 186. 3-3o. B. b. ealearalus Pilsbry. Cold Bay, Alaska. Cat. No. 32949, U.S.N.M. Group of entire animals, natural size. Scutum, both sides, and inner view of tergum. Page 188. 4, 4a. B. b. calcaratus. Sitka, Alaska. No. 2058, A.N.S.P. Lateral and basal views of an extremely thick and solid individual, 19 mm. in greatest diameter. The depression shown in tig. 4 is where a specimen of B. crenatux sat. Page 188. 4b, 4c. Tergum and scutum of same individual. THE SESSILE BARNACLES. 351 PLATE 46. B alarms cariosus Pallas. Page 189. FIG. 1. Unalaska. Cat. No. 9226, U.S.N.M. Part of basal edge of lateral compartment and rostrum. 2, 2a. Unalaska. Cat. No. 4S042, U.S.N.M. Lateral views of cylindric specimens, the larger one deeply corroded. Natural size. 3. Nazan Bay, Atka. Cat. No. 48045, U.S.N.M Young, natural size. 4. Unalaska. Cat. No. 48043, U.S.N.M. Lateral view, natural size. Basal edge of same specimen shown in fig. 8. 5. Neah Bay, Washington. Cat. No. 43044, U.S.N.M. Natural size. 6. Unalaska. Cat. No. 9226, U.S.NM Colony of yoxing specimens on a clam shell Natural size. 7. Nazan Bay, Atka. Cat. No. 48045, U.S.N.M. Immature stage, not corroded. Natural size. 8. Unalaska. Cat. No. 48043, U.S.N.M. Part of the basal edge, of the rostrum. 9. Sanborn Harbor, Shumagin Islands. Cat. No. 3r.ll, U.S.N.M. Two specimens which grew upon and in a sponge, part of which re- mains on the right side, the rest removed to show the barnacles. Natural size. PLATE 47. FIGS. 1-1 c. Balanvs cariosus (Pallas). Scutum and tergum of specimen from Unalaska. Page 189. FIGS. 2-2(1. Balamis aeneas Lanchester. Scutum and terga of the type, and tergum of a para type. Page 221. PLATE 48. FIGS. 1-10. Balamis liatniicnsis Pilsbry. Interior view of rostrum; interior and outside views of tergum and scutum ; an isolated individual, and two groups. All enlarged. Page 222. 2-2e. Balanus tantilliis Pilsbry. Interior and exterior views of the opercular valves ; group on a sea-urchin spine, and more enlarged view of three individuals of the same group. Page 224. Figures le, If/, 2e X 2$ 352 BULLETIN 93, UNITED STATES NATIONAL MUSEUM. PLATE 49. FIGS. 1-lrf. Balanus hesperius Pilsbry. Bering Sea, Albatross station 3483. Cat. No. 32935, U.S.N.M. Type. Id, Scutum viewed from the basal edge, the articular ridge projecting to the left. Page 193. 2. Port Townsend, Washington. Form Icevidomus, ribbed in the lower part, growing on Pectcn caurinus. Greatest diameter 17 mm. Page 197. 3, 3a. Albatross station 3G75. Cat. No. 32936. Form l&vidomus, growing on smooth shells of Natica, and varying from smooth to ribbed. 4. Sitka, Alaska. Cat. No. 12418, U.S.N.M. Form Iccvidomus on shell of Teyula. 5. Puget Sound. Cat. No. 48067, U.S.N.M. Form Iwvidomus, growing on shell of Thais. 6. B. h. nipponensis, Japan, Albatross station 3768. Type-specimen, growing on shell of Natica. Page 199. 7-76. B. hesperius. Off Kamchatka. Albatross station 3780. Cat. No. 48066, U.S.N.M. Growing on egg capsules of Chrysodomus, containing embryos. Page 193. 