wees ee + reef eee ee & & © © © © 2 ~n ee ee ee ee ee ee en eee + es eee _~_-— es ee Peer oe ett te eo eee or ee @ . ~~“ ee oe ee ee ene - + + © we etre et ee - ee tees eee ew ewe oe & ee ee & © Oe © He Be eee & ne Oe ee me ee ee Se Oe Oe ee Ee Oe Oe me ee Oe ee he ee Be Oe Oe Oe She me Oe Oe OO > Om Oe Pte ein bey Sa et te he tr ea EE Ot ok EE Of OL OT or ee eee ee ee ee ere & eee bee ee Pett eee Oe ee ee oe EO Oe Oe ee ee et ot ee - oe ee me 0 Oe em OO 6 ee Pe ee ee Ce Oe to me eee ee ee ee ee ee ee ee eee eet te ee ee ee em Ce ane "zt ee Oe Oe © ee ee pay ° le eae ee te tt et -- < e e eo ee bee * #8 ee Pers =. * + © Ort & © & we O- 8 e ie eo. eee OO ee Oe O&O OO © wo tO DD wwe ee eee + ee oe mee 4) vials ate 4 4 . LJ . se 4 - pn Ce ——* PP & ¢- eo ¢ Oe OO ee oe OR & One +» —* sie'* 2 eletets eee . a er a or > . ~ Leese ee et ed eee eee - = eee & eee e. 2-2 >» oe eee = pales a" or wets Pear et tt ot Sd ee Oe 6, BH OO He Oe f- Oe ORE Lee eee eee ee ; oe sie ee oe ‘? ‘at - Caos ore <3 ee sa @ (3 eels = we ee - 5 Cri ha he ne by be + oe bt eee > ; . * * > © ee ee ee © Loy “* ow *-« - ee OO OO O- Oe ee = te ry Ona Sh eG Ore ; . “—e-* SO ae * ¥ ewewe me one - *-¢ 3 oe oe + eh. — 2 ele e «alee Fe See wig Dm ldle ag ee (ty » Sotetae er ae om Oe Oe he On Oe Bs Lfigpag hy} ror (oft etele ~—** ee ee ig a a es one te Ee Oe oe ee eh ah ed np ad - oe St Os Oe att %. : at see ee ~ 2 ee eee ee ee A ee Oe ee a eo oo ee we ee ee x ee ee OS FO ene -* rhe’ hee ~om bean MAAC? ae ied ar ee be f aia e Pau eX (Ceport ot TU, COmMmwissiorery of Tuna rs shanien (27 | in P 3 i 7 xe Ren a State of Rhode Island and Providence Plantations. THIRTY-SEVENTH ANNUAL REPORT OF THE COMMISSIONERS OF INLAND FISHERIES, GENERAL ASSEMBLY AT ITS JANUARY SESSION, 1907. PROVIDENCE: E, L, FREEMAN COMPANY, STATE PRINTERS. 1907. COMMISSIONERS OF INLAND FISHERIES OF RHODE ISLAND. HENRY T. ROOT, President, Treasurer, and Auditor.......°Providence, R. I. aM. AK. SOUTHWICK, -Vace-Presidents 3,2. face ewe Newport, R I. Wastin bs MOR TO Nas Seereany: ..<.--.. Sores ae P. O. Box 966, Providence, R. I. EES WW ce WE LAO so 00 (os See sae a aig ae ea eS ..» Westerly, R. I. Peg bel “2: . MEAD: pst. 2.0). Ris sn) ee ee ee ee Brown University. ADELBERT D. ROBERTS................P. O. Box 264, Woonsocket, R. I. BVM tlio CVAUR, DPMEAGN. 22 2.5 nia heve ge Sta i ee Central Falls, R. I. REPORT. To the Honorable the General Assembly of the State of Rhode Island and Providence Plantations, at its January Session, 1907: The Commissioners of Inland Fisheries herewith present their annual report for the year 1906: The work undertaken by the Commissioners during the past year may be tabulated and discussed under the following heads: I. The stocking of our ponds and streams with fresh-water fish, through the distribution of eggs and fry. Page 18. II. The collection of data and statistics relating to the commer- cial fisheries. Page 19. III. The location of fish traps within the waters of Narragansett Bay, and the collection of statistical data bearing upon their owner- ship. Page 24. IV. The continued examination of the physical and biological conditions of the Bay, begun in 1898. Page 32. V. A continuance of the survey of the shores of the Bay, for the purpose of determining those portions which are most productive of young seed clams and most suitable for the planting of clams and for the distribution of lobster fry. Page 81. VI. Continued investigations into the methods of clam culture Page 83. VII. Efforts to prevent the illegal taking of short lobsters and egg lobsters. Page 85. : VIII. The propagation of lobster fry for the purpose of increasing the supply of lobsters in the waters of the state. Page 87. 7 REPORT OF COMMISSIONERS OF INLAND FISHERIES. IX. The continued investigation of the life history of the lobster and the habits of the lobster in all stages of growth, to furnish a basis for legislation and commercial enterprise. Page 95. X. The preparation of an exhibit illustrative of sea farming, in- cluding live fishes in salt water aquaria, for the Washington County Fair, for the purpose of interesting the people of the state in the mag- nificent possibilities of “sea farming.” Page 211. XI. The preparation of an exhibit for the international exhibi- tion at Jamestown. Page 218. Appended to the report are the following: A. Officers of the United States Bureau of Fisheries and of the State Fisheries Authorities. Page 219. B. Fisheries Laws of Rhode Island. Page 227. C. General Index to the Reports of the Commissioners of Inland Fisheries of the State of Rhode Island. Page 241. D. Titles of Special Papers published in the Annual Reports of the Commissioners of Inland Fisheries of the State of Rhode Island. Page 257. Under some of these captions are submitted special articles as follows: Under IV. The Fishes of Rhode Island, III: The Fishes of the Mackerel Family. H. C. Tracy. A List of Rare Fishes taken in Rhode Island in the year 1906. H.C. Tracy. List of the Rhode Island Copepoda, Phyllopoda, and Octracoda, with new species of Copepoda. Dr. Leonard W. Williams. Under VIII: Lobster Culture at Wickford, R. I., in 1906. Ernest W. Barnes. Under IX: Regenerated and Abnormal Appendages in the Lobster. V. E. Emmel. REPORT OF COMMISSIONERS OF INLAND FISHERIES. o The Stomach of the Lobster and the Food of Larval Lobsters. L. W. Williams. Regarding the Behavior of the Larval and Early Adolescent Stages of the American Lobster. P. B. Hadley. During the past year your Commission has pursued the same gen- eral policy as for several years past, but has extended its work con- siderably along certain lines. The beneficial effect of stocking the fresh waters with appropriate fish is now so obvious that it needs no argument. The work has been carried on by the Commission for many years, and has so far won the confidence of the anglers that they are now giving invaluable co-opera- tion in enforcing the laws which give reasonable protection to the fishing. About 40,000 fingerling trout were bought and distributed last year. By act of the General Assembly a few years ago this Commission was especially required to enforce the short lobster law, and has since that time pushed the work with vigor and success. The first effect of the enforcement was to cut down the amount of lobsters taken, but the gradual increase in catch since then has proved the wisdom of the measure. The expenses and salaries of the deputy Commission- ers in enforcing this law is between $2,000.00 and $2,500.00. One great need of your Commission has been definite and reliable information regarding the marine fishes which inhabit the waters of the state, regarding their times of arrival and departure, their abund- ance, their breeding habits and food, and the effect of fishing upon the supply. It would be inexcusable if no effort were made to obtain information regarding the extent and condition of so valuable an industry as our fisheries. Your Commission has been for several years systematically collecting and recording such data and from time to time publishing in its reports such information as could be put together with any degree of completeness. (See index.) During the last two years, especially, we have been able to publish considerable data of this sort. 6 REPORT OF COMMISSIONERS OF INLAND FISHERIES. While complete and accurate data on the actual catch of fishes is exceeding difficult, or impossible, to obtain, the figures taken from the books of shipping firms and of dealers give some idea of the status of the fishings. The data regarding the number, location, and ownership of traps (Ch. III), when compared for several years, is significant and points to a remarkable increase in this branch of the fisheries indus- try. The tables show that from 1898, when the records were begun, to the present year there has been a steady gradual increase from 119 traps to 249. An examination of the charts showing the location of these traps through the series of years shows an interesting de- velopment of ideas regarding the movements of fishes. From the studies on fisheries in various parts of the world there seems to be no doubt but that the abundance or scarcity among many species of fishes depends in large measure on the food supply; but the question of food supply of marine fishes is as complex as it is interest- ing and important. Since some species feed on others, these again on a third, and these perhaps on minute crustacea or diatoms, it soon appears that no form of animal or plant can safely be neglected in a study of the food and consequent movements of fish, or, for that mat- ter, of shell fish. or of any other valuable marine animals. Your Commission, therefore, with what time can be spared from more immediately important work, is conducting a survey of the biological and physical conditions of the Bay, and is gradually getting together such information. The fact that the federation of the fish- eries boards of all the northern countries of Europe is conducting this sort of a survey systematically and on a large scale is a fair indica- tion of its value. The work of the Commission at its Wickford station has each year increased in extent and efficiency, and much of what a few years ago was experimental has now a just claim to be called practical. This work was undertaken with a view to the especial needs of Rhode Island fishes, which could not be met by known methods of proced- ure, so that most of the problems had to be worked out and methods REPORT OF COMMISSIONERS OF INLAND FISHERIES. r developed from the beginning. Of these the following are cases in point: the working out of the life history, habits, and means of de- struction of the starfish, which is an enemy to the oyster; the dis- covery of the means of distinguishing “seed scallops’’ certain enough to be used as legal proof; the development of a practical clam cul- ture, together with the discovery of the breeding habits, rate of growth, conditions of best growth, means of collecting spat, etc.; The complete working out of a practical method of rearing lobster fry to a point of comparative safety. All these have been tackled as unsolved problems and worked out to practical application. The principal work at the station last year was upon lobster cul- ture, including investigations looking forward to future steps in this business. As for several years past, the output of fingerling lobsters has doubled that of the preceding year. This year nearly 200,000 were reared and liberated in the Bay. The effect of liberating these lobsters in previous years is already marked, and fishermen through- out the upper part of the Bay have for two or three years been report- ing considerable numbers of small lobsters in localities where they had not been found for many years. Several new discoveries were made this season which will, we believe, greatly increase the efficiency of this branch of the work. For example, it has been shown that the rate of growth of the lobster can be so increased or diminished, as to make a difference of more than 100 per cent., according to the amount and kind of food given. The difference in growth due to the loss of limbs and regeneration has also been shown to be of great importance from acommercial point of view. It was found that the fourth-stage lobsters could easily be carried in quantities through the next molt, with little loss in numbers, and with great gain to their chances for the future. In solving the problem of rearing lobster fry, your Commission has succeeded in doing what has been unsuccessfully attempted by many state and national fisheries boards. It is with gratification, which we hope your Honorable Body may share, that we learn that several of these national governments are 8 REPORT OF COMMISSIONERS OF INLAND FISHERIES. contemplating the adoption of our method of lobster culture. Your Commission appreciates the fact that the success it has had in its various undertakings has been made possible by the continuous sup- port of the General Assembly. Interruption and uncertainty are fatal to the success of experimental work which of necessity must extend through several years. Having thus far led by a long dis- tance all other stations in this important work, we have a pride in keeping the lead for the State of Rhode Island. Although the method of rearing fry by the Wickford apparatus is a practical success, we see clearly how it can be improved. Among the discoveries made last summer was the very significant fact that a great improvement can be made by getting the egg lobsters fresh from the traps, not handled over, carred, packed in ice, and shipped. From 56 fairly fresh egg lobsters, with about the average number of eggs, nearly 85,000, lobsters were reared to the fourth stage, an aver- age of about 1,500 for each lobster. Fresh egg lobsters should by all means be had, and the only way to get them is by having a launch large enough to go about in the Bay, and short distances outside with safety. The launch must have a well for carrying the lobsters. Improvements are also to be expected in at least two other points: in the feeding of the fry and in the matter of their exposure to light and shadow. In view of these facts, yourCommission through its scientific staff is making a careful investigation of the food of the young lobsters (Ch. [X), and a study of their behavior under various conditions at the several stages of their early development. These studies have already indicated some possible forms of improve- ments. Your Commission has for a long time foreseen the necessity of a careful study of the lobster after he has reached the lobsterling stage and before he is sexually mature, for obviously the next step in the lobster culture is the raising of fingerlings to adult condition. Ex- perience in working out methods for rearing the young lobster fry, as well as young clams, scallops, starfish, etc., proves most conclusively that the way to attack such a problem is first to find out what the REPORT OF COMMISSIONERS- OF INLAND FISHERIES. 9 habits, rate of growth, peculiarities, and requirements of these crea- tures are. There has been almost entire lack of knowledge regarding these points for the adolescent lobster, and your Commission has there- fore conducted investigations along this line for several years. The rate of growth, the effect of varying food on growth, the extraordinary effect of loss of limbs on frequency of shedding, and consequently on growth, the fact that little lobsters can withstand the cold and fresh- ness of our estuary waters, and many other hitherto unknown facts have been worked out to a point where they should now be tried on a larger scale in an inclosure or pound of considerable size. The natural configuration of our shores does not give such good oppor- tunities for enclosing small bodies of tide water as does that of the coast of Maine, for example, but if a suitable place can be found and enclosed for the purpose of experimenting on raising lobsters to the adult stage, and for further experiments in breeding clams, scallops, crabs, and quahogs, the opportunity should by all means be seized. The work of the Commission in all departments has undergone a steady and normal growth and while the appropriation of $7,500.00 which has been made annually for several years has been so far suffi- cient, it is not now possible to continue the work we have been doing, and to take advantage of opportunities of increasing its efficiency, without a larger appropriation. In carrying out the object of this Commission, namely, that of main- taining and developing the fisheries of the state, we realize the em- portance of informing the public on the subject of fisheries. With this in view we have devoted considerable effort to the preparation of exhibits for the international exposition and, during the past two years, for that of the Washington County Agricultural Association. The United States Government has again invited us to co-operate with it in the fisheries exhibit at the Jamestown Exposition, and the invitation has been accepted. Finally, your Commission cordially invites the members of your Honorable Body to inspect the work and the expenses of the Com- 2 10 REPORT OF COMMISSIONERS OF INLAND FISHERIES. mission, and especially to visit the experiment station at Wickford when the apparatus for rearing lobster fry is in operation. The following is the financial statement for the year 1906: State of Rhode Island in account with Commissioners of Inland Fisheries. 1906. Dr. Sept. 12, To paid American Fish Culture Co., for 40,000 trout and distribution: of ‘sande: saa. et ee ee ee Dec. 31. To expenses and salary of Deputy Commissioners under lobster law 3.05. ste eet meets oe re hee eaeer ere To expense at Wickford laboratory rearing lobsters, in- vestigating clams, scallops, and other fisheries... ... To expense of; Commissioners... e624) ee See Por printing .4 shc.25 ae eres aS eee ee bey eee ee ee To legal expense.......:... he cot uc Rate NU eed ee 1906 Cr. Jan. 3: By received from State Treasurer...:.4......+-0.20 720° ce iz cc ce as ins “ec “ee 5. re ie peeN ar! Re PR I Ne RE ti weet ce “ ‘ ce “ec ‘ ce “ec 7h ri my ¢ Site ex Sept recy es RIM NEP oo Bie “ec ce 73 ce ce iz ce “cc = 31. ey ae DIN RRE SMM te ‘ rt & ‘ “cc ec ce ce ce ec ce Heb. 2 rs i . PPM RR Ps c0 ct ce “ee oe ce 23. Se a a Loe : 28. ss agra f Cs) eee . ‘ ; ; Semen gts 13 37 88 1906. Feb. Mar. April 28. 30. 18. 10. REPORT OF COMMISSIONERS Cr. OF INLAND FISHERIES. By received from State Treasurer.................... “cc “c ce “cc “cc “cc “ec cc “ “ ce cc as uh ms ee ee are Soret te) siie) siitaiis iin ah lopertal lala vc“ “ee “ce ce ce ce “ee ce ae ce “e “cc ins as “ce ae “ce ae “ec “e se oe “ “ “ee e “ec ae ce “ce “ ce ee ae “ee é ae ae “ce ae ‘é “e “e oe ins ae “ce ae ce ce ce ac “ce oe oe a “cc a ce oe ce ce “cc “ec “ “ee “e ee “ec “cc “cc oe “cc cc “ “e ia ec “e ae “cc “ “ce oe “ce ce oe ee ce oe ce “cc “ec “ec “ce ce ce oe oc zy ce ims é “ ce ce oe é “ee “ec ce ce oe “c “c cc “ “cc “cc “ec “ce “c “ce e ce ce “ce “ce “ec cc “ce 12 1906. June 16. fe 18. 31. 6. 14. 20. REPORT OF COMMISSIONERS OF INLAND FISHERIES. Cr. “oa we Sah s)Celjeu fo" Ap Oat win 50.08 nares: 20 00 1906. June 20. 27. July REPORT OF COMMISSIONERS OF INLAND FISHERIES. 6. fae 18. Cr. 6) a.) Uh is fel, oMe slis* so, gers e) a Spe) s){e) ») © ni, (e| (0 ekelsel elope: eierelie) (neyo: \6- 6, & By ablot elie: a) esha f &: [on alii te" e, ie, 0, 9i ome ers oa eal einer en ae Np) wes et ane el ee) ei elle o| o: Wi leiie .ee;feise:,e' 8) a) 10) a) Bt (0) .¥. ¥) 6, Je. = eljniieiellave).b ere) 0109 elje o/s (e\"e »'s\\0 15 Sept. jl. 5. REPORT OF COMMISSIONERS OF INLAND FISHERIES. Cr. By received from State Treasurer.......-..----+--+++5 20 “ ‘“ “ MNO RMS, Area AA 87 toothy mec at an Okc 20 “ ‘“ ae OD he retusa ce ee ee 21 “ “ & ME 8 PPAR Acer mei ca evar 20 “ “ “ i A ORS MEN DRE yes cere 8S Toy AA 20 ““ “ $6 Ce ame: pM aM eR SN hey Dimes RIDE APTOS 20 “ ‘“ “ OE aaa ener et ee eg ee 20 «“ “ &“ LOR k PO EA RTE Dearth 9 “ “ U OS dyn eee: fa 50 pe Pie tod oue tase eemapats 71 “ “ ‘ tee list ie ee en Mea eer aa cic 25 Se : SME | eG Soichiniokh oeeaG co oO 4 _ - “ pee SI abit bare ain epone i ceos aioe! 154 : : COR Mr naeeete eke eae AU EN 47 i a Paes Ph ee PO IO Moni tece tO 12 : : : Ls oto ror od ten OS 46 Z . SE PR Seach Sa aor Oro DO" 20 oe : rs MEE ES Seon OOOO 20 *, ; : Pn errata totter a-se 20 - : se LMR he Fin Alattc 6 oman pig OX 12 : : a RiP mn Ae Sircroratrol co.cc 15 1906. Sept. Oct. 7. 13. 12. 24. REPORT OF COMMISSIONERS OF INLAND FISHERIES. Cr. my aie, =i) s} (wie; (e/ je) "s' (0) (ol (het else! .0) (0), 0) 8) 0 15 16 1906. (Oyare Ae dl. Nov. Dec. elas Or REPORT OF COMMISSIONERS OF INLAND FISHERIES. Cr. By received from State Treasurer.....-.---------0 +--+: 89 ss Se st DPM ct ny eee Sarl restco ol ora :0 13'C 75 if ce nh Ce Goats Bena eet etait ete te tt 30 es 4 ie OOo Nae kit Weuel clean eg Rabo oe ae atest eee 19 HE ef sr DAT RINN RA cP absshris rider aaatora 26 o i ie Sn Ae treo eee ouericti Ul ttn 24 as x ‘a OE A cs ri atte Tee ee 10 rs ‘ oe SLB iaee ge ae Planes i cota aie aeastian Ut 20 nS 1 ee eRe BEN on Wintec as alts otldec non ia tetas 7 et e MUI FP Ome Cr ne LG, Shh, cbt ao 3 ne NSLS Ney me oan OeoRT 3 8 0. o.% 1 é Slain mien Lashes PAM RAS OCHS 3 40 ; oh OS a cae gain eaten aay ck eel e 10 ; : Lome On ie gon ac o.mole oetD ese 4 : he er ae hic a ee hee eee ana 56 : FN AEN Ren chia Aero ad Aon oe 25 : I rae eon aa dc. 235 ; ‘ Sea Re Aeneid 5 2) orn otro, © 86 : cS i pe ret ge ort Sin ee cate 78 ‘ es > poten Aer Scr enA pha tere fee 85% 1 ; : a pee AAR crete en cris So oo 25 : ; s CE AS BRRNCURLS eee eee 34 : 2 eae arias Coot ay ey Oa Oru. ora.o.C 1 cr ET ae ce a etete te dectawe sei Bate oti 10 Ot NO tka euepira aie Gi ata 3 Lemar Meek Secs Sheri Pd. boatS 6 deme Saati Berlin Ap ved ob alo cc 15 Os ome aisle Sek ee agen severe token 109 : : fe VE ite eee aaa Bae ee 30 i OO Faker dete Rae eo 20 1 aco ast ama hake eats Rae nee 16 o EMER re JERE Src a oidti ono. 30 : : Bo De ae a ae 30 es Lee ee a ng nee 16 eau aL Vier PREC rence Boag co, afd) sense 'o - 6 : 5; i SORE I PNPe Staci ap ACen by dad. ow 48 : : ; CE Ser se i cca Re a a i? U eee SAAN UP cinih Ga 6.0 cro 23 REPORT OF COMMISSIONERS OF INLAND 1906. Cr. Dec. 26. By received from State Treasurer........... Respectfully submitted, FISHERIES. ly $9,212 50 RHODE ISLAND COMMISSIONERS OF INLAND FISHERIES, HENRY T. ROOT, President, Treasurer, and Auditor. December 31, 1906. 18 REPORT OF COMMISSIONERS OF INLAND FISHERIES. I. Tur SrockInGc oF OuR PONDS AND STREAMS WITH SUITABLE FRESH-WATER FISH, THROUGH THE DISTRIBUTION OF EGGs AND FRY. Trout. The Commission has purchased of the American Fish Culture Company, of Carolina, R. I., 40,000 yearling trout. These have been distributed in the various streams of the State. We wish to take this opportunity to acknowledge the assistance rendered by many of the fishermen in the work of distribution. Shad. For a few years past the United States Bureau of Fisheries has been unable to supply your Commission with shad fry because of the scarcity of the spawn. REPORT OF COMMISSIONERS OF INLAND FISHERIES. 19 Il. Tuer CoLuEcrion oF Data AND Statistics RELATING TO THE COMMERCIAL FISHERIES. The fishing season on the whole was very good, and it was quite free from severe storms. Among the various fish caught in Rhode Island waters, the following deserve special notice. Scup. The scup season was one of the best in a good many years. Not only was there an abundance of fish, but they were also quite large. The run began about April 23 and ended near the first of July. Mackeral. The mackerel season was not very good, although a number of good catches were reported by the menhaden boats and others out- side of the “ fleet.”” The school seemed to be broken up and the “fleet ’’ did not have good success in finding the fish. Codfish. These seemed to be as plentiful as ever, and the dogfish menace was not particularly severe. Menhaden. The menhaden in the Bay were as abundant as usual. There were no indications of the plague which destroyed so many in 1904. The first menhaden caught in the West Passage in 1906 was caught April 16. The line fishing was slightly above the average. Tautog, squit- eague, flatfish, ete., were fairly abundant. Many schools of young fish were observed, and this is a good omen for the future. The difficulty of collecting complete and accurate statistics of the 20 REPORT OF COMMISSIONERS OF INLAND FISHERIES. total catch of fishes was mentioned in the introduction, and has been remarked upon in previous reports. There are so many and so various channels through which fishes reach the market or the pri- vate consumer that it is practically impossible to keep track of them all. This difficulty is not peculiar to Rhode Island, but applies to the fishing industry generally. Nevertheless, a fair indication of the relative status of the fisheries is to be had by comparing the statistics taken year after year from the same sources. With this word of explanation, the following tables of the catch of fishes and lobsters, based upon the records of dealers and transportation lines, are, as heretofore, submitted: Table Showing the Amount of Fish, Lobsters, and Other Sea Product Shipped Monthly from Newport by the Principal Transportation Companies During the Year 1906. | a g a o (stele felt ee SS ee 9) eel ee ete ele me le ae etre eumeei es eee Fae Go SB lijes |) ao Pea eae iS eslele#lecls mi fees ad ie (Seto) suet ime ste Plesbal acetal eae ees |S oy ne Fale fe eee es eee UM esd tale chayle ee, a a ane al eta ar are eeielle tlre lec es | = = 2 >) & | & q ee & = Gy | a Gy Ce Cs) Cy = =] 2 =) =) =] 3 mo} pk et ee eee pce | amine kal Pest eI (rs DADUATY ttc. 2 1,413 | LOG |e 52. Seca hall) RO) RR tel ell cee tee | | | February....... 638 A 3 lerdal ebro! lao Aio| pn octclheae o|/otolain| |p Coolloqa.cllace alisidc.a|loid o.o|,ore Marche ase fal 208], LIS Sie ce alana [Pe ele {ohere-allaicsaral| esd. [A eset saa aa Anne ae 10309) (SUF ; oe s 3 £ s i} — o - peer cen Wee tp cee ieee i YEAR. 5 : a se 3 z g = Gs) o) py 2 = oy a i ci » = & ad a 5 » n 3 ° + DQ ° wo E & = e fe E ie & 3 Ay eal e = a ea) fo) oa) r= “R= aaa ek 4 6 26 9 34 15 Pee ee de ieee 119 it ie 3 10 23 11 35 15 DA grits Se 121 (Ch ae 4 16 24 16 34 12 Dot gl Eee a 135 ON eae 7 15 24 13 52 14 iter apes, 151 1 ince es 6 22 27 13 52 14 TB ln ei ee 161 LOGSENS. aos) 7 21 32 13 72 16 SOP ato 195 POOH. ss ces 25 6 27 33 7 78 14 49 6 220 UMS ces ates 6 26 33 11 82 20 56 6 240 MOOGE ES She 6 35 27 11 80 20 64 6 249 Compiled by E. W. Barnes, A. M. 26 REPORT OF COMMISSIONERS OF INLAND FISHERIES. 1906. LIST OF TRAPS AND OWNERS. Off-Shore Traps. (See Charts.) mn dersone | 2 Ni, aes epee tee och ae South Cormorant Rock. ATO STSONG Sewer ee ee ee ae ee, ais are ee South Sakonnet Light. Andersons sie eet One en. ks cnae South Narragansett Pier. rishi mari: Wem OO) yet. 2a... oy! ss aha aia oc) oat eee Seal Ledge. Sig ted oy sO 0 02 GAR Nok ce ee ei eS South Sakonnet Light. Brigitmian, WeOO jen ae... <6. aa teas Below Cormorant Rock. Brownellha7 Chien... 250 /\4. See oe Coggeshall’s Ledge. PB TO WHGIL, eee see haet hea 3 Nils (ale Watches ee Eanes, Lower Pier. RO WMC este a ee. oa uc EN okt ae aks North Narragansett Pier. PO WHE lied ime eerie ct Qa Pete Fak td make ee South Sakonnet Light. ESTO Ve ete erent Gane LOR esccied Soh, Some ee South Cormorant Rock. (O/H icsiel nia! G2(((0/010) ai errr aie Meriam voter a Umaga teer ce Spouting Rock. Chitrelmndinimesten rece. 2 oa Shea teen. Sa ees South Lower Pier. Chir leave smo giants ule se Some Ray aa Coggeshall’s Ledge. Cottrell, Cottrell, Church & Luther............ Coggeshall’s Ledge. Cottrell, Cottrell, Church & Luther........South Cormorant Rock. Cottrell; Cottrell’ Church & luther: ..0:5 222...27- Cormorant Rock. Cooks Gnas (GO) tw str ea ck eee North Sakonnet Light. HASteErbrOOkSe em OO) te a. as is satis «pete see ee eu Price’s Neck. ishenes: COss eerie: 2. co le ee late oe Coggeshall’s Ledge. Hisheries Co. (OO0O0O00D) fs... 2.525 eee tee South Sakonnet Light. Gririnell ue = pe eereernne te S. . a ss ee eee South Sakonnet Light. OCKImM Ger, Vela pero tree bois. > «2 03 2 ee eee pees: South Breakwater. luockin@er, Tig ete sete rice. is « 2s je tae ee Sakonnet Light. Macomber at: Simmiguie occ... 2 2 oso a eee South of Pier. Macomber dé: SimmO@nsteac as.) =. So le Below Coggeshall’s Ledge. Macomber & Simmons.....................south Sakonnet Light. *The ciphers indicate the number of traps set in line on one string of leaders. REPORT OF COMMISSIONERS OF INLAND FISHERIES. 27 | 2EEURG) Gd loge. rae A oP eae South Cormorant Rock. ProwiGemeerhishiOO. 6.04% oa ng aee kes ea Ss West Cormorant Rock. ProvidencePish(Co: 2. ct lee ete ee South Sakonnet Light. ERS CAA e ne ay eke ad os ows Below Cormorant Rock. USN RSs ass specs al shes Dok ie DLA M Ker oat! Scns South Cormorant Rock. BRVOSE? GG COs (OU). IA sn bak lak tee he batted North Sakonnet Light. PRISE? COM a i cee fn ti Hie wt hes See oa) oe South Sakonnet Light. SakonmetaOysver/Gol(O0)iinic5¢es esses tee sees anaes ee Seal Rock. SUMinoee A Manes. Vader eave ene ed es Lae N AN ee Eastons Point. alana en(OO) Mohs cae sa dacdaaee se eux South Cormorant Rock. (Ue EN oo ee a eer South Sakonnet Light. SE, Lao Sg gue CLR ene Ree ARE! ALR West Price’s Neck. TSS al ee eee a Minho ee ene PP er West Sachuest Point. IS GAIEEDS) Bis iy Aakash A ee ROY eee SE SMB ARETE es free Breakwater VEEL OIE ee Leos, halen snchUotonorore sete telomere fos tater South Cormorant Rock. VRGUIGOR C16 La 9G AOR RRA Cosine tenet a red ee South Cormorant Rock. Wilcoxon; 0082 S04 kate ns. sort bh: Sachuesteemia WMeGrn et AM ech SEEK R abate Ay sakes en a TA Sakonnet Light. Wilcox, Chas..... eee South Cormorant Rock. Other Traps. Pitta ee pir ee ee ge RNA Seer rare) Ss 2. ods «+ CANO BUM ONIN eallite Ren@l typ] Bie 0 (G10) ee Roa aR arias on! Daa ile ere nie Quonset Point. Jes SERENE NIT eS ar a CEE a Pe Pn AE High Hill Point. EMAAR ATM (OMe e's a eee aie seers siel'a ata ae. eas South High Hill Point. sever bemestorah (Crd 6 ite tie Ree en Nee ee Coddington Cove. EMG CTS OM eC mabyatlg neem ert tle ae tert id ee Se Coddington Cove. Pa eee He rer ak aac sacle ere Oates = Aa West Vials Creek. POT END OM Urereyr och. hoc Re 5 Grape aes arsae OR aya Wes ot Northwest Hope Island. everett On Gra (OO) a8 oa nk arneterteiade 4 cote « North Prudence Park. LESAT SSN TOLgve rate crime CRMC tek Te AA is cn a Podjac Point. LEADS WOT \ GA eit a ae ee te ea Pine Hill Point. cE SVCLS DATEL AG CLO Ra he GPa Ce ga South Ferry. eecemale ea OW imc emecte desc cc eae ain sss scr.» Wood's Castle: 28 REPORT OF COMMISSIONERS OF INLAND FISHERIES. Coggeshall, Uuaale stipe: sours smaunets Lower west shore Sakonnet. Cozpesinalls Wary easler Sait tee an Negara aoa : .South Sandy Point. Ceereslialll, Age? he Wein sytney sil oes oa tien eae North Sandy Point. Gorey, pds OOO) Otten teeta. ee pels Lower west shore Sakonnet. Gorey;aeid.: (OU) 224) eh ier Breit oc alphotes pms eens ae Wood’s Castle. Corey ce, Allen: (OO) gainers eile eres son ees South High Hill Point. Gorey Woy Allen OW) pth Oo ney Se siege oi 45s be ateetgen ie Miata Brown’s Point. Corey a artim COO) soe eee eGo. sna ate kee South High Hill Point. Corey; cs Marvin (OUD) Deer cee nis aa ernie ce ae North Brown’s Point. Core yee Mare COM) 2 reyege map ooo, nbn\ sceeueyepmaegears North Church’s Point. Gottrelles Ace cere ees os. sss vane nee West Popasquash Neck. Cotirelle ask ninseeeeecxccls sik y's" 5\o gheiesp preven ntee- ire West Popasquash Neck. COtLTe las: eRe ee 5 (Suet scone te West Popasquash Point Neck. Copirel see ee ees Ue se eS hie he eee West Popasquash Neck. Wire lnm aeee eee ER Ose erences stale tes Sik SIR BIE Mount Hope Point. Wot erelema eta: eater cthe ams htensarp epee South Mount Hope Point. Sobtrelligms OOM) teceolos sax tote yy £0 Upper East Sakonnet River. Gantirelbeay ie iale ies ree eos eta) oe ei esas Seale ayaa North Tiverton. Contre piece me ietEetals Sapo cs eee ee Ree ewes North Tiverton. Pelkey Cease eee ak. koe ee ee ser atuact mene South Portsmouth. BU Slt: AC WG OM Sete he gare eress!s oct eet «emilee ee tora mone eine eee North Tiverton. PRIS SO nna a Seas. ct a steely oe eedeeepes Tee North Tiverton. BUSht, Mobi bOl eens gee. sete hte Re ease eens Eee North Tiverton. EE TSTy, BO Mimi eran UMON eee oe sistcoe w: 1 0 2 aspilewuw ter mietatene ee ete McCurry’s Point. Gladaanm Ny EGU) ie it 5. tens ices Bum eloreevanevels ee Castle Hill South. Gra yorlomosey (OO eet Deere. o:- cote leteie eae yee eer East Hope Island. Gray AenOss (OMW eerie clin. = (ens elesewte le Mean ae ee Prudence Park. Pay WES: Aes ere ete cts ote ews Je ee ogee Southwest Prudence Island. GT VinGr ONT Lee ase eee Gs ts aon chie ewe te eaohe ae ee Een Prudence Park. Grayvee OWE errata ee cea vise 6 widen eter East Hope Island. Grays, Ges es emma auton oreo (ao a ee even South Sandy Point. Grays: Geo. Wisi CG rete peice ays! wie = eae North Sandy Point. Gray; Geocshe SCO MOU) caeeer tus ome ace South McCurry’s Point. Grinnell. cH: (000) owes er sei 52 a cine North Pine Hill Point. REPORT OF COMMISSIONERS OF INLAND FISHERIES. 29 Harvey, Chasse. .24:....: South Coal Mine, West Shore Rhode Island. DRIGIS OTC) CR Soe PS ok ae eo are a Castle Hill South. Helicuyyl ener hc is a, Wier eats Phaty os Bis eats oo pee ga Se Island Park. MEU arm RIN eee a oa era ae oh a) a) ac bry Gea el Stee Taylor’s Point. = SLEDS VS SEC 6 Ae hn eg a eRe AT Jamestown. TG SEIES SVE TET 6 Re RUN a rc a RE Mackerel Cove. “ESTAS CE Pea a on a PR Fogland Point. Mom cade av ate (OO) ao seis Sie eas ge re Se ye es South McCurry’s Point. LESTE) (OG ETT E Re er ge South McCurry’s Point. SSS, 1 BYE TTT 1 (09) Re oe oe ae Fogland Point. irises eats Barra te. each Peo tes io sth aos 8 Sige tere West Vials Creek. JOG LSS LON oie 2 mS oa a Northwest Conanicut Island. LUSSIER AICOTOS | EWG [ESS 2 ee gg Rr A aE a Mackerel Cove. LORRI OTRE VCO. CSG ann tear rs Oe aro icra ar aged ea Mackerel Cove. raat ee aPNS keer sss poo es ees a) vars woke woes share lara e Mackerel Cove. Pata Le Wachee ole aie es weale ae n Pee oe we Se Mackerel Cove. LD RREEEC SS TEs (0) 0) a ea er arene am gti Brenton’s Cove. EVES HLS EOS GAR Nee ar, OR Packards Rocks. Rasp SROs Rs fares Sale Uns aee wen ty peers diate os West Vials Creek. Micro ia tary DU) pr ccthe Am the mca mict salsa 00s sels 0! et Wild Goose Point. Bemus a amore (OM asa Mat a Sia civiten Sach wk cee ese Se Dutch Island Harbor. Lewis Bros....... Tat a nee eee On ees North Dutch Island Harbor. We wis aLOSGe scsi. citeieiset so eis eas eye este a aaa OReay Exige Sandy Point. PB apr carey see, soso tel eno Shade ac toes vo, cal South Sandy Point. fMemise vals (OOO) aia ss ata tvacnale veg; ccerescc Rasen: 082 North Black Point. Mamas sy Wvilsom (OOO). Po nis cece share co wae dees 8 North Sandy Point. MisaveesINUASE GUNG Dn Te ait cesictirn etn oleh a ken oe ev ares + ee Buttonwoods. JL FBI ICRICISU SR ie gc Urea ae eer ara ara aE PLE Chepiwanoxet. Mearcomberck.. A. (OO), sss 508s news seco e ete 3 North High Hill Point. IME MeIATIN DET. Qo eIROS Eis ai\ccde css shale ois ata eck eee oer North Pine Hill Point. Pelee le (OU dein: « oo Wis dose oyeCage Sosa es Northwest Hope Island. Mea Tela. (OO cies is jae ech thee sie saan Ys 5 aes Northeast Hope Island. 2 SPOS STO Se Ea cnet eng ce Buttonwoods. Madison: chro kes. Sa Ut Coan Buttonwoods. 30 REPORT OF COMMISSIONERS OF INLAND FISHERIES. Ma TONeRLCIN eA COU). 62s iuie tse eee oe ee ee South Sandy Point. Mamenesther At (O00) 25.2.) 22. oe ee ee pee North Sandy Point. Manchester, D....... Lhd Soo SERA Pe ee Re Quonset Point. Mangwester Dos .c.s REE ER SERRE E Ee Cee ete ee Vials Creek. IETS ONE Ors oooh fn A tee een eet ee Fox Hill. Matteson, (Csi)... 2 2. Seeks Ae ee ee eee eee Conanicut. MitelellieBrh. ioe 22 be ee cee tee ee Be ee North Prudence Park. iY bees 002) | El D pene a reg ile eins IRA Mas es tat A South Podjac Point. INe@otis (Bros acer cht st eho ee teh cena North Mount Hope Point. Northup (COs ee hee eee Rae a heen ee Ne ee te ete ee Austin’s Hollow, rere. Bs) T: ee ee reeee CAA es eee eee eee eaee South Black Point. Bierce, Bivins see en oe a meee cee eee y North Sandy Point. Providence Wish CO.e27 4.4558 44.2 2555226 ee me ee Off Wood’s Castle. Rice; Te Hise pera cs hehe es cnt er ees nee omee Warwick Neck. PROSE Gem eee ec eho tse tral ota lalole Sa teretetdeaateh same etna Church’s Cove. Rose nGeGs eee ety 2 ieee ane at eA North Mount Hope Point. Hose GEOr es Ite ae aa ead deed cei ae North Mount Hope Point. Rode sHLG? Wok Shee eee ee ee eye. Upper East Shore Sakonnet River. uose (die Se tere cee on Ree, GOle Soret on Se ee ee South Stone Bridge. O66,“ Santee mee roe Nore he cane et Upper East Shore Sakonnet River. Rosen. pam (00) fc he ee eee we eee eee eee North Sapowet Point. DAMPON Os .. Sse eae ee ee tere cere etens rae tahoe Oana eats South High Hill Point. Shepherd, J.-(00)...:............+.....-North Point Popasquash. Silvia; Ps (OO) AAC NASe aoe etn eae ek eee SS Sect Meee oe: Flint Point. SISSON; PERE C LER S MERGES Sh South Greenwich Bay. Smith Bros. eee eae eat neers Stet Southeast Prudence. DMG hy TOsy FS eG Rese Sete ent Ei es aA East Shore Conanicut. Sinbh: Wi oy od Pee nee West Quonset Point. PoJO0VUH COM) tea aeMR EAM SER 20 Gir Se map Oita, Sic. Poplar Point. sirellAcs(OO).s Sab Ae ARRR eee eee oe ae oe South Sapowet Point. Smell Agee ty Pte te ASO ere ee hee eye ets re South Sapowet Point. DET MASE ee oo PLE Ae oe ere et aie South MeCurry’s Point. Sonal ATES esti. | ae eee ete eee eee North Point Conanicut. Ske Te Wee iso os pa ee Southeast Prudence. REPORT OF COMMISSIONERS OF INLAND FISHERIES. 31 THES S(T sig a nth ge eee Re cn OP North Tiverton. mu res Inet Stipe Gr steer eye fee as'cl cM aceh ed ote eiaty Sv lee One are Warwick Point. Bonu eees tema rre. s s Cie, cake oe OseioNe Wid Mk Als Austin’s Hollow. PourscePea...% PR ee he rE ee ene South Saunderstown. Wal COxme Leer ho Aa tth Ae eee cee Sole WE Church’s Cove. Dp co erielen (OM) ee ie Aa Se seas Aes High Hill Point. Race wAccite anak Me thOn A MEU E Soe CT Mn hes South Sapowet Point. VARIO SAL Bo entam Meee eer ave soa his Stic at ee, SAP ea Buttonwoods. NURS G Mee Neg Ae eer aeien ccieRacle eee ea x el ees sete South Podjac. 32 REPORT OF COMMISSIONERS OF INLAND FISHERIES. IV. Tue ContTINUED EXAMINATION OF THE PHYSICAL AND BIo- LOGICAL CONDITIONS OF THE Bay, BEGUN IN 1898. This work has been carried on continuously, and from time to time, as the data bearing upon particular subjects accumulated so as to warrant publication, they have been brought together in our report in the form of special papers. See index. ; We should be glad to receive from fishermen or from other sources reliable information regarding the condition of the fisheries. This report includes the following papers: THE FisHES OF RHODE Isuanp, III: ‘“ The Fishes of the Mack- erel Family,” by H. C. Tracy, A. M.; ‘‘ A List of Rare Fishes taken in Rhode Island in the Year 1906,” by H.C. Tracy; A. Me ‘““A List of the Rhode Island Copepoda, Phyllopoda, and Ostracoda, with New Species of Copepoda,” by L. W. Williams, Ph. D. THE FISHES OF RHODE ISLAND. | Ill. *THE FISHES OF THE MACKEREL FAMILY. BY HENRY €. TRACY, A. M., BROWN UNIVERSITY. One of the most important of the natural groups of fishes is the Mackerel family. The Mackerels are of especial interest, since they have, for a long time, been of great value to man on account of their desirability for food, and because of the commercial importance of the enormous number of fishes which are caught every year from their vast migratory schools. The Mackerel family, as a whole, is cosmopolitan, and has repre- sentatives in the oceans of all temperate and tropical regions. None of them occur in the Polar seas. Most of the species of the family, also, have a wide distribution. Some of them, like the Common Mackerel, prefer the cool water of the temperate zone, while others, like the Frigate Mackerel and the Spanish Mackerel, prefer warm and tropical seas; but in either case their migratory habits cause them to traverse wide areas of ocean and thus become, perhaps, the most widely distributed of any of the groups of fishes. In habits and mode of life all the Mackerels show a strong family resemblance. They all feed on similar kinds of food and have essentially the same breeding habits. Since feeding and _ repro- duction are the dominant factors in the lives of all organisms, it is * The first paper in this series was entitled **A List of the Fishes of Rhode Island,” and ap_ peared in the thirty-sixth Report, for 1905, page 38: the second paper, ‘‘The Common Fishes of the Herring Family,” appeared in the same report, page 100. 