8. B. hesperius. Alaska. Cat. No. 48065, U.S.N.M. Growing on an- terior end of a Chrysodomus. Diameter 18 mm. Page 195. PLATE 50. Balanus hesperius Pilsbry. Page 196. FIGS. l-l/. San Juan Island, Puget Sound. Form Icevidomus. Upper view, opercular valves, rostrum (fig. Ic) and a carinolateral compart- ment (fig. I/). 2-2b. Albatross station 3096. Cat. No. 48068, U.S.N.M. Opercular valves and lateral view, the latter from specimen 5.5 mm. in diameter. PLATE 51. FIG. 1. Balanus flosculus Darwin. Chile. Cat. No. 48050, U.S.N.M. Group on shell of Concholepas. Diameter of individual speci- mens about 7 mm. Page 219. la, Ic. Terga of specimens from the same group. 1ft. Carina of specimens from the same group. 1- BALANUS HAMERI FOR EXPLANATION OF FIGURES SEE PAGE 353. U. S. NATIONAL MUSEUM BULLETIN 93 PL. 54 3b BALANUS EVERMANNI. FOR EXPLANATION OF FIGURES SEE PAGE 353. U. S. NATIONAL MUSEUM BULLETIN 93 PL. 55 2d 1-1D, BALANUS DECLIVIS; 2-2D, BALANUS ORCUTTI. FOR EXPLANATION OF FIGURES SEE PAGE 353. U. S. NATIONAL MUSEUM BULLETIN 93 PL. 56 1-1D, BALANUS GALEATUS ; 2-2o, B. SCANDENS. FOR EXPLANATION OF FIGURES SEE PAGE 353. U. S. NATIONAL MUSEUM BULLETIN 93 PL. 57 , >' t I .T^f •* " "*;,£. 2c ACASTA CYATHUS. FOR EXPLANATION OF FIGURES SEE PAGE 353. U. S. NATIONAL MUSEUM BULLETIN 93 PL. 58 2a "j? ~,i • V 1-3A, TETRACLITA SQUAMOSA JAPONICA; 4, T. ROSEA; 5-6A, T. SQUAMOSA RUFOTINCTA. FOR EXPLANATION OF FIGURES SEE PAGE 353. U. S. NATIONAL MUSEUM BULLETIN 93 PL. 59 ^•£*+* » ^^ »«*•• f Zfy* ^^v»^. ^-SS'-' ' 5, JV •^p^ 6b 1-5e, TETRACLITA SQUAMOSA STALACTIFERA; 6-6e, T. s. STALACTIFERA FORM FLORIDANA- FOR EXPLANATION OF FIGURES SEE PAGE 354. U. S. NATIONAL MUSEUM •~* - - -,- BULLETIN 93 PL. 60 3a 1-1D, TETRACLITA SQUAMOSA MILLEPOROSA; 2, T. SQUAMOSA FORM CONFINIS; 3-3B, T. S. PANAMENSIS. FOR EXPLANATION OF FIGURES SEE PAGE 354. U. S. NATIONAL MUSEUM BULLETIN 93 PL, 61 3a 3b 3c 1-1 E, TETRACLITA SQUAMOSA RUBESCENS; 2, T. s. RUBESCENS FORM ELEQANS; 3-4, T. RADIATA. FOR EXPLANATION OF FIGURES SEE PAGE 354. U. S. NATIONAL MUSEUM BULLETIN 93 PL. 62 1-4, 6, CHELONIBIA TESTUDINARIA; 5-5A, C. MANATI CRENATIBASIS; 7-7A, C. M. LOBATIBASIS. FOR EXPLANATION OF FIGURES SEE PAGE 354. U. S. NATIONAL MUSEUM BULLETIN 93 PL. 63 5a 1-3A, CORONULA COMPLANATA; 4, 4A, CHELONIBIA PATULA ; 5, 5A, CHELONIBIA CARETTA. FOR EXPLANATION OF FIGURES SEE PAGE 355 U. S. NATIONAL MUSEUM BULLETIN 93 PL. 64 CORONULA REGINAE. FOR EXPLANATION OF FIGURES SEE PAGE 355. U. S. NATIONAL MUSEUM BULLETIN 93 PL. 65 1-2B, XENOBALANUS GLOBICIPITIS; 3, 4, CORONULA DIADEMA; 5, TUBICINELLA MAJOR. FOR EXPLANATION OF FIGURES SEE PAGE 355. U. S. NATIONAL MUSEUM BULLETIN 93 PL. 66 5a CRYPTOLEPAS RACHIANECTI. FOR EXPLANATION OF FIGURES SEE PAGE 355. U. S. NATIONAL MUSEUM BULLETIN 93 PL. 67 - 1a lc \ "Tf^T -, -. a 1b ^ 1-1c, 3, 4, PLATYLEPAS HEXASTYLOS; 2, P. H. ICTHTHYOPHILA. FOR EXPLANATION OF FIGURES SEE PAGE 356. U. S. NATIONAL MUSEUM BULLETIN 93 PL. 68 2a la 3a 3b 1-1B, STOMATOLEPAS PRAEGUSTATOR ; 2, 2A, S. ELEQANS; 3-3B, CYLINDRO- LEPAS DARWINIANA. FOR EXPLANATION OF FIGURES SEE PAGE 356. U. S. NATIONAL MUSEUM BULLETIN 93 PL. 69 1e If 3 3a HEXELASMA AMERICANUM. FOR EXPLANATION OF FIGURES SEE PAGE 356. 