5 34 REPORT OF COMMISSIONERS OF INLAND FISHERIES. not strange that these fishes should be so alike, even in many of the details of their existence. All the fishes of the Mackerel family are, to a high degree, of active and pelagic habits. This mode of life is made necessary by the kind of food on which they subsist and it furnishes the most favor- able conditions for their method of reproduction. The Common Mackerel feeds partly upon minute surface creatures, chiefly crust- aceans and larval invertebrates, and partly upon small fishes; all the other species of Mackerel feed on other fishes, such as the herring, menhaden, sand launce, etc. It is supposed that they hunt by sight, since they snap at all kinds of moving objects in the water, especially if they are shiny like small surface fishes. Most of them are rivals of the bluefish in voracity and exceedingly fierce in their pursuit of prey. The mackerels are thus for the most part surface feeders and, consequently, differ widely in habit, general activity, and manner of life from those fishes, like many of the Cod family, for instance, which prey largely upon the sluggish and sessile invertebrates of the ocean bottom. The fishes of the Mackerel family, therefore, find their most natural abode in the surface waters of the open ocean, where there is an abundance of all kinds of free-swimming organisms. These waters, also, especially their more shoreward areas, furnish conditions most favorable for reproduction. The breeding process in all the mackerels is probably similar to that of such fishes as the herring and cod; spawn and milt are simultaneously shed out free into the water and fertilization of the eggs must, to some extent at least, be a matter of ‘chance. The eggs are buoyant and must be widely dispersed by the waves and tides. The conditions conducive to the securing of the most favorable results from this method of reproduction are furnished by the surface waters of the open ocean. The active and pelagic habits, which are possessed in common by all fishes of this family, are thus an adaptation to the character of their food and to their method of reproduction. Characteristic, also, of the fishes of the Mackerel family are their gregarious and migratory habits. Some of the species of this group REPORT OF COMMISSIONERS OF INLAND FISHERIES. 35 form vast schools, in some cases of many square miles in area and containing an immense number of fishes. The fishes of the same school are usually of nearly uniform size and apparently do not tend to mingle with other schools which may be in their immediate neighborhood. Of the manner in which the fishes keep together in the schools, very little is known. Observations on some fishes seem to indicate that they keep together by sight. But however this may be, it is possible, in the case of the Mackerels, to indicate certain factors which are doubtless of influence in determining the instinct which leads to the formation of the schools. One factor may be their habit of feeding on other fishes which form large schools, for instance, the herring, menhaden, anchovies, etc. In the vast areas of the ocean, fishes of solitary habits are doubtless widely scattered and of such uncertain occurrence that the compact masses of such fishes as form large schools are the most available food supply for fishes of such fierce and voracious feeding habits as the Mackerels. These conditions probably favor the massing together of a large number of the Mackerel for the purpose of feeding. That the individual fishes of aschool may co-operate in “‘ running down ”’ other fishes is not improbable, as this is said to be an observed fact in the ease of the bluefish which has similar habits as the fishes of the Mackerel family. But a stronger influence in determining their gregarious habits is probably to be found in the conditions required by the spawning process. The successful accomplishment of reproduction in the case of such fishes as the mackerel, herring, and the cod, where the sexual products are shed out free into the water, demands the aggregation of an immense number of fishes. If they did not breed together in large schools it is obvious that the spawn and milt would become so scattered by the movements of currents and tides that the chances of the eggs becoming fertilized in sufficient numbers would be ex- ceedingly small. It is also true that the greater the number of spawning fishes massed together in a given area, the greater will be the proportion of eggs which can be successfully fertilized. It there- 36 REPORT OF COMMISSIONERS OF INLAND FISHERIES. fore seems safe to say that, in the case of the Mackerels, the forma- tion of dense schools is a necessity for the most successful fulfillment of the reproductive process. These influences in determining the schooling instinct may, per- haps, be more evident when they are considered in connection with the migrations of the schools of these fishes, particularly in the cases of the Common ‘Mackerel and the Spanish Mackerel whose migrations are, to some extent, definite and regular. While these movements are influenced, to a great extent, by temperature and other conditions, their fundamental causes are to be found in the reproductive instinct and in the necessity of securing food. The initial impulse which drives them from their winter home and starts them on their spring migrations is probably given by the approach- ing maturity of their reproductive organs; the course which they follow, although determined to some extent, perhaps, by tempera- ture and the available food supply, has for its ultimate goal condi- tions of water and temperature which are suitable for spawning. On the other hand, the later movements of the schools, in the summer and autumn after spawning has taken place, are doubtless regulated partly by temperature, but chiefly by the movements of schools of other fishes upon which they are feeding. To sum up briefly the habits of the fishes of the Mackerel family: They feed exclusively, for the greater part of the year at any rate, upon the free-swimming animals of the surface, and they spawn in the open waters of the ocean; for the securing of food they are necessarily of pelagic habits, and extremely active and predacious; for the securing of conditions suitable for spawning, extensive move- ments to favorable localities are necessary, and the formation of large schools is essential for the most successful completion of the process. These fishes are thus, to a high degree, predacious, pelagic, gregarious, and migratory. Besides the similarity in their habits, the great degree of the adaptation of the external features of their bodies to their active and pelagic existence is very characteristic of all the fishes of this REPORT OF COMMISSIONERS OF INLAND FISHERIES. BYE family. The perfection of this adaptation is perhaps best seen in the case of the Spanish Mackerel. Its body is spindle shaped and so smoothly rounded in every part of its surface that it affords the least possible resistance to the motion of the fish through the water. The forward half of the fish-is perfectly smooth, symmetrical, and somewhat cone shaped; it serves admirably as a cut-water for the rest of the body. It is made more perfect for this purpose by the wedge-like shape of the head, all the surfaces of which are perfectly rounded, and its external structures fitted together in such a way that there are no irregularities or projections to break the smoothness of its curves and furnish resistance to rapid progress through the water. The margins of the jaws fit tightly to each other, the surfaces of the eyes conform perfectly to the curvature of the surfaces of the head, and the gill covers close smoothly to its sides. All these parts fit together with such accuracy that, from the apex of the jaws, the surfaces bounding the head diverge gradually in long, slightly convex curves and without a break pass over to the body region of the fish; then, near its middle, they gradually become merged into the slightly concave surfaces of the posterior region. This portion of the body tapers gradually backward and ends in the strong, broadly-forked tail fin; its surfaces run in smooth, slightly hollow curves, which allow the water displaced by the forward movement of the fish to pass backward with the least resistance. A strong median longitudinal ridge is developed on each side of the caudal region of the trunk. This serves as a horizontal keel and is supposed to prevent the stroke of the tail from varying from the vertical plane. When viewed from in front, the outline of the body ‘““appears as a perfect ellipse and surprisingly small in size;’’ the margins of the fins now appear scarcely Front view of the Spanish Mack- erel. (After Dean). very little resistance to the water. The skin of the distinguishable and are so sharp and thin as to offer body is perfectly smooth, since the scales are very small and with- 38 REPORT OF COMMISSIONERS OF INLAND FISHERIES. out spines. It is entirely covered with a considerable quantity of slime, which still further smooths off the surface of the skin by filling in its lesser inequalities. All these modifications of the external structure of the body of the fish reduce to a minimum the resistance to its rapid motion through the water. It is strong and muscular; the vertebrz are rela- tively small and numerous, an arrangement which is conducive to flexibility of the body. The Spanish* Mackerel thus possesses a combination of qualities which makes it one of the swiftest and most powerful swimmers of the sea. The same applies equally well to the Bonito, and all the fishes of this family possess the above described characters with greater or less modification. They are thus, perhaps, the best adapted of any fishes for an active and predacious existence in the open waters of the ocean. The external structure of the fishes of the Mackerel family is distinguished by the following characteristics: The body is elon- gate, spindle shaped, and slightly «compressed. The head is cone shaped, and pointed in front; the mouth is large, the jaws strong, the teeth sharp and, in most of the species, small. The gill open- ings are very wide. They have two fins on the back, the first one spiny and depressable in a groove; the second is made up of soft rays. Directly under the latter, on the ventral side, is placed the ventral fin. Behind each of these two is placed a row of small fin- lets. The pelvic fins are placed directly below the pectoral fins. The tail fin is strong, broadly forked, and adapted for rapid motion. Most of the species have a median longitudinal keel just in front of the tail fin. The scales are usually minute and without spines, but in some of the species they are somewhat enlarged and confined to a distinctly defined area on the front part of the body so as to form a corslet. The lateral line is present and is usually very wavy in its course. In size the different species vary much; the Chub Mackerel is scarcely over 14 inches in length, while the Horse Mackerel some- times reaches a length of 10 feet or more and weighs up to 1,500 pounds. REPORT OF COMMISSIONERS OF INLAND FISHERIES. 39 Seven species of the Mackerel family are found in Rhode Island waters. According to the peculiarities of their structure they may be divided into the following three groups: I. SMALL SPECIES WITH NO MEDIAN KEEL at the root of the tail fin. The two back fins are widely separated; the body is covered with very small scales, and there is no sign of a corslet; the mouth is large; there is a single row of very small, slender teeth on each jaw and on the roof of the mouth. In this group there are two species: 1. The Common Mackerel. Scomber scombrus. Plate II1. This has no air bladder; there are 11 or 12 spines in the first dorsal fin; a groove connects the two dorsal fins; the body is dark blue above, with about 35 wavy, blackish, transverse streaks; the under sides of the body below the middle line are silvery and irridescent. 2. The Chub Mackerel. Scomber colias. Plate LV. The air bladder is present; the eye is somewhat larger than in the Common Mackerel; 9 or 10 spines in the first dorsal fin; no groove connecting the two fins; its color is blue with about 30 wavy, blackish streaks across the back; these are less definite than in the Common Mackerel; below the middle line the sides are silvery, but in the adult they always have roundish, dusky spots or cloudings; in size it is smaller than the Common Mackerel. Il. SMALL SPECIES WITH A MEDIAN KEEL at the root of the tail. Dorsal fins well separated; the posterior region of the body has no seales except along the lateral line; the forward part is covered with small scales of which those in the breast region are enlarged and form a corslet; mouth rather small; teeth very small and on the jaws only; the air bladder is not present. In this group there is only one species: 40 REPORT OF COMMISSIONERS OF INLAND FISHERIES. 3. The Frigate Mackerel. Auzis thazard. Plate V. _ Ill. SPECIES OF LARGE SIZE.—The dorsal fins are not well separated; well-developed keel at the sides of the root of the tail; the body is wholly covered with small scales. There are four species in this group, which may further be subdivided into two divisions: a. Large species in which a well defined corslet is present : 4, The Horse Mackerel. Thunnus thynus. Plate VI. . The mouth is wide; on the jaws is a series of cone-like teeth; on the roof of the mouth are bands of sand-like teeth; about 14 spines on the first dorsal fin; the eye is small; the body is very stout and thick, and reaches a very great size; its color is dark blue above, and grayish below with silvery spots. 5. The Bonito. Sarda sarda. Plate VII. Body elongate; the corslet is small but distinct. The mouth is large; strong, cone-shaped teeth are on the jaws and the roof of the mouth; the first dorsal fin is long, with about 20 strong spines; the second is small, followed by 8 or 9 finlets; no air bladder; dark steel blue above, with numerous narrow, dark stripes from the back obliquely downward and forward; silvery below. b. Large species in which a well defined corslet is not present : 6. The Spanish Mackerel. Scomberomorus maculatus. Plate VIII. Head pointed, short and small; mouth wide, with strong knife- like teeth on the jaws; fine sand-like teeth on the roof of the mouth; air bladder present; first dorsal fin with about 17 spines; color silvery, bluish above; sides with many ellipitcal spots of yellowish bronze color; fins variously colored, white, blackish, and yellowish. 7. The Kingfish. Scomberomorus regalis. Plate LX. Similar in all respects to the Spanish Mackerel, except that its sides have two blackish, longitudinal bands which cross the lateral REPORT OF COMMISSIONERS OF INLAND FISHERIES. 41 line below the soft dorsal fin and breaks up into spots posteriorly; above and below these are numerous brownish spots arranged in rows. The following synopsis of the most important of the characters distinguishing these species may be useful: A. Species with dorsal fins widely separated. I. SMALL SPECIES WITH NO CAUDAL KEEL. 1. The Common Mackerel. No air bladder; groove connects dorsal fins; sides of body silvery. 2. The Chub Mackerel. Air bladder present; no groove con- necting dorsal fins; sides of body silvery with dark spots; small in size. ” II. SMALL SPECIES WITH CAUDAL KEEL. 3. The Frigate Mackerel. No scales on posterior region of the body; corslet present; teeth on jaws only; no air bladder. B. Species with dorsal fins not separated. III. SPECIES OF LARGE SIZE WITH CAUDAL KEEL. a. Species in which a well-developed corslet is present. _4. The Horse Mackerel. Body very large, stout, and thick; cone-like teeth on jaws only; dark blue and grayish, in color with silvery spots; 14 spines in first dorsal fin. 42 REPORT OF COMMISSIONERS OF INLAND FISHERIES. 5. The Bonito. Body elongate; cone-shaped teeth on jaws and roof of mouth; dark blue above, with oblique stripes: 21 spines in first dorsal fin. b. Species in which a well-developed corslet is not present. 6. The Spanish Mackerel. Sides with many elliptical spots of yellowish bronze color; fins with white, black, and yellow. 7. The Kingfish. Sides with two blackish, longitudinal stripes and numerous, brownish spots. THE COW ON MAC kK hans (Scomber scombrus.) PLATE IV. I. Distribution and Habitat.—The home of the common mackerel is the North Atlantic Ocean. On the American coast its southern limit is off Cape Hatteras. Here they are taken in the spring by the New England mackerel boats in water at some distance from the shore. Throughout the summer they are abundant along the coast of the Middle States and of New England and in the Gulf of St. Law- rence. They are not found in any numbers in shoal water south of Long Island, although stragglers are sometimes found in the Chesa- peake Bay and in the sounds about Cape Hatteras in the latter part of the summer. The natural northward limit of the species seems to be not far from the Straits of Belle Isle, though in exceptional REPORT OF COMMISSIONERS OF INLAND FISHERIES. 43 instances they have been known to visit the coast of Labrador. They appear irregularly off the northeastern coast of Newfoundland and are never found in Hudson’s Bay or on the coast of Greenland. On the European coast their southerly limit is the Canary Isles and the Mediterranean, where they abound, especially in the Adriatic. They range northward to the south coast of Norway and Sweden; they occur in the Baltic and are found along the shores of Denmark and Prussia; they are abundant in the North Sea. At the British Isles they abound in the channel north to Norfolk, but they also occur to some extent along the east coast of Britain to the Orkney Islands; also in the Irish Sea and off the south and southwest coasts of Ireland. As far as records go, they have never been taken on the African coast (except possibly in the Mediterranean), nor in South America, the West Indies, or the Gulf of Mexico, or even at the Bermudas. Thus the common mackerel seems to be confined to the coast waters of the temperate region of the North Atlantic, never straying into tropical or polar regions nor habitually wandering long distances over the ocean. II. Muigrations.—The annual movements of the schools of the common mackerel have, for a long time, been of great interest and the subject of much speculation. These are partly a matter of practi- cal interest because the success of the commercial fisheries would be greatly facilitated by a knowledge of such definiteness regarding the laws and conditions of their appearance and disappearance in differ- ent years at different points along the coast that the fishermen could regulate their operations accordingly. But the particular reason why the question of the migrations of the common mackerel has received more attention than those of any other fish is on account of the disputes between the United States and the Canadian govern- ments “ concerning the value to our fishermen of the right to parti- cipate in the mackerel fisheries in the Provincial waters.’? But in spite of all this discussion about the habits of the mackerel, they are little better understood in some respects than those of many other 44 REPORT OF COMMISSIONERS OF INLAND FISHERIES. fishes which have not attracted so much attention. There is, of course, little doubt as to the general significance of these move- ments themselves in the life history of the mackerel, but the course and extent of these migrations involve many questions which are still open to debate. The mackerel first approach the coast in spring or early summer for the purpose of spawning. The shore waters are more favorable for this on account of the obvious advantage to the newly hatched young near the coast, where an abundance of the more minute sur- face organisms are present. The females, during the breeding sea- son, do not feed and can not be taken with a hook. The first migra- tion towards the coast must, then, be looked upon as, to a large extent, independent of the food supply, and therefore what Sars called a “‘ spawning migration.” But the presence of the mackerel in shore waters during summer and autumn, after spawning has taken place, is for the purpose of feeding on the young of other fishes which abound in those waters during the latter part of the season. The latter movements of the mackerel are therefore “‘ feed- ing migrations.”’* Notwithstanding the fact that the final causes of the migrations are to be found in the feeding and reproductive processes, the move- ments of the schools are largely influenced by various physical factors, the most important of which is probably the temperature of the sea water. According to Goode, the appearance of the mackerel takes place off the American coast when the average harbor temperature is not below 45° F. The temperature in the open sea at this time is somewhat lower, probably as low as 40° or even less.f On the European coast, according to Allen,t the mackerel first appear off the southwest of the coast of Ireland when the surface temperature is about 50° F.; off the Mediterranean coast of the south of France, when the temperature approaches 60° F. This may indicate the existence of three separate races of mackerel which have become * Allen, Jour. Mar. Biol. As., 1897, 25. + Report, U. S. Fish Com., 1881, 99. tf Loc. cit., 25. REPORT OF COMMISSIONERS OF INLAND FISHERIES. 45 adapted to different temperature conditions. This is consistent with the investigations to be mentioned later, which apparently establish the existence of local races. On the American side of the Atlantic the mackerel first appear off Cape Hatteras, usually between March 20 and April 25. Their appearance at other places along the coast takes place at about the following dates: ‘‘ Off Norfolk, Va., March 20 to April 30; off the Capes of Delaware, April 15 to May 1; off Barnegat and Sandy Hook, May 5 to May 25; and at the same date along the whole southern coast of New England and as far east as Nova Scotia, while in the Gulf of St. Lawrence they appear late in May and in abund- ance early in June.”* Stragglers often appear at dates much earlier than those given above. The mackerel remain in northern waters during the summer; they -are most abundant in the Gulf of St. Lawrence and the Bay of Fundy in July and August. In September and October they remain plenti- ful along the New England coast and in the Gulf of St. Lawrence; they finally disappear from the northern coasts in November. They have been observed to leave the Gulf of St. Lawrence in large schools, passing out by the same routes by which they entered, 7. e., around the north of Cape Breton Island or through the Straits of Canso. In two instances the schools have been followed along the south shores of Nova Scotia, past the coasts of Maine and Massa- chusetts, as far as Cape Cod and Nantucket Shoals.+ After the departure of the mackerel in the autumn, they remain absent from the coast until the arrival of the spring schools of the next year. Sporadic cases have been reported, however, of the capture of scattering individuals in northern waters in the winter.t In 1906 such a specimen was presented to the Rhode Island Fish Commis- sion by J. T. Fearney & Son, of Providence; it was taken in Narra- gansett Bay, near Saunderstown, on January 30. The winter of that year was exceptionally warm. * Goode, Report, U. S. Fish Com., 1881 + Collins, J. W., Report U. S. Fish Com., 1881, 121. t Report, U. S. Fish Com., 1881, 97. 46 REPORT OF COMMISSIONERS OF INLAND FISHERIES. Along the European coast it is not possible to trace the move- ments of the mackerel with the same definiteness. In January and February a very few fish are present in the western part of the English Channel, and off the southwest coast of Ireland, and in the Gulf of Marseilles. On the west coast of France they may appear in February and remain from that time onward. Toward the end of March or early in April large schools of full-grown fish approach the southwest coast of Ireland and the west coast of France, and at these places now begins the great spring mackerel fishery. At about the same time mackerel fishing begins in the Mediterranean. In May and June the fish are all along the coasts of the British Isles and France, and the spring fishery is at its height. In Norway the large schools appear toward the end of May, and the principal fishery is carried on during the latter part of that month and in June; it con- tinues to be good until the middle of July, when it practically ceases. Professor Sars mentions large schools which are observed near the Orkney Islands at the end of July; these he considers to be the schools returning from Norwegian coasts to the Atlantic. As a general rule, along the whole European coast there is a season of scarcity during July and August. The autumn fishing is very important and takes place during September and October on the southwestern coast of Ireland, in the southern part of the North Sea, and in the eastern portion of the English Channel, and also on the west coast of France. In Norway in the autumn there also exists a very considerable fishery; the mackerel at this time are crowding into the deep water fjords to feed on the young herring and other small fish which abound there; they leave and go to sea again as soon as this small fry becomes searce. On the south coast of France a small number of mackerel remain until winter. The fisheries practically close in November and December along the whole European coast, though a very few are sometimes taken in winter in various localities, especially off the southwest coast of Ireland.* * Allen, loc. cit. 12. REPORT OF COMMISSIONERS OF INLAND FISHERIES. 47 Perhaps the most important of the questions connected with the migrations of the mackerel is—where do the fish go after leaving the coast in the autumn? To answer this question with complete certainty is, at the present time, as impossible in the case of the mackerel as it is with most other migratory fishes. The theory once held that the mackerel hibernate at the ocean bottom not far from the regions of their summer sojourn, is now considered highly improb- able. There are, then, at the present time two possible theories regarding their winter habitat. The first theory is that during the winter the mackerel may con- tinue to live in the surface waters of the sea where the temperature is suitable. In order to reach this region extended coastwise migra- tion toward the south would be necessary. But it is practically certain that this is not the case, since there is no record of mackerel being taken during the cold months of the year south of Cape Hat- teras, or in the West Indies, or on the coast of Africa. Neither have any ever been seen in the warm waters of the open ocean. On the other hand, it is possible that the schools may break up with the approach of winter and that individual fishes may wander about independently, thus possibly escaping detection. Yet this is scarcely probable, and is contrary to what is known regarding the habits of the fish. On the whole, however, with regard to this theory it must be said that ‘‘ until the contrary is shown to be the case, it must remain one of the possible solutions of the question, although it is not very probable, since were it so, specimens would almost certainly have been captured at some time or other.” According to the second theory, the mackerel may live in the deeper layers of the sea, at a greater or less distance from their summer home. At the present time this seems a much more probable view of the case. The fact that on the American coast the spawning season becomes later as the schools appear further northward indicates that a large number of fishes probably move in from waters more northerly than off Cape Hatteras, where they first appear. There is also little to 48 REPORT OF COMMISSIONERS OF INLAND FISHERIES. suggest any very extensive southward journey of the schools in the autumn after their disappearance from northern coasts. Observa- tions on the behavior of the European mackerel are also consistent with this theory. Further, there are certain facts which seem to indicate that the mackerel, when not present at the surface near the coasts, may be in deeper water not far away. In certain bays on the west coast of Ireland large spring mackerel are taken in nets close to shore two or three weeks before any are captured outside in water 40 to 80 fathoms deep. This suggests a shoreward movement of the fishes in the deeper layers of water. Also, several cases have been observed of the capture of mackerel by trawls of boats fishing in deep water when the fish were not present at the surface. In one such case a large number of mackerel were taken in trawls at the beginning of March, 1891, at about six miles off Cape Couronne at depths of 50 to 75 fathoms. Such facts are consistent with the finding of mackerel in the stomachs of cod taken in American waters some time before the schools had showed at the surface. If it be true, then, as the facts known at present seem to indicate, that the mackerel retire to deeper waters to spend the colder months of the year, the question then remains as to whether there is a deeper layer of water accessible to the fish where they can find a temperature similar to that of their summer haunts. That such a substratum of water actually exists is shown by a series of observa- tions taken in 1873 by H. M. §. Challenger between Bermuda and Halifax, and Bermuda and New York. In the Report of the U. 8. Fish Commission for 1877, Goode has an extended discussion ‘of this matter and shows that out near the Gulf Stream, at a depth of 50 to 100 fathoms, there are, in April and May, extensive layers of water which have a temperature of about 50°F. There is also reason to suppose that similar conditions of temperature exist in parts of the Atlantic off the European coast, though no exact records have been taken in that part of the ocean. The evidence which has been adduced above to support the second REPORT OF COMMISSIONERS OF INLAND FISHERIES. 49 theory of the location of the winter home of the mackerel rests entirely upon fragmentary observations and the somewhat uncer- tain deductions based upon them. The problem of the course of the migratory fishes has always been a peculiarly difficult one because the movements of these fishes take place in such breadths and depths of the ocean that only an exceedingly meagre opportunity is afforded for direct observation upon them. There is, however, one possible line of approach to the problem which has been applied with success to the European mackerel. I refer to the methods used by Mr. Walter Garstang, M. A., of the Marine Biological Laboratory at Plymouth, England, in his work on the “ Variation, Races, and the Migrations of the Mackerel.”* This is probably the most important piece of scientific work ever done bearing directly upon the ques- tions connected with the periodical migrations of the ocean fishes. A brief statement of his methods and results will suffice in this place. He obtained as large a number of mackerel as possible from different localities and “‘ by the detailed study of the variations of certain chosen characters in the mackerel of these different locali- ties’ he endeavored to determine whether or not local races exist. The range of variation in these characters in the different local groups of mackerel were compared and the frequency with which particular variations or combinations of variations occur in any one local group were compared with their frequencies in all the other groups. ‘“‘ For example, if we suppose that the number of fin rays in the first dorsal fin varies between 10 and 14, the value 12 wil] probably occur with the greatest frequency. But other possibilities occur; and while 12 might be constantly the most frequent value in one local group of fish, it is quite conceivable that 13 might be constantly the most frequent value in samples of another group.”’ In this case, if the two groups were examined under similar condi- tions and the variation determined upon a sufficient number of specimens, these two groups should be regarded as two distinct races. * Garstang, On the Variation, Races, and Migrations of the Mackerel, Jour. Mar. Biol. As., 5 N. S., 1897, 235. od ‘ 50 REPORT OF COMMISSIONERS OF INLAND FISHERIES. The characters selected for comparison in the various local groups were the following: 1. The number of black transverse bars or stripes across the sides of the fish. 2. The number of the same transverse bars which meet or cross the lateral line. 3. The number of round, black, dorso-lateral intermediate spots situated between the transverse bars. 4. The number of rays in the first dorsal fin. 5. Number of fin rays in second dorsal fin. 6. Number of dorsal finlets. Having thus stated the general method, it will be sufficient here to state the general conclusions to which Mr. Garstang’s work led. The American mackerel were found to constitute a distinct variety or race and to differ from the European mackerel in having a greater number of spots and a greater number of finlets; but it has a less number of fin rays in both the first and the second dorsal fins. The European mackerel were found to belong to two principal races: an Irish race, and a race frequenting the English Channel and the North Sea. The Irish race again is divisible into two distinct stocks, one of which belongs to the west coast of Ireland and the other to the south coast of Ireland. ‘‘The Western Irish stock represents more closely than any other race the primitive type of mackerel from which all, whether British or American, have been derived.” The south Irish fish are distinctly intermediate between the west Irish fish and the channel fish. These facts led Garstang to say that the peculiarities which distinguish one local race from another “are greatest between the races of localities which are geographically remote and least between those which are geographically contiguous.” This establishment of local races throws much light on many aspects of the migration problem. The differences between the American and European races show that they do not mix, and that therefore no long migrations take place across the Atlantic. With REPORT OF COMMISSIONERS OF INLAND FISHERIES. Hy the mackerel of the British Isles, the difference between the Irish and the Channel fishes makes it extremely probable that no extended coastwise movements can take place; each race of fishes must have its own winter home, its own spawning grounds and its own distinct course of migration, and these must all be so far distinct as to pre- vent any considerable intermingling of fishes of the different races. The geographical configuration of the ocean bed lends further proba- bility to these conclusions. Reference to a contour map of the British fishing grounds show that off the southern and southwestern shores of the British Isles are three submarine plateaus, separated from one another by deep depressions; one of these plateaus is adja- cent to each of the three localities frequented by the separate races of mackerel. On these plateaus in the deeper layers of water the temperature is probably favorable for the mackerel during the winter. The deep depressions between the plateaus apparently form relatively impassable barriers to the mackerel, and thus delimit the area normally inhabited by them. This geographical distinct- ness of their winter habitat probably effectually prevents inter- mixture of the different races while away from the shores during the cold season. But in order to completely preserve the purity of the local varieties the spawning grounds of each race must also be separate from that of the other races and constantly in nearly the same locality from year to year. Itis well knownin the case of many kinds of fishes that they instinctively return to the waters in which they were spawned. This is doubtless true of the mackerel, and would suffice to prevent intermixture of the local races during the breeding season. With regard to the course of the migrations, they can probably take place only through comparatively short distances; otherwise the chances for intermixture increase and the different races could hardly be maintained. ‘‘ Indeed the only migra- tion which can, for the most part, be conceded, are migrations from shallow to deep water off the same coast.’’ There is one exception to this, which proves the rule. The North Sea mackerel are racially identical with those of the Channel, and there must therefore be a 52 REPORT OF COMMISSIONERS OF INLAND FISHERIES. complete mixture between mackerel of the two regions during the winter. The North Sea fish, then, must migrate through the Channel; only by that way is the warm, deep water accessible to them in the winter. Here, then, is a case in which racial identity coincides with the geographical conditions which are such that the winter habitat and the course of the migrations of the fishes of the two localities cannot be separate. These facts all point strongly to the conclusion that the racial distinctness of the fishes of these different localities indicates the geographical distinctness of the winter habitats, of their spawning grounds, and of their courses of migration, and further, that the length of their migrations can scarcely be of greater extent than from shallow to deep water off the same coast. Similar investigations of the American mackerel have been under- taken by the United States Fish Commission. Their work led to the following conclusions: ‘1. The existence of a marked racial distinction between American and British mackerel, as indicated by the studies of Garstang is strongly confirmed. ; “2. The evidence thus far accumulated fails to disclose the existence on the American coast of distinct bodies of mackerel, characterized by color or structural features, such as are found on the shores of the British Isles. The examination of further material from extreme southern and northern localities is desirable, however, before the question can be considered settled.’’* This discussion of the migrations of the common mackerel may be summarized as follows: The spawning season of the mackerel occurs later in the season in the schools appearing further north; this is probably due to the arrival on the coast of new schools which have moved in from deeper water not far away: the capture of mackerel in nets near the shore before they have appeared at the surface fur- ther out, the presence of slightly digested mackerel in the stomachs of codfish taken in the winter, the capture of mackerel in trawls in winter, * Report, U. S. Fish Com., 1900, 127. REPORT OF COMMISSIONERS OF INLAND FISHERIES. 53 —these facts indicate the presence of mackerel in deeper strata of water before the spring migration: careful comparison of variable external characters of mackerel from different localities has shown that separate local races exist, while adjacent to the summer haunts of each of these local races, on the British coast at least, is a limited area of ocean of such a depth as to preserve in winter a temperature suitable to the mackerel, but separated from other similar areas by barriers of much deeper water which the mackerel apparently do not readily cross. All these facts seem to indicate that in winter the mackerel live in the deeper layers of the sea where they find suitable conditions, probably at no great distance from their summer habitat. Their migrations, then, are limited for the most part to movements between the surface waters of the coasts and the deeper layers of water off the same shores. III. Abundance.—The remarkable abundance of the common mackerel in our waters has often been noted even since Colonial days. Francis Higginson, in his “ Journal of His Voyage to New England, 1629,” speaks of seeing off Cape Ann, June 26, ‘“‘ many schools of ) mackerel, infinite multitudes on every side of our ship.” There are several other similar notices in those early days. In later times almost incredible stories.of immense schools of mackerel have been told by fishermen. Captain Harding, of Swampscott, Mass., thus describes a school which he saw in the South Channel in 1848. “ It was a windrow of fish, about half a mile wide and at least twenty miles long, for vessels not in sight of each other saw it at about the same time.” Schools have been seen so large that only one edge was visible at a time. The abundance of the mackerel at various localities along the coast is subject to great fluctuations from year to year. In some places, in fact, where they are usually so numerous that important fisheries are carried on, they have at times almost disappeared for a series of years, subsequently returning again after a longer or shorter absence. Although usually abundant on the United States coast, 54 REPORT OF COMMISSIONERS OF INLAND FISHERIES. they have some times been rare, and indeed there is some reason for believing that, in the early history of the country, they were totally absent for several years. These periods of scarcity have often been erroneously attributed to overfishing, and this is the reason for the useless restrictive legislation which has been intermittently applied to the mackerel fisheries since as far back as Colonial times. The causes which bring about these fluctuations in the abundance of the mackerel are very little understood at present on account of . the difficulty of direct observation on the conditions to which their lives are subject. It is perhaps not entirely certain that the non- appearance of the mackerel in a given locality signifies their absence from that place; they may be present in the depths and refuse to “show up ” at the surface on account of some unusual conditions of the food supply or for some other reason. It is probable, however, that the apparent abundance or scarcity of the fish is real. Merely ° local variations in numbers may be due to variations from year to year in the course of their migrations, but a general abundance or scarcity, throughout a large area, must of course be caused by a variation in the total numbers of the mackerel. Variations in the course of their migration may perhaps be induced by the presence or absence in particular localities of an available food supply, or by the unusual number or occurrence of enemies, or by some irregularity in temperature or other conditions somewhere in their path which may turn them aside. On the other hand, the extreme fluctuations of the actual numbers of the mackerel is probably to be explained as the cumulative result through a series of years of a succession of favorable or of unfavorable condi- tions in the environment. The numbers of mackerel in existence at any particular time must depend on the balance of the various external influences in the world round about them; such influences, for example, as the water tem- perature at the time of spawning and during the incubation of the eggs, the direction and strength of currents which may affect the fertilization of the eggs, the size and density of the schools of spawn- REPORT OF COMMISSIONERS OF INLAND FISHERIES. EST) ing fish, the abundance of other carnivorous fishes which feed on the young and adult mackerel, and the existing number of fishes and other organisms which furnish the food supply of the mackerel them- selves. Independently of the others, each of these conditions may vary from year to year about a certain average. Some of these con- ditions will be favorable at times when the remainder will be unfavor- able, but in most years, according to the law of chances, the favorable and unfavorable conditions will nearly counterbalance, so that usually there are nearly the average number of mackerel in existence. But in exceptional years the favorable and unfavorable influences do not offset each other, but one set of conditions is so predominant that either a far greater number of mackerel survive than usual ora much greater number perish. For instance, if a large number of eggs are fertilized and hatched, if a smaller number of enemies are present than usual, if the food supply is unusually abundant, then more mackerel will survive than usual, and if such exceptional con- ditions exist for a series of years, then they will thrive in extra- ordinary abundance. But such an exceptional state of circumstances can not long exist unless the environment as a whole is changing. Each of these conditions, in order to maintain an average, must return to the mean, and then after a longer or shorter time vary to the other side of the mean and become unfavorable. Then, when the sum total of conditions becomes exceptionally unfavorable and remains so for a series of years, a period of exceptional scarcity of mackerel results. Thus the balance of forces swings back and forth about the mean, and an extreme fluctuation in the numbers of mackerel results. Such an alteration in the abundance and scarcity of a species, due to a fluctuating combination of favorable and unfavorable condi- tions, is a universal principle throughout the animal and. plant world, and is the means by which the numbers of individuals of a species are kept constantly adjusted to the fluctuating conditions in the environ- ment. The mackerel doubtless forms no exception to this general law, and the causes of its variation in numbers must be due to vary- 56 REPORT OF COMMISSIONERS OF INLAND FISHERIES. ing combinations of the conditions in its environment. It is impos- sible at present to speak more definitely on this subject, and the time is probably considerably remote when our knowledge of specific conditions in the vast and comparatively inaccessible spaces of the ocean is such as to enable us to predict the movements of schools of the mackerel and the times of their abundance and scarcity. IV. Reproduction.—The first investigation of the breeding habits of the mackerel was made in 1865 off the coast of Norway by the Norwegian scientist, Professor Sars. He found that the mackerel spawns in coastal waters and that the eggs are buoyant. His observations have later been confirmed and extended by other naturalists, both European and American. At Plymouth, England, where the eggs and young have been carefully studied by Cunning- ham, spawning fish are taken from 14 to 50 or more miles from the coast while the temperature was about 54° F. and the water density, 1.0269. The breeding season varies in different localities, being considerably later towards the north than at the south. In America the mackerel spawn in May in southern New England; in May and June in Massachusetts Bay, and in June and early July in the Gulf of St. Lawrence. Spent fish have been taken off of the Virginia coast in April. In Europe the spawning season is in March and April in the Gulf of Marseilles, in May and June off the southwest coast of Ireland, from the end of May to the end of July on the southwest coast of England, and during the first half of July along the Norwe- gian coast. The fish of the first spring schools are very poor and of compara- tively little value as food. Ripe males will take the hook, but ripe and spawning females can be captured only in nets. The eggs are spherical and transparent; the yolk is simple, but with a large oil globule which distinguishes it from the cod’s egg. The diameter of the egg is about one-twentieth of an inch. At a temperature of 68° F. the incubation period is about six days. The number of eggs in a medium sized female has been estimated at a little less than half a million. REPORT OF COMMISSIONERS OF INLAND FISHERIES, 57 V. Rate of Growth.—The rate of growth of the mackerel is not known to a certainty, since those who have investigated it have reached somewhat different results. The following table shows in brief the length of mackerel of different ages according to the esti- Similar The original measurements in millimeters are reduced approximately to mates of different European and American observers. figures for the cod and herring are added by way of comparison. inches. Beiter: Cornwall. hare America. Cod. Herring. AGE. Marion puede Dunn. Cogning: Atwood. | Dannevig. Meyer. HDIBEHN CHING IAS escape) loca ets ces" syle vil \ohels sts cvctenehe Di tow S" eters ast gel 6 -62 2 months.....| 1.6 to 2 ZESLTO psi |leatie eta eets 5) s 2.8 t03.2 | 2.2 1.24 as gE ANNE TRAE NSE SP eae 1 BR A A nt eae 1.8 to 2.0 4 ALO SAT Ae le ar eles eceveboreres| ict seuss oar esemsrel ni [ovvoha: evej.d) sha ree 3.4 2.2 to 2.4 5 ae AMS TGOL OR omit stay mete ster eyet a PMeroicieteieys "001 o)l\eretecene see'eha. ce | 4.6 to 6.25) 2.6 to 2.82 6 - Deo) CONGO? G24 COs sap lier cilens «acts si» OR ASLONT( (2 Ws) cteinsn) aio hol reaper at eke Gn i Pal A ane eee cated nce ae Sk 2, Cog ae eee ee ae 9.2t09.6 | 8.4t09.2 | 8.8to9.2 |........... | Laisi ee iP SAAN Fp en eal Aa eR ca Bedi S/Ouh. aha te Ree aume ie. 22 Bee pirate la To Woy sets sepayrebsi/eeatcl| fstence stat aps at's a¥er| Micse: sys et se ard lenfhen at sy reiheien ang) Soa-3 14:0. toxlGs Olle. erence aes Young mackerel, newly hatched from the egg, are one-fifth inch in length, according to Cunningham. They have not been reared in confinement to a greater age than four days. posed to be two years old, “ tinkers,” three years, and adults of 17 or 18 inches, four years old. Observations as to the age and size of mackerel at the time of “Blinks ” are sup- sexual maturity are as yet too few to justify general conclusions. Marion states that fish 9 inches long in February, which he thought to be a year old, had the reproductive organs well developed. At Plymouth, in June, Cunningham found no signs of maturity in 8 58 REPORT OF COMMISSIONERS OF INLAND FISHERIES. fish 8.7 to 9.2 inches long, nor in a female 10.5 inches. The smallest ripe female which he found was 11.5 inches, and the smallest ripe male 11.8 inches. VI. Food.—The mackerel, as stated above, is a surface feeder and lives exclusively upon free-swimming organisms. These organ- isms are of two different kinds, each of which it captures in a different way. The young mackerel and the mackerel of the early spring schools feed upon all sorts of minute surface creatures, such as small crustacea, larval invertebrates, etc. These it captures in the same way as the menhaden, by swimming open-mouthed through the water and straining the sea-water through its gill rakers. This includes what ce is known to the fishermen as ‘‘ redseed.”’ During the latter part of the summer, however, and until the autumn migration away from the coasts, small fishes and the young of other species become plentiful, and the mackerel then feeds chiefly on these. These they hunt by sight, and capture them chiefly by darting at them individually.* The most important of these fishes are, perhaps, the sand launce, anchovies, silversides, young hake, smelt, and young herring and menhaden. VII. Hnemies.—According to Goode, the gannet is perhaps the most destructive enemy of the mackerel. Porpoises and whales also feed on mackerel schools. Their worst enemies among the “ finny ) tribes ’’ are the mackerel shark and dogfish. In shallow water, also, squid feed on the young mackerel, in the capture of which they show a considerable degree of ingenious strategy by changing their color until it so perfectly resembles that of the sand that they are invisible. THE CHUB MACKEREL OR THIMBLE-EYE. (Scomber colias.) PLATE IV. The Chub Mackerel is of very wide distribution and occurs in the Atlantic and Pacific oceans, north to England, Maine, and San *Allen, Jour. Mar. Biol., REPORT OF COMMISSIONERS OF INLAND FISHERIES. 59 Francisco; it is very common in the Mediterranean, at the Madeiras, and at Southern California. It is said to be plentiful at the Cape of Good Hope. This is the “‘ Spanish Mackerel ” of English writers. The abundance of the Chub Mackerel on the coasts of the United States has always shown great variation. At the beginning of the last century it was very abundant all along the coast of New England and New York. In 1814 Mitchell wrote of it: ‘‘ Comes occasionally in prodigious numbers to the coast of New York in autumn. This was memorably the case in 1781 and 1813.” Up to 1840 it seems to have been a very abundant fish, but for a number of years after that time it apparently disappeared along the whole coast. In the summer of 1874 a considerable school came into the harbor of Pro- vincetown. It was not present in 1880, but has appeared at inter- vals since that time. In 1886 it was common. July 19, 1887, a menhaden steamer took 50,000 near Ocean City; on July 25 of that year 6,000 were taken by a mackerel schooner off Manasquan, N. J. At Gravesend Bay, L. I., it was very abundant in 1896, but rare in 1897.. According to Dr. Smith, it is abundant in some years in Vineyard Sound and the lower part of Buzzard’s Bay. It is caught in traps and also on lines while fishing for Common Mackerel. It usually arrives in the vicinity of Woods Hole about July 15 and leaves late in October. A peculiar fish taken at Block Island by Dr. Seth E. Meek was supposed to have been a hybrid between the Chub Mackerel and the Common Mackerel. The Chub Mackerel is a good fish, and compares favorably in that respect with the Common Mackerel. It is inferior in size, however, being not over 14 inches in length. THE FRIGATE MACKEREL. (Auaxis thazard.) PLATE V. The Frigate Mackerel finds its natural home in the tropical seas. It occasionally strays north as far as Cape Cod, but is very erratic 60 REPORT OF COMMISSIONERS OF INLAND FISHERIES. in its movements and rarely reaches the coasts of the United States. It is known on the coasts of Great Britain, where it is called the ‘“ Plain Bonito.’”’ None were observed before 1880, when it sud- denly appeared in countless numbers. Since then it has been some- what rarely observed. At Woods Hole it is rare; the first one recorded was taken at Menemsha Bight in 1885; one was taken in a pound, June 29, 1892. One was taken at the mouth of Narragansett Bay in the autumn of 1904. It reaches a length of about 15 inches. It is a comparatively poor fish and of little value as food. THE HORSE MACKEREL, OR TUNNY. (Thunnus thynnus.) PLATE VI. The Tunny is found in all warm seas. In the Atlantic it occurs as far north as Newfoundland and the Lofoden Islands; in the Pacific as far north as Monterey Bay and Japan. It is sometimes very abundant on our Atlantic coast, and is taken in rather large numbers off Block Island, Cape Cod, and Cape Ann. It was formerly plentiful at Woods Hole, but a few years ago it was becoming rare. Of late it has been becoming more common around Newport and Narragansett Pier. In 1903, 79 were shipped from Newport, and in 1904, 336; in 1905, 91. Mr. Brownell, of Tiverton, R. I., says that in the autumn of 1904, off Long Island, he ran through an immense school of these fish, extending for ten miles. It is present from June to October, but is most abundant in July. Little is known of its breeding habits, but it is said to spawn in June. According to Yarrell, the recently hatched young weigh 14 ounces and grow to 4 ounces by August, and to 30 ounces by October. The Horse Mackerel is pelagic and carnivorous in its habits; the menhaden is said to form its chief article of diet. This is by far the REPORT OF COMMISSIONERS OF INLAND FISHERIES. 61 largest fish of the mackerel family and among the largest of the whole group of Teleosts; specimens 15 feet long have been taken weighing 1,500 pounds. In European waters they apparently do not reach so great a size; a 500-pound fish there is considered a monster. As a food fish it has been considered of great value in the Old World since the time of the ancient. Romans. In this country it has never been so highly prized. When it first appears on the coast it is poor and of little value, but during the summer it becomes very fat and valuable for its oil. Its flesh is eaten fresh, or salted, or preserved in cans. In Southern California it is very highly regarded as a game fish. THE BONITO. (Sarda sarda.) PLATE VII. The Bonito occurs on both coasts of the Atlantic. On the United States coast itis found occasionally in the Gulf of Mexico, off Cape Hatteras, at the mouth of the Chesapeake, and north to Cape Cod. Specimens have been taken about the Canaries and Madeira, at the Cape of Good Hope, and in the Mediterranean, and it occurs north in British waters. The Bonito finds its most natural habitat in the open: ocean, wandering about in large schools which are very erratic in their movements. It is said to approach the land only for spawning pur- poses and when attracted by an abundance of food. It is extremely active and predacious, and its insatiable appetite is perhaps unsur- passed even by that of the bluefish. In the early part of the last century it was apparently not abun- dant. In 1815 it was spoken of by Mitchell, in 1842 by De Kay, and in 1856 by Gill; in the early seventies, however, it became exceed- ingly abundant in the waters about Block Island and the east coast of Long Island. Since that time it has been common in some locali- ties, though fluctuating greatly in numbers from year to year. At 62 REPORT OF COMMISSIONERS OF INLAND FISHERIES. Woods Hole it is usually common, though sometimes quite scarce. in traps at Menemshaas many as 1,000 a day have been taken in July, August, September, and early October. It feeds on other fishes, especially mackerel and menhaden. It is an excellent food fish, being scarcely surpassed in this respect by any other. It reaches a length of 2} feet and sometimes weighs 10 or 12 pounds. THE SPANISH MACKEREL. (Scomberomorus maculatus.) PLATE VIII. The Spanish Mackerel is confined to the Atlantic and Pacific coasts of America; on the Atlantic coast it ranges from Maine to Brazil. In the West Indies it has been found about Jamaica and Porto Rico, but is said to be unknown at Cuba. Like most of the other fishes of this family, the Spanish Mackerel has shown great fluctuations in abundance. In the early part of the last century it was scarcely known. The first definite allusion to the fish in literature was made by Mitchell in 1815. In 1854 Gill referred to it as a species of slight importance. According to Mr. J. M. K. Southwick, the first Spanish Mackerel taken in the vicinity of Newport were found in the summer of 1857. It was not until about 1870 that this fish came in sufficient numbers to be of any importance. It is very gregarious in its habits and sometimes forms enormous schools of many square miles in area. ‘‘ The fish make annual excursions to the coast of the United States in summer; starting from their home in the warmer waters of the South, or, perhaps, from the deeper waters along the inner edge of the Gulf Stream, in the early spring and proceeding northward or landward as the season advances. After remaining for a few weeks, or months at most, they again move southward, or seaward, and at the approach of cold weather entirely disappear. They seem to prefer water ranging REPORT OF COMMISSIONERS OF INLAND FISHERIES. 63 from 70° to 80° F., and seldom enter that which is colder than 65°. “Off Charleston, 8. C., the fish are first seen about the last of March, and late in April they enter the sounds of the North Carolina coast. By the 20th of May the vanguard reaches the Chesapeake, and others follow in rapid succession, so that by the middle of June the capture of mackerel constitutes the principal occupation of the fishermen. Off Sandy Hook the first individuals are not seen till late in July, and from that time they continually increase in numbers till the middle or even the last of August. Their time of arrival at Narragansett Bay is about the same as that for Sandy Hook. In this northern region they remain till the middle of September, after which the number gradually diminishes, and by the first of October the last individuals have disappeared. A little later they leave the Chesapeake, and few are seen on the Carolina coast after the first of November. Their summer movements are doubtless affected to a considerable extent by the movements of the menhaden and other small fishes on which they feed, as they are usually most plenty in the localities where these fish are found.’* Prior to 1880 nothing definite was known regarding the spawning habits of the Spanish Mackerel. In that year an extensive investi- gation of the matter was carried on by Mr. Earll, and at subsequent times our knowledge has been further increased by the work of the United States Fish Commission. It has been shown that this fish spawns along many portions of the Atlantic coast in midsummer. The temperature seems to have a decided effect on the spawning time, since the reproductive organs apparently do not develop until it is about 70° F. They spawn on the Carolina coast in April or May, in the lower Chesapeake during the first half of June, and at Sandy Hook and Long Island during the last of August. The spawning season in any particular locality lasts from six to ten weeks; the time of spawning for individuals of the same schools varies con- siderably, and each fish isa number of weeks in depositing its eggs. The eggs are very small, being about one-twenty-fifth inch in dia- *Earll, quoted from Nat. Hist. of Aquatic Animals, U. S. Fish Com., 1884, 310. 64 REPORT OF COMMISSIONERS OF INLAND FISHERIES. meter; they are very numerous, and a six-pound fish will produce 1,500,000 eggs. The eggs are buoyant. The period of incubation is about twenty-four hours. When hatched the young are very small, transparent, and about one-tenth of an inch in length. It usually weighs from 6 to 10 pounds. One of the largest ever taken was captured in October, 1901, off Chesapeake Bay; it was 41 inches long and weighed 25 pounds. Very little is definitely known of the rate of growth, but it is believed that it grows very little in the first two years of its life and does not exceed a half-pound in weight at the end of that period. KINGFISH, OR CEREEEN. (Scomberomorus regalis.) PLATE IX. This fish is apparently confined to the western coast of the Atlantic, though it is not common anywhere except about Florida and Cuba. It ranges from Cape Cod to Brazil. It closely resembles the Spanish Mackerel and is not usually distinguished from it by the fishermen. At Woods Hole it is not uncommon; it appears in Vineyard Sound about July 1, where it is said to be more numerous than the Spanish * Mackerel. It is rare in Narragansett Bay. This is one of the largest of the mackerel, reaching a length of 5 or 6 feet and a weight of 20 pounds. It is an excellent food and game fish. It feeds on other fishes. Little is recorded of its habits. TARPON (Tarpon atlanticus). PLATE I, ae Sanp LAUNCE (Ammodytes americanus). Paty IL. ALVIg ‘III “(snaqmoos S) 2) O TAUAMOVIL AML, a ‘Ay TREN SaeF s358 Ps Thavatr A s Sone cedthaes CHUB MACKEREL. THIMBLE-HyE (Scomber Golias). PLATE IV, FRIGATE MACKEREL (Auxis thazard), PLATE V. Horse MACKEREL, TUNNY. (Thunnus thynnus), PLATE VI, Bonito (Sarda sarda). PLATE VII. SPANISH MACKEREL (Scomberomorus maculatus), Puare VIII. CERO. CEREEN (Scomberomorus regalis). PLatTeE IX. “X Givig ‘(SNYRVSIAVR] snpuydao0sr]) UGatO qd 'HLOOWS AH, THE FISHES OF RHODE ISLAND. Iv. A LIST OF RARE FISHES TAKEN IN RHODE ISLAND IN THE YEAR 1906. BY HENRY C. TRACY, A. M., BROWN UNIVERSITY, 1. Dasyatis centrura. Sting Ray. A small specimen 3 feet, 4 inches long, was taken August 8 in a trap on the west side of Narragansett Bay, at Goose Neck, about half way between Wickford Light and Fox Island. It had on its head, just back of the eye, a large parasite, which was identified as Branchiobdella ravenelii. The Sting Ray is said by fishermen to have been much more abundant formerly than now. At the present time, in Narragansett Bay, they are small and rare. 2. Tarpon atlanticus. Tarpon. Plate I. An unprecedented number of these fishes were taken in Rhode Island waters during the past season. This is usually a very rare fish and only a very few instances of its capture here are on record, though there have doubtless been cases not reported. For the following information we are indebted to Mr. J. G. Costello, of the Newport News. On August 11, 1906, Mr. John Souza, of Newport, caught three tarpon in his trap off Second Beach near Purgatory. One of these weighed 97 pounds, and the other two together weighed 90 pounds. A few days later, in the same trap, Mr. Souza took two more, each somewhat smaller than the large one above referred to. About the first of August a medium sized tarpon was taken by Mr. Lawton in a trap in Mackerel Cove. 9 66 REPORT OF COMMISSIONERS OF INLAND FISHERIES. Mr. Costello has also collected the following instances of the capture of tarpon which have not previously been recorded. About the year 1895 two tarpon were taken in a trap in Coddington Cove just north of Newport; one of these weighed over 100 pounds. Later, one was caught north of Coddington Cove, at Bailey’s Point in Middle- town, and sometime after that, another was secured off High Hill, on the Portsmouth shore of the Sakonnet river. All these fish were taken in the month of August. 3. Ammodytes americanus. Sand Launce. Plate II. A specimen of this fish, 9 inches long, secured by Mr. J. M. K. Southwick, was taken off Newport about the first of July. It is very likely that this fish is much more abundant in these waters than the meagre reports of fishermen and others would indicate; its shape and its small size probably prevent its frequent capture in the large- meshed fish traps. It forms schools containing very large numbers of individuals, and is an important item in the food supply of such fishes as the cod, halibut, and mackerel. 4. Caranx hippos. Crevalle ; Hardtail. This species was taken several times in the Lewis Brothers’ traps in the West Passage of Narragansett Bay during August and Sep- tember. It is usually associated with the nearly related species, Caranx crysos, though not so numerous as the latter. In these waters large specimens are rare; the usual size is not far from 8 or 10 inches in length. 5. Alectis ciliaris. Thread Fish. This is an exceedingly rare fish, and only a very few specimens have ever been taken in Rhode Island waters. One was taken about September 15 in one of the Lewis Brothers’ traps in the West Passage of Narragansett Bay. REPORT OF COMMISSIONERS OF INLAND FISHERIES. 67 6. Vomer setipennis. Pug-nosed Shiner ; Dollar Fish. A remarkably large number of these fishes were present in Rhode Island waters last season. Young specimens are not uncommon most years, though adults are usually very rare. During the last season, however, adults were rather numerous; from the first of August until the last of September, traps in the West Passage were found at nearly every haul to contain from one to a half dozen or more of these fishes. A male specimen taken on September 11 gave milt on gentle pressure. For a picture of this remarkable fish see the report of last year (1906), Plate III. 7. Selene vomer. Lookdown ; Moonfish. A specimen of this singularly-shaped fish, taken October 5, 1906, at Second Beach, Newport, was presented to the Commission by Mr. W. T. Luth. This species is rare, and only a few specimens have been previously recorded from Rhode Island. They are usually captured in late summer and early autumn. 8. Lobotes surinamensis. T'riple-tail. Only one specimen of this fish came to our notice last year. This was taken by Mr. Isaac Lake, of Wickford, in his trap near Sauger Point. This was a medium-sized specimen for these waters, being about 18 inches long. This species, although rare, is a food fish of excellent quality. For a picture of this fish see last year’s report, Plate IV. 9. Balistes carolinensis. Trigger Fish. A large specimen, 17 inches long, presented by Mr. Southwick, was secured off Newport about the first of July. Four specimens of Trigger Fish from Rhode Island waters have come to our notice in the past two years; these were all identified by us as B. carolinensis. B. vetula, the nearly related species, is apparently much more rare or of irregular occurrence. See Plate V. of last years’ report. 68 REPORT OF COMMISSIONERS OF INLAND FISHERIES. 10. Monacanthus hispidus. File Fish; Fool Fish. A small specimen was taken in a trap off the west shore of Conani- cut Island, September 11. 11. Lagocephalus levigatus. Smooth Puffer. Plate X. A specimen of this rare fish was sent us by Mr. C. Abbott Davis, of the Museum at Roger Williams Park. He reported that it was taken by Mr. A. A. Wilbur at East Greenwich on August 25, 1906. This specimen was a female 20 inches in length; the ovaries were large and apparently only partially spent. Several rare fishes are reported to have been taken by the New- port fishermen, but such specimens were unidentified. On August 14, 1906, Mr. Edward Lawton, of Newport, caught a Flying Fish in Mackerel Cove, south of Jamestown. It was said to have been larger and of more brilliant color than any Flying Fish caught in these waters in recent years. From the description given it seemed possible that it may have been Cypsilurus heterurus, though definite identification was impossible. A LIST OF THE RHODE ISLAND COPEPODA, PHYLLOPODA, AND OSTRACODA WITH NEW SPECIES OF COPEPODA. THREE PLATES. LEONARD W. WILLIAMS. The Entomostraca, the class to which these orders belong, is a group of crustacea which in vast numbers inhabits nearly all bodies of water, fresh or salt. The economic value of these minute forms at first glance seems slight, but their importance as a food supply, the effect of the numbers which live as parasites on fish, and the work they perform in destroying other still more minute forms, injurious to fish, make them a group by no means negligible by the practical fish culturist. Many small fish undoubtedly depend on copepods and phyllopods for food. The stomachs of young pickerel (Hsox reticulata) which we examined were filled with the remains of phyl- lopods, while larval lobsters were proved conclusively to prefer copepods and phyllopods to other food. Many food fish subsist partially at least on entomostracas, and the appearance of ‘‘ schools ”’ of fish may depend directly or indirectly on the presence of these crustacea. The entomostraca, therefore, are one of the most impor- tant links in food supply between the lower plants and animals and the higher animals. This list makes no pretence at completeness, but merely brings together all previously recorded species and those identified in the tows taken during a year and a half. Further work could easily enlarge the list, as the entomostracal fauna of the State is very rich and has received but little study. No especial attempt has been made to obtain fresh-water forms, but such as have been identified are included. The marine forms were largely secured by towing 70 REPORT OF COMMISSIONERS OF INLAND FISHERIES. during the winter in upper Narragansett Bay, and in summer in the Wickford region and in Charlestown Pond, a brackish inlet from the ocean. A special examination was made of the common mollusks to find whether they were inhabited by copepods. The mussels and scallops yielded negative results, but the common clam (Mya arenaria) was found to be almost invariably the host of a new copepod which occurred also in the quahog (Venus mercenaria) and in the sea clam (Mactra solidissima). It had been hoped to secure a large number of the forms parasitic on fish, but diligent search throught the summer discovered only a few species, the fish in Narragansett Bay being apparently unusually free from parasitic copepods. Our thanks are here due to Mr. Henry C. Tracy for specimens of a number of parasitic forms. The species starred in the list are recorded from Rhode Island for the first time. COPEPODA. Argulus laticauda Smith. On tautog and eel. Wickford and Charlestown Pond. Argulus megalops Smith. On flounder. Matunuck. *Argulus funduli Kroyer. On Fundulus heteroclitus. Wickford. Caligus rapax Milne Edwards. On the skate, dogfish, and many other fish. Cox Ledge. (M. J. Rathbun: Fauna of New England, 5. List of the Crustacea. Boston Soc. Nat. Hist.) *Lepeopthheirus edwardsi Wilson. On flounder. Wickford. Dinematura latifolia Steenstrup & Lutken. On Lamna cornubica. Cox Ledge. (Rathbun’s List.) *Lerneenicus radiatus (Lesueur). On menhaden. Wickford and off Montauk Point. REPORT OF COMMISSIONERS OF INLAND FISHERIES. 71 Clavella uncinata (O. F. Muller). On cod and haddock. Cox Ledge. (Rathbun’s List.) Calanus finmarchicus (Gunnerus). Narragansett Bay. January. This species, so well known as the food of the pollock whale, appeared in winter tows only. Pseudocalanus elongatus (Boeck). Narragansett Bay. January and February. Centropages hamatus (Lilljeborg). Narragansett Bay. Common throughout the year. Pseudodiaptomus coronatus Williams. Narragansett Bay and Charlestown Pond. Abundant through- out the year. Many pairs in copula were taken during the summer in Mill Cove, Wickford. Our attention has been called to the similarity between this species and P. pelagicus Herrick from the Gulf of Mexico, and we admit the striking resemblance in general features. We suspect that Herrick’s description and drawings, upon which we depended and which cer- tainly cannot be harmonized with our specimens, may represent a species of which ours is a northern variety. A comparison of the type specimens would be necessary to settle this point. We may note in passing that the structure which Herrick describes as a spermato- phore is, in our specimens, a reduced egg-sac containing two, occa- sionally three, eggs. Temora longicornis (O. F. Muller). Narragansett Bay. Abundant throughout the year. Kurytemora americana Williams. Narragansett Bay. Throughout the year. Eurytemora hirunoides (Nordquist). Narragansett Bay and Charlestown Pond. EKurytemora herdmani Thompson & Scott. Wickford. Abundant in summer. Acartia tonsa Dana. Narragansett Bay and Charlestown Pond. Summer. 2 REPORT OF COMMISSIONERS OF INLAND FISHERIES. Acartia clausii Giesbrecht. Narragansett Bay. Throughout the year. Tortanus setacaudatus Williams. Narragansett Bay and Charlestown Pond. Though occurring in winter tows in the bay, this species was not found at all in summer tows in the Wickford region. Oithona plumifera Baird. Narragansett Bay. February. Oithona similis Claus. Wickford. Summer. -*Oithona nana Giesbrecht Wickford. This is the first record of the occurrence of this species in American waters . *Cyclops serrulatus Fischer. Wickford and Fruit Hill ponds. *Cyclops lucidulus Koch. Fruit Hill. *Cyclops leuckarti Claus. Mill Pond, Wickford. Longipedia coronata Claus. Narragansett Bay and Charlestown Pond. Ectinosoma normani T. & A. Scott. Charlestown Pond. Summer. Ectinosoma curticorne Boeck. Wickford and Charlestown Pond. Microstella norvegica (Boeck). Narragansett Bay. Tachidius littoralis Poppe. Upper Narragansett Bay. Tachidius brevicornis (Muller). Charlestown Pond. Summer. Parategastes sphezricus (Claus). Wickford and Charlestown Pond. REPORT OF COMMISSIONERS OF INLAND FISHERIES. 73 Diosaccus tenuicornis (Claus). Wickford and Charlestown Pond. Dactylopusia vulgaris (G. O. Sars). Wickford and Charlestown Pond. Thalestris serrulata Brady. The record for this species rests on one specimen from Rock Point. Harpacticus uniremis Kroyer. Upper Narragansett Bay. Harpacticus chelifer (Muller). Wickford and Charlestown Pond. Many of the specimens show points of resemblance to H. gracilis. Idya fureata (Baird). Narragansett Bay. Common. *Ilyopsyllus natans n.sp. Plate I. Body heavy, short, and pear-shaped, except that its ventral edge is almost straight while its back is correspondingly elevated. Color, opaque reddish-brown with seattered brilliant red spots. Rostrum, strong, large, and jointed at base; its apex with two down-curved, ciliated, movable spines. Eye, large, red, T-shaped, with three lenses in front, one on each side, and one in the middle in base of rostrum. The Ist of the ten segments is very large, strongly convex above, and has nearly straight ventral and posterior edges. The following segments taper rapidly to the small abdomen. Thoracic segments of nearly equal width; ventro-lateral angles of first three free thoracic segments form triangular, acute processes, that of the 2nd and 38rd has also an accessory tooth. Preanal abdominal segments of equal width; anal segment very short with a blunt, median, dorsal projection. Posterior edge of the abdominal segments spinose on the belly and sides. Furea short, spinose, with a small, jointed dorsal seta, a minute inner bristle, and two terminal sets; inner terminal seta as long as body, its proximal half broad and naked, its distal 10 74 REPORT OF COMMISSIONERS OF INLAND FISHERIES. half tapering abruptly and plumose exteriorly; outer seta one fourth as long as inner, plumose exteriorly. Female:—First antenna short, less than half as long as the head segment, and six-jointed; 1st joint large, quadrate, with a row of coarse spines on the inner side of its upper surface; 2nd joint as broad as the first, very short, and prolonged in front into a rounded promi- nence fringed with blunt spines; 3rd joint smaller, bearing on its anterior distal angle a large esthetask, one third longer than the antenna, and supported by a 2-jointed accessory branch; 4th, 5th, and 6th joints small, about equal, and bearing a number of bristles. Second antenna longer and heavier than the first, three-jointed; 1st and 2nd joints large, a little longer than broad, the 2nd spined on the upper edge at the end; 3rd joint more slender, bearing six strong, curved spines of unequal length. Mandibles and maxille reduced and adapted for sucking. Mandible pointed at the end, bearing a two-jointed palp and forming with its mate a tube-like trough. First joint of palp small; 2nd joint elongated and bearing two bristles, one slender and long, the other shorter and plumose on both edges. First maxilla (?) about a third as long as the mandible, and similar in shape, but with two or three slender teeth at apex. The maxille appear to be partially enclosed in the mandibular tube. The 2nd maxilla was not found. The maxillipeds are partially united, hav- ing acommon quadrate basal joint; each branch is further made up of two joints, the first long and slender, the second minute and bearing a rather long seta. The basipodite of the 1st foot is formed of two broad, heavy joints, each spinose anteriorly, the second with two heavy curved spines at the distal angles; inner ramus 2-jointed, the 2nd joint somewhat longer than the first, with two terminal spines, the inner about a third longer than the outer and slightly plumose on the outer side; outer ramus 3-jointed, twice as long as inner, each joint spinose distally and with a strong curved spine at the external distal angle, last joint with two additional terminal spines. Second to 4th feet alike, both rami 3-jointed and with slender setz sparingly and delicately plumose. REPORT OF COMMISSIONERS OF INLAND FISHERIES. 