3b U. S. NATIONAL MUSEUM BULLETIN 93 PL. 70 CHTHAMALUS FRAGILIS. FOR EXPLANATION OF FIGURES SEE PAGE 356. U. S. NATIONAL MUSEUM BULLETIN 93 PL, 71 4a 1-4A, CHTHAMALUS STELLATUS; 5-5e, C. s. ANGUSTITERGUM ; 6, GA, C. s. BISINUATUS. FOR EXPLANATION OF FIGURES SEE PAGE 356. U. S. NATIONAL MUSEUM BULLETIN 93 PL. 72 5a 6a 6b 1-4A, CHTHAMALUS CHALLENGERI; 5, BA, C. MALAYENSIS; 6-6B, C. MORO. FOR EXPLANATION OF FIGURES SEE PAGE 357. U. S. NATIONAL MUSEUM BULLETIN 93 PL. 73 2e 3b 1-1B, CHTHAMALUS CAUDATUS; 2-2c, C. WITHERS; 3-3e, C. DALLI ; 4, 4A, C. SCABROSUS. FOR EXPLANATION OF FIGURES SEE PAGE 357. U. S. NATIONAL MUSEUM BULLETIN 93 PL 74 la 2b 2e 2f 1-1B, CHTHAMALUS FISSUS; 2-2F, C. ANISOPOMA. FOR EXPLANATION OF FIGURES SEE PAGE 357. U. S. NATIONAL MUSEUM BULLETIN 93 PL. 75 1e 2e 1-1E, CHTHAMALUS IMPERATRIX; 2-2E, C. PANAMENSIS. FOR EXPLANATION OF FIGURES SEE PAGE 357. U. S. NATIONAL MUSEUM BULLETIN 93 PL. 76 \ 2c CHTHAMALUS HEMBELI. FOR EXPLANATION OF FIGURES SEE PAGE 357. INDEX. Page. Acamptosowata 12, 14 Aoasta 49, 241 conica 242 coxi 241 cyathus 244 doflciiii 247 fenestrata 242 fischeri 242 formae 242 funiculorum 242 glans 242 idiopoma 247 japonica 243 lacvigata 242 muricata 242 nitida 247 pectinipes 247 purpurata 242 sarda 242 schafleri 242 scuticosta 242 s^ongites 242 sp'orillus 242 striata 242 sulcata 241 undulata 241 aeneas, Balanus 221 alaskensis, Balanus 141 alatus, Balanus 110 albatrossiana. Verruca 47 alba, Verruca 17, 25 albicostatus, Balanus 90 albus, Balanus 204 algicola, Balanus 72 allium, Balanus 228 Altiverruca 40 Amalthca coxi 241 amaryllis, Balanus 217 americanum, Hoxelasma 330 amphitrite, Balanus 80,89 anglicum, Pyrgoma 262 angulosa, Octomeris 334 angustitergum, Chthamalus 305 angustus, Balanus 123 Lcpas 123 anisopoma, Chthamalus 317 antennatus, Chthamalus 294 antillensis, Balanus 63 anulata, Tubicinella 281 apertus, Balanus 144 aquila, Balanus 127 arafurae, Hexelasma 330 Archaeolepas 14 arcuatus, Balanus '. 228 arenatus, Balanus 105 4720°— Bull. 93— K Armatobalanus 51, 226 armatus, Balanus Ill, 114 Ascmus 248 assimilis, Balanus 84 Astrolcpas 262 laevis 268 rotundarius 264 testudinaria 267 aucklandicum, Hexelasma 330 augubra, Octomeris 334 aurantiacum, Pachylasma 328 auricoma, Balanus 221 Austrobalanus 51, 218 azoricus, Balanus 62 balaena, Balanus 273 balaenae, Tubicinella 281 balaenaris, Coronula 276 Lepas 273 balaenarum, Tubicinella 281 balanarum, Coronula 276 Balanidae 47,48 Balaninus 234 balanoides, Lepas 182 Balanomorpha 14 Balanus 7,49 aeneas 221 alaskensis 141 alatus 110 albicostatus 90 albus 204 algicola 72 allium 228 amaryllis 217 amphitrite 80, 89 angustus 123 antillensis - 63 apertus 144 aquila 127 arcuatus 228 arenatus 165 armatus 111,114 assimilis 84 auricoma 221 azoricus 62 balaena 273 balanus 149 bimae 204 brevicalcar 337 calcaratus 188 calceolus 238 calidus 118 californicus 65 callistoderma 332 campbelli 53, 54 candidus 205 359 360 INDEX. Page. Balanus capensis 77 carenatus 89 cariosus 189 cassis 235 cepa 228 cltdytrypetes 267 chesapeakensis 103 ciliatus 221 cirratus 89 claroviUata 217 clavatus 182 coccopoma 68 communis 55, 89, 90, 189 compressus 221 concavus 100 concinnus 69 convexus 103 coosensis 108 coquimbensis 122 cornutus 235 costatus 54, 72, 149 cranchii 123 crenatus 139, 165 crispatus 54,60,68 curviscutum 175 cuspidatus 230 