75 Fifth feet forming a symmetrical plate, each side of which is three- lobed, the external lobe bearing a short curved bristle. Male:—First antenna 8-jointed; two basal joints like those of female antenna; 38rd joint shorter than in the female with similar accessory branch and esthetask; 4th joint of similar size and shape to the 3rd joint of the female antenna, but with an esthetask upon an unjointed projection; 5th joint smaller, broader than long; 6th joint longer than broad, concave in front; 7th and 8th joints small; 7th with a projecting knob in front, 8th with four moderately long bristles. The 5 foot is similar to that of the female, but is more slender and lacks the bristles. Length, 0.47 mm. This species is very similar to I. coriaceus B. & R. (Brady & Robertson, Ann. and Mag. Nat. Hist., ser. 4, vol. xii, p. 132, pl. i), figs. 1-5. 1873; and Brady’s Monograph of the British Copepoda, vol. ii, p. 148, pl. Ixxxu, figs. 1-10. 1880), and to I. holothurie (Edwards) (C. L. Edwards, Abacola holothurie, Arch. f. Nat. p. 92, pl. 5, figs. 1-17. 1891), but differs markedly from them in its habit of swimming actively near the surface. It was taken in a number of surface tows in the channel of Mill Cove, Wickford.- The rostrum and lst antenna of the female are very similar to those of I. holo- thurie. The Ist foot of male and female and the mouth-parts are similar to those of I. coriaceus. This species has 5th feet entirely different from those figured by Edwards, and we do not find the organ between the fourth limbs of male figured by Brady. *Lichomolgus fucicolus Brady. Wickford and Charlestown Pond. *Lichomolgus adherens n. sp. Puate II. Female.—Thorax ovate; cephalic segment forming more than half of thorax, three free thoracic segments nearly equally broad, 2 3 4 5 6 7 outer angles rounded. Abdomen 6-jointed, {=—-—s—e-r First and 2nd (genital) segments broader than the others; pos- 76 REPORT OF COMMISSIONERS OF INLAND FISHERIES. terior edge of anal segment beset with spines. Furca with branches slightly divergent, each branch twice as long as broad and bearing two dorsal and four terminal sete; dorsal sete short, the outer slightly in advance of the inner; inner terminal seta one-half longer than furea, plumose; 2nd bristle as long as abdomen, jointed at base and plumose; 3rd bristle more than half as long as second and like it jointed at base and plumose; outer bristle shorter than furca, slender, D Oo 5 0 We 3 do ome 16 naked. First antenna 7-jointed ; length of joints ;,-g-—4s3-m 1s 16-30 shorter than the cephalic segment; Ist two joints with many flaccid bristles, other joint with fewer bristles. Second antenna 4-jointed ; Ist as long as other three combined; 2nd joint about one-third as long as Ist, expanded at tip and bent backward so that the distal limb of the antenna is nearly parallel to the proximal limb ; 3rd joint short with three or four strongly curved stiff bristles upon its distal lower angle; 4th joint with seven long curved unequal ter- minal bristles; the upper edges of the last two joints are fringed with short spines. Mandible strong with a hooked toothed and jointed terminal claw; palp(?) one-jointed with three strong, and as many slender, bristles. First maxilla(?) one-jointed with three irregular lancet-like bristles. Second maxilla two-jointed ; proximal joint much swollen with two lancet-like plumose bristles on its inner edge; distal joint small, with one large heavy claw and two heavy bristles. Maxilliped two-jointed; proximal joint bearing a small lobe (inner ramus ?) with two large bristles; distal joint long, broadly elliptical, with a single two-branched terminal claw, anterior branch bristle- like, posterior branch larger, broad, with four or more bristles on its posterior edge. First to 4th feet with both rami three-jointed. First foot with bristles and spines divergent; 4th foot scarcely differing from the third. Fifth foot two-jointed; distal joint ellipti- cal, twice as long as broad, with two spines on the distal portion of the outer edge, one terminal spine and a short terminal bristle. Two egg sacs. Male not found. Length 1.2 mm. Wickford, very abundant under small stones between tides. *Lichomolgus major, n. sp. Plate III. REPORT OF COMMISSIONERS OF INLAND FISHERIES. rare Large, long female, (1.3 mm. male 1.9 mm. without caudal sete), of transparent grayish or pinkish color. Body tapers regularly from the cephalic segment. Female.—Three free thoracic segments of equal width and rounded at the sides. Abdomen 5-jointed, relative length of joints and furca 1 age A 5 6 . . . . ao air a Furca six times as long as broad, with six sete; one on outer edge nearer the proximal than the distal end of furca, a minute dorsal bristle, and four terminal setz, inner and outer minute, 2nd twice the length of furea, 3rd one-half the length of furea. The lower portion of posterior edges of the abdominal joints and the lower surface of the furea fringed with heavy short spines. First antenna 6-jointed, a little more than one-half the length of head segment, beset with short bristles, relative length of joints i: «©: Second “antenna 4-jointed, Ist joint long and directed forward and inward, 2nd and 3rd short, 4th slightly longer and armed below with heavy triangular spines, with two heavy terminal claws and three heavy terminal sete. Labrum ending in an acute, backwardly directed spine. Mandible with an apparently movable terminal claw which has at base a hemispherical pad beset with recurved bristles. First maxilla with a single shoe-shaped joint from whose tip arises one long and two short bristles; lower surface with a similar trio of bristles. Second maxilla 2-jointed basal joint swollen, terminal joint heavy, straight, spine-like, with one bristle midway upon its posterior edge. Maxilliped absent (?). First to 4th swimming feet with both rami 3-jointed. Many of the bristles and spines of the legs are irregularly swollen or con- stricted. The sternite between each pair of legs forms a ridge which is shaped like half of a dumb-bell and has several heavy, flat, spines on each rounded projection. The spines of all legs are entire. Distal joint of basipodite of Ist leg with a broad spine upon its internal angle. The edges of both rami and of the basipodite as well as the distal edge of the 2nd joint of the basipodite are fringed with heavy, triangular, acute spines. Fourth foot does not differ from the others. Fifth foot 2-jointed, lst joint short with a single bristle upon a slight 78 REPORT OF COMMISSIONERS -OF INLAND FISHERIES. stalk, distal joint three times as long as broad, with a conical end and with two heavy serrate outer spines, a long serrate terminal spine, and a short stalked bristle on its upper surface near the distal end. The outer angle of the basal, and the outer side and end of the distal joint are covered with short, heavy, unjointed spines. Male.—Thorax like that of female. Abdomen 6-jointed, relative length, ~~: Second joint swollen, bearing on each side a fringe of spines and a single bristle. Abdomen otherwise as in female. Antenna and mouth parts as in the female except that a large 3-jointed maxilliped is present, 1st and 2nd joints of maxilliped of equal length; 2nd swollen and with a number of acute tubercles upon its inner side near the base and two rows of tubercles near the distal end of the joint, with a short bristle at the proximal end of each row of tubercles; distal joint sickle-shaped and serrate, enlarged at base and bearing there a small bristle. Feet as in female. Wickford and Matunuck, in the common clam (Mya arenaria) the quahog (Venus mercenaria) and in the sea clam (Mactra solidissima). Almost every clam and quahog which we opened contained one or more of these copepods in the mantle cavity. A very characteristic matanauplius which is very abundant in the Bay during the spring and summer, resembles this species, and though all efforts to rear the metanauplius were unsuccessful, we suspect that it is the young of this species. PHYLLOPODA. *Ceriodaphnia reticulata Jurine. Mill Pond, Wickford. *Sida crystallina (Muller) Mill Pond, Wickford. *Pseudosida tridentata Herrick. Mill Pond, Wickford. *Scapholeberis mucronata (O. F. Muller). Wickford. Common throughout the eastern United States. ~ REPORT OF COMMISSIONERS OF INLAND FISHERIES. 79 *Podon polyphemoides Leuckart. Abundant in the tows taken in the middle of Narragansett Bay together with the following species. Summer. *Evadne normanni Lovén. Abundant in tows from Wickford to Newport. Summer. We have been able to find no previous American record for this or the preceding species. *Camptocerus macrurus (O. F. Muller). Mill Pond, Wickford. *Polyphemus pediculus (Linné). Mill Pond, Wickford. Limnetis gouldii Baird. Near Providence. (A. 8. Packard, Twelfth ann. rept. U. 8. geol. & geogr. sur. for 1878 (1883), pt. 1.) Eubranchipus vernalis (Verrill). Pawtucket, Newport. (Packard.) OSTRACODA. *Sarsiella zostericola Cushman. Wickford. In tow taken at night. This species has been previously reported from the Wood’s Hole region only. *Loxoconcha impressa (Baird). Wickford. On eel grass and in dredgings. Plate I. ILIOPSYLLUS NATANS. 2. sp. Female, x 20. Rostrum, eye, and basal joints of first antenna of female, x 360. Furea, x 44. First antenna of male, x 360. First antenna of female, x 360. Fifth pair of swimming feet of female, x 360. Fifth pair of swimming feet of male, x 360. Maxillipeds, x 360. Maxilla (first or second ?), x 360. Mandible, x 360. First swimming foot of male, x 360. First swimming foot of female, x 360. Second antenna, x 360. Puate I. n. sp. Tliopsyllus Natans Plate II. LICHOMOLGUS ADHERENS. n. sp. 2 Female, x 57. N Nauplius, x 370. At First antenna, x 260. A? Second antenna, x 260. M Mandible, x 260. MX! First maxilla, x 260. MX? Second maxilla, x 260. MP Maxilliped, x 260. | Be Fourth foot, x 260. je) Fifth foot, x 260. Priate II. Tichomolgus adherens n. sp, Plate III. LICHOMOLGUS MAJOR. n. sp. 2 Female, x 44. TNS First antenna, x 260. J\Z Second antenna, x 260. M Mandible, x 260. MX? First maxilla, x 260. MX? Second maxilla, x 260. MP Maxilliped, x 260. ips Fifth foot, x 260. REPORT OF COMMISSIONERS OF INLAND FISHERIES. 81 V. A CONTINUANCE OF THE SURVEY OF THE SHORES OF THE Bay, FOR THE PURPOSE OF DETERMINING THOSE PorTIONS WHICH ARE Most PRODUCTIVE OF SEED CLAMS, AND Most SuITABLE FOR THE PLANTING OF CLAMS AND FOR THE DISTRIBUTION oF LOBSTER FRy. The systematic survey of the shore was continued this past year and the charts and the specimens taken were placed on file, in accordance with the plan outlined in previous reports. Dredgings and collecting were systematically carried on at the following places this past summer: Academy Cove, Wickford; Bissel’s Cove; Cold Spring Beach; Duck Cove; Little Tree Point; Plum Beach to Narragansett Pier; Poplar Point. Many isolated spots throughout the Bay were also dredged. The remarkable abundance of clams mentioned in the last report was still observed in 1906. This abundance, which was general over the whole clam territory, came almost entirely from the set of 1904, as the 1905 set was not large. An idea of the amount of clams in certain areas may be gained from the following: A stretch of shore on the south side of Cornelius Island, not larger than seven acres at extreme low tide, has had, as in other years, an especially large supply of clams. Since May, 1905, this area has been dug over every day by at least four or five diggers, and often there has been as many as ten or twelve. Notwithstanding the fact that the clams were small and required more than the ordinary number for a bushel, these diggers in 1906 averaged two bushels per man at each tide, and some very frequently took away more than a barrel. During the season from May to October, 1906, over 3,500 bushels were taken from the bed, and there is still a good supply left. What has been said in regard to the clam supply on Cornelius Island is true of a number of other places. In fact, the abundance of 1 82 clams of the set of 1904 is still very general. REPORT OF COMMISSIONERS OF INLAND FISHERIES. The condition set of the last three years is shown in the accompanying table. of the Condition of Clam Grounds Visited in August, September, and October, 1906, with Abundance of Clam Set in 1904 and 1905. LocatLity. Academy Cove, Wickford........... Bullockss2ointe sane eee Shoredsi gs tare eee @onanicut=(west)re ascetic ore Buttonwood’s Cold Spring Beach. . Cornelius Island (S. Ww. Pt.). re Atg re Cornelius Island (elsewhere)....... Muck Cove... < ii chee meer es Fishing Cove. Greene’s Toland (east snore Sia oeee Kickemuit River (west bend)....... Kickemuit River (elsewhere)....... Mill Cove, Wickford (west shore).... Mill Cove, Wickford (south shore)... Mill Cove, Wickford (north shore)... Poplar Point. . Prudence eae Prudence Island Grext share): Vanes Quonset Point to Greenwich Bay.... Sakonnet River (upper east shore)... Sal Cave ont. sone cies eee Nheep) ben Cove... ec- ee ee ee Vial’s Creek. . ; Village Cove, W Chiari. The Abundance of Clam Set in. 1904. 1905. 1906. Extremely thick...| Scant....... Scant Very rood. 25/023 Nones 2. Scant POOR SE ey SE ieee ie Se a eae Good WeWiseie. ca: Scant Fair. . Pees] ALE W tae cies Scant Wieiremiely phielc: Ja LC Wa Rs eae: Scant Matcher etsy eee nee None se .er. Few Goodiaece. seuss | SLEW series Few Good: .-22...-...°| Seatterng Few None-ieo cee | |S NODeE Ee ae Good Very good........ Scattering... | Few Meseren 5 tic hic as Scattering...| Fair Pair.........>....)| seattering....| (seant Very good. 2.027: BOWie se eh a Scant Good esrad Hot ed RLEW en enee Few Good RG Winnie ati Few SA eas AR a ee Re None.......| None ae iW ROLE ae her as None.......| None Good Nonesanernc Few So Pa RIRIEA Seine, ee eee HeW sacs =| Bews Good Hewaseceons Scant Good Kewielseescee Few GOOG here Eee eee eee Few Good Fe isiee ar eis oe une eee Fair REPORT OF COMMISSIONERS OF INLAND FISHERIES. 83 VI. THE ConTINUED INVESTIGATION INTO THE METHODS OF CLAM CULTURE. During the past year little work has been done in the way of new experiments or actual clam culture. The condition of the clamming territory, however, has given an opportunity to make many observa- tions which, taken together with our previous experiments in clam culture have an important bearing on the question of the future development of a clam industry in Rhode Island. The effect of digging over clam beds was mentioned in the last report. The statement that the digging over seemed to render the soil unfavorable for the establishment of a new set has had new support in the condition of the set at Greene’s Island. The extensive digging attendant on a previous large set apparently prevented the Island from receiving its share of the abundant set of 1904. The old set was therefore gradually dug out, and in 1906 little digging was done on the Island. Consequently there was a good set on the Island this year, while other shores which were constantly dug over received a very meager set. The slow growth of clams in the overstocked beds has also been noted during the past two pears. Clams which on account of age should have been three inches or more in length, are on the average barely two inches long. In places where the tide runs swiftly this retarding of growth can not be regarded as due to a lack of food, but is apparently attributable to interference with the burrowing and feeding. When living in the water uncovered by soil, clams will grow quite rapidly for a short time and then very slowly. Such small clams, whose thick shells indicate a considerable age, are often seen on the timbers of wharves where they are held in place by mussel threads or by their own byssus. A certain depth of soil is necessary for a favorable growth of a clam, as has been ascertained from experiments with clams grown in boxes with various depths of soil. In the overcrowded beds, however, the majority of the clams 84 REPORT OF COMMISSIONERS OF INLAND FISHERIES. are either forced entirely out of the soil or are kept from reaching a proper depth, and consequently their growth is interfered with. Whenever the clams are covered by the tide a renewed activity occurs, and the constant moving about of some in each group in their efforts to burrow disturbs the whole mass of clams. This disturb- ance causes the clams to draw in their siphons frequently, and thus stops their feeding. Since the growth of the clam, as of most marine animals, depends almost entirely on the amount of food that is obtained, this disturbance amounts to considerable in retarding the growth. The clams which are crowded out of the too thinly settled beds, and often die in considerable numbers, have naturally a dele- terious effect upon those that remain alive. A well-stocked bed is distinctly beneficial to the adjacent ones if it is allowed to remain undisturbed through the spawning season. The undisturbed spawning sets afloat millions of seed clams which the tide spreads over the neighboring shores. While the Commission does not take the credit, often attributed to it, of being responsible for the recent large set on account of the spawn from its reserve beds, yet it is quite noticeable that a heavier set has occurred on the shores in the immediate vicinity of these beds. The set of 1906 was very small. Some spots, as at Greene’s Island, where the soil was undisturbed, received a good set, as has been men- tioned before. In the accompanying table is a list of the shores visited in 1906, with notes on the clam sets of the previous three seasons. REPORT OF COMMISSIONERS OF INLAND FISHERIES. 85 VII. Errorts To PREVENT THE ILLEGAL TAKING OF SHORT LOBSTERS. Your commission has continued its endeavors to enforce the lobster law and thereby to protect the industry from the abuse of the ignorant, indifferent, or shortsighted persons who formerly made a practice of destroying short and egg lobsters in great quantities. During the few years of enforcement of this law the effect has, we believe, been decidedly beneficial. The dealers and the more intelli- gent fishermen realize, of course, that the law was drawn and its enforcement attempted for their benefit. The constitutionality and legality of the law have been called in question in a manner and with the result which appears in the follow- ing opinion of Judge Douglas, of the Supreme Court: SUPREME COURT. STATE, Je Q. No. 409. Ex. &e., No. 3773. PATRICK SHEEHAN. / OPINION. Doveuas, C. J. This is a complaint charging the defendant with having in his possession seventy-five short lobsters, in violation of Public Laws, cap. 969. After being found guilty in the District Court, on his plea of not guilty, the defendant appealed to the Superior Court, where the jury found him guilty of having had sixty short lobsters in his possession. Before sentence he moved to dismiss the complaint on the ground that the provisions of Cap. 969 are void, being contrary to article I, sections 10 and 14, of the constitution of Rhode Island. During the progress of the trial several exceptions were taken which are now brought to this court in a bill of exceptions. The constitutional question and the bill of exceptions were tried together and are now before us for consideration. The constitutional question is not stated with sufficient definiteness to enable us to ascertain what specific objection to the statute is intended to be relied upon. 86 REPORT OF COMMISSIONERS OF INLAND FISHERIES. We find nothing in the sections mentioned which can be supposed to be violated by the provisions of the statute. The argument in support of this motion was addressed to the clause of the law which provides: ‘‘ The possession of any such lobster, cooked or uncooked, not of the prescribed length shall be prima facie evidence to convict.’’ As the offence charged in this case was having in posses- sion, it could be no infringement of the defendant’s constitutional rights to enact that proof of the fact should be prima facie proof of the offence. If the clause has any effect in a case like this one, it is only to emphasize the right of the defendant to introduce evidence to show that his possession was not with guilty knowledge, as he was admitted to do at the trial before the jury. We can not see that any constitutional question properly arises in this case. The first exception is that a witness was allowed to testify to facts which are matters of public record without producing such record. The transcript shows that this objection was expressly waived by the defendant rather than submit to an adjournment, that the record might be produced. The second exception is taken to the refusal of the presiding justice to dismiss the complaint on the ground that the complainant had not given surety for costs and was not an officer authorized by law to bring such complaint without giving surety. The motion to dismiss grounded on the objection to the complainant’s official status came too late. It should have been made before the defendant had pleaded in bar to the complaint. State v. McCarty, 4 R. I. 82. The third exception is to the refusal of the court to the offer of the defendant to prove that lobsters which he had had in his possession on previous occasions were of lawful size. This evidence was obviously incompetent. The fourth exception is to the refusal of the court to charge the jury that: “The possession of short lobsters is only prima jacie evidence of guilt. The defendant can explain the possession and if he did not know he had short lobsters in his possession, he is not guilty.” The court had already allowed the defendant to introduce evidence explaining his possession of the lobsters in question and had charged the jury to the effect that if the defendant, knowing that he had lobsters in his possession, and having full opportunity to examine them, neglected to inform himself that they were under legal size, he might be found guilty of the offence charged. We think this instruction correctly stated the law as applicable to the case, and the request was properly refused. The last exception was taken to the charge as a whole, and, as we have re- peatedly held, can not be considered. The exceptions are overruled, and the cause is remanded to the Superior Court for sentence. REPORT OF COMMISSIONERS OF INLAND FISHERIES. 87 VIII. THe PROPAGATION OF LOBSTER FRY FOR THE PURPOSE OF INCREASING THE SUPPLY OF LOBSTERS IN THE WATERS OF THE STATE. Your commission has devoted a great deal of energy to the con- tinuance of this work, which has now passed the experimental stage. In our introductory remarks we mentioned the unique success of the efforts in this regard and the fact that there has been already a noticeable increase of short lobsters in the upper part of the bay, apparently due to the artificial propagation carried on at the Wick- ford station. This work last year was under the immediate superintendence of Mr. E. W. Barnes, who has made valuable improvements in the methods of hatching and has offered suggestions for further improve- ments which we hope to test next season. Mr. Barnes’s report of the season’s work is herewith submitted. LOBSTER CULTURE AT WICKFORD, R. I. IN 1906. BY EARNEST W. BARNES, SUPERINTENDENT OF THE WICKFORD EXPERIMENT STATION, The first egg lobsters were placed in the hatching crates on the morning of the 30th of May, and on the 11th of August, after a con- tinuous run of 73 days, the season closed. The weather was excep- tionally free from winds and storms, but the season’s work suffered as a result of a period of fog and rain in the early part of June. The low temperature, the absence of sunshine, and the freshness of the water were unfavorable to the best results. Nevertheless, during the season 190,000 fourth-stage lobsters were counted out as against 103,000 in the preceding year, and in addition 25,000 were reared to the fifth stage. These lobsterlings were liberated in various places on the shores in Narragansett Bay. Some of the more important features of the season’s work in lobster rearing is as follows: Rearing to the Fijth Stage.—As has been pointed out in previous reports, many unfavorable natural conditions are overcome by rearing the recently hatched lobster larvee through the first 10 to 16 days of life, which form a critical period due chiefly to excessive cannabilism and very feeble swimming powers. — In the fourth stage, which is then reached, the lobsterlings are far better able to care for themselves; for, while they are very vigorous swimmers, they are inclined to seek the bottom and to secrete themselves between pebbles and under shells and stones. The swimming habit, early in this stage, is, however, strong. This is a very unfavorable circumstance, inasmuch as the lobster‘s greatest safety is in hiding. In the two REPORT OF COMMISSIONERS OF INLAND FISHERIES. 89 or three stages following the fourth stage the shelter-seeking instinct becomes more and more pronounced and the swimming habit is given up. It is therefore apparent that the older the lobsters when liberated, the greater will be their chance of surviving. An attempt was made, at the close of the season in 1905, to rear some lobsters to the fifth stage. This was not entirely successful, apparently because the lobsters were reared from the very last lot of eggs and were undersized and weak. Another attempt was made “during the past season with a lot of 5,000 which had come into the fourth stage on the same day. These were counted into a rearing bag and treated like the fry in the first three stages. Although a number of these escaped over the top of thebag, which was accidentally submerged for a short time, over 4,000 fifth-stage lobsterlings were counted out. Because of this encouraging result it was decided to rear the remainder of the season’s output to the fifth stage. The best results obtained were 80 per cent. of the fourth-stage lobsters reared to the fifth stage, and the average percentage was 60. Fourth and Fifth Stages Compared.—Observations made on the behavior of the lobsters in fourth and fifth stages, when they were in the confinement of the rearing bag and when they were liberated under various circumstances, revealed certain very desirable advan- tages which those of the later stage possess. These observations may be briefly summarized as follows: In the confinement of the rearing bags the lobsterlings which have recently entered the fourth stage occupy an area quite near the surface and swim vigorously against the current created by the paddle (negative rheotropism). The claw-limbs are stretched out in advance and kept close together, making the lobsterlings appear like little black lines. Very few at this period cling to the sides of the bag. As they become older they swim deeper in the water, and more of them cling to the sides. When the fifth stage is reached very few of the lobsters are in sight. The rest may be found hidden among the tufts of alge which grow upon the sides of the bag, or upon the bottom of the bag in the grooves made by the inside slats. 12 90 REPORT OF COMMISSIONERS OF INLAND FISHERIES. When they do swim they appear to be heavier in the water and the swimming is undertaken with a definite goal in view, and the direction of their swimming is not much affected by the current. The claws, instead of being stretched out in front, as is so frequently the case in the fourth stage, are drawn back so that the tips are just in advance of the head, as in the adult lobsters. A number of lobsters which had recently passed into the fourth and fifth stages, respectively, were liberated in deep water and also along shore in shallow water, and were observed carefully in order that their behavior at this important crisis might be compared. When liberated in deep water the fourth-stage lobsters would often swim for a time actively at or near the surface of the water. A few going deeper into the water would come up to the surface again, When there were bits of sticks, eelgrass, etc., close at hand they would often bump into them, stop and investigate a moment, and then swim away. The fifth-stage lobsters, when liberated in deep water where there was nothing to attract attention, would soon be lost sight of in their descent. Very few would return to the surface again. Where there were objects strewn about they would either descend unattracted by them or would swim to the nearest object and attempt to crawl uponit. If the object were too small to hold them they would fall off and perhaps remount two or three times, and, failing to stay on, would seek another object. When liberated in very shallow water along shore, the fourth-stage lobsters would swim about till attracted by something on the bottom, and would then drop down and investigate, not infrequently going down and coming up several times. Some would swim back and forth between the deeper water and the shore. It is true that many of these would establish themselves more or less permanently on the bottom, and it should further be stated that fourth-stage lobsters which are nearing the fifth stage anticipate the habits of that stage. The fifth-stage lobsters liberated near the shore would, almost with- out exception, go down to bottom at once; often crawling down a REPORT OF COMMISSIONERS OF INLAND FISHERIES. 91 blade of eelgrass or other object. Very few minutes would be required for them to establish themselves in their bottom life. The chief advantages which the fifth-stage lobsters possess over the fourth stage, aside from the fact of their being older and stronger, are as follows: The instinct to seek shelter is stronger. The swimming habit is almost entirely abandoned, and propor- tionately the instinct to crawl about is more strongly developed. The claws are used more effectively as defensive weapons. When liberated they seek the bottom more quickly, and for this reason there are fewer chances of being devoured by fishes. Number of Fourth-stage Lobsters per Egg Lobster.—The method usually employed to demonstrate the economy of our rearing plant has been to get percentages from certain counted lots. From a lot of 1,000 first-stage lobsters more than 50 per cent. have been carried to the fourth stage, and over 48 per cent. from 20,000 lots. While this is a very exact method of determining the efficiency of the plant in rearing newly hatched lobsters, it does not, of course, take into account the matter of hatching the eggs themselves. During the past season we have further tested the efficiency of our apparatus by ascertaining the number of fourth-stage lobsters that may be obtained from a single egg-bearing female. The shipment of egg lobsters from Newport closed rather abruptly the last of June. There were consequently no egg lobsters on hand when through the courtesy of the Connecticut Fish and Game Com- mission we received a number from Noank. These were of medium size and possessed an average number of eggs in quite good condi- tion. From 56 of these lobsters 84,896 fourths were obtained. This makes an average of over 1,500 fourths per egg lobster. It is safe to assume that, taking everything into account, this is an average number that may be obtained under normal conditions from the method as developed at present, provided the eggs are in good condition. 92 REPORT OF COMMISSIONERS OF INLAND FISHERIES. The success of the experiment emphasized the importance of especial care in the treatment of the egg lobsters. Considerable difficulty was experienced during the past year in this respect, and many of the eggs were dead before they were taken from the lobster. This was attributed in part to the unusually cold and rainy weather, which delayed development and freshened the water, and in part to inadequate provision for collecting and shipping the egg lobsters. The first difficulty can be in part corrected by the construction of deeper cars, so that the lobsters will not be kept near the surface of the water during the time when the eggs are maturing. The crates which. are placed in the rearing bags to hold the ripe egg lobsters while the eggs are hatching have been remodelled for this same reason. The new crates are ten inches deep and as large as the size of the bags will allow. They are made of heavy galvanized wire about eight meshes to the inch, and provided with a solid cover to shade the lobsters from the sun. The difficulty in getting the lobsters fresh from the pots can best be solved probably only by visiting the cars, or even the pots, with a boat containing a well. It is hoped that such a boat may be provided. SUMMARY OF RESULTS. This year 190,000 were reared to the fourth stage and 25,000 to the fifth stage. The previous year 103,000 were reared to the fourth stage. All lobsters reared were liberated in the waters of the bay, except a few which were used for experimental purposes. The egg lobsters were tagged and liberated when stripped. From 210 which were tagged, 36 tags were returned with the desired information. REPORT OF COMMISSIONERS OF INLAND FISHERIES. 93 LIBERATION OF FouRTH AND FirrH Stace Lopsters, 1906. NUMBER Locarry. "||. Character of Shore. Fourth | Fifth Stage. Stage HASTE ODIARUE OIE vac ier rae ss aloes eistineis ol clsl create ave als NO'OOON eae see Rocky. MTHICOVeRNO Be sacrants Acieres e niaitelele alee WiSramuare e 2,000 1,000 | Rocky. EEC OVGENG Soe ee eee ae nneins cts 1,000 200 | Muddy. PGP UGILAS ONG sc cee oie i os bekala o aibcdtebat nie are LOLOOO | eisetete oir Stony, light seaweed. PROC ISyM OUND rea als ots oiste crore ale svat aaetre, steele sears oe, oe ZOOOOM eroropeicnters Rocky. OTESM OM Iiy seem yom etary elonaece (oe) aieia/ars esatgeay Tolar ose cuens 10,000 2,000 | Stony. Ree ler Pe hU Lye teen in atacise sitacs alice bel vaver vous Seca Sean sheile 20,000 5,000 |-Stony. WOTAIICULTIA LANG reine go eriecere eo etahe Tere he roe enone 50,000 2,000 | Rocky ledge. JGHET CGR ews TStaye cero Lire kc «WAP lenete enue ee iene eater PUA nich octal RHEE ON te 4,500 | Eelgrass. lope nlslaniclermeensrrers crscie eincesolera ooo ects ais evant weetewe 10,000 8,000 | Stony. Total Miberated!:: \.)..tciao. oe esye te ese asc LSS: OOO 22 7OOM |(-\-cct ro farterer create octets WSeHOniexpPerimMentss C&C.j.tiehacieietess ecsievelss eyece e's <8 6,384 DAOOs |sraekacad Bievsevtorel vere siete Wsediin-rearimeto fifth! Stages... <2 canes om SOOO eireree ha |Wrcre are ake eeareueseeeeencete RotalicountediOubrans: sae scree Geman oases TS9;S845 | 24 SOO! [ete see eid cose ete . ToraL NuMBER OF LOBSTERS EACH YEAR SINCE 1900. YEAR. oe Bae OOO aecvateloey stone eave oxcheyornital aan leis ete ecuste) orca cece Mle ler Seasiavene fer s)oyeitays or aisfeleveeceioal ste SDB ele ersumie ete LOO Teter etree a teker sce RL eee RT eS TES SOR ED Fee ede tlcaeios one ete fee Sliens SL OAs | ies, earces NGO Deer apcnatccer cosa ate eraneh ovane avea eo iotnis icin cicasliac lente aieiehere usin. © Sauer bus era ed ec Zit OO) A ieee veatheda ote UTS ales Sok hci core rca ils OO eae eT AES Par Pc On CHRP RRC IPR en ee 13500)" |eeevereretonts TIE oats oie ce Od OOM ecIO Acre idia p Giaicidin WS eR Coron he Gc AIC Ere eR nee ene BORGO TAS |eretereruoiete OOS Rot sie Soke Sea ooig ida ctot oo denc.a oo Octo opine OUD Oe Hon SOMO OOOO LOSS F215 cryeieeoneree 1906 Esc jeie gOS Caez0 wb nGRRUCMS he BESO Es hate (Clarchc eau DCHDI CPR ichel cae nae DC Sa ae RE 189,384 24,800 ARTI Goh 8 ae CSO IOTROIS IONE SIO SERIE Ente CARLES Aa SC a ree aa 396,752 24,800 94 REPORT OF COMMISSIONERS OF INLAND FISHERIES. Occasion is here taken to acknowledge the courtesy of the U. S. Bureau of Fisheries in sending two cans of fry from Woods Holl, and to the Connecticut Fish and Game Commissioners for the ship- ment of some egg lobsters late in the season when the local supply was exhausted. REPORT OF COMMISSIONERS OF INLAND FISHERIES. 95 IX. THE CONTINUED INVESTIGATION OF THE LIFE HISTORYAND THE HABITs OF THE LOBSTER IN ALL STAGES OF GROWTH, TO FURNISH A Basis FOR LEGISLATION AND COMMERCIAL ENTERPRISES. It has been our custom (adopted from the U. S. Bureau of Fish- eries), ever since the experiments in lobsters were begun, to liberate the old lobsters from which the eggs had been taken. Tags have been placed upon the beaks, with a number and a request that the tag be returned by the finder. In this way considerable information has been collected each year in respect to the movements of lobsters in the ocean. We submit the record of the past year in the same tabular form as in former reports. Recorps o£ TaGGEp LOBSTERS. 0) o mH Sls : LIBERATED. RECAPTURED. Ss = & : S| > 3 5 Als ® 2 ae a ee 18 A= | E Sl reoul caest =| o {>} az Z F ; 2) § 5 re) Locality. Date. Locality. Date. = = s x 2 gs ZziAl & = ae == 3026 |North of North Pt., Conanicut.|July 2|Beaver Tail Ledge..... Aug. 6/35/10 |S. W 3057 ne Feat ee Hs ail ase mAh FES oe te be eos July 20/18/10 |S. W 3130 a sa ey “ . Ae PAs ee a erase Aug. 6/35/10 |S. W. 3163 : ss | es iS ddr Pay ses July 13/11/10 |S. W 3176 os ay eke ue ae ilies: ZlHopertslandcrie acess eect “26/24! 1 IN. SAO els Ce ors i ue Al se 2|\Beaver Tail Ledge..... “-19]19]10 |S. W. 3204 ec aK * _ aac 2\ Wihtale Rock. ric. a) elise Aug. 8/37|103)/S. W. 3207 o iat 3 ‘ oleae 2|Hope Island...........|Suly 22/20) 1 |N. 3222 . ts bo be i Alpers 2|/Whale Rock...........;/Aug. 26/55|103/S. W 3268 " aa < : mle A ite Mee estas aaa ta cr “26/55/10 |S. W. 3271 : : iP ZUNOTeneeOmite sacs ee aly oS Gi Oller 3282 ; s 2|Beaver Tail Ledge..... * 22/20/10 |S. W 3306 ef 2 3 3 een ESOS IS Ws 3382 ; ¥ 2) ts les a 2624 10 WwW 96 REPORT OF COMMISSIONERS OF INLAND FISHERIES. RecorD oF TacceD LossrERs.—Concluded LIBERATED. g < Locality. Date. | a | « 3447 North of North Pt., Conanicut.