cymbiformis 235 dalli 147 declivis 230 decorus 53, 77 delicatus 177 democraticus 337 dilatatus 55 discors 120 dissimilis 217 dorbignyi 54, 71 dybowskii 78 eburneus 79,80,337 elongatus 183 estrellanus 126 evermanni 210 eversmanni 210 fissus 183 fistulosus 123, 182 flos 135 flosculus 219 galapaganus 70 galeatus 236 geniculatus 149 gladalis 165 glandula 178 glyptopoma 102 gregarius 125, 126 gryphicus 84 hameri 205 hamon 205 hawaiiensis 222 hesperius 193 heteropus 142 hoekianus 201 hystrix 78 imperator ... 219 Improvisus 80, 84 inexpectatus 97 intermodius 54, 71 intenuptus 183 invcstitus.. 235 Page. Balanus kriigerl 214 laevidomus 196 laevis 120 longirostruni 229 inaculatus 204 malayensis 89 maldivensis 220, 226 maxillaris 53, 77 minor 89 minutus 78 mirabilis 79, 92, 123, 125 modestus 89 navicula 235 nigrescens 53 nipponensis 199 nitidus 121,122 niveus 92, 217 nubilis 131 obscurus 89 occator 59 orcutti 233 ovularis 183 pacificus 79, 104,337 pallidus 89 palmulatus 182 patellaris 79 peninsularis 66 pentacrini 328 perforatus 123 poruvianus 80, 97 picas 75 plicatus 54, 72, 249 poecilotheca 110 poecilus 110 polythalamius 264 porcatus 149 proripiens 235 proteus 103 psittacus 53, 75 pugetensis 163 purpurca 89 quadrivittatus 229 quinquevittatus 227 radiatus 89 regalis 108 rosa 61 roseus 217 rostratus 138 rugosus 167 scandens 239 tcotica 149 socialis '. 221 sordidus 219 spinosus 58 spongicola 79, 115 spongicula 115 squamosus 249 stalactiferus 254 striatus 15 stultus 235 stutsburi 89 suturalis 148 tantillus 224 tenuis 216 terebratus 227 tessellatus 149 tintinuabuluni 53, 54 . INDEX. 361 Pago. Balanus trigonus •. 79, 111 tulipa 205 tulipiformis 53 uddevalensis 205 variegatus ". — 89 venustns 89 vesiculosus 64 vestitus'. 219 vinaceus 53, 54 violaccus 78,92 volcano 60 zebra 57 balanus, Balanus 149 Lepas 149 balenaris, Lepas 276 barbadensis, Verruca 28 barbara, Coronula 273 Bathybalanus 293,328 pentacrini 328 bicornuta, Verruca 17, 43 biflda, Coronula 273 bimao, Balanus 204 biscayensis, Coronula 273 bisexloba, Platylepas 285 bisexlobata, Coronula 285 bisinuatus, Chthamalus 306 bissexlobata, Platylepas 285 Brachylepadidae 14 Brachylepas 5 brevicalcar, Balanus 337 brunnea, Octomeris 334 Calantica superba 22 calcaratus, Balanus 188 calceolus, Balanus 238 Lepas 239 calidus, Balanus 118 californica, Balanus 65 Diadema 274 californiensis, Coronula 285 callistoderma, Balanus 332 Hexelasma 332 calotheca, Verruca 17, 33 Cameraverruca 39 campbelli, Balanus 53, 54 Campylosomata 12, 14 cancellatum, Pyrgoma 262 candidum, Diadema 273 candidus, Balanus 205 capellinii, Chelonibia 263 capensis, Balanus 77 capsula, Verruca 46 carenatus, Balanus 89 caretta, Chelonobia 267 caribbea, Verruca 28 cariosa, Lepas 189 cariosus, Balanus 189 cassis, Balanus 235 Lepas 235 Catomerus 335 Catophragmus 293, 334 darwini 335 imbricatus 335 polymerus 336 caudatus, Chthamalus 314 cepa, Balanus 228 Ceteopirus 271 complanatus 277 Page. Cetopirus 271 balaenaris 271 challengeri, Chthamalus 307 Chamacsipho 7, 292 Chelonibia 49, 262 capellinii 263 caretta 267 crenatibasis 266 depr^ssa 263 emisphaerica 263 hemisphaerica 263 lobatibasis 266 manati 265 patula 268 testudinaria '. 264 Chelonibiinae 47, 49 Chelonobia 262 caretta 267 manati 265 patella 263 patula 268 testudinaria 264 chelytrypetes, Balanus 267 chesapeakensis, Balanus 103 chinense, Pachylasma 329 Chirona 51, 203 Chthamalidae 48, 290 Chthamalus 7, 293 angustitergum 305 anisopoma 317 antennatus 294 bisinuatus 306 caudatus 314 challengeri 307 cirratus 321 communis 302 dalli 316 darwini 295 dentatus 294 depressus 304 europaeus 183 fissus 317 fistulosus 301 f ragilis 297 germanus 183 giganteus 329 glaber 304 hembeli 324 hembelli 324 imperatrix 320 intertextus 324 ligusticus 295 malayensis 310 moro 311 nipponensis 309 panamensis 319 philippii 183 punctatus 301 scabrosus 323 stellatus 301,302 vitreus 301 withersi 312 ciliatus, Balanus 221 cirratus, Balanus 89 Chthamalus 321 claroviltata, Balanus 217 clavatus, Balanus 182 362 INDEX. Clisia Clisiadae CHt ia Clysia striata. Page. 15 14 15 15 15 coccopoma, Balanus - - 68 coerulescens, Lepas 259 Tetraclita 259 Columellina • 284 communis, Balanus 55, 89, 90, 189 Chthamalus 302 Tetraclita 254 complanata, Coronula 276 compressus, Balanus 221 concavus, Balanus 100 concentrica, Coronula 285 concinnus, Balanus 69 conflnis, Tetraclita 255 Conia 248 depressa 249 monstruosa 24 rosea 260 conlca, Acasta 242 Conopea 51, 234 elongate 236 Conoplea 234 ovata 238 convexus, Balanus 103 coosensis, Balanus 108 coquimbensis, Balanus 122 cornuta, Verruca 40 cornutus, Balanus 235 corolliformae, Hexelasma 330 Coronula 270, 271 balaenaris 276 balanarum 276 barbara "- 273 bifida 273 biscayensis 273 bisexlobata 285 californicnsis 285 complanata 276 concentrica 285 darwini 277 denticula 268 dentulata 268 dladema 273 diluviana 273 elegans 289 flcarazzensis 273 patula 268 reginae 275 sulcata 267 tuUcinella 281 Coronuladae 268 Coronulinae 47, 268 Coronulites 271 costata, Tetraclita 259 costatus, Balanus 54, 72, 149 Lepas 149 coxi, Amalthea 241 cranchii, Balanus 123 crenata, Verruca 40 crenatibasis, Chelonibia 266 crenatum, Pyrgoma 262 crenatus, Balanus 139, 165 Creusia 49, 261 Page Creusia monstruosa 24 spinulosa 261 crinoidophilum, Pachylasma 329 crispata, Lepas 60, 61 crispatus, Balanus 54, 60, 68 cristallina, Verruca 41 cristallinus, Elminius 261 Cryptolepas 270, 278 ophiophilus 285 rachianecti 279 rachianectis 279 curviscutum, Balanus 175 cuspidatus, Balanus 230 cyathus, Acasta 244 cylindrica, Lepas 77 Cylindrolepas 271, 187 darwiniana 288 cymbiformis, Balanus 235 dalli, Balanus 147 Chthamalus 316 darwiniana, Cylindrolepas 288 darwinianum, Pachylasma 329 darwini, Catophragmus 335 Chthamalus 295 Coronula 277 Verruca 17, 45 dcclivis, Balanus 230 deeorata, Platylepas 285 decorus, Balanus 53, 77 delicatus, Balanus 177 democraticus, Balanus 337 dentatus, Chthamalus 294 denticula, Coronula 268 dentulata, Coronula 268 depressa, Chelonibia 263 Conia 249 Lepas 304 depressus, Chthamalus 304 devonica, Palaeocreusia 12 Diadema 271 californica 274 candidum 273 japonica 273 vulgaris 273 diadema, Coronula 273 Lepas 273 dilatatus, Balanus 55 diluviana, Coronula 273 discors, Balanus 120 dissimilis, Balanus 217 dofleini, Acasta 247 dorbignyi, Balanus 54, 71 Duplocona 261 laevigata 261 dybowskii, Balanus 78 eburneus, Balanus 79,80,337 echinata, Lepas 5S, 61 elegans, Coronula 289 Stomatolepas 2S9 Tetraclita 257, 258 Elminius 49,260 cristallinus 261 kingii 260 modestus 261 plicatus 261 rugosus 261 simplex 261 INDEX. 