|July 2 3456 Ske cee Q = Kf 2 3508 7, oe i ; st ; 2 3516 i ‘ * by es 2 3526 a : ; ‘ "3 2 3632 oe : % : By 2 3636 |“ hee 3648 a : my % 2 3683 | “ uty S73.) Nag 3776 - : “ 2 3784 a ; e 2 3807 i as 2 3809 | “ fet ep 825 Is cea, 3855 | “ Tae 3858) If RE, 3880 | “ ee 3883 He Z “ 2 3886 | “ “ 9 3933 | “ “9 3956 | “ “9 RECAPTURED. Locality, Date. Beaver Tail Ledge.....|Aug. 23 Mopeilslands sya sei July 26 oi i maarsisiersitone Shek 026 INortheP oinitienr-jerpreie som uilley Sandy Point, Conanicut| ‘“ 26 Hopesland=-.. 10. ok e226 os i Seam 2, NorthsPoint es receerere Sean eo) Hope Island....... Peed |) OOD rs SRL OS perm ota ei 1326 Beaver Tail Ledge..... St 40) Hope sland ej. Appendagées: 5.7: dar smen ce ed SA Ree ks Ae Ooo Pee 102 Arr Bex plea GIOM Ole CTIA sas Wali ce) ap o)e Sins -a0S ncn hahe| helo leben 102 B. Abnormal Chel found in the Lobster...................... 103 1. Extra Processes arising from the Normal Dactyl........ 103 2. Abnormal Processes arising from the Normal Propodite. 105 a. Two Extra Dactyls and Double Extra Index..... 105 b. Two Extra Indices and Double Extra Dactyl.... 107 3. Two Extra Chele arising from the Meropodite.......... 108 4. Similar Claws on both Sides of the Body............... 112 bile Regenerate, Abnormal Chelipeds 5 <2. )6s5 516, 6..)00 0 sees a svaraeincd aise ale 113 1. The Regeneration of a Triple Claw on a Walking Leg......... 113 Ghent Disa isl (65 av 012104 pam eget Sayan RRC RPE nea SPE Nr scree 114 bs “Morpholovieal Characteristics..:.. 2. 222.2... JPos. sudo: 116 2. Other Experiments and Observations on Abnormalities in Re- BoveratiMenbaEA Sh croc wena ier is acy desi sod ws vata cued ewe 118 a. An Extra Bud on a Regenerating Leg.................. 118 b. A Double Regenerating Papilla.. Mahara cok oseata Cicer ees TELG c. Various Methods of Mutilation and items. Ramone Al) 3. The Regeneration of Two Crusher Claws...................- ie Ce ALD EV NS 2 ee ge ier A 121 b. Morphological Comparison of the Normal and Regener- AGOUCC ME ta pecan rarer ees ans, whe Midas matters a ond Spoons 123 CRMEUEVES WIN Glee ress fer eric atthe ir licbowacab tray obese shewel ay Giunta nals 128 100 REPORT OF COMMISSIONERS OF INLAND FISHERIES. Vee VDISCUBSIOMe se ness). 2 to eR ga Dae pap. pap. et emer MPI MEO Ese oe ons ese [be acd o anh arierdagda eta 13mm. | 14mm. eer | Meme > Ra erat ice rea [b bs be eds ch cv a pect ak heey 18mm. | 18mm. a SECIS. (25) co Bar er ieee ee 21mm. } 21mm. eee OE use ete rarecel|\ i case rk ti esa eee dase 25mm. | 25mm. Moulted....... Oct. 5 | 227mm. | Both “Nippers’’ | 130mm. | 128 mm. * Original normal chelz. From this data it may be seen that the lobster moulted on October 5, eighty-six days after the amputation. The chelew, which had regenerated by this time, are shown in figures 8 and 9. Here again both appendages are not only very similiar in form, but the arrange- ment of the pointed cutting teeth and the presence of tactile hairs clearly show that this pair of regenerated limbs are also of the “nipper”’ type of chele. BE REGENERATED ABNORMAL CHELIPEDS. It will be observed that all of the abnormal appendages so far described were found either in museum collections or on lobsters taken from the traps, and consequently we have no positive data as to their origin. The next specimens about to be described were obtained during a series of experiments on regeneration made at the Experiment Station. 1. The Regeneration of a Triple Claw on a Walking Leg. Specimen No. 7. Figs. 10-18. The lobster on which this abnormal regeneration occurred was a female and measured 8 3-16 inches in length. The animal had been recently taken from the traps and placed in a floating car. It was in normal condition, and its chele showed the usual asymmetry, with 15 114 REPORT OF COMMISSIONERS OF INLAND FISHERIES. a “erusher” on the left and a “nipper”’ on the right. On July 26, 1905, both chelipeds, together with the second and third right walk- ing legs, were autotomously removed. Soon after the limbs began to regenerate a curious .ertra bud was observed on the regenerating second right walking leg. The data obtained for this abnormal leg is given in the following table: Length of Length of Date. Lobster. | Regenerat-_ Remarks. ing Leg. WivinlleEnsO Mao. 6 ol} diwlhy AAO || Ailisyiaavans es oe eee Original leg was normal and measured 196 mm. Observationse.|| Awe. WSs 2 ee 71 aee SuMMM.: |laa-3, es 2, os Cle Se eee ¢ WRONG LO Ole ee eee 9mm. | Attention was attracted for | the first time to a double | bud. See Fig. 10. : Mees) his) 31: Je eee te fe MOANA 5.125 Sse eee et een ae eee . oa. Ee ORNS Sere neta 21mm. | Extra bud became injured.* | | See Fig. 13. Moulted:.c.20..l> “S28. |) 22 aomimaes|, S62 mains 2 oe kee ee eee Fortunately, attention was attracted rather early to the extra bud growing out from the regenerating leg. It became possible, therefore, to learn something of the history of this abnormal limb, and also secure several drawings at different stages of its growth. We will describe, first, the development; and, second, the morpho- logical characters of this regenerated leg. a. Development. The development of this regenerating leg, by days, was as follows: Thirty-fijth day. Fig. 10.—It was on the thirty-fourth day after mutilation that the abnormal regeneration was observed. In the drawing made on the following day (Fig. 11) it will be seen that in addition to the usual regenerating structure there is an extra process *This was, no doubt, caused by the limb accidentally rubbing against some obstacle as the lobster moved about in the car. The injury consisted in brushing the extra bud abruptly upward (Fig. 13) from the original position in which it was growing. REPORT OF COMMISSIONERS OF INLAND FISHERIES. 115 branching off from the third segment or carpopodite (c). This abnormal bud takes its origin from the ventral surface of the carpop- odite, but instead of growing upward in a normal direction it makes an abrupt bend and hangs down. At this stage of the regen- eration the outlines for all the normal segments except the basal one are all clearly defined, and the groove (g) for the jaws of the claw is well developed. The extra bud at this time also showed two definite segments, 1 and 2, which apparently corresponded, respec- tively, to the dactyl and propodite of the normal limb. Forty-third day. Figs. 11 and 12.—At this stage the basal segment or ischiopodite (IS) is now also becoming differentiated. Observing the abnormal bud more closely, a distinct longitudinal cleavage was found in the tip of the propodite segment (2), which divided this segment into two equal parts, I’R’ and I’L’. In the extra dactyl there was only a slight indication of a similar bifurcation (g). In size, the propodite of the abnormal bud was somewhat smaller than the corresponding normal segment, the two segments measuring, respectively, 64 mm. and 74 mm. The general color of the regen- erating limb is now beginning to show a darker hue. In the preced- ing stage it was characterized by a bright red or pinkish color, but at the present stage dark blue pigments are developing at the joints for the various segments. Forty-eighth day. Figs. 18 and 14.—On the forty-seventh day of regeneration an accident occurred in which the abnormal bud was mechanically displaced and thrown abruptly upward, so that it assumed a position practically parallel with the distal extremity of the normal limb. This displacement was probably the result of striking against some obstacle as the lobster moved about in the ear. A wound or rupture (w) was at the same time produced at the union of the extra bud with the normal limb, which was so severe that I feared the abnormal bud would eventually become completely sepa- rated from the limb and lost. But fortunately the wound healed and the abnormal structures survived through the next moult. 116 REPORT OF COMMISSIONERS OF INLAND FISHERIES. On the sixty-fifth day the lobster moulted and the regenerated limb now assumed the proportions shown in figure 15. b. Morphological Characteristics. Figs. 15-18. Beginning with the distal extremity of the normal leg, it may be readily seen that the dactyl (D) and propodite (PR) are normal in form, have the usual distribution of hairs and serrated teeth upon the jaws formed by the dactyl and index, and the claw itself opens upward in the normal dorso-ventral plane. The third segment or carpopodite (c) is relatively very broad, and massive, with its distal region split into two unequal forks. The larger of these two forks represents the normal segment, while the smaller abnormal one (c’) shunts off from the lower surface (slightly posterior of ventral) of the carpopodite at an angle of about 45 degrees. The last two proximal segments are abnormally thick and massive. One notice- able feature in the meropodite (m) is a variation in the form of the V-shaped groove on the distal ventral surface, into which the third segment plays when in motion. Normally, this groove is single, but in the present specimen there are two grooves, as shown in figure 16, g,o’. One of these grooves (g’) is considerably larger than the other, but it is difficult to determine from the external form which one represents the normal structure. The last proximal segment (IS), aside from its relatively great size, shows two unusual markings: the one is a triangular-like scar (s), which may possibly be the result of a previous injury, although I observed nothing of the sort before the moult occurred; the other marking is a slight groove (g’’) at right angles to the scar just described. This shght groove on the ischropodite, together with the double groove on the meropodite (Fig. 16, g, g’), indicate that these segments may be morphologically doubled by the proximal extension of the abnormal process on the carpopodite (c). Turning our attention now to the abnormal branch of the carpop- odite, it may be observed that it tapers rapidly distally, to relatively REPORT OF COMMISSIONERS OF INLAND FISHERIES. UR i small dimensions. The irregular form at this region (Fig. 17, a) is partially the effect of the injury received during its development. Just distal to this irregular region is a rudimentary joint? (j). It is indeed rather badly deformed, but it still presents the characteristics of a joint between the carpopodite and the next distal segment. I watched the live lobster to see whether it had any ability to move this abnormal claw. Occasionally there was a display of activity in which the abnormal structure would be carried past the posterior face of the normal propodite, so that its plane of motion would be at an angle of approximately 45 degrees to the corresponding plane of motion for the normal propodite. But it was very rarely that this abnormal process was seen to function in this manner, and, indeed, this might be expected in view of the severe injuries which the muscu- lature at its base sustained during development. - Farther distally, 7. e., beyond the joint just described, this abnormal structure enlarges again and finally terminates distally in three large prongs, Figure 17, I’R’, I’L’, and D’(R+L). Upon closes examina- tion it becomes evident that IR and IL represent two extra indices. They diverge from each other at an angle of about 45 degrees. The dorsal border of each index is dentated with a row of serrated teeth (Fig. 18,T); the tips are capped with the usual horny points; neither prong has any indication of a joint, and their morphological con- tinuity with the propodite is most clearly evinced by a row of hair on the ventral surface of each index (Fig. 17, h, h’): These two rows of hair begin at the distal extremity of each index, continue proximally along the ventral surfaces in two distinct linear series, and extend down almost the entire length of the abnormal propodite. The third prong D’(R+L) is even more interesting; for while at first glance it may appear single, it is evidently morphologically a double dactyl. It takes its origin from the dorsal surface of the propodite, near the angle at the base of the two indices; and pro- jects upwards at right angles to this pair of indices. Near the base is a constriction (Fig. 18, }) which may be interpreted as a rudi- mentary joint, although I was unable to observe that it was func- 118 REPORT OF COMMISSIONERS OF INLAND FISHERIES. tional as such. The two lateral surfaces of this compound structure are each dentated by a row of serrated teeth (T, T). These two rows of teeth begin near the rudimentary joint and traverse the opposite lateral surfaces in a distal direction; distally they converge but do- not quite meet over the flattened and slightly furrowed tip of the extremity. The tactile hairs are grouped more or less about these dentated margins. The evidence that this abnormal structure represents the double dactyl seems even more conclusive when it is perceived that if we were to split the whole structure in a dorso- ventral plane, each half, with its row of teeth, would form a dactyl for the opposing index. According to the above interpretation, the abnormal structure on this walking leg is morphologically a double claw, composed of two extra dactyls and a compound index. That this abnormality may extend farther into the proximal segments of the normal limb has already been indicated in the preceding description of certain struc- tural features in the meropodite and ischiopodite. In this walking leg, therefore, we have a clear case of a “triple-claw”’ which has arisen through a process of regeneration. 2. Other Experiments and Observations on Abnormalities in Regen- erating Limbs. Aside from the fact that the triple claw just described has arisen through regenerative processes, I can add nothing further in regard to the factors casually related to its origin. As a preliminary, how- ever, to a further experimental study of this subject, it seems desir- able to record here the following observations: a. An Extra Bud on Regenerating Leg. The first case is that of a regenerating fourth left leg. On July 27, 1903, in one of my experiments, an 8-inch male lobster was muti- lated by cutting off the first pair of swimmerets. At this time the fourth left leg of this lobster was gone, but it soon began to regener- REPORT OF COMMISSIONERS OF INLAND FISHERIES. 119 ate. By the time this regenerating leg had attained a length of 9 mm. (August 28), my attention was attracted to an unusual bud- like process on the regenerating limb. Figure 19, drawn three days later (August 31), shows the location of this abnormal protuberance (b) on the basal segment or ischiopodite. The general appearance of this protuberance suggested that it might be the beginning of another extra limb, similar to specimen No. 7; but this did not prove to be the case, for instead of growing larger, this abnormal bud begun to decrease in size, and by September 9 it had almost entirely degener- ated and disappeared. The lobster in which this abnormal phenomenon appeared was an 8-inch male specimen which was being used in an experiment on the regeneration of the abdominal appendages. After the extra bud just described had degenerated, I cut off the regenerating leg just above the basal segment, to see if the degenerating bud might be made to grow again; but no result was obtained, because the entire stump was finally dropped. b. A Double Regenerating Papilla. In another lobster two regenerating papille (pp. 1, pp 2) were dis- covered, as shown in figure 20. These two papille were in the stump of the second right leg from which the limb had been autotomously removed on July 26. When these two protuberances were first observed (August 18) they were about 24 mm. in height; the inner one (pp 1) being slightly the larger. At first it was anticipated that these papillae might develop into two limbs, but this did not occur. The growth of the outer bud became retarded and it increased but little more in size (see Fig. 21), while on the other hand, the inner bud grew at the usual rate and finally differentiated into a normal thoracic leg. In both the above cases it seems at least a plausible suggestion that some of the regenerating cells may have been temporarily shunted off in an abnormal direction from the direct course of 4 120 REPORT OF COMMISSIONERS OF INLAND FISHERIES. development, but were later re-absorbed by the predominating normal regenerative processes. c. Various Methods of Mutilation and Results. The observations just recorded suggested the possibility of getting similar results by artificial mutilation. In one experiment the tips of regenerating buds were touched with a redhot forceps. I thought it might be possible to destroy certain cells of the regenerating struc- ture and thus produce an abnormality in these parts. Although six or more buds at different stages of divelopment were operated upon, no positive results were attained. The wound would nearly always heal over and the regenerative processes proceed again in a normal manner. A different method of mutilation was then tried by cutting the regenerating buds at various regions. In about six cases the tips of the buds were slit with a sharp instrument; six more specimens were injured by nipping out small pieces from the fundaments of various segments; and again, in other instances, the buds were cut off at different levels. These mutilations were made upon buds at all stages of development, ranging from minute papillze up to stages, in which the segments were clearly evident, but in no instance was an abnormal structure obtained. In all cases the result was either that the whole regenerating bud would be finally dropped at its base, or else the wound would heal and the regenera- tion continue. An illustration of the latter result is shown in Figure 22. This regenerating bud had been cut near the tip with a pair of fine scissors. The wound healed rapidly, and the direction of growth among the regenerating cells was such that the scar (s) was finally pushed to one side. After the moult only a slight trace of the wound was evident. In a third experiment, mutilations were made by cutting normal limbs at various levels. In all these mutilations of this character, the limbs were either autotomously dropped after the operation, or else regeneration began at the region of injury. This experiment was REPORT OF COMMISSIONERS OF INLAND FISHERIES. 121 A made primarily for the purpose of comparing the power of regenera- tion at different levels of the appendages, but one of the results was so unusual that it may be fittingly described here. In one of the lobsters the normal second left leg, the propodite had been cut off at a level just above the second distal joint. The structure which regenerated at this cut was the very small claw shown in Figure 23. This rather remarkable structure was very rudimentary and no evidence of its being functional was observed. With the exception of this last case the artificial mutilations thus far attempted, therefore, have not given any very promising results, but still this is no ground for discontinuing such experiments. They only show that we have not yet discovered just where we may insert an obstacle between the cogwheels, if the figure is permitted, which will cause the growing machine to duplicate its products. 3. The Regeneration of Two Crusher Claws. As far as I am aware the following two specimens are the only authentic cases on record in which a lobster has developed a crushing chela on each side of the body through the process of regeneration. Accordingly, a somewhat detailed description of these specimens will be given. a... Data. Specimen No. 8. Figs. 24-31. This lobster is the same animal which regenerated the triple claw on the walking leg described on page 113. It will be recalled that it had been recently taken from the trap, was a female, and meas- ured 8 3-16 inches in length. On July 26, 1905, both chele and the second and third right walking legs were autotomously removed by pinching the tip of the limb with a forceps. On September 28, sixty-four days after the amputation, the lobster moulted and then measured 84 inches. It had, meantime, regenerated both chele, and the second and third right thoracic legs. 16 122 REPORT OF COMMISSIONERS OF INLAND FISHERIES. The original chelz of this lobster were of the normal asymmetrical type. The left claw (Fig. 24) was a completely developed “ crusher,”’ characterzied by the wide massive claws with an almost entire absence of tactile hairs, and by the presence of broad tubercle-like teeth. The right chela (Fig. 25) was of a characteristic “nipping” type, with a relatively slender claw, pointed cutting teeth, and a fringe of tactile hairs along the jaws. The right and left chele measured, respectively, 146 and 140 mm. in length. Soon after the amputation of these limbs another pair of chele began to regenerate from the remaining stump or basipodite. On July 18, twenty-three days after the amputation, the regenerating buds measured 5 mm. in length. By the time the segments of the future limbs were well outlined, attention was drawn to the very similar appearance of the two regenerating structures. Usually, as the lobster approaches the culmination of the moulting period, the regenerating chele become so clearly differentiated that a distinction between the “crusher” and “nipper” can often be readily detected. In the present case, however, no characteristic differences could be observed between the right and left regenerating buds, and, more- over, the general morphological appearance of each was such that it led to the prediction that both were developing into the crushing type of claws. The correctness of this prediction was shown at the next moult. — | After the lobster had moulted, the regenerated chele resumed their normal shape and both measured 63 mm. in length. ach cheliped was very similar to the other in form, and displayed the morphological characters of a true “crusher.” All the other append- ages were in a normal condition except the regenerated second right leg, which had developed the triple claw previously discribed. Specimen No. 9. Figs. 32-35. This specimen was an 8-inch male lobster. On August 4, 1906, both chele and the second left leg were autotomously removed. As in the preceding case, the original chele were of the normal REPORT OF COMMISSIONERS OF INLAND FISHERIES. ts asymmetrical type, only in this specimen the right chela (Fig. 33) was the crusher, and the left, the nipper (Fig. 32). They both measured 162 mm. in length. Soon after the amputation another pair of chele began to regener- ate. By the time the segments of the future limbs were well out- lined, the two regenerating chele in this case again looked very much alike. And the fact that their external characteristics also resem-. bled those of a crusher, led me to anticipate that both limbs would develop chelz of the “crusher” type. By the middle of October, 1906, the lobster had moulted and regenerated both chilipeds and the second left leg. When the chele had hardened and assumed their normal shape, they were practically equal in size and each measured 111 mm. in length. Both chelipeds were remarkably similar in structure and each displayed the characters of a true “crusher” claw. The second left leg had also regenerated, but it, as well as all the other appendages, were in a normal condition. After these lobsters had moulted, the limbs were again removed and an attempt made to keep the lobsters through the winter in order to see what type of chele would be reproduced by the next regenera- tion. Unfortunately, the unnatural conditions under which it was necessary to keep lobsters during the winter resulted in the death of lobster No. 8 on January 6, 1906. But so far we have been more successful with the other specimen, and lobster No. 9 is at the present date (February 1, 1907) still in a healthy condition at the experiment station. It may yet be possible, therefore, to obtain an answer for the question as to what will be the character of the next regenerated chele. b. Morphological Comparison of the Normal and Regenerated Chele. Specimen No. 8. - Figs. 24-31. The morphological comparison of the normal and regenerated chele of the lobster may be best presented by making, first, a detailed analysis of some of the characters not clearly shown in the photo- 124 REPORT OF COMMISSIONERS OF INLAND FISHERIES. graphs. For this purpose drawings (Figs. 28-31) have been made of the index or propodite part of each claw to show the characteristic dentition and distribution of tactile hairs. The original right “nipper”’ index (Fig. 30) is of a characteristic normal type. Tactile hairs (h) are distributed in a dense fringe on each side of the dentated margin and along the distal outer border of the jaw. The teeth are narrow and pointed. These cutting teeth are arranged in a linear series, and in a periodic sequence with a formula of 1:4:3:4:2:4:3:4 for a perfect period (P).* All the teeth of the propodite are included in the single linear series, except a stout displaced tooth (t) about midway in the dentate mar- gin, which forms the “lock” to the claw (Herrick, ’05). Another characteristic feature in the arrangement of the teeth is that at the posterior part of the jaw the single series of teeth are shunted off to- ward the upper face of the propodite in the direction of the upper or outer side of (y) the joint (j) formed by the union of the two segments of the claw. The original left claw (Fig. 29) is a typical normal “crusher.” The index or propodite part of the claw, in marked contrast to the - morphological characters just described for the “nipper,”’ 1s charac- terized by the almost entire absence of tactile hairs, only a few iso- lated tufts (h’) remaining near the angle of the jaw. The “stout displaced tooth” of the nipper is absent. Instead of the pointed cutting teeth, the jaw is dentated with broad “ crushing” tubercles (t) formed by the fusion of periodic teeth (according to Herrick, ’05). A normal feature in the dentition is the double row of tubercle teeth (t”) at the posterior part of the index. An equally typical feature is that these two rows of teeth do not shunt off toward one side of ‘ the joint, as in the “nipper,” but are arranged along either side of the median line of the jaw. In this lobster the propodite of the regenerated lejt claw (Fig. 28) closely resembled the original “crusher.” No tactile hairs are apparent, except a few tufts (h) near the angle of the jaw. The * According to the scheme of Stahr ('98) and Herrick (’05). REPORT OF COMMISSIONERS OF INLAND FISHERIES. 125 teeth (t) are broad and tubercle-like in form; periodic sequence in arrangement is not evident, and at the posterior part of the jaw the . characteristic ‘‘ double-crushing”’ teeth have re-appeared. The regenerated right claw, on the other hand, is plainly unlike the original “nipper.’’ If we examine the propodite part of the claw (Fig. 31), it is seen that only a few tufts of tactile hairs (h) have regenerated in place of the prominent fringe on the former claw. The teeth are not like the pointed ‘cutters,’ but are of the broad tubercle form; and finally, the wide departure of the regenerated structure from the original “nipping” type, and its identity as a “crusher” is completely established by the presence of the character- istic double toothed arrangement of the tubercles (t’”) at the posterior part of the jaw. Specimen No. 9. Figs. 32-35. The description just given for the preceding specimen applies with equal truth to the morphological characters of the chele for the second lobster. Only in the later case the positions of the nipper and crusher are just reversed; so that the original crusher claw (Fig. 33) is on the right, and the original nipper (Fig. 32)on the left, side of the body. The regenerated right claw (Fig. 35) closely resembled the original crusher, while the regenerated left claw (Fig. 34),on the other hand, is plainly unlike the original nipper. In both claws no tactile hairs are apparent on either dactyls or indices, except a few tufts near the angle of the jaws; the teeth are broad and tubercle-like in form; periodic sequence in dentition is not evident; and finally, as in the preceding case, the identity of these two regenerated claws as crushers is completely established by the presence of double-crushing teeth at the posterior dentate margin of each index. The detailed morphological analysis of the original and regenerated chelze of both lobsters is more completely compared in the following tabulated data: OF INLAND FISHERIES. REPORT OF COMMISSIONERS 126 “Mel jo 9[suB Bou sin} Moy 8 ydeoxe ‘sirey 9[tj08} ON “mel jo 9[sue IvE8U S}jN} Moz B® jdeoxe ‘siTey 9[1}0e} ON ‘a0B} Iapunfey} jo 1op10q [ejstp seyno 94} sBuOTe pus ‘ulsi1eur 9}8}Uep Jo apis 1ay}Ia UO BsULIZ ssue(T “mel jo o[sue vou S}jn} MO}j ew ydeoxe ‘sirey 9[1}0e} ON "SIIB 9[TVOR, “mel JO o[sUB IvIM ATIOLIO} -sod ajqnoq = “q}99} ,,suUr -Ysnid,, dYT[-efo1eqn} peor “mel jo o[sue avou ApIOMWI0} -sod gjqnoq = “Yy}90e} ,, sul -YSNid ,, OYT[-ePo1eqn) pRolg. ; || ULs1eUr ayByuep 9y} jo s][pprur aq} awBou =Yy}00} ~=peovyd -SIpP gnoj}s B YIM ‘soles Ivoul] e]suIs B UT pesuBI -18 ‘Y499} ,,SUIND,, poyUlod “Mel jo ojsue avou ATION} -sod oyqnog = “qyee} ,, sur -YSNA9 ,, 94 T[-O[o19qn} PBolE “UOT TUT *OAISSBUL pus proiq AleaAtpereduro/) “Mel jo o[sue wSU SjjN} MoF ~% ydeoxe ‘siley 9[tjoeV} ON “OAISSBUL pue proiq ApeAyeiedui0() ‘xode pavaoy Sutrodey pus sspuels AlsAtyereduro/) ‘QAISSBUI PUB PBOI “UIO} [B1OUY) “met jo o[sue iweuU S}jn} Mot ® ydooxe ‘sileq 9[1}0v} ON “UIsIBUL 9YBJUBpP JO apis Jey}Ie WO esULIy BSue(T “Mel jo ojsue rwoU Sjjn} Mo§f 8 ydeoxe ‘surey a[tjo8} ON “SUIBY, OTIBOR T, “gouenb -98 oIpoted jo suolRorp -UI [BUOTISBIDO $Y }00} ,, SUT -Ysnio,, @YT-9pseqn} pwoigd “queq AyOULySIp ‘Aq -qnjs pusw y1oys ATeAT}e]OYY ‘PE BLT MBP YET Ca) "26 3 Mep yasrr CV) :poe}Bi19uesey ‘aouenb -98 orpolied jo suor}BoIp -UT [BUOISBIIO +4}90} ,, SUL -Ysniod ,, @YT]-ePo19qn} pworg ‘queq ApjouTysIp ‘Aq -qnjs pue y10ys ATOATP VIO Y EVEEOPE ES PT B]NULOF YAIM voueNb -98 orpoled ul paxsuBiie 'q9003) «,,suryjno,, poe Ulod ‘9ouenb -98 orpoled jo suort}BoIp -UT JBUOTSBODO $Y }99} ,,5UT -Ysnio,, OT]-9p1eqn} pwolg ‘uoT ued “yysteiys AyIBveu frepues[s puew Huo] ATOAT BOY ‘quoq ATjoUTSIP ‘Aq -qnjs puBw Joys ATPAT} BOY “UIOJ [BI9UOY) ‘aytpodoig “TAB “Cg “BI “MRP FYSTIY Ca) 96 “SIT “MET YET CV) [p97 B19me59 YY ‘Se BI “MBO FO] [LUO (e1) "CG “BIA “MBO JUS [VUISUOQ (CV) 2 [BULLION “eg “ST “MBO USL [BUDO (qd) ‘FSG “STA “MELO JOT [BUIBNO (V) :[BULLON "6 “ON JoISqo"T=(a) "8 (ON JaIsqoT—(V) 127 REPORT OF COMMISSIONERS OF INLAND FISHERIES. ‘9u03 SBA [AJOVP oy} JO dy ay} asn¥voeq xXepuT oy} jo dy oy} Woy UsyB} SBM [AJOVP oy} 1OJ JUSUIEINSveUT VY} ‘qq UsUUPOedS UT y+ ‘yO UIOM A]}BIIS UVEq GAY SITeYy 9[1}9e} EY} ‘gq UsUITOeds UT]| OUT] JOOIIP MOTE SI 9UO PUODaS ‘aTqnop euTds 101I1a}SOg§ *‘s104}O OY} JO oul] JOoIIpP 9Y} MOTE SI paryy oY} PUB ‘a_qnop st suTds 1ot1eysogt *s1oy}O 9Y} JO oul] JooIIp oy MOTeq AT}YSTS ourds parm yt "(GQ,) YoUusoP Pus (RG,) 1YBIG Jo Buleyos o1edul0p, , Tysniy,, , JeYsn1y,, , LddIN ,, “mu OF Pee SULA G 7 ee enna EP rssssereerenl (30. I P= amen ze ol =saareo “mul 9% 2 “WIUL OG at hale “UIT Se Led = Sear aes) G = aaa ei) deren Oe WIUL 9% 7 mitiuemere) ie tes ED S1= que (@) A “udu GG ae UUs OT AS = arr a) G1 =.anur qe (V) DU warcrrag) , TYsnly,, MBO YORI UI SIOJOBIBYO JUBUIMIO oval ay eee “‘qurol pz Oe ee “UU OF (@) ay} 0} Mel Jo a[suUB UWUOI] 9931p -odoid ey} UO svUBISTP 9yy OF “UU Se ayIpodojAyoep jo YASue] jo oney Lal se orang OW) “WUE EF = Gam OF (aq) ‘aytpodoid Jo YQpPIM 48e}BeIs 07 a}yIpodofAyoep Jo YQSus], fo ony __ “UU OF Sacer A) 128 REPORT OF COMMISSIONERS OF INLAND FISHERIES. C. Resumé. a. The normally asymmetrical chele of two adult lobsters were autotomously removed. The right claw of lobster No. 8 was a “e “‘nipper,” and the left a ‘‘ crusher;” in lobster No. 9, left was the nipper, and the right a crusher. b. After amputation the chele of both lobsters regenerated, but the regenerative processes did not reproduce the original asymmet- rical types of chele. The regenerated left claw of No. 8 and the “ce regenerated right claw of No. 9 were both true “crushers” like the original claws; but the regenerated right claw of No. 8 and the left of No. 9 had the general characters, not of the original ‘“ nipper,” but of a typical “crusher.” e. A close analysis of the structural features of the latter two regenerated claws demonstrated that, in all their morphological characters, they respectively, corresponded point for point, with both the normal and the regenerated crushers of the opposite sides, in respect to the general form, size, and proportions, in the shape and arrangement of the teeth, and even in the number and distribu- tion of the tufts of tactile hairs. The regenerated claws of these two lobsters are, therefore, symmetrical in form, and in both specimens they are of the “crushing” type of chele. LY: DISCUSSION. 1. Frequency of Occurrence of these Various Types of Abnormalities. Specimens Nos. 1 and 2. (Figs. 1 and 2.) Cases of extra processes arising from the dactyl are the most common of crustacean deformities. For the lobster, Faxon describes at least three cases similar to specimen No. 1, with two extra pro- cesses upon the smooth border of the dactyl, (Faxon, Plate I, Figs. 1, 2, and 8). He further states that ‘there are several speci- REPORT OF COMMISSIONERS OF INLAND FISHERIES. 129 mens similar to this in the collection of the Peabody Academy of Science, Salem, and two or three in the collection of the Boston Society of Natural History” (p. 258). Herrick (Fig. 191) describes another similar instance, and Bateson, in figure 186, No. 1, shows an abnormality almost exactly parallel to our specimen No. 1. There does not, however, seem to be a record of an extra process on the toothed border of the dactyl as in specimen No. 2. The nearest approach to it is that of Faxon (Plate I, Fig. 9), which has a double- toothed process on the toothed border of the index, instead of upon the dactyl. Specimen No. 3. (Fig. 3.) There seems to be no authentic record of a lobster claw similar to this one. Faxon does, indeed, cite the case of two chele on one of the legs of a lobster (Plate II, Fig. 2), which Bateson was inclined to regard as a case of a chela with an extra pair of dactyls and indices. Faxon states: ‘This leg is provided with two chele. One of them has the ordinary form and structure, but is bent at a strong angle with the long axis of the leg. The second claw appears to have budded off from an amputated surface of the propodite. It consists of two fingers, which have the form of the normal dactylus and index but neither is articulated with the other at the base” (p. 261). Bateson (p. 530) interpreted Faxon’s extra ‘“dactylus and index” 9 as a ‘‘complementary pair of extra dactyls,”’ and he thought it was possible to bring this abnormal claw into the category of ‘two extra dactyls and a double extra index” by interpreting a certain protub- erance shown in Faxon’s figure, as a double extra index. But it seems that Bateson was here lead into an error, as the result of inaccurate drawing; for Andrews (’05), referring to this same specimen, states that he has been informed by Faxon that “the artist unfortunately represented a protuberance which does not exist”’ (p. 82). Consequently, this case of Faxon’s must be excluded from ‘‘the category of claws with two extra dactyls and a double extra index.” 17 130 REPORT OF COMMISSIONERS OF INLAND FISHERIES. It should be added, however, that while the present abnormal claw is apparently the first case of this kind recorded for the lobster, a few cases of somewhat similar deformities have been found among other crustacea (see Bateson, 528-530). Specimen No. 4. (Fig. 4.) It will be recalled that this specimen was described as a normal claw with two extra indices and an extra double dactyl arising from the normal index. This form of abnormality is very rare. Bateson describes a number of cases among crabs and lobsters in which two extra indices alone arise from the normal index, but there seems to be no record of two extra indices plus a double extra dactyl. Specimen No. 5. (Fig. 5.) This is a most remarkable case of the ‘“‘triplication” of chele. Apparently the only recorded specimen which approaches it is the right chela of a lobster described by Faxon (Plate II, Fig. 6). In Faxon’s specimen the meropodite divides distally into two parts, each bearing an articulated appendage. One of these two branches is a normal chela, but the morphological character of the abnormal branch remains a question. The carpopodite of this latter structure is not normal in form, “‘but is slenderer, subcylindrical, and much more spiny.” It “bears at its distal extremity an abortive propodus in the shape of a small stump-like segment, bifurcated at the end and armed with a blunt spinous tubercle on its inner margin” (p. 263). Interpretations of this abnormal and rudimentary structure differ; Bateson is inclined to consider it as “morphologically a double structure” (p. 536), and, consequently, that the whole limb may be a triple chela. But Faxon does not regard this extra structure as double, and thinks that in this specimen we have an approach to a duplication, rather than a triplication, of chele. At any rate, in our present specimen there can be no question as to its triple character, at least as far down as the meropodite if not REPORT OF COMMISSIONERS OF INLAND FISHERIES. 131 farther. And this case is evidently the nearest approach to a true triplication of the chela yet discovered in the lobster. Specimen No. 6. (Figs. 6-9.) Normally in the adult lobster the “great claws” are almost invariably asymmetrical with reference to each other—the claw on one side being a ‘“‘crusher”’ and the other a “nipper.’”’ The crusher claw seems to occur about as frequently on one side of the body as the other,* but it is only very rarely that we find an adult lobster with both chele alike. In examining over 2,400 lobsters Herrick (96) found only 3 which had similar claws on each side of the body (p. 143); and in a personal examination of over 600 specimens as they came from the traps at the experiment station, I found only one lobster with both claws alike. This specimen, therefore, makes the fourth lobster out of 3,000 which has been found with both claws alike. It is important, moreover, to note here that these four cases were all of the “nipper”’ type of chele. Specimen No. 7. (Figs. 10-18.) This case of a triple claw is especially unusual because it occurs upon a walking leg. The fact that such abnormalities are very seldom found on a walking leg has been pointed out by Andrewss(’04) in his statement that: “Of the thirty cases of abnormal appendages quoted by Bateson, two are of the antenne, four are of non-chelate legs, and all the rest of chelze except one, which is a chelate walking leg. . . . . and of the eleven additional cases given by Herrick, only two are of the walking legs” (p. 81). Incomparing the present specimen with other described cases in *It is an interesting question whether this right and left ‘‘handedness’’ of the lobster is inherited and congenital, or whether it may be determined during development and by other * factors. I hope later to give the results of some experiments now almost completed, in which I have tried to throw the crusher to either side of the body by making appropriate mutilations during the larval stages; 7. e., at a stage before the claws have differentiated into crusher or nipper. Fora further discussion of this subject see an article in Science (Emmel, ’07),in which it is shown that the results so far attained in these experiments establish a strong presumption that the right or left handed asymmetry of the lobster may be determined by other than hereditary factors. 