3G3 Page. Elminlus sinuatiis 261 elongate, Conopea 236 Lepas 165, 182 elongatus, Balanus 183 emisphaerica, Chelonobia 263 entobapta, Vernioa 17, 38 erecta, Verruca .'. 40 estrellanus, Balanus 126 euglypta, Vernica 17,39 Euraphia 293 hembcli 324 europaeus, Chthamalus 183 evermanni, Balanus 210 eversmanni, Balanus 210 fenestrata, Acasta 242 ficarazzensis, Coronula 273 flscheri, Acasta 242 fissus, Balanus 183 Chthamalus 317 fistula, Lepas 165 fistulosus, Balanus 123,182 Chthamalus 301 FlabdcoroM 271 flavidula, Verruca 17,34 floridana, Tetraclita 255 Verruca 17, 31 flosculus, Balanus 219 foliacea, Lepas 205 formae; Acasta 242 fragilis, Chthamalus 297 fungites., Lepas 249 funiculorum, Acasta 242 galapaganus, Balanus 70 galeatay Lepas 236 galeatus Balanus 236 geniculatus, Balanus 149 germanus, Chthamalus 183 gibbosa, Verruca 41 giganteum, Paehylasma 329 giganteus, Chthamalus 329 glaber, Chthamalus 304 glacialis, Balanus 165 glandula, Balanus 178 glans, Acasta 242 globiclpltis, Xenobalanus 270, 282 glyptopoma, Balanus 102 gregaria, Tamiosoma 126 gregarius, Balanus 125,126 gryphicus, Balanus 84 halotheca, Verruca 17,46 bameri, Balanus 205 Lepas 205 hamiltonensis, Protobalanus 11 hamon, Balanus 205 hawaiensis, Balanus 222 hembeli, Chthamalus 324 Euraphla 324 hembelli, Chthamalus 324 hemisphaerica, Chelonibia 263 Hesperibalanus 51, 192 hesperius, Balanus 193 heteropoma, Verruca 17, 45 heteropus, Balanus 142 Heiameridae 13 hexastylos, Lepas 285 Platylepas 285 Hexelasma 293, 329 Page. Hexelasma americanum 330 arafurae 330 aucklandlcum 330 callistoderma 332 corolliformae 330 hlrsutum 330 velutinum 330 hlrsutum, Hexelasma 330 hoekianus, Balanus 201 hoeki, Verruca 17, 41 hystrix, Balanus 78 Ichthyophila, Platylepas 287 idiopoma, Acasta 247 imbricatus, Catophragmus 335 Imperator, Balanus 219 imperatrix, Chthamalus 320 improvisus, Balanus 80,84 incerta, Verruca 41 Inermis, Verruca 40 Inexpectatus, Balanus 97 insculpta, Verruca 37 intermedius, Balanus 54, 71 interruptus, Balanus 183 Intertextus, Chthamalus 324 intexta, Verruca 29, 47 investitus, Balanus 235 japonica, Acasta 243 Diadema 273 Tetraclita 252 kingil, Elmtnius 260 kleinii, Polylepas 273 koehleri, Verruca 29 kriigeri, Balanus 214 Platylepas 285 laevidomus, Balanus 196 laevigata, Acasta 242 Clitia 25 Duplocona 261 Verruca 25 laevls, Astrolepas 268 Balanus 120 lamarckii, Tubicinella 281 Lepadidae 14 Lepadomorpha 14 Lepas 49 angustus 123 balaenaris 273 balanoides 182 balanus 149 balenaris 276 calceolus 239 cariosa 189 cassis 235 coerulescens 259 costatus 149 crispata 60,61 cylindrica 77 depressa 304 diadema 273 echinata. 