132 REPORT OF COMMISSIONERS OF INLAND FISHERIES. crustacea, I was unable to find that either Bateson, Faxon, or Her- rick record an instance of a double extra claw arising from the third segment or carpopodite. The only case at all similar to it is that of a crayfish, Astacus fluviatalis; this most “unique” specimen differed, however, from the present case, in that, instead of two there were three extra chele which arose from the carpopodite. (See Bateson, No. 827.) Specumens Nos. 8 and 9. (Fig. 24-35.) The fact that in the four specimens out of over 3,000 lobsters which were found with similar chele (see specimen No. 4) the claws were all of the nipper type emphasizes the point that it is extremely rare to meet with a lobster with two “crusher” claws. Indeed it has been a matter of considerable doubt whether or not a lobster is ever found ¢ with a crushing claw on each of the two “great chele;’” for in the adult lobster the “great” claws are almost invariably asymmetrical with reference to each other—the claw on one side being “nipper”’ and the other a “crusher.” On the other hand, in the young lobster (z. e., in the fourth, fifth, and sixth stages) the two claws are alike and similar to the nipping type; and the fact that in the rare in- stances in which symmetrical claws have been found in adult lobsters both were always of the “nipping” or embryonic type has created a strong presumption that a “crushing” claw would not be developed on each chela of this crustacean. Until a year ago the only case recorded of two crusher chele on the lobster was in a footnote to Herrick’s (’96) description of varia- tions in the form of lobster chele: ‘I have heard of a single case reported by a fisherman, where similiar crushing claws were developed on both sides of the body” (p. 148). To Przibram, writing in 1901, this seemed such an incredible phenomenon that, in view of the theoretical reasons indicated in the preceding paragraph, he con- cluded that: “Der eine Fall von einer Hautung beiderseitigen’”’ crushing-claw, von dem Herrick nur vom Horensagen durch Fischer REPORT OF COMMISSIONERS OF INLAND FISHERIES. 133 Kenntni’s erheilt, wird wohl in der Reich der Fischermythen zu verweisen sein” (p. 333).* Apparently it was not until the year 1906 that any authentic account was given of a lobster with two crushing chele. During this year two such lobsters were recorded; one of these was specimen No. 8 of the present article, which was obtained in 1905 (see Emmel, ’06); the other was reported for a European lobster by Dr. W. T. Colman, in the Proceedings of the Zodlogical Society of London for 1906. On page 633 of that journal is “exhibited the photograph of a lobster (Homarus grammarus, Linn.) with symmetrically developed chele [z. e., two crushers], recently presented to the Natural History Museum by the Directors of Harrod’s Stores, Ltd.” (p. 634). Finally, lobster No. 9 of this report adds a third specimen to the list. We have now on record, therefore, at least three authentic eases of lobsters with similar crushing claws. 2. The Theoretical Significance of these Abnormal Structures. A. Inmbs with Paired Extra Processes. 1. Bateson’s Principles for Secondary Symmetry. Bateson, in his masterly work on variation, has been able to formu- late certain relations or principles to which a great majority of variations seem to conform. These relations are all the more strik- ing because they enable one even to predict with a considerable degree of accuracy what certain characteristics of a given abnormality will be! ) indicates the plane of section shown in the corresponding figure at the REPORT OF COMMISSIONERS OF INLAND FISHERIES. 137 appendage”’ (D’R’) is the mirror “image of the nearer’ one (D’L’). The claws sketched at the right of the diagram may make clearer the significance of these relations. The arrow in each figure indi- cates the plane of section shown in the corresponding figures at the left. One of the important points in this diagram is that a definite morphological relation distinguishes the dorsal (Fig. II) and ventral positions (Fig. III) from each other. Namely, that when a pair of extra processes arise on the dorsal or smooth border of the dactyl, they turn their toothed or ventral borders toward each other (Fig. II); but on the other hand, when the abnormal processes occur on the ventral or toothed surface of the dactyl, they turn their smooth borders toward each other (Fig. III). We may now compare our actual specimens with the theoretical relations just described. In specimen No.1 the abnormal pair of process arise from the dorsal surface, and consequently their rela- tions should correspond to those given for the dorsal position in the diagram. A glance at the specimen quickly shows that such is actually the case; the toothed borders oppose each other; the two extra processes are mirror images of each other, and the one nearer the normal dactyl is also the mirror image of this segment; and, finally, it is readily seen that the process nearer the normal segment may be interpreted as an extra left dactyl (D’L’) and the other process as an extra right dactyl (D’R’), and consequently that these two abnormal structures evidently morphologically represent an extra and complementary pair of dactyls. In specimen No.2 the abnormal part arises on the toothed border of the dactyl, and the relations should correspond to those shown for the ventral position in Fig. II of the diagram. In this case the abnormal part is not. spatially separated into two distinct processes, nor is there even a slight bifurcation at the tip to indicate that it is a double structure. On the other hand, however, this abnormal process is itself symmetrical in form, and, accepting Bateson’s interpretation that ‘‘whenever an extra part is itself symmetrical it always may be a double structure,” we may 18 138 REPORT OF COMMISSIONERS OF INLAND FISHERIES. regard this process as consisting of two fused extra dactyls. Inter- preted in this way, it will be seen that we might split this abnormal part in such a way that we would have two extra processes which could be shown to conform to all the criteria in regard to mirror images, relation of the toothed borders, etc., as in the preceding case. Specimens 1 and 2 may, therefore, be regarded as conforming with Bateson’s principles for secondary symmetry. And, indeed, the above somewhat elaborate demonstration of this fact would hardly be necessary were it not that it finds its justification as an intro- duction to the following more complicated cases. 3. Extra Processes Repeating more than One Segment. This group includes specimens Nos. 3, 4, 5, and 7. The extra segments for each of these four segments arise from the following morphological surfaces of the appendage; No. 3, from the dorsal surface; No. 4, somewhat ventral to the posterior surface; No. 5 slightly dorsal from the direct anterior face: and, finally, in speci- men No. 7, the abnormal structure arises slightly posterior from the ventral surface. The comparison of the actual spatial relations among the elements of these abnormal limbs, with the relations theoretically demanded by Bateson’s principles, will be facilitated by the following diagram. (Diagram B.) The figures I-V in this diagram represent cross sections of the normal and extra claws taken through homologous points on the dactyls and indices. In each case the smaller section represents the dactyl, and the larger one, the index. As in the preceding diagram, the pointed portion of each cross section indicates the toothed mar- gins of each jaw, and the light and dark areas, respectively, indicate the anterior and posterior surfaces. Fig. I shows a section through the normal dactyl and index of the right chela; the sections in figures II-V represent the extra pair of claws for the specimens about to be described, and show the theoretical relations of these claws corre- sponding to the surface origin given for each specimen. REPORT OF COMMISSIONERS OF INLAND FISHERIES. 139 Figures I’ and IJ’ at the right, represent, respectively, a normal claw and a pair of extra claws for the purpose of illustrating the significance of the relations shown in Figs. I and IJ. The extra pair of claws (Fig. II’) arise from the dorsal surface of the appendage, and the arrow in each case indicates the plane of section shown in the corresponding diagrams. By means of this illustration the rela- tions indicated by the cross sections in the remaining figures may be readily perceived. Specimen No. 3. (Dorsal origin of abnormal structure. See Dia- gram, Fig. IT.) A glance at the drawing for this specimen is sufficient to show that the two extra dactyls and the double extra index conform almost exactly with the theoretical relations for the dorsal position; the three pairs of claws lie in the same plane; the extra dactyls and double index are minor images of each other, and the extra dactyl nearer the normal dactyl is also a minor image of the latter. While comparing this specimen with the diagram it will be kept in mind, of course, that the present specimen is a left chela. Specimen No. 4. (See diagram, Fig. V, position PPV.) In this specimen the abnormal parts arise from a position slightly ventral of the posterior surface. Here again the actual relations between the normal and abnormal claws correspond to the theoret- ical schema. The morphologically anterior surfaces are in opposi- tion; but they are inclined at such an angle that the toothed margins are turned toward each other, while the ventral or smooth borders of each claw are thrown apart. It may also be observed that here, _ again, the extra index nearer the normal index is a mirror image of the latter and belongs to the right or opposite side of the body. Specimen No. 5. (Origin slightly dorsal of the anterior surface. See diagram, Fig. III, position AAD.) This specimen presents certain peculiar exceptions to Bateson’s 140 REPORT OF COMMISSIONERS OF INLAND FISHERIES. principles, but we will first observe the points in which there is agree- ment. The pair of extra chele are mirror images of each other, and the chela nearest the normal claw is also the mirror image of the latter and belongs to the opposite side of the body, 7. e., it is a left chela. So far the relations seem to conform to the principles of secondary symmetry, but a closer examination reveals a wide variation. The extra pair of chela arise somewhat dorsally of the morphologically anterior surface, and this places init the position AAD of our diagram. Theoretically, therefore, the extra claws should have their posterior faces opposing each other (the dark sides in the diagramatic sections) ; the claws should be inclined at such an angle to each other that the indices should be brought toward each other and the dactyls thrown apart; and, furthermore, the anterior faces of the normal claw and of the member of the extra pair lying nearest it, should also be in opposition (see diagram). But upon examining the actual specimen, we find these relation to be just the reverse from the theoretical requirements; for instead of the posterior it is the anterior faces of the extra pair which are opposed; in place of the indices, it is the dactyls which are thrown toward each other; and, finally, it is the posterior, and not the anterior faces of the normal claw and the nearer abnormal chela, which are in opposition. At first I was at a loss as to how to account for this apparent contradiction. But finally the idea suggested itself that this whole difficulty could be explained by taking into account the process of “torsion”? which takes place during the development of the “ great chele”’ of the lobster. It is a well-known fact that, both in the ontogeny (Herrick, ’05) and in the regeneration (Emmel ’06) of the chelipeds, ‘‘ The terminal segments gradually rotate over and inward,”’ so that a torsion of about 90 degrees is produced and the claw now opens inward on the naturally characteristic horizontal plane” (Emmel, ’06, p. 613). This means, therefore, that in our present specimen the upper surface of the normal claw as shown in the drawing should be its morphologically posterior surface, and such is actually the case. But now, curiously enough, it seems that each REPORT OF COMMISSIONERS OF INLAND FISHERIES. 141 member of the pair of extra claws have in turn also rotated another 90 degrees during this development; and each of the extra claws has thus come to assume a position practically’ at right angles to the normal chela. In a word, we have the remarkable conditions here that, while the normal has rotated inthe usual manner through an angle of 90 degrees, each of the extra chele, or the other hand, has gone through a torsion of 180 degrees. Now if we were to turn these three chela backwards again to the position they originally held at the beginning of developmental torsion, it is surprising how closely their relations will then in every respect conform to our principles for secondary symmetry; for, if in the case of the two extra chela, both claws are rotated 180 degrees on their long axis, the claw nearer the normal chela being turned contra-clockwise and the other claw clock-wise, it will be seen that their anterior faces will then be opposed, and the indices in place of the dactyls will be thrown toward each other. Finally, if in a similar manner we rotate the normal chela clock-wise 90 degrees, it is evident that instead of the posterior, the morphologically anterior faces of the normal and the nearer extra claws will now be in opposition. By thus taking into account the developmental history of the lobster cheliped, it seems clear, therefore, that the morphological relations between the members of this triple chela do not fundamentally con- tradict, but rather furnish a remarkable confirmation of the principles of secondary symmetry as formulated by Bateson. This factor of “torsion” does not seem to have been considered in previous discussions of crustacean deformities, but it may possibly serve to clear up other exceptional cases. A case in point is the right cheliped of a lobster described by Faxon (Plate II, Fig. 6) and Bateson (No. 826). With reference to this specimen Faxon states that, “curiously, the supernumerary carpus is set upon the meros in a position almost the reverse of that of the normal carpus. It is as if the normal carpus were rotated upon the meros nearly 180 degrees to the left. . . . . .This distortion seems to me very singular, and I think nothing like it has been observed among 142 REPORT OF COMMISSIONERS OF INLAND FISHERIES. insects” (p. 263). Bateson placed this specimen under his list of “exceptional cases”’ and offers no explanation for the unusual condi- tions pointed out by Faxon. It seems clear, however, that the rela- tions which Faxon regarded as very singular in this case may be adequately accounted for as the result of the torsion of the normal and abnormal chele during their development.* Specimen No. 7. (See diagram, Fig. IV, position VVP.) In this specimen the extra parts appear to arise slightly posterior to the ventral surface of the leg. It will be seen in the diagram for this position that the two extra claws should be inclined to each other at an obtuse angle of at least 150 degrees. But in specimen No. 7 there is a great variation from this; for instead of 150 degrees, the two extra claws are inclined to each other at an angle of not more than 45 degrees,—a relation which corresponds to a more posterior point of origin (see diagram, Fig. V, position PPV). Furthermore, the relation between the minor images also correspond to a point of surface origin farther posterior than is apparently actually the case. While this specimen, therefore, seems to furnish a variation from the above principles, is should, however, be taken into consideration that a severe injury was sustained by these extra claws during their re- generation and that, consequently, this variation in relations may be largely due to an interrupted development in which the two claws were inhibited from diverging in their angular relations as widely as they might otherwise have done. On the whole, then, we may conclude the discussion of these six cases of abnormal appendages with the observation that with a few minor exceptions these six specimens conform to a remarkable degree with what might have been theoretically predicted, and that they *Since writing the above paragraph I have re-examined Bateson’s work and find that he has suggested explaining certain irregularities among vertebrate limbs in something of a similar manner. He observes that in the case of double limbs among vertebrates, ‘‘there is generally a relation of images between the extra pair,” but ‘‘a definite geometrical relation between them and the normal limb is seen more rarely.’”?’ And he suggests ‘‘that this may bein part at least attributed to the normal twisting of the vertebrate limb, especially of the hind limb, from its original position”’ (p. 556). REPORT OF COMMISSIONERS OF INLAND FISHERIES. 143 consequently furnish an additional confirmation of the principles of secondary symmetry as formulated by Bateson. B. Symmetrical Chele. Specimens Nos. 6, 8, and 9. It seems difficult at present to bring the regeneration of two “crusher” claws in the lobster under any definite principles of reg- ulation or developmental mechanics. The phenomenon of two similar “nipper”’ chels, indeed, does not seem so remarkable, especially when we take into account the larval development. The adult lobster normally has two distinct types of claws; the more primitive toothed or “nipping” claw, and the larger and phylogenetically younger (according to Stahr, ’98, and Przibram, 01) “crushing” claw. But in the larval stages, on the contrary, both are similar and of the nipper type. At about the sixth stage (Hadley, ’05) one of these claws begins to differentiate into a “erusher.”’ During ensuing moults this claw passes through transi- tional stages and is finally completely transformed into a crusher claw. It seems very plausible, therefore, that the presence of two similar “nipping” chele in an adult lobster, as in specimen No. 6, may be accounted for as due to a retarded differentiation during normal development. . Furthermore, the writer has found in several experiments that when the crushing claw has been autotomously removed, the regen- erated “crusher” is not always distinguishable as such, but may rather present characteristics intermediate or transitional between the more primitive nipping and the more highly developed crushing type (Emmel, ‘06).. If the crusher claw is phylogenetically the younger type, this might, perhaps, be expected, for then this varia- tion in the regenerating structure may be regarded as a reversion to the phylogenetically older or nipping type of claw. We may thus, in another way, again account for a lobster with two “similar nip- ning”’ chela. 144 REPORT OF COMMISSIONERS OF INLAND FISHERIES. But the regeneration of two crusher claws can not be brought into either of these two categories; for, of course, they cannot be > nor does it appear ‘ explained as due to a “retarded differentiation,’ that they may be regarded as a “reversion to a phylogenetically later type.” It is apparently impossible to interpret such a regeneration as a case of “compensatory regulation” in Zeleny’s (’05) sense, for the regenerated chele are almost identically similar both in size and form. Nor is it clear that they can be brought under the category of ‘revisal”’ phenomena, if by this term we imply a reversed order of asymmetry. At present, therefore, this phenomenon must rather be described merely as the substitution by regeneration of a “ crush- ing’’ claw in place of an original “nipping” claw. I have no suggestion to offer in explanation of these two cases of the regeneration of similar crusher chele. Evidently the regenera- tive cells in the stump remaining after autotomy may have the “crushing” or “nipping” claw. But what potentiality of either a factors determined that a claw of the crusher type be produced is another question. Wilson’s (’03) suggestion for Alpheus, “that the initial factor (Ausl6sung) that sets in motion the complex process of differentiation of which either side is capable is primarily only a difference in the amount of material on the two sides”’ (p. 210), can hardly apply here, for the chele were both removed autotomously and at the same time, consequently there seems no reason to believe that the “amount of material”? was unequal on the two sides. As far as the present data goes, the regeneration of similar “crushing” claws still remains unexplained. 3. Regarding the Origin of Abnormal Appendages. a. Discussion of Theories with Special Reference to the Regeneration Theory. Three possible theories have been proposed for the origin of ab- normal chele among crustacea: 1. That they are congenital or inherited. REPORT OF COMMISSIONERS OF INLAND FISHERIES. 145 “2. That they are caused by injuries sustained after moulting. 3. That they are regenerative products. But there is considerable divergence of opinion regarding the relative importance of these different theories. Faxon, in discussing his case of “duplicate” chela in Homarus, which resembles somewhat specimen No. 5, of our list, remarks that “whether this monstrosity be congenital, or the result of injuries received later in life, I can not tell” (p. 263); although later, when referring to this same case he adds, that “it is very probable that we are dealing with a monstrosity which is not the result of injury” (p. 267). Again, in regard to another case, a double index and two dactyls (Plate I, Fig. 13), he thinks that “one can easily believe that this is g congenital monstrosity”’ (p. 260). A fair interpretation of Faxon’s conclusions seems to be that he is inclined to consider all cases of duplicate or triple chele as congenital in their origin, while he considers that simpler deformities, as, for example, specimens 1 and 2 of our list, “are more naturally explained as malformations arising from injuries received after moulting” (p. 260). Bateson evidently gives least importance to the second and third theories, for, in regard to this question, he says: ca good many authors from the time of Roésel von Rosenhof onward, have said that these cases are a result of injury, or of regeneration after injury. For this belief I know no ground. It should be remembered as an additional difficulty in the way of this belief, that when the limb of a crab or lobster is injured it is usually thrown off bodily, while the extra parts most often spring from the periphery of the chela” (p. 526). Andrews, in discussing his case of “an aberrant limb in a erayfish,’’ states that “The appearance of the limb suggests a new growth fol- lowing some injury in which the material for claw making was partly severed and displaced.” As.to when this injury may have occurred, he merely suggests that it “might happen, we can suppose, not only in the egg and in the young, but in the adult, especially at the periods of shedding when the interior of the claw is soft and the blood 19 146 REPORT OF COMMISSIONERS OF INLAND FISHERIES. peculiar;” or, again, that probably “such a monstrosity as this might arise in regeneration following an injury to the propodite”’ (p. 83). Herrick, (’95) on the one hand, is inclined to favor the regeneration theory for these deformities. Although he points out that “repeti- tion of parts, however, occurs in many insects and vertebrates where no such regeneration of lost appendages is known,” he finally con- cludes that “while it would appear that the various deformities which have been described can not be explamed as the result. of injuries and the attempted regeneration of injured parts, yet I can not escape the conviction that the problem is in some way directly concerned with that of regeneration” (p. 148). But in regard to lobsters with similar chele, Herrick evidently favors the congenital theory; for in his discussion of symmetrical chele, he states “That there seems to be about as much variation as _ regards the details here mentioned in normal symmetrical claws as in the abnormal symmetrical ones, and it is probable that in either case the conditions met with are to some extent congenital” (p. 144). Quite recently Dr. Calman’s (’06) case of a lobster with two crusher claws has been interpreted as further discrediting the regeneration theory for symmetrical chelz, as may be seen in the following state- ment: “It has been supposed that this might be due to regeneration after injury, since it is known that in Brachyura, on the removal of the crushing claw, a cutting claw is regenerated. Przibram,* how- ever, failed to obtain such “heteromorphic” regeneration in the lobster, and the present specimen throws still further doubt on the regeneration theory, since it possesses well-developed and quite typical crushing chelz on both sides of the body” (p. 634). In this brief review of theories for abnormal chelz, it appears that the majority of the above investigators have emphasized the origin of such abnormalities through congenital sources, and injuries after moulting; while others have discussed the possibility of their being regeneration products. But it is important to note that in no case #02, p. 12, and 705, p. 191. REPORT OF GOMMISSIONERS OF INLAND FISHERIES. 147 have any of these writers furnished positive experimental evidence for their conclusions. I have been unable to fimd in their descrip- tions any proof that double limbs or symmetrical crusher chela have ever arisen in a congenital manner. While the theory of injuries after moulting seems very plausible, proof still remains to be pro- duced. Apparently the first case of double claws of which the origin and history is positively known is the specimen recently discribed by Zeleny (’05); who, in one of his experiments, obtained the regener- ation of a double chela in the fiddler crab. It is evident, then, that before we can hope to clear up this question, we need more accurate data on the formation of these abnormal structures. Specimens Nos. 7, 8, 9, may be something of a contribution toward this required data. Attention has been called to the fact that all these cases are regeneration products. In these specimens we have at least two authentic cases of the regeneration of similar crushing chele, and one case of the regeneration of a triple claw of the type which both Faxon and Bateson were strongly inclined to be only congenital in origin. These three cases, together with Zeleny’s, serve, therefore, to establish the process of regeneration as a factor in the origin of abnormalities in crustacean limbs. b. Further Considerations Favoring the Regeneration Theory. 1. That the Abnormal Crustacean Limbs Found so far have been only on Adult Animals. If double or triple claws are congenital in their origin, we might expect to occasionally meet such abnormalities in very young lob- sters. The lobster hatchery at the experiment station of the Rhode Island Commission of Inland Fisheries furnishes an excellent opportunity for such observations. But among the hundreds of thousands of lobsters reared yearly from the egg, no case of chela repetition has yet been reported; and I have also personally exam- ined with care something over 2,000 fourth and fifth-stage lobsters without observing a single case of duplication of parts in the chelipeds. 148 REPORT OF COMMISSIONERS OF INLAND- FISHERIES. I have also casually examined many thousands of young “fry”’ as they were being individually counted and taken from the hatching pools during the hatching season, but I did not find a lobster with double limbs. 2. That the Great Majority of these Deformities are also Found only on the More Distal Segments of the Limbs. In some sixty-five cases of abnormal chele recorded by Bateson, all but three of these deformed parts are found on the two distal segments of the appendage. It will be recalled that Bateson con- sidered one difficulty in the regeneration theory to consist in the fact “that when the limb of a crab or lobster is injured it is usually thrown off bodily;” although it should be observed that he hastened to add that “since, according to Heinekin, such mutilated parts are some- times retained, this must not be insisted upon” (p. 526). Now it is quite true that when the limb is injured the whole appendage may be autotomotsly thrown off, but this requires an important qualification; for whether the limb is always thrown off or not depends upon the character and location of injury. In some experiments on regenera- tion (05) I had occasion to mutilate the limbs of lobsters at different levels of the appendages. Inthe course of these mutilations I found that if the cheliped or leg was crushed by a pair of tweezers the whole limb was almost invariably autotomously dropped, practically regard- less of the region of injury. But by the exercise of considerable care it was discovered that if the tip of the limb was cut off with a quick, sharp stroke, the remainder of the appendage was usually retained. On the contrary, however, #f the cut was made near the base of the appendages, say in the region of the ischiopodite and meropodite, the remaining stumps were usually dropped. Furthermore, I have since found that the same conditions also hold true for regenerating buds; if the buds are injured near the tip the remaining structure is much less likely to be dropped than if the injuries are made in the proximal regions. In view of the fact, therefore, that im proximal REPORT OF COMMISSIONERS OF INLAND FISHERIES. 149 wounds the whole limb is usually autotomised, while in distal injuries the limbs are quite frequently retained and the lost parts restored by regeneration,—it follows that if abnormal structures do arise as the result of the injury of normal and regenerating buds, it would be most natural to expect that such abnormal structures would be most frequently found on the distal segments. In our examination of Faxon’s and Bateson’s lists, we have found that this is exactly the case. Taking into account, then, these relations between the nature of the injury, autotomy, and regeneration, it appears, therefore, that the fact that the great majority of crustacean deformities occur on the distal segments of the limb readily lends itself to the interpreta- tion that they are the result of regenerative processes. & 3.°_ The Regeneration of Extra Legs Following an Artificial Splitting of Nerves. 3. A third point of importance is the effect of injuries which involve a division of the nerve. Miss Reed (’04) in her study of regeneration mentions certian results which she obtained in the hermit crab by splitting the stump of the leg lengthwise after autotomy had taken place. “In several cases after splitting the stump, two extra legs appeared in a short while. Sections through this region show that the nerve is split, one branch going to each leg. It is probable that a new leg was developed at each end of the split nerve, since in all other cases where only one leg regenerated the nerve shows no sign of any injury. In this case it is probable that the nerve was not cut” (p. 315). Unfortunately, Miss Reed has not described these regenerated extra legs, but this result is certainly very suggestive; it not only furnishes further evidence for the origin of extra structures through regenerative processes, but also indicates an important method for future experiments. In view of these results one is also tempted to ask whether the rare case of triple legs recorded by Bateson for the European lobster (No. 808) may not 150 REPORT OF COMMISSIONERS OF INLAND FISHERIES. have arisen through an accidental fracture of the nerve stump and a consequent triple regeneration. In the conclusion of this study of abnormal structures, therefore,. we may say that sufficient evidence has now been adduced to prove that both abnormal symmetrical and duplicated appendages among curstacea do arise through the process of regeneration. And the experimental results so far attained indicate that we may yet be able to control the formation of these abnormalities by proper muti-- lation, and thus open up for experimental study an important field of organic variation. LITERATURE CITED. AnpREws, E. A., ’?04—‘“ An Aberrant Limb in the Crayfish.” Bvol. Bull., Vol. V1, No. 2, pp. 75-83. Bateson, W., ’94—“ Materials for the Study of Variation.”’ London,. 1894. CatMan, W. T., ’06—“ Exhibition of a Photograph of a Lobster with Abnormal Chele.”’ Proceed. of the Zodl. Soc. of London,. p- 633. EmMet, V. E., ’?05—“ The Regeneration of Lost Parts in the Lobster.” Thirty-fijth Annual Report of the Rhode Island Commission of Inland Fisheries, pp. 81-117. Special paper, No. 20. Emmet, V. E., ’?06—“The Relation of Regeneration to the Molting Process. of the Lobster.” Thirty-sixth Annual Report of the Rhode Island Commission of Inland Fisheries, pp. 257-3138; Special paper, No. 27. EmMeEt, V. E., ’?06—(a) “Torsion and Other Transitional Phenomena in the Regeneration of the Cheliped of the Lobster.” Journal of Exp. Zodlogy, Vol. III, No. 4, pp.603-618. Emmet, V. E., ’?06—(b) “The Regeneration of Two ‘Crusher-claws’ following the Amputation of the Normal Asymmetrical Chele of the Lobster (Homarus Americanus).” Archiv. f. Entw- Mech., Bd. XXII, pp. 542-552. REPORT OF COMMISSIONERS OF INLAND FISHERIES. leat Emmet, V. E., ’?07—“ Regeneration and the Question of ‘Symmetry in the Big Claws of the Lobster.’ ”’ Science, 1907,(now in press). Faxon, W., ’81—‘‘On Some Crustacean Deformities.”” Bull. of the Mus. of Comp. Zoél., Harvard, Vol. VIII, No. 18, 1881. Hap.ey, P. B., ’?05—“Changes in Form and Color in Successive Stages of the American Lobster.” Thirty-fijth Annual Report of the Rhode Island Commission of Inland Fisheries, pp. 44-80. Special paper, No. 19. Herrick, F. H., ’95—‘The American Lobster.” Bull. U. S. Fish Commission, 1895. Herrick, F. H.,’05—“ The ‘Great Forceps’ of the Lobster.”” Science, N.8.; Vol. XX1, p. 375. Morean, T. H., ’04—“ Notes on Regeneration.” Biol. Bull., Vol. VI, pp. 159-172. PrzipraM, H., ’01—“ Experimentelle Studien uber Regeneration. I.” Archiv. f. Entw.-Mech., Bd. XI, pp. 321-345. PrzipraM, H., ’02—“ Experimentelle Studien uber Regeneration. Il.” Archiv. fj. Entw.-Mech., Bd. XIX, pp. 181-247. PrzipraM, H., ’05—“ Die ‘ Heterochetie’ bei decapoden Crustacean, Ill.” Archiv. jf. Entw.-Mech., Bd. XIX, pp. 507-527. ReEeEpD, Marcaret A., ’04—“ The Regeneration of the First Leg of the Crayfish.”” Archiv. f. Entw.-Mech., XVIII, p. 307. Sraur, H., ’?98—“Neue Beitrage zur Morphologie der Hummer- schere.” Jenaische zeitschr. f. Naturw., Bd. XXXII, p. 475. Witson, E. B., ’?083—“ Notes on the Reversal of Asymmetry in the Regeneration of the Chele in Alpheus heterochelis.” Bvrol. Bull., Vol. 4, p. 197. ZELENY, C., ’05—“Compensatory Regulation.” Journ. of Exp. Zoology, Vol. 2, p. 197. ZELENY, C., ’05—(a) “The Regeneration of a Double Chela in the Fiddler Crab (Gelasimus Pugilator) in Place of a Normal Single One. Biol. Bull., Vol. 9, p. 152. 152 C C’(R+L). 1B D’L. D/R. D/(R-+LL). IS. VR’. VL’. V(R+1). ea < bo REPORT OF COMMISSIONERS OF INLAND FISHERIES. REFERENCE LETTERS FOR PLATES I—IX. Injured regions. Sixth limb segment or basipodite. Third segment or carpopodite. Double extra carpopodite. First segment or dactyl. Extra left dactyl. Extra right dactyl. Abnormal processes interpreted as being morphologically double extra dactyls. Groove. Tactile hairs. Jaw part of second segment or index. Fifth segment or ischiopodite. Extra right index. Extra left index. Abnormal process interpreted-as being morphologically double extra indices. Joint. Extra left chela. Fourth segment or meropodite. Extra meropodite. Group of teeth in periodic sequence. Papilla. Second segment or propodite. Extra right propodite. Extra left propodite. Extra right chela. Scar. Teeth. Characteristic double teeth on crusher claw. Ventral surface. The two parts of the extra bud shown in Figs. 10-14. Ir PuatTe I. Fig. 1 (Page 103).—Crusher claw of left chela with two extra processes (D’R’, D’L’) on the outer or smooth border of the normal dactyl. (4 x natural size.) Fig. 2 (Page 104).—Nipper claw of left chela with an extra process D’/(R’+L’) on the inner or toothed border of dactyl. (4 x.) Fig. 3 (Page 105).—Left chela with two extra dactyls (D’R’, D’L’), and an extra double index, I'(R+L). (4x.) Fig. 4 (Page 107).—Nipper claw on right chela with two extra indices (I’L’, I’R’) and the stump of a double extra dactyl (?), D’(R+L). (4x.) Puate II. Fig. 5 (Page 108).—Abnormal right chela consisting of the approximately normal claw €D; 1) plus the two extra claws R’ and L’. This appears to be one of the most perfect cases of triple claws so far recorded for the lobster, (Natural size.) i vee CX $) ‘ArQeuwAs [BuUOUqY Shotasid at, peonpoidar aavt] sesseooud ovAljBieuezed ey, “2 PUB g SeINSIA ul uMOYS squit| aj [BOLeUIUIAS [BUIZTIO BY} JO UONBINdUIF dy} 1a}ju poyBIeUEsaL Yorum wBleyoO—'6 pun g ‘sb1y7 CX $) ‘SqUII] JUS pus qjol ay} JUaseIdar ‘AJOATJOedSeI ~Y pu a Q seinaty “edA} teddtu ey Jo wyeyo RomjouruIAs ATTRUIIOUGW— (ZTT a6Dq) 2 pun g ‘shry & ‘TI] Gtv 1d PLATE IV. Figs. 10-15 (Page 113).—Successive stages in the regeneration of a double extra claw on a second right walking leg. (14 x.) Fig. 10.—Thirty-fifth day after the amputation of the original leg, showing the development of an extra bud (1,2). (Posterior view.) Fig. 11.—Forty-third day of regeneration. (Posterior view.) Fig. 12.—Anterior view of the extra bud. Fig. 13.—Forty-eighth day. Extra bud had been accidently injured and pushed upward. (Posterior view.) Fig. 14.—Anterior view of the extra bud. PLATE V. Fig. 15 (Page 116)—Regenerated right walking leg with a pair of extra claws D’/(R+L), I'L’, and I’R’. Drawn just after the moult. See earlier stages shown in Figures 10-14. (Pos- sterior view. 14x.) Fig. 16.—Sketch of ventral view of the extra claws te show the two indices, I’R’ and IL. (13 x.) PuatTe VI, Figs. 17 and 18 (Page 116). Drawings to indicate the structure and relations in the extra claws shown in Figure 15. (Posterior view. 4x.) Fig. 19 (Page 118).—Regenerating fourth left leg with an abnormal bud (b). (4 x.) Figs. 20, 21 (Page 119).—Two regenerating papille, (pp. 1 pp 2) on a second right leg. (Posterior view. 2x.) Fig. 22 (Page 120).—Regenerating bud of a walking leg. The tip had been cut off at the region indicated by the sear (s), but had grown out again. (2 x.) Fig. 23 (Page 121).