58, 61 elongata 165, 182 fistula 165 foliacea 205 fungites 249 galeata 236 hameri 205 hexastylos 285 364 INDEX. Page. Lepas mitra 249 plicata 165 porosa 249 psittacus 75 purpurea 89 quinquevalvis 276 rosata 205 scotica 149 spinosa 58 stellatus 301 stromia 24 tintinnabulum 54 tracheaeformis 281 trachcalis 281 tulipa 205 verruca 24 violacea 78 Lepidocoleidae 13 ligusticus, Chthamalus 295 lobatibasis, Chelonibia 266 longicarinata, Verruca 40 longicarinatum, Scalpcllum 228 longirostrum, Balanus 229 Loricula 14 Lorieulidac 14 maeulatus, Balanus 204 major, Tubiclnclla 281 malayensis, Balanus 89 Chthamalus 310 maldivensis, Balanus 220, 226 manati, Chclonibia 265 maxillaris, Balanus 53, 77 Megabalanus 51 Membranobalanus 51, 229 Metabalanus 51,200 Metaverruca 21 milleporosa, Tetraclita 257 minor, Balanus 89 Tubicinella 281 minutus, Balanus 78 mirabilis, Balanus 79, 92, 123, 125 mitra, Lepas 249 Tetraclita 249 Verruca 41 modestus, Balanus 89 Elminiue 261 Monolopus 50 monstruosa, Conia 24 Creusia 24 Verruca 24 moro, Chthamalus 311 muricata, Acasta 242 Stephanolepas 271 navicula, Balanus 235 nexa, Verruca 17, 29 nigrescens, Balanus 53 Tetraclita 254 nipponensis, Balanus 199 Chthamalus 309 nitida, Acasta 247 Verruca 41 nitidus, Balanus 121, 122 niveus, Balanus 92, 217 nubilis, Balanus 131 obliqua, Verruca 40 obscurus, Balanus 89 occator, Balanus 59 Page. Ochihosia 15 Octomeridae 13 Octomeris 293,334 angulosa 334 augubra 334 brunnea 334 ophlophilus, Cryptolepas ". 285 Platylepas 285 orcutti, Balanus 233 Ortho-Balanus 50, 77 ovata, Conoplea 238 ovularis, Balanus 183 Pachylasma 6,293,327 aurantiacum 328 chinense 329 crinoidophilum 329 darwinianum 329 giganteum 329 paclficus, Balanus 79, 104,337 Palaeocreusia 12 devonica 12 pallidus, Balanus 89 Xenobalanus 284 palmulatus, Balanus 182 panamensis, Chthamalus 319 Tetraclita 256 Patclla-Balanus 234 patella, Chelonobia 263 patellaris, Balanus 79 Tetraclita 248 patula, Chelonibia 268 Coronula 268 pectinipes, Acasta 247 peninsularis, Balanus 66 pentacrini, Balanus 328 Bathybalanus 328 perforatus, Balanus 123 peruvianus, Balanus 80,97 philippii, Chthamalus 183 picos, Balanus 75 plana, Verruca 41 Platylepas - 270,284 biscxloba 285 bisseilobata 285 decorata 285 hoxastylos 285 ichthyophila 287 kriigeri 285 ophiophilus 285 pulchra 285 plicata, Lepas 165 plicatus, Balanus 54, 72, 249 Elminius 261 poocilothoca, Balanus 110 poocilus, Balanus 110 Polylepas 271 kleinii 273 vulgaris 277 Polylopas 271 polymerus, Catophragmus 336 polythalamius, Balanus 264 Polytrcma porcatus, Balanus 149 porosa, Lopas Tetraclita 249 praegustator, Stomatolepas 289 proripions, Balanus 235 INDEX. 365 Pago. proteus, Balanus 103 Protobalanus 11 liauiiltoueiisis 11 Proverruca 14 psittacus, Balanus 53, 75 Lepas 75 pugetensis, Balanus 163 pulclira, Platylepas 285 puuctatus, Chthamalus 301 purpurascens, Tetraclita 249 purpurata, Acasta 242 purpurea, Balanus 89 Lepas 89 Pyrgoma 7, 49, 261 anglicum 262 cancellatum 262 crenatum 262 stokesi 262 Pyrgomalidae 48 P yrgopsis 49 quadrangularis, Verruca 41 quadrivittatus, Balanus 229 quinquevalvis, Lepas 276 quinquevittatus, Balanus 227 rachianecti, Cryptolepas 279 rachianectis, Cryptolepas 279 radiata, Tetraclita 259 Verruca 40 radiatus, Balanus 89 Radiolitcs gregaria 126 rathbuniana, Verruca 41 regalis, Balanus 108 reginae, Coronula 275 rosa, Balanus 61 rosata, Lepas 205 rosea, Conia 260 Tetraclita 260 roseus, Balanus 217 rostratus, Balanus 138 rotundarius, Astrolepas — 264 rubescens, Tetraclita 257 rufotincta, Tetraclita 253 rugosus, Balauus 167 Elminius 261 sarda, Acasta 242 scabrosus, Chthamalus 323 Scalpellidae 14 Scalpdlum aucklandicum 330 longicarinatum 22 scandens, Balanus 239 schafferi, Acasta 242 scotica, Balanus 149 Lepas 149 sculpta, Verruca 40 scuticosta, Acasta 242 Semibalanus 51, 182 sorrata, Tetraclita 249 simplex, Elminius ,. 