—An unusual rudimentary claw (D+I) which regenerated on the tip of a leg which had been cut off just above the second distal joint. (14 x.) 24 26 26 27 PuatTe VII Figs. 24-27 (Page 121).—Figs. 24 and 25 are photographs of the original normal chele of an 8-inch female lobster, showing the usual asymmetry of claws with a nipper on the right (Fig. 25) and a crusher on the left (Fig. 24). (About 4 natural size.) Figs. 26 and 27.—Photographs of the left and right chele, respectively, which regenerated after the amputation of the original limbs. In this case two crushers, in place of the former nipper and crusher, have regenerated. (About 4 natural size.) Puate VIII. Figs, 28-31 (Page 121).—4-3 natural size. Figs. 29 and 30 show the index or propodite part of the original claws represented in Plate VII, Figs. 24 and 25. Fig. 29, index of normal left erusher. (Drawn from the upper face.) Fig. 30, index of normal right nipper. (Drawn from the lower face.) . Figs. 28 and 31 represent the index of the regenerated claws shown in Plate VII, Figs. 26 and 27. Fig. 28, index of regenerated left crusher. (Drawn from upper face.) Fig. 31 index of regenerated right claw. (Drawn from lower face.) ‘eysnio pues seddiu [eurou aq} jo sovyd Ul SleYysN19 OM Paonpord oAvy sossad01d sATVVIoUEFeI oY, “SquIt [BUIsI10 yy Jo u0T]Ry -ndwie 9} 10}fe po}Bisuese. yoryM ATPATJDedSaa ‘eypeyo YysI pue 9J9T OU L— Cg pun FE ‘shrug “(Eg “sTy) teddru 8 4YsII eYyy pue (ZE “ByT) 1eysnaod v ST 4J9] 94} :10}SqOy eyBuT Your -§ UB JO Bleyo [BULOU [BUISTIO oY} MOYS EE puB Ze ‘SBI «((X £)— (GZT 26nd) GE-Ze “sbi XX] aivid WHY S 3 \ We SS 4 —S SS 7 parE des Siemans ic a ; ‘ a Eg aT a Sh ogee cient tpl AE ae eI Oi m ol ; @ 7s | , , “~ roar , om et Paetik a SAM id,” 4 00 Sch le Vege SN pte ssa Sn Pity Cin pay hd THN er | e Os eg eee ADS behead ates PU ee LR et eer bot er | ide otha’) eee Cals Oy Sor, VC meri ee aeRO Re gear Oey ae = - THE STOMACH OF THE LOBSTER AND THE FOOD OF LARVAL LOBSTERS, LEONARD W. WILLIAMS, PH. D. The external anatomy of the bizarre and attractive larval lobsters has been studied, described, and figured with great care, but the internal anatomy of these forms has received scant attention, and for this reason we hope that the work recorded here will be of interest. The Commission of Inland Fisheries of Rhode Island is studying the various problems, anatomical, biological, and physiological, concerning the natural history of the lobster in connection with its experimental and economic work of hatching and rearing lobsters at the Wickford station. Asa part of this work, we were asked to investigate the food of the larval lobsters in the hatching and rear- ing bags of the station. While examining the alimentary canal of many lobsters we discovered the metamorphosis of the stomach which we here figure and describe. This work naturally demanded an understanding of the adult stomach, and, not finding satisfactory descriptions of the structure and functions of the adult stomach, we were compelled to extend our work to include the anatomy of the stomach of lobsters of all ages. . We are indebted to the Commissioners of Inland Fisheries, espe- cially to Dr. A. D. Mead, for the opportunity to do this work, and to Mr. V. E. Emmel and to Mr. P. B. Hadley for the use of serial sections of young lobsters prepared by them. 20 154 REPORT OF COMMISSIONERS OF INLAND FISHERIES. THE STOMACH OF THE ADULT LOBSTER. The Mouth. The mouth of the lobster lies on the lower surface of the head between the mandibles which, when closed, hide the mouth opening. Just in front of the mandibles there is a large median fleshy lobe, the labrum, or upper lip, which forms the anterior margin of the mouth opening. When the mouth is closed, the hinder surface of the labrum projects backward as a median vertical ridge which is prolonged upward through the csophagus and which makes the mouth V- shaped. The sides of the mouth are formed by a pair of rounded ridges which become higher and converge posteriorly where each ridge expands into a flat boot-shaped plate which is fringed with bristles. These two lobes form the metastoma, or lower lip, which projects downward in the narrow cleft between the mandibles and the first maxille. The dilation of the mouth is affected by the pulling forward of the posterior ridge of the labrum so that the opening becomes approximately circular. The Esophagus. The cesophagus is a short vertical canal which passes upward from the mouth between the circumesophageal connectives and enters the lower side of the stomach. The empty cesophagus is externally cylindrical, except that it is somewhat flattened laterally. The ridge which is a vertical prolongation of the labrum projects backward into the lumen of the cesophagus and makes it trough- shaped (V-shaped) in cross section. This ridge is everted forward during dilation of the cesophagus, and so serves to increase largely the size of the cesophagus. The Stomach. The stomach, in all stages, is divided by an oblique constriction into a capacious anterior storage chamber, the cardiac portion of REPORT OF COMMISSIONERS OF INLAND FISHERIES. 155 the stomach or cardiac sac, and a small posterior straining and sort- ing chamber, the pyloric portion of the stomach or pyloricsac. Corresponding to the external constriction, internally there is a grinding apparatus which, in the adult form of the stomach, consists of a median tooth and a pair of lateral teeth. The wall of the stomach is formed of four layers of tissue: 1. An outer layer of connective tissue. This sheet stretches over the irregularities of the stomach and gives the whole exterior a some- what rounded form. In places this outer layer of the stomach is covered by the vascular epithelium (Plate VI, Fig. 9). 2. A layer of loose connective tissue. This tissue fills up the irregular cavities between the inner and outer contours of the stom- ach wall and contains the blood vessels and intrinsic muscles of the stomach. 3. The gastric epithelium. This varies in thickness and, cor- respondingly, in the shape of the cells according to the thickness of the chitinous stomach lining. 4. The chitinous lining of the stomach. This is generally covered with sete of various kinds and in places it is thickened. A deposi- tion of lime in these thickened areas converts them into “the ossicles” which form the skeleton of the gastric mill. The Gastric Ossicles and Muscles. In the American lobster the gastric ossicles are essentially like those of the European lobster (Homarus vulgaris) and the crayfish (Astacus fluviatalis), which have been adequately described by Milne Edwards, Oesterlen, Huxley, and T. J. Parker, hence we will omit an extended description of them. We will give generally two names for each ossicle, the shorter names used by Huxley and Parker, and the longer but more descriptive names of Albert. Beginning at the . anterior end of the dorsal surface: 1. The cardiac ossicle or anterior dorsal cardiac plate. This covers nearly the whole of the dorsal surface of the cardiac sac. In 156 REPORT OF COMMISSIONERS OF INLAND FISHERIES. our specimens it is divided by a transverse joint into two plates. The anterior plate is calcified only at the postero-ventral angles. The anterior gastric muscles (Plate I, Fig. 1), a pair of heavy flattened muscles, arise from the procephalic processes (which are reniform plates attached to the septa between the eyes and the rostrum) and are inserted upon the anterior end of the anterior portion of the dorsal cardiac plate. 2. The urocardiac ossicle or posterior dorsal cardiac plate. This is narrower than the cardiac ossicle and inclines downward and back- ward so as to form part of the posterior wall of the cardiac sac. 3. The prepyloric ossicle or median tooth. This forms the antero-dorsal wall of the pyloric sae. 4. The pyloric ossicle or anterior dorsal pyloric plate. This plate is covered by the insertion of the posterior gastric muscles which arise from the carapace just in front of the cervical groove and from the internal ridge corresponding to the groove. On the upper part of the side of the stomach there are: 5. The pterocardiac ossicle or anterior dorso-lateral plate. 6. The zygocardiac ossicle or middle dorso-lateral cardiac plate or lateral tooth. This is an irregular parallelogramic vertical plate whose upper anterior angle is bent outward and downward to articu- late with the lower end of the pterocardiac ossicle and whose upper posterior angle is turned inward nearly to the pyloric ossicle. The inner surface of the lower edge of this plate is heavy and irregular and forms the grinding surface of the lateral tooth. 7. The anterior dorso-lateral pyloric plate. This is a triangular plate interposed between the lateral tooth and the pyloric plate. The postero-lateral gastric muscle arises from an area of the cara- pace bounded behind by the cervical groove, below by the branchio- cardiac groove, and above by the posterior gastric muscle and, pass- ing inward, forward, and downward, is inserted upon the anterior dorso-lateral pyloric plate. The division between the posterior and postero-lateral gastric muscles and between the pyloric and anterior dorso-lateral pyloric plates seems to be lacking in other forms or to REPORT OF COMMISSIONERS OF INLAND FISHERIES. 157 have been overlooked by everyone except Albert and is, in our opinion, of great importance (see page 158). The cardio-pyloric muscle, a small band, extends from the upper end of the anterior dorso-lateral pyloric plate and the adjacent upper edge of the lateral tooth forward above the outer end of the cardiac ossicle to the upper part of the anterior edge of the ptero-cardiac ossicle. The plates, teeth, and muscles described above form the essential parts of the gastric mill, which consists of two portions, the median and the lateral, which are so closely connected that their actions are absolutely codrdinated. The median portion of the gastric mill includes the four median plates mentioned above and the anterior and _ posterior gastric muscles. The two horizontal plates, the cardiac and pyloric, are connected by the urocardiac plate and the median tooth, the former being attached to the latter at the junction of its lower and middle thirds. The contraction of the anterior and posterior gastric muscles draws apart the cardiac and pyloric plates and as these plates sepa- rate the urocardiac ossicle pulls the lower end of the median tooth forward, the former acting as the power applied to the latter as a lever of the third order at a point about two-thirds of the length of the lever from the fulcrum, 7. e., the articulation of the median tooth with the pyloric plate. Thus the median tooth is drawn forward with great force. The lateral portion of the gastric mill consists of : The pterocardiac bar which is hinged on the outer end of the cardiac plate so as to make a right angle with that plate and so that its lower end moves from the position of rest inward and backward in a ver- tical plane inclined forward at an angle of 75 or 80 degrees with the sagittal axis; the lateral tooth whose anterior upper angle is attached to the pterocardiac bar and so moves inward and backward with that point and whose posterior‘upper angle is fixed to the outer anterior angle of the pyloric plate; and the anterior dorso-lateral pyloric plate which receives the insertion of the postero-lateral gastric muscle and which is attached to the posterior edge of the lateral tooth. The 158 REPORT OF COMMISSIONERS OF INLAND FISHERIES. posterior intermediate cardiac bar is attached to the lower side of the lateral tooth at a point about one-third of its length from the anterior end. The separation of the cardiac and pyloric plates necessitates a downward, inward, and upward swing of the anterior upper angle of the lateral tooth which carries the anterior end of the grinding surface of that tooth toward the median line. At the same time the con- traction of the postero-lateral gastric muscles pulls the posterior end of the lateral tooth outward and upward, and the tooth, rotating on the line between its articulations with the upper end of the anterior dorso-lateral pyloric plate and with the posterior intermediate cardiac plate, drives its anterior cusps inward with considerable force. When the gastric muscles relax the elasticity of the structures, coupled with the pull of the cardio-pyloric muscles, draws the median tooth backward and the lateral teeth outward. Returning to the enumeration of the ossicles of the stomach we find on its sides the following: 8. The gastrolithic bar. This is a sigmoid bar whose upturned posterior end articulates with the pterocardiac ossicle, the anterior end of the lateral tooth, and the bar to be described next. Its anterior end follows for a short distance the upper edge of the gastro- lithic plate, which is a triangularly ovate epithelial plate that during the latter part of the period between molts secretes a thick plate of lime, the gastrolith (see page 172). 9. The accessory lateral cardiac ossicle or upper intermediate cardiac bar extends with a gentle curve backward and then down- ward from between the preceding bar and the pterocardiac bar to: 10. The infero-lateral tooth, which is an irregular plate with three acute cusps upon its anterior edge. 11. The lower intermediate cardiac bar. This extends back- ward from the preceding tooth to: 12. The upper ventro-lateral cardiac bar, which passes forward along the ventral side of the cardiac sac to the cesophagus where it bears upon its upper side: REPORT OF COMMISSIONERS OF INLAND FISHERIES. 159 13. The antero-lateral cardiac bar. This bar extends obliquely upward and forward almost to the antero-ventral angle of the gastrolith. The posterior lateral dilator muscle arises from the postero-lateral angle of the mandibular sternum, extends upward, inward, and back- ward to its insertion upon the antero-lateral cardiac bar. 14. Immediately below the upper ventro-lateral cardiac bar lies the lower ventro-lateral cardiac bar, which has much the same shape as that bar ‘but extends farther backward. The posterior ends of these two bars are hinged upon one another so that they open and shut like a pair of pincers. 15. The ventral cardiac plate. This is a small oval median plate lying between the posterior ends of the lower ventro-lateral cardiac bars. 16. The posterior intermediate cardiac bar passes obliquely upward and forward from the posterior end of the lower ventro- lateral cardiac bar to the lateral tooth. The lower lateral cardiac constrictor muscle extends upward and forward from the entire upper edge of the lower ventro-lateral cardiac bar to a slight thickening of the stomach wall which lies midway between the gastrolith and the lower ventro-lateral cardiac bar. The contraction of this muscle draws together the two edges of a fold of the stomach wall and thus causes the fold to project farther into the lumen of stomach. The ventral cardiac constrictor extends between the right and left lower ventro-lateral cardiac bars. The cardiac sac is irregularly ovate. Its greatest width lies between the pterocardiac ossicles and its smaller end opens into the pyloric sac. Its dorsal surface follows the curvature of the adjacent carapace and its anterior surface is uniformly convex when distended. The somewhat flattened sides of the sac converge below so that its ventral surface is reduced to a narrow band between the ventro-lateral cardiac bars and a larger area in front of the cesophagus. 160 REPORT OF COMMISSIONERS OF INLAND FISHERIES. As the stomach becomes empty its anterior wall is drawn inward in the form of a pair of large upper folds and a pair of smaller lower folds. At the same time the portions of the side wall of the sac above and below the gastrolith push, respectively, inward and downward, and upward and inward over the inner surface of the gastrolith. The dorsal dilator muscle arises from the dorsal surface of the carapace, and, as it passes downward and backward, its fibres diverge and are inserted upon the upper part of the anterior wall of the stomach. | The anterior dilator muscle is a moderately strong round muscle, which arises from the outer surface of the socket of the eye, passes backward and slightly downward to the outer surface of the lower fold of the anterior wall of the stomach. The anterior lateral dilator muscle arises with the posterior lateral dilator from the man- dibular sternum and is inserted upon the lower part of the anterior wall of the stomach. The upper lateral cardiac constrictor muscle is a fan-shaped muscle which extends from its broad origin on the upper edge of the lateral tooth to the posterior end of the lower ventro-lateral cardiac bar. The middle lateral cardiac constrictor muscle arises from the upper end of the upper intermediate cardiac bar, and, extending down- ward and backward, is inserted in front of the preceding muscle. Removing the muscles and the loose tissue of the second layer of the stomach wall, we expose the following invaginations of the two inner layers of the stomach wall which correspond to internal pro- jections. A deep broad dorsal pit which extends downward between the median tooth and the urocardiac bar to the cavity of the tooth. On each side of the median tooth there is an oval elevation, the posterior dorsal pad, which projects inward into the space between the median and lateral teeth and the outer wall of the stomach, and which is densely covered with downwardly directed bristles. Just in front of this pad is a small cusp which forms the postero-lateral angle of the urocardiac plate. This cusp is connected with its mate by a strong transverse ridge on the upper side of the plate. These cusps form a kind of flange on each side of the median tooth which REPORT OF COMMISSIONERS OF INLAND FISHERIES. 161 prevents it from going too far down between the lateral teeth. A little in front and outside of this cusp there is another elevation, the anterior dorsal pad, which is covered with downwardly directed bristles. A deep longitudinal groove extends backward from the lower side of the gastrolith into the lateral tooth. Just below the anterior end of the lateral tooth a deep tubular invagination, whose walls form the upper lateral pad, extends upward in front of the tooth. Behind the infero-lateral tooth, below the lateral tooth, and below and behind the preceding pit,is a larger, but shallower, pit, the middle lateral pad. 3 The cesophageal opening is guarded by a median and a pair of lateral valves. The median valve is formed by a triangular broaden- ing of the upper end of the vertical ridge of the cesophagus. The lateral walls of the cesophagus are prolonged upward into a ridge-like valve which nearly encircles the cesophageal opening and which is higher on each side than behind the opening. The three valves are covered with a thick pile of long slender bristles which point towards the stomach. The anterior constrictor muscle arises from the middle of the man- dibular sternum and, passing backward and slightly upward, is in- serted upon the upper edge of the median cesophageal valve. Its contraction pulls down the anterior wall of the stomach and causes it to fold inward. The anterior wall of the stomach is covered with a similar coat of bristles which are inclined in various directions in such a manner that when the anterior folds are pushed inward the bristles point toward the gastric mill. The upper wall of the stomach is smooth, as also is the inner face of the gastrolith. Upon the inside of the stomach we find the anterior two thirds of the upper part of the side occupied by the smooth surface of the gastrolith and the posterior one-third by the upper and middle lateral pads. The lower part of the side is formed by a large lateral plate which is bounded below by the upper ventro-lateral cardiac bar, above by the lower intermediate cardiac bar, the infero-lateral tooth, 21 162 REPORT OF COMMISSIONERS OF INLAND FISHERIES. and the gastrolith, and in front by the anterior lateral bar... The lower edge of this plate forms a large fold, the lower lateral pad, which overlaps the ventral surface of the stomach so as to enclose on each side a deep groove which extends the whole length of the ventro-lateral cardiac bar, 7. e., from the cesophagus to the pyloric sac. : The ventral surface of the sac is raised into a low narrow median ridge which ends abruptly above the ventral cardiac plate in a rounded point. Near the middle of this ridge, there begins on each side a ridge which quickly becomes higher posteriorly and, meeting its mate, the two spread out in a broad deeply channeled elevation, the cardio-pylorie valve, which has, in addition to its bilobed chan- neled anterior portion, a median posterior lobe. Its anterior surface is covered with a close pile of short, strong, upwardly and back- wardly directed bristles, and the posterior lobe is armed with long upwardly directed bristles. The posterior portion of the lower edge of the lower lateral pad and the posterior edge of the middle lateral pad overlap the edges of the cardio-pyloric valve. Each of the two grooves between the ventral and lateral walls of the cardiac sac is divided by a row of long, large, close-set, back- wardly inclined bristles into two canals; an upper and outer, the upper cardiac canal, and a lower and inner, the lower cardiac canal. The bristles of the ventral ridge and of the lower lateral pad interlock so as to enclose both of these canals and the bristles separating them interlock with the bristles of the lower lateral pad, so that material can enter the upper cardiac canal only by passing through the lower canal and between the bristles which separate the canals. The outer and upper wall of the upper canal is smooth, while the lower and inner wall of the lower canal is closely beset with very short, heavy, upwardly-pointed bristles. The lower cardiac canal opens posteri- orly into the groove upon the anterior surface of the cardio-pyloric valve, while the upper cardiac canal passes beside the valve and opens into the lower canal of the pyloric sae. REPORT OF COMMISSIONERS OF INLAND FISHERIES. 163 The Pyloric Sac. The pyloric sac is irregularly ovate and is considerably flattened laterally. Its cavity is a narrow vertical slit which is partially divided by ridges and pads into an upper and lower chamber and an upper, a middle, and two lower canals. The opening from the pyloric sac into the intestine is guarded by four valves: The dorsal pyloric valve or “funnel’’* is a pen-point shaped plate which reaches far into the intestine and partly separates the intestinal cecum from the remainder of the intestinal cavity. The right and left lateral pyloric valves are triangular plates fringed with bristles and attached to the sides of the gastro-intestinal open- ing. They enclose a narrow passage which leads upward into the concavity of the dorsal valve. The ventral pyloric valve is a broad triangular horizontal plate which is separated from each lateral valve by a deep sinus and whose upper surface is covered with bristles. The wall of the intestine is attached to the bases of the dorsal and lateral valves, to the edge of the sinus between the lateral and ventral valves, and to the edges of the ventral valve. The intestinal cecum is a broad pear-shaped evagination of the intestinal wall. It extends upward and forward over the posterior part of the dorsal wall of the stomach. The tubular duct of each half of the liver or digestive gland, an immense compound tubular gland, opens into the intestine between the ventral and the corresponding lateral pyloric valve. Jordan has shown that the finely comminuted food from the lower canal of the pyloric sac passes into the liver and is there digested and absorbed. The dorsal surface of the pyloric sac is directed upward and back- ward, and is divided into two convexities and one concavity. The anterior convexity is formed by the pyloric and the anterior dorso- lateral pyloric plates, and it forms the roof of the upper pyloric *That the funnel is not an essential structure is shown by the fact that a perfectly well, actively feeding lobster examined by us had lost the funnel. It probably acts as a valve to prevent the return of material to the stomach as is shown by the fact that it is sometimes found ‘drawn down across the mouth of the middle canal. 164 REPORT OF COMMISSIONERS OF INLAND FISHERIES. chamber which extends forward to the median tooth and downward to the level of the lateral tooth, where two longitudinally oval pads, the upper and lower pyloric pads, projecting from each side and covered with forwardly directed bristles, separate the upper pyloric chamber from the lower. The posterior convexity of the dorsal wall of the plyoric sac is formed by the middle dorsal pyloric plate (17), whose upper end and lateral edges are more heavily calcified than the remainder of the plate. The superior dilator arises from the carapace in front of the cervical groove and, passing downward and forward, is inserted upon the middle dorsal pyloric plate. 18. The posterior dorsal pyloric plate is a small, scarcely claci- fied, dorsally concave, oval plate which supports the dorsal pyloric valve and which is covered with numerous backwardly directed bristles. The concavity of the dorsal wall is formed by this plate and is filled by the intestinal cecum. An inwardly projecting ridge which is supported by the corre- sponding edge of the middle dorsal pyloric plate, and which is covered anteriorly with long thick-set bristles directed forward and upward, separates the lower pyloric chamber from the upper canal. This canal extends the whole length of the middle dorsal pyloric plate and divides posteriorly, passing around the posterior dorsal pyloric plate in a pair of lateral canals which are formed by the wall of the pyloric sac adjacent to that plate and which open upward into the intestinal cecum. 19. _The upper intermediate pyloric bar passes forward hori- zontally from the upper end of the middle dorsal pyloric plate across the side of the pyloric sae. It supports the upper edge of the out- wardly convex wall of the lower pyloric chamber. 20. The posterior intermediate plate is irregularly triangular and is concave inwardly. Its broad base supports the lateral pyloric valve. Its antero-dorsal edge supports the ridge that forms the lower side of the middle chamber. This ridge is heavily beset with bristles which seem to radiate upward, inward, and downward from REPORT OF COMMISSIONERS OF INLAND FISHERIES. 165 the center of the ridge: those which are directed inward are curved downward at the tip as though bent down by the force of the food current. The wall of the lower chamber bears a few slender for- wardly directed bristles. At the level of the posterior dorsal pyloric plate the ridges which form the upper and lower boundaries of the lower chamber meet and close completely the posterior end of that chamber. The right and left posterior intermediate pyloric plates enclose the middle canal, which is narrow in front and broadens posteriorly. Each lower pyloric canal is divided into an anterior portion lying between the middle and lower intermediate pyloric plates and a posterior portion enclosed between the posterior part of the middle intermediate and the ventral pyloric plates. The posterior parts of the lower pyloric canals form the most essential structure of the pyloric sac, and they are contained in the lateral pouches. 21. The middle intermediate pyloric plate extends in a sigmoid curve from the posterior end of the lower ventro-lateral cardiac bar upward, backward, downward, and then backward and upward again. The plate is broad in the middle and narrower at each end. It is almost bisected by a curved cleft which reaches from its lower edge nearly to its upper edge and divides the portions connected respectively with the anterior and posterior portions of the lower canal. 22. The lower intermediate pyloric plate is roughly quadri- lateral and is concave ventrally. It is connected with the lower ventro-lateral cardiac bar and, forming the floor of the pyloric sac behind and on the outer side of the cardio-pyloric valve, it supports the posterior side of that valve. 23. The ventral pyloric plate is formed by two pointed half- spiral portions which extend from the tips of the lateral pouches forward, inward, and upward, and unite in the median line, forming there a prow-like septum which projects upward between the posterior portions of the two lower canals. This septum supports the median portion of the ventral pyloric valve and is continued backward as a ° 166 REPORT OF COMMISSIONERS OF INLAND FISHERIES. horizontal oval plate which lies between the lower edges of the lateral pyloric valve and separates the posterior ends of the middle and lower canals. The concave upper surface of each half of the ventral pyloric plate is covered by high parallel ridges which arise at the an- terior edge of the plate and pass backward to a point two-thirds of the width of the plate from its anterior edge, where each ridge ends in a heavy band of chitin which diverges upward to the upper wall of the lower canal. Each ridge and band bears upon its distal or mesial side a row of close-set bristles which overlap the next ridge and band. These bristles cut off from the posterior part of the lower canal a number of parallel canals which open into a large transverse canal, the ventral part of the posterior portion of the pyloric canal. The bands, ridges, and bristles form a fine-meshed sieve over which the food stream passes. The fluids and the fine-grained portion of the food pass from the dorsal part of the canal through the sieve into the ventral part of the canal, and through it, as Jordan has shown, into the liver whose duct opens into the posterior end of the ventral part of the lower canal. The particles which can not pass through the filter are carried inward and upward into the middle pyloric canal. 24. The posterior lateral intermediate plate is an irregular calci- fication which lies between the middle and posterior intermediate pyloric plates and the lateral pyloric valve. It faces the corre- sponding side of the septum of the pyloric plate. The Muscles of the Pyloric Sac. The upper constrictor muscle arises from the posterior part of the lower edge of the pyloric ossicle and, passing downward, and slightly forward, is inserted upon the anterior end of the middle intermediate pyloric plate. The lower pyloric constrictor muscle arises from the middle dorsal pyloric plate and, its fibers converging, is inserted upon the middle intermediate pyloric plate behind the preceding. The lateral pyloric constrictor muscle is a short, broad muscle which extends from the concave anterior surface of the middle inter- REPORT OF COMMISSIONERS OF INLAND FISHERIES. 167 mediate pyloric plate to the corresponding edge of the lower inter- mediate pyloric plate. The inferior pyloric dilator muscle has a double origin and a double insertion. One head arises from the cephalic apodeme near the ceso- phagus; the other head arises from the lower ventro-lateral cardiac bar. These bands, passing backward, unite, and then the muscle divides: One branch is inserted on the anterior surface of the lower intermediate pyloric bar; the other, uniting with the corresponding muscle from the other side, is inserted upon the median portion of the ventral pyloric plate. Before attempting to explain the action of this extremely com- plicated stomach it is well to summarize briefly the facts described in detail above. The bristles of the cardiac sac are all directed toward the gastric mill with the apparent exception that those of the lower part of the side walls are directed downward and backward. All the bristles of the pyloric sac except those of the lower and middle canals are also directed toward the gastric mill. The alternate contraction and expansion of the anterior, posterior, and postero-lateral gastric muscles (assisted feebly by the cardio- pyloric muscle and the elasticity of the stomach wall) cause the median tooth to move back and forth across the surfaces of the lateral teeth and also cause the lateral teeth to move inward. | The contraction of the lower lateral constrictor pushes the lower lateral pad inward and backward. The cardio-pyloric valve is practically hinged upon the posterior ends of the ventro-lateral cardiac bars, and we believe that it is driven forward and upward by the contraction of the upper and middle lateral cardiac constrictors. Again, we must remember that the upper cardiac canal leads along the base of the cardiac sac to the beginning of the lower pyloric canal. This canal passes along the base of the pyloric sac to the lateral pouches, where the coarser particles of the food are separated from the remainder. 168 REPORT OF COMMISSIONERS OF INLAND FISHERIES. Finally, we maintain that particles between plates which move back and forth on one another, and which are covered with bristles all inclined in one direction, will invariably be carried in the direction of the inclination of the bristles. If this be so, the modus operandi of the stomach is as follows: (Plate III, Fig. 3) Food entering the stomach is retained by the cesophageal valve and is carried backward and upward between the lateral plates, the lower and middle lateral pads, and the cardio-pyloric valve to the gastric mill: Here it is partly comminuted and the greater part of it is carried forward by the median tooth; some of it, however, is carried into the pylorie chambers, and the fluids with minute particles of food filter backward and forward from the chambers into the upper and middle canals. The food entering the middle canal is carried backward between the lateral valves to the gut. That entering the upper canal is carried through it into the intestinal cecum. The larger particles of food are retained by the marginal bristles of the middle pyloric chamber, and the upward sweep of the bristles upon the posterior lobe of the cardio-pyloric valve carries them again to the mill. The larger portion of the food and that containing large pieces is retained in the cardiac sac, and the fluids with small particles of food percolate down- ward into the ventral part of the sac and are drawn by the inward and outward movements of the upper and lower ventro-lateral cardiac bars into one of the lower cardiac canals. From this canal the finest particles pass into the upper cardiac canal and through it into the mouth of the lower pyloric canal. The food passes through this canal into the lateral pouch where it is subjected to a final sifting, the most minute parts and the fluids pass down through the sieve into the liver, while the less minute particles are carried upward into the middle pyloric canal and through it into the gut. Thus four streams of food material enter the intestine: 1. Two streams from the right and left branches of the dorsal pyloric canal. These pass outward around the posterior dorsal pyloric plate and the base of the dorsal valve into the capacious intestinal cecum. REPORT OF COMMISSIONERS OF INLAND FISHERIES. 169 2. A stream from the middle pyloric canal. This contains the rejected material from the lateral pouch and is probably formed almost wholly by that material. Bristles from five to fifteen mm. long are the only large objects which we have found in the pyloric sac. These pass through the lower chamber and the middle canal. It is possible, however, that the relaxation of the constrictor muscles may allow relatively large objects to pass through the sae. 3. A stream from the lower canal. This contains the greater part of the material brought into the pyloric sac by the upper cardiac canal. In addition, it doubtless contains a portion of the fluids which enter the pyloric sac through the upper and lower chamber °* and which gravitate into the canal. The coarser particles are re- moved from the lower canal by the sieve of the lateral pouch and are carried into the middle canal. This lower stream of food enters the lobes of the liver and is there, in part at least, digested and absorbed. The view of the function of the stomach which is here presented is in radical disagreement with the common explanation which, without accounting for the final disposition of particles caught by the bristles of the pyloric sac, regards the sac merely as a filter. It is in slight disagreement with the admirable work of Jordan who failed to discover the cardiac canals and so was led to believe that the food stream entered the lateral pouches from the middle canal. The Stomach of Larval Lobsters. The stomach of lobsters of the fourth stage is like that of the adult. The less strongly calcified plates of the adult, for example, the anterior lateral, the upper intermediate, and lower intermediate cardiac bars, and the anterior dorso-lateral cardiac plate, are not recognizable in the stomachs of the earlier stages which have the adult form. The stomachs of lobsters of the first, second, and thirdestages (the larval stages) have the same general form and musculature (extrinsic and intrinsic) as the adult stomach. These stages are unlike the adult in the following important points: 22 170 REPORT OF COMMISSIONERS OF INLAND FISHERIES. 1. The gastrolith is not present. 2. Calcifications of the stomach wall are entirely lacking and the gastric “ossicles” ate formed entirely by thickenings of chitin. 3. The dorsal cardiac plate is covered internally with sparsely arranged pairs of slender bristles and extends laterally over a large part of the areas on the sides of the stomach occupied in the adult by the gastroliths. 4. The gastric mill differs more or less fundamentally from that of the adult. The upper and lower cardiac canals, the cardio-pyloric valve, the lower pyloric canal, and the pyloric valves, which are the most essen- tial structures of the stomach, retain through all stages the same form and relationship. The Stomach of the Third-Stage Lobster. (Plate VII, Fig. 11.) The stomach of the third-stage lobster is the first of the series in which the gastric mill appears. The median tooth is comparatively small.and ends in a round median knob and a pair of lateral cusps which remind one of the bilobed form of the median tooth of Astacus. The anterior dorsal and posterior do:sal pads are united in a single large lateral pad covered with backwardly directed bristles. The lateral tooth appears with its accessory cusp and with the general form of the adult tooth. The infero-lateral tooth is also present and has one large and one small cusp. The middle and lower cardiac pads have the same form as in the adult. The ventral surface of the cardiac sac of the stomach of this, and also of the first, second, and fourth-stage lobsters, unlike that of the adult, is covered with small brushes of bristles. The simplest of these (Plate V, Fig. 5 A) consists of two parallel bristles, and the more complete brushes have three, four, or more bristles which are inserted upon a slightly crescentic ridge. The bristles which separate the upper and lower cardiac canals in the stomach of this and of the first and second stages are round and are not plumose. The cardio- REPORT OF COMMISSIONERS OF INLAND FISHERIES. 