261 sinuatus, Elminius 261 Siphonicella 282 Siphonicinclla 282 socialis, Balanus . 221 Solidobalanus 51, 220 sordidus, Balanus 219 spengleri, Verruca 23 spinosa, Lepas 58 spinosus, Balanus 58 Page. spinulosa, Creusia 261 spongicola, Balanus 79, 115 spongicula, Balanus 115 spongites, Acasta 242 sporillus, Acasta 242 squamosa, Tetraclita 249, 251 squamosus, Balanus 249 squamulosa, Tetraclita 249 stalactifera, Tetraclita 254 stalactiferus, Balanus 254 stellatus, Chthamalus 301,302 Lepas 301 Stephanolepas 271 murlcata 271 stokesi, Pyrgoma 262 Stomatolepas 271, 288 elegans 289 praegustator 289 striata, Acasta 242 Clysia 15 Tubicinella 282 Striato-Balanus 203 striatus, Balanus 15 stromia, Lepas 24 Verruca 17, 24 stultus, Balanus 235 stutsburi, Balanus 89 sulcata, Acasta 241 Coronula 267 Verruca 41 super ba, Calantica 22 suturalis, Balanus 148 Tamiosoma 126 gregaria 126 tantillus, Balanus 224 tenuis, Balanus 216 terebratus, Balanus 227 tesselatus, Balanus 149 Tesseropora 259 testudinaria, Astrolepas 267 Chelonibia 264 Tetraclita 7, 49, 248 coerulescens 259 communis 254 confinis 255 costata 259 elegans 257, 258 fioridana 255 japonica 252 milleporosa 257 mitra 249 nigrcscens 254 panamensis 256 patellaris 248 porosa 249 purpurascens 249 radiata 259 rosea 260 rubescens 257 rufotincta 253 serrata 249 squamosa 249, 251 squamulosa 249 stalactifera 254 viridis 249, 251 vitiata 259 Tetraclitinae.. 48 366 INDEX. Page. Tetrameridae 13,48 tintinnabulum, Balanus 53, 54 Lepas 54 tracheaeformJs, Lepas 281 trachealis, Lepas 281 Tubicinella 282 trigonus, Balanus 79, 111 Tubicinella 270,281 anulata 281 balaenarum ' 281 balanae 281 lamarckii 281 major 281 minor 281 striata 282 trachealis 282 tubicinella, Coronula 281 tulipa, Balanus 205 Lepas 205 tulipiformis, Balanus 53 Turrilepadidao 13 Turrilepadomorpha 13 uddevalensis, Balanus 205 undulata, Acasta 241 variegatus, Balanus 89 velutinum, Hexelasma 330 venustus, Balanus 89 Verruca 15 alba 17,25 albatrossiana 47 barbadensis 28 bicornuta 17, 43 calotheca ." 17, 33 capsula 46 caribbea 28 coraliophila 21 cornuta 40 crenata 40 cristallina 41 darwini 17, 45 entobapta 17, 38 erecta 40 euglypta 17, 39 flavidula 17, 34 floridana 17, 31 Page. Verruca gibbosa 41 halotheca 17, 46 heteropoma 17, 45 hoeki 17,41 incerta 41 inermis 40 Insculpta 37 intexta 29, 47 koehleri 29 laevigata 25 longicarinata 40 mitra 41 monstruosa 24 nexa 17, 29 nitida 41 obliqua 40 plana 41 quadrangularis 41 radiata 40 rathbuniana 17, 41 sculpta 40 spenglerl 23 stromia 17, 24 sulcata 41 xanthla 17,36 verruca, Lepas 24 Verrucidae 14 Verrucomorpha 14 vesiculosus, Balanus 64 vestitus, Balanus 219 vlnaceus, Balanus 53,54 viridis, Tetraclita 249, 251 vitiata, Tetraclita 259 vitreus, Chthamalus 301 violacea, Lepas 78 vlolaceus, Balanus 78, 92 volcano, Balanus 60 vulgaris, Diadema 273 Polylepas 277 withersl, Chthamalus 312 xanthia, Verruca 17,36 Xenobalanus 270,282 globicipitis 283 pallidus 284 zebra, Balanus 57 O