171 pyloric valve is relatively higher, it lacks the posterior lobe, and it is armed with long heavy bristles. The Stomach of the Second—Stage Lobster. (Plate IX, Fig. 15.) The stomach of the second-stage lobster (and of the first) lacks the median, lateral, and infero-lateral teeth. In the place of the first, there is a high grooved projection from the dorsal wall of the stomach. This is very much like the cardio-pyloric valve, and we will call it the dorsal cardio-pyloric valve. Its sharp edge bears a row of long heavy serrate spines which point downward and forward. The cardio-pyloric valve is high and is similarly armed. Between the cardio-pyloric and the dorsal cardio-pyloric valves, on each side of the stomach, there is a long (partly double) row of bristles like those of the cardio-pyloric valve, but directed inward and backward. The postero-lateral gastric muscle is inserted upon the plate of chitin which supports this row of spines. The pyloric sac seems to be divided into a broad upper, and a lower canal. All the bristles of the sac are directed backward. The Stomach oj the First-Stage Lobster. (Plate X, Fig. 16.) The stomach of the first-stage lobster is like that of the second- stage lobster, except that it is more nearly tubular and that it has thinner walls and fewer bristles. In conclusion, we wish to call attention to the following facts: 1. That while the gastric mill of the adult is a grinding and crush- ing organ, that of the first and second-stage lobsters is a tearing and shredding organ. 2. That the lower pyloric canal, the lateral pouch, and the two cardiac canals remain throughout the whole metamorphosis essen- tially unchanged, and that their persistence is suggestive of their importance. 72 REPORT OF COMMISSIONERS OF INLAND FISHERIES, THE GASTROLITH. (Plate V, Fig. 5, and Plate VI, Figs. 7 and 8.) The gastrolith is an irregular triangularly-ovate plate of lime, formed of numerous angular prisms that extend from the epithelium of the stomach wall to a plate of chitin which lines the stomach and which is secreted early in the period between two molts by the epithe- lium which later produces the gastrolith. Each prism appears first as a dise in the center of an irregular shallow pit in the secretory epithelium and gradually is pushed inward until it becomes a slender irregular prism whose inner and outer ends are rounded. These prisms increase in size until they fit snugly together and their rounded ends give the surfaces of the gastrolith a knobbed appearance. The gastrolith becomes quite thick before the molt (one-quarter of an inch in a lobster 11 inches long [Herrick], .5 mm. in a fourth-stage lobster). After the molt the gastrolith falls into the lumen of the stomach, is broken up, and dissolved in a few hours. Two rival theories of the function of the gastrolith are widely known, and we will present a third theory which is a modification of the older of the two theories in accordance with some newly dis- covered facts. The older theory regards the gastroliths as a mass of mineral matter reserved when the old shell is cast for the hardening of the new shell. The objection offered to this theory is that the gastroliths are entirely too small to be effective for this purpose, Herrick suggests that the gastroliths are formed by the deposition of the lime absorbed from the shell in preparation for the molt and that they have no further important function than to remove a temporary excess of lime from the blood. Thanks to the courtesy of the Commission of Inland Fisheries, we had at our disposal last summer a large number of larval lobsters of known age. We found that the gastroliths do not appear in the first three stages, nor would we expect mineral matter in the wall of the stomach REPORT OF COMMISSIONERS OF INLAND FISHERIES. 173 when absent from the skeleton generally as is the case in these larval lobsters. We found that the older fourth-stage lobsters, and also fifth-stage and older lobsters, have gastroliths. This observation is suggestive because it shows that the gastroliths appear in conjunc- tion with the limy skeleton, since the fourth is the first stage in which the lobster has a calcareous skeleton. So far as we know, the gas- troliths have not been found before in lobsters smaller than 74 inches. We determined to discover, if possible, the time of appearance, the rate of growth, and the rapidity of solution of the gastroliths in fourth and early fifth-stage lobsters. At the beginning of our observations for this purpose we had about 500 fourth-stage lobsters which molted from the third stage on the night of August 7 and 8. Mr. Emmel, who obtained these lobsters for experiments on regeneration, and to whom we are indebted for the opportunity to perform this collateral experiment, isolated a number of these in bottles and fed them daily as controls. After removing a number of others for mutilation, the remaining lobsters were kept in a large receptacle and fed daily. The controls began to molt on the eighth day, but the molting of the reserve supply was delayed until the eleventh or twelfth day. We examined the stomachs of several lobsters each day, and found that the gastroliths appeared on the fourth day—that is, the gas- troliths begin to be formed in the middle, or at the beginning of the middle third, of the eight to twelve day period. At the periphery of the ovately-triangular area, which is finally covered to a considerable thickness by the gastrolith, the calcifi- cation begins with the formation of irregular discs which are thick at the edge and thinner toward the center of the gastrolith where at first each disc is undefined, but later has a definite edge which, for a long time, is markedly thinner than the outer edge. The ealci- fication proceeds by the thickening of the peripheral discs, by the addition of central discs, and by the gradual expansion of all the 174 REPORT OF COMMISSIONERS OF INLAND FISHERIES. dises until they unite and so form the gastrolith. Each disc become one of the prisms of the gastrolith. On the fifth and on subsequent days, the gastrolith was perceptibly thicker and more complete up to the eighth day, after which we did not observe any increase in size, although the growth probably continued. After the molt we found that the gastroliths are dissolved within a few hours and that they may either remain in situ or fall into the lumen of the stomach and be broken up during the process of disso- lution. There proceeds pari passu with the dissolution of the gastroliths a hardening of the gastric teeth, of the mandibles, and then of the chelipeds and abdominal tergites. As soon as the gastroliths are dissolved the lobster attacks his cast, beginning to eat the bristles and small parts and proceeding to devour more or less of the harder parts. The newly molted lobsters seldom seriously attack their sloughs within three or four hours, and generally eat the greater part of the cast within twelve or eighteen hours. These observations do not in the least contradict those of other workers, but merely extend into a new field. They suggest the following conclusions, which are somewhat contradictory to Her- rick’s theory of the function of the gastrolith. It seems improbable that the preparation for the molt, by a soften- ing of the shell and by a corresponding deposition in the gastrolith of the excess of lime from the blood, begins at or before the middle of the period between the molts. The hardening of the gastric teeth and mandibles before any other skeletal structures, the hardening of the chelipeds, and the subse- quent eating of the shell contribute to make us believe that the gastroliths are a supply of lime reserved for the hardening of these structures so that the relatively vast supply of mineral matter in the cast and in other shells may be made available quickly for the hardening of the new shell. REPORT OF COMMISSIONERS OF INLAND FISHERIES. 175 THE FOOD OF LARVAL AND YOUNG LOBSTERS. The lobsters used for the work recorded here were taken from the large hatching bags of the Wickford Station in July and August of last year. The eggs were hatching rapidly at the time, and for this reason the lobsters in each bag were nearly of the same age. The lobsters were taken from the bags for examination at different times and on different days, so as to avoid as far as possible accidental factors. 2 It is the rule of the station to put a generous supply of finely chopped clams into each bag every three hours, and hence we may infer that food other than particles of clam was taken, at least in the majority of cases, in preference to the clam. Each lot of lobsters is started in a clean bag, but organisms drawn into the bag through the bottom window seem unable or unwilling to escape, probably because the rotatory current is much stronger than the radial, outgoing, current,and soon a mass of plants and animals is crowded into the bag. The alge and sessile diatoms attach themselves to strings of clam cuticle which is not usually eaten by the lobster, or to other fibrous matter, and sooner or later the colonies become attached to the bag and, with the tubes of annelids and amphipods, form a dense moss-like coating upon the bag. The following forms were found in the bags or upon their walls: Acartia tonsa, very abundant. Centropages hamatus, very abundant. Amphipods, very abundant. Harpacticus chelifer. Diosaccus tenuicornis. Balanus eburneus, very abundant at times. Loxomacha impressa. Decapod larv (crabs, shrimps ?). Many larval and young gastropods and bivalves. Caprella geometrica, abundant. 176 REPORT OF COMMISSIONERS OF INLAND FISHERIES. Larval Polydora ciliatum and other larval worms. Many nauplii. Striatella. Melosira. Grammatophora. Schizonema, Non-colonial diatoms. Young alge, red and brown. The stomach and intestine were dissected from each lobster, teased on a slide, and examined. The stomachs and intestine of all lobsters except those of very young first-stage lobsters contained a number of diatoms which do not seem to be taken as food, but merely because it is impossible to avoid these omnipresent organisms. The lobsters examined were taken at random, except that very dark colored lobsters (shedders) were avoided because, as Mr. Emmel has shown, these do not eat at all for some time before the molt. One hundred lobsters, twenty-five from each of the first four stages, were examined, and the results are presented in the appended table. In presenting this table we must mention the fact that, while particles of clam and small animals lacking hard parts may readily have failed to be recognized, the characteristic scales, trachee, wings, and compound eyes of insects are readily and positively recog- nized: moreover, the fifth limbs, spermatophores, and the antenne of copepods are so characteristic that three species were positively identified, 2. e., Acartia tonsa, Centropages hamatus, and Harpacti- cus chelifer. REPORT OF COMMISSIONERS OF INLAND FISHERIES. 177 * Taspite SHOWING THE CONTENTS OF THE STOMACH OF ONE HuNDRED LARVAL AND FouRTH-STAGE LOBSTERS. STAGE. 1st. 2d. 3d. 4th. Tora. IOV ao aoa me oO DD OD DOGO OG 17 3 1 Ui 28 Wath copepodst ss ac15... (005 19 13 3 37% Per cent. with copepods..... 76 52 12 37 MEOW SLATE itso se evel aucter aisle el oisie 1 Il Se 1 3 ALOMIS SAC ie criel en aes Few. All. All Nearly all.) 3. aaceee™ CIN sb Sod fond Dore POeeaoe 0 Lee, 0 7 8 LNEOO Gio 6 Sts beG SOO H Garp ere 60 |O Ceiepeeee ace fastentc rey Ce eel thins EEG 4 Clniha cu aren oaeted co oplco.e 10] GSS Cree OG (eae ia Orne RAL D Waters chy s)e'ig 30: het Rok Metens Unrecognizable matter...... i 2 5 i) 11 *One decapod larva; 1 amphipod ?. The number of copepods found in the stomachs of the second and third-stage lobsters is very surprising, and, although it must be taken in connection with the fact that copepods swarm in the bags, it seems to indicate that these larve prefer live copepods to dead clams. The absence of parts of larval lobsters is quite astonishing, in view of the well-known omnivorousness and cannibalism of lobsters, and we believe that this indicates that a lobster in the presence of abundant food will not attack his kind. In this connection one record is particularly interesting: a number of fourth-stage lobsters which had not been fed for several hours were examined and the stomachs were empty or contained masses of the cuticle of the clam which is regularly rejected by the lobster. Moreover, some of these . hungry lobsters left in a finger bowl did not attack one another, 7. e., lobsters hungry enough to eat what they ordinarily refuse will not attack one another (unless, perhaps, one or more of the number.is newly molted). The insects eaten are found floating on the water, sometimes alive, for we saw a full grown cricket fall into a tub containing fourth-stage 23 178 REPORT OF COMMISSIONERS OF INLAND FISHERIES. lobsters, and, despite its struggles, it was soon dragged under, dis- membered, and eaten by a swarm of lobsters. WORKS REFERRED TO. AuBert F.—“Das Kaugerust der Dekapoden.” Zeit. j. wiss. zodl., 39, pp. 444-536. 1884. JorpAN, H.—‘ Die Verdauung & der Verdauungsapparat des Fluss- krebses.”’ Arch. ges. physiol., 101, pp. 263-310. 1904. Herrick, F. H.—‘The American Lobster.” Bull. U. S. Fish Comm. 1895. Huxuey, T. H.—“The Crayfish.” New York, 1888. Parker, T. J.—“On the Stomach of the Freshwater Crayfish.” Jour. of anat. & physiol., 11, pp. 54-60. 1876. EXPLANATION OF PLATES. Plate I, Fig. 1. Stomach of the lobster. x 4. oe II, ‘* 2. Median section of the stomach. x 4. “Y III, “ 3. Diagram showing the course of food in the stomach. ee IV, ‘. 4. The ossicles of the stomach. x 4. V, “ 5. Stomach of fourth-stage lobster. xi. ; “« «6. Ventral surface of the pyloric sac. x 8. oy VI, “ 7. Gastrolith of a fourth-stage lobster four days after the molt. VI, “ 8. Gastrolith of a fourth-stage lobster eight days after the molt. x 20. i “« «9. Section through the gastrolithic plate of a fourth-stage lobster just before the molt. x 260. a “10. Cross section through the middle of the lower part of the cardiac sac. x 14. “VII, “ 11. Floor of the stomach of the third-stage lobster. x 57. " “12. Roof of the stomach of a fourth-stage lobster. x 27. “VIII, “ 13. Cross section through the posterior part of the pyloric sac of a fourth-stage lobster just before the molt. x 27. ze YY 14. Stomach of a third-stage lobster. x 20. A. Lateral tooth. x 57. B. Median tooth. x 57. REPORT OF COMMISSIONERS OF INLAND FISHERIES. 179 Plate IX, Fig. 15. Stomach of a second-stage lobster. as X, “ 16. Stomach of a first-stage lobster. 1. Cardiac ossicle or anterior dorsal cardiac plate. 1’. Posterior part of above plate. 2. Urocardiac ossicle or posterior dorsal cardiac plate. 3. The prepyloric ossicle or median tooth. 4. Pyloric ossicle or anterior dorsal pyloric plate. 5. Pterocardiac ossicle or anterior dorso-lateral cardiac plate. 6. Zygocardiac ossicle or lateral tooth. 6’. Lateral bristle plate of larval stomach. . Anterior dorso-lateral pyloric plate. 8. Gastrolithic bar. 9. Accessory lateral cardiac ossicle or upper intermediate cardiac bar. 10. Infero-lateral tooth. 11. Lower intermediate cardiac bar. 12. Upper ventro-lateral cardiac bar. 13. Antero-lateral cardiac bar. 14. Lower ventro-lateral cardiac bar. 15. Ventral cardiac plate. 16. Posterior intermediate cardiac bar. 17. The middle dorsal pyloric plate. 18. The posterior dorsal pyloric plate. 19. The upper intermediate pyloric plate. 20. The posterior intermediate pyloric plate. 21. The middle intermediate pyloric plate. 22. The lower intermediate pyloric plate. 23. The ventral pyloric plate. 24. The posterior lateral intermediate pyloric plate. A’ The lower lateral dilator. A.D. Lower anterior dilator. A.D.’ Anterior dilator. A.P. Posterior dorsal pad. C. Lateral pyloric pouch. C.M. Intestinal cecum. C.C. Partition of bristles between the upper and lower ¢ardiac canals. C.P. Cardio-pyloric valve. C.P.’ The dorsal cardio-pyloric valve. Dp: Dorsal pyloric valve. D.C. The upper pyloric canal. D.P. Posterior dorsal pad. 180 REPORT OF COMMISSIONERS OF INLAND FISHERIES. E. (Esophagus. i’. The median valve of the cesophagus. G. Gastrolith. Ge The gastrolithic epithelium. Ei The hepatic duct. Te The intestine. L. Lateral pyloric valve. L.C. Lower pyloric chamber. L.D. Lateral dilator. L.G. Postero-lateral gastric muscle. L.P. Lower cardiac pad. L.P’. Lower pyloric pad. L.T. Lateral tooth. M. Upper cardiac canal. M.C. Middle pyloric canal. M.P. Middle cardiac pad. N. Lower cardiac canal. P.G. Posterior gastric muscle. Q. Posterior opening of the upper cardiac canal. R Upper cardiac constrictor. S. Middle cardiac constrictor. S.D. Superior dilator. dis Lower cardiac constrictor. U.P. Upper lateral cardiac pad. U.P’. Upper pyloric pad. We Ventral pyloric valve. Wi. Septum between middle pyloric and lower pyloric canals. V.C. Lower pyloric canal. V.C’. Ventral portion of the lower pyloric canal. V.D. Ventral dilator. V.E. Vascular epithelium. Connective tissue wall of stomach. Ww NE Upper pyloric constrictor. ry Lower pyloric constrictor. Z Lateral pyloric ‘constrictor. PuatTe IX, Fig. 15.—Stomach of a second-stage lobster. x 44. PLATE X. Fig. 16. Stomach of a first-stage lobster. x 57. Prats J. Fig. 1.—Stomach of an adult lobster. x 4, ‘FX “F[NpB sy} Jo yowurojzs oY} Jo 10L1e}U,—'*z “B27 TI GLvVIg ‘1a1SqO] EY} JO YOVUIOYS AY} Ul POO} Jo asanoo ayy Burmoys weissiq—'g ‘bry TI] @iv1g $x “T9ISCOT 9G JO TYORUIOJsS 9} JO SapoIsso 9} SUTMOYS WUBI Bl. —' P BUT "AI Givig --7 ee. FIG, 6 PuatTe V. Fig. 5.—Stomach of a fourth-stage lobster. x 11. Fig. 6.— Ventral surface of the carding portion of an adult lobster. x 6. None as ae bots as aie SoS 262A ieee SES AY UR a Be TSBs J, errant, FIG. 10 Puate VI. Fig. 7.—Gastrolith of a fourth-stage lobster, five days after the molt. x 20. Fig. 8—Gastrolith of a fourth-stage lobster eight days after the molt. Fig. 9.—Section through the gastrolithiec plate of a fourth-stage lobster killed a short time before the molt to the fifth stage. x 260. Fig. 10.—Section through the base of the cardiac portion of the stomach of an adult lobster, a short distance in front of the cardio-pyloric valve. x 6. 1@ X “19}SQOT 9HR4S-YJANOJ B JO YoRuIojs oy} Jo [[VM add yQ—ZI “buy “LG X “194SQO] 9BBJS-Paly] BV JO YoORVUIo}s 9Y} JO [TBM 1aMOT— TT] “biy TIA SivIg Ot 2 ae Se 4 ij Bsekesy “GIT X ‘Y}00} VIDIBT -“q “GILT X ‘“Wjooj,uvipey “y ‘Op X “1e}SQOT 95v4S-pily} BJO YORuUlojyS— fF] Puy ‘2% X ‘eBBIS YIJY OY} O} J[OUI OY} aIOJoq aUIT) JOYS B ‘19}sqo] eBBIs-GJANOF B JO UOTZI0d awofAd ay} YRnoiyy uotjooes osiaasuvsiy— Ee] “U7 MG Cae Ata re CONTINUED OBSERVATIONS ON SOME INFLUENCES OF LIGHT UPON THE LARVAL AND EARLY ADOLESCENT STAGES OF THE AMERICAN LOBSTER. CONTINUED REPORT. BY PHILIP B. HADLEY. BROWN UNIVERSITY, PROVIDENCE, R. I. The advantage of investigating the influences of light upon the lobster in the early stages of development has been mentioned by the writer in an earlier report.* The. present paper is presented with the purpose of giving the results of continued investigation on the reactions of the larval and early adolescent lobsters to light; and with the view of applying the facts thereby gained to the explanation of certain phases of the behavior of the young lobsters when they are under natural condi- tions of environment. This study of the reaction to light naturally divides itself into two parts: First, the reactions proper (positive or negative to the in- tensity or to the directive influence of the light) ; secondly, what may be called the mechanics of reaction. The first of these two heads is subdivided into (1) the study of the photopathic reactions (the reactions to the intensity of light), and (2) the phototactic reactions (the reaction to the directive influence of the light rays). We may first limit our discussion to a consideration of the reactions proper, and then turn our attention to the second phase of the question, the mechanics of reaction. *Report of the Rhode Island Commission of Inland Fisheries for 1905. 182 REPORT OF COMMISSIONERS OF INLAND FISHERIES. I. Tse REAcTIONS. Reactions to Light.—In the discussion of this problem it will be found of advantage not to separate our considerations of photopathy and phototaxis. It is still a problem among students of animal behavior, whether these two kinds of response are actually different, or are one and the same form of reaction. Many facts demonstrate that they are really different, and that, although the phototactic reactions do depend upon a certain optimum intensity of light, still the re- action of organisms may be brought about sometimes by one and sometimes by the other of these two factors. Indeed we shall find in the case of the larval lobsters, that they may be either photo- pathic or phototactic; moreover, that positive photopathy is not necessarily associated with positive phototaxis, nor negative photo- pathy with negative phototaxis, but that one form of reaction may be positive, while the other is at the same time negative, and vice versa. Yet, in view of the differences of opinion regarding what consti- tutes a phototactic and what a photopathic reaction, it is perhaps advisable to state more definitely just what meaning is given these terms as they are used in the following pages. In other words, how shall we differentiate between the intensity of light and the directive influence of the light rays. It is hardly to be doubted that the direction, per se, of the rays has no influence upon the movements of organisms, other than that it determines what side of the organism shall receive light of greater intensity. For this reason in the present article, the term directive influence of light has no other meaning than that the light coming from a certain direction strikes the eyes of the organism and, by virtue of the unequal illumination, brings about a constant form of response manifested by the turning of the organism in one direction or another. In the following pages, then, a photo- tactic response (which necessarily involves both a body orientation and a progressive orientation) will be conceived of as a reaction in which the organism tends to place the longitudinal axis of the body in a REPORT OF COMMISSIONERS OF INLAND FISHERIES. 183 certain definite relation to the direction oj the rays of light, and to move toward or away from source of those rays. But what, then, is the nature of the so-called photopathic reaction? It seems probable that, as Yerkes* has suggested, a photopathic reaction is one in which an organism “selects a particular intensity of light and confines its movements to the region illuminated by that intensity.” This type of reaction constitutes what will be con- sidered in the following pages as the photopathic response, whether or not it is brought about through a series of phototactic reactions as Yerkes believed to be the case for Daphnia. Thus, to restate, it will be assumed that a photopathic reaction is one in which an organism, without previous assumption of a body orientation to the direction of the rays of light, selects a region of a certain optimal light intensity. It is hoped that continued investigations may throw further light on the problem of the manner in which light brings about the pro- gressive orientation in one direction or another; also on the method by which the reaction, here assumed to be photopathic, is produced (if so) without the previous assumption of a body orientation to the direction of the light rays. It seems extremely probable that the behavior of the larval and early adolescent stages of the lobster is determined in a large measure by both kinds of response. Indeed the relation between phototaxis and photopathy appears to be a very intimate one, and we can not study one without taking the other into careful consideration. Therefore in the following pages it will be found advantageous to examine both the photopathic and the phototactic reactions in more or less close connection, that we may understand, not only their individual and separate, but also their mutual and combined, effect upon the behavior of the larval lobsters. Method and Apparatus.—The experiments which are to be reported involved the use of the apparatus mentioned below: (1) Cylindrical museum jars, 20 to 25 centimeters in diameter. These were used in *Reactions of Daphnia pulee to Light and Heat, reprinted from the Mark Anniversary Volume, 1903, Article X VIII, pp. 359-377. 184 REPORT OF COMMISSIONERS OF INLAND FISHERIES. studying the reaction of large groups of larve which were placed therein. The conditions of light were modified either by using screens of black paper over one side of the jars, or by placing the jars on a black or a white background. (2) Glass tubes. These were for the most part straight glass tubes sealed with glass at each end. These varied in length from 18 to 40 centimeters, and in diameter from 2 to 4 centimeters. Other tubes were Y-shaped and were constructed of glass tubing 3 centimeters in diameter. The horns were 8, the stem 10, centimeters in length. The straight variety of tube was used in various ways to test both the photopathice and the phototactic reactions, under different conditions of light, background, etc. The Y-tubes were used for a similar purpose and also to test the reaction to different intensities of light. In this case sometimes colored glass plates of different intensities were laid over the horns, and sometimes the horns were laid over backgrounds of black or | white. It was under the conditions last mentioned that some of the relations of photopathy to phototaxis were best studied. (3) Wooden boxes supplied with glass bottoms, glass slides, or glass ends. These boxes were 12 by 6 by 6 inches, painted black on the inside, and fitted with light-tight covers. They also were used for testing the photopathic and phototactic reactions either separately or in combination. In the latter case the glass-bottomed box was set up over a hollow tube or shaft, through which the light was reflected from a mirror, or from a plane, white surface at the bottom of the shaft. Just beneath the glass bottom of the box was ranged a linear series of monochromatic glass plates, — red, orange, green, and blue, by means of which the intensity of light entering the bottom of the box could be regulated. But light could also enter the box through the end windows, and pass through the box lengthwise. By this arrangement the larve, when they were placed in the box, could be subjected to two light influences: One the light from below; the other, the horizontal rays entering the end window of the box. By these conditions of experiment it was possible to secure reactions both to the intensity and to the directive REPORT OF COMMISSIONERS OF INLAND FISHERIES. 185 influence of the light rays, and to learn which reaction was more instrumental in determining the final reaction of the larve. (4) The last piece of apparatus to be mentioned was a rectangular glass box 6 by 3 by 2 inches. This was used especially in studying the mechanies of reaction in the case of isolated individuals. For illu- mination, daylight (reduced to varying intensities by graded wedge sereens of colored gelatin, or colored glass plates) was used in most of the experiments. In some cases, however, acetylene lanterns were employed, or, in a few instances, a brilliant oil burner. Experiments involving the use of the various pieces of apparatus mentioned above were performed with young lobsters in the first five stages. Instead of finding a uniform and constant type of reaction for all stages and all individuals, it appeared that the reactions underwent a great modification, not only from stage to stage, but even during a single stage-period. It will not be attempted here to describe in detail all the reactions of the larval lobsters. We shall mention only the general results of a long series of experiments, and attempt to present a clear view of the changes in reaction to light which accompany the metamorphosis of the lobster as it passes on from stage to stage. First Larval Stage. When the photopathic and phototactic reactions of the first-stage larve were first tested, they were both found to be positive; that is to say, the first-stage larva appeared both to “choose” the lights of greater intensity, and to move in the direction of the light rays (in case of the phototactic reaction) toward their source. No phase of their behavior could be more striking than the definiteness of these two forms of reaction to light. And it may be said here that in no period in the later life of the larve is there manifested a type of response so universally invariable as the reaction given by the first- stage larvee within the first few hours after hatching. This universal positive response, both to the intensity and to the 24 186 REPORT OF COMMISSIONERS OF INLAND FISHERIES. directive influence of the light rays, remained unchanged, under nearly all degrees of illumination, for the first 24 to 36 hours of the lobsters’ existence. After this period of time, however, it was usually observed that the first signs of 4 negative reaction began to appear; and that, by the time the larve were two days old, in the majority of instances the negative phototactic reaction had assumed prominence in determining the behavior of the first-stage larve. Even at this time, however, whether the reaction was posi- tive or negative appeared to depend very largely upon the intensity of the light to which the larvee were submitted. It very frequently happened that larvee which gave a very definite positive reaction in light of low intensity, would manifest just as definite a negative reaction when the intensity of the light was augmented beyond a certain point. The negative reaction to daylight was usually main- tained by the first-stage larvee until the approach of the first molting: period. At the approach of the molting period, which usually occurs on the fourth or fifth day of the first stage-period, a return of the positive reaction that had characterized the behavior of the larve during the first two days after hatching was observed. This positive reaction began by a decreasing sensitiveness to lights of greater intensity, and culminated, during the few hours before the molting, in a striking positive reaction even to lights of great intensity. During this change in the phototactic reaction, the photopathic reaction re- mained invariably positive. To summarize the reactions of the first-stage larvee it may be said that: (1) The photopathic reaction remained positive throughout the stage. (2) The phototactic reaction of the larve, aged about 2 days, was definitely positive; but after 2 days it changed to nega- tive, only to return to the positive reaction as the molting period with the second stage approached. (3) The phototactic reaction of first-stage larvee invariably overcame the photopathic reaction, and although any phototactic reaction requires a certain optimum intensity of light, the general behavior of the first-stage larve is REPORT OF COMMISSIONERS OF INLAND FISHERIES. 187 probably determined more by the directive influence of the light rays than by the light intensity. Second Larval Stage. Unlike the first-stage larve just after hatching, the second-stage larvee, just after molting, were found to be more frequently negative than positive in their phototactic reaction. The negative photo- tactic reaction, as in the case of the first-stage larve, was maintained until toward the last of the second stage-period. As the time of molting to the third stage approached, the phototactie reaction commonly changed again to positive. Throughout the second stage- period the photopathic response, as was the case in the first stage- period, remained positive. Generally speaking, the reactions of the larve of the second stage were not as definite and invariable as the reactions of the first-stage larvee. In the second stage-period photo- taxis still appeared to retain the dominating influence over the behavior of the larve; for they could be made at any time to move from a region of less into a region of greater light intensity in order to travel, in the direction of the rays, either to or from their source. Third-Stage Larve. Regarding the behavior of the third-stage larve, it is sufficient to say that, in general, the reactions were similar to those of the second stage. When newly molted from the second stage, these lobsters commonly manifested a negative phototactic reaction, and this reaction endured until toward the end of the third stage-period. Then the reaction usually became definitely positive, even under light of great intensity; and continued so until the larve had again molted and entered the fourth stage. During this third stage-period the photopathic reactions, as was the rule for larve in the first and second stages, remained constantly positive. Thus it was again demonstrated that, in certain periods of the larval stages at least, a positive photopathic might accompany a negative phototactie 188 REPORT OF COMMISSIONERS OF INLAND FISHERIES. reaction. As was also the case in the previous stages, the photo- tactic response appeared to be the dominating factor in determining the behavior of the larve in the third stage, although the reactions of the third-stage larvee were, as a rule, much less definite than the responses of larvee in the earlier stages. Fourth-Stage Lobsters. In the molt from the third to the fourth stage occur the most important changes that the young lobster undergoes in the whole course of his life. These changes appertain not alone to modifica- tion in the body form, morphology, and function of many of the appendages, but also to points of internal structure as well. Among the more general features of the metamorphosis we may enumerate: (1) The loss, in the molt from the third stage, of all functional swim- ming branches on the thoracic appendages. (2) The great develop- ment of the chelipeds and of the first and second pairs of antenne. (3) The accession of functioning swimmerets on the underside of the second, third, fourth, and fifth abdominal segments. (4) A great change in the body form,—and consequently, in the manner of swimming. In view of the importance of these changes which take place when the lobster enters the fourth stage, it is reasonable to expect that they are to have some influence on the behavior of the fourth-stage lobster. And we shall find that, just as a certain change in the nature of the response was shown during the progress of each of the earlier stages, so in the fourth stage, but for different reasons, there is a gradual modification of the manner of reaction as the lobster passes on through the fourth stage and enters the fifth. The phototactic reaction after the molt from the third stage was found to be negative. We have observed that, in the earlier stages, this negative reaction changed to positive as the molting period to the next stage approached. This was not found to be the case in the fourth-stage larve; for, as the stage-period advanced, the photo- REPORT OF COMMISSIONERS OF INLAND FISHERIES. 189 tactic reaction, instead of changing to positive, became only the more strongly negative. The photopathic reaction, on the other hand, which, in the earlier stages, remained positive throughout, was found in the fourth stage-period to undergo a change. While the early fourth-stage lobsters manifested a positive phototactic reaction, this gave place, during the advancing fourth stage-period, to a negative reaction to the intensity of light. This reaction was invariably manifested by the late fourth-stage larvee. One other point of interest in the behavior of the fourth-stage lobster may be noted in the relation between the phototactic and photopathic reactions. We have observed in the earlier stages that the phototactic reaction was dominant over the photopathic, and was largely the controlling factor in determining the behavior. In the fourth-stage lobsters the condition of affairs appeared to be somewhat different. It was found that the photophatic reactions had assumed a greater stability and were not so easily overcome by the phototactic; and, as will be shown subsequently, the photo- pathic reaction assumed a still greater importance in determining the behavior of the fifth-stage lobster. Fijth-Stage Lobsters. The body form of this stage is very similar to that of the fourth- stage larve, and we might therefore expect similar types of reaction. But we shall see that there are differences in behavior, and in this case the points of difference are of such a nature that we cari not attrib- ute them either wholly or in part to changes in body form or in the swimming appendages. But it is undoubtedly the consequence of modifications in the body-processes of the lobsters themselves, and may well be ascribed, perhaps, to changes that have resulted from the cumulative stimulation during the earlier life of the lobsters. Generally speaking, we may say that the reactions of the fifth-stage lobsters were typical of the adult form, and were chiefly characterized by the light-shunning instinct. This form of behavior could be 190 REPORT OF COMMISSIONERS OF INLAND FISHERIES. readily observed by merely watching the lobsters in their confinement cars, but for the sake of certainty the fifth-stage lobsters were sub- mitted to the same form of experiment to which the larve of the earlier stages were submitted. The type of reaction presented in the early fifth stage-period was found to differ in no way from the behavior of the late fifth stage-period; and both were characteristic of the behavior of lobsters in all later stages. To the last subject the writer hopes to give his attention later. Regarding the phototactic reactions of the fifth-stage lobsters, it may be said that they were invariably negative, and differed in no way from the phototactic reaction of the fourth-stage larve,—save that in the former case the reactions were more definite and more strongly manifested. Unlike the photopathic response in the fourth-stage larve, these reactions in the fifth stage were invariably negative from the begin- ning of the stage to the end of it. The photopathie reaction of the fifth-stage lobsters, moreover, was even more stable than in the fourth stage, and it was with some difficulty that a group of fifth- stage lobsters could be driven, by virtue of their negative photo- tactic response, from a region of lesser to a region of greater light intensity. It will be recalled that in the early larval stages the reactions to intensity were invariably subservient to the reactions determined by the directive influence of the light rays. Phototuxis Leading to Fatal Results.—It was interesting to note that the negative phototactic reactions of lobsters in the fourth and fifth stages might often be of so extreme a nature that injury to the larve resulted. In other words, it was frequently observed that, if the box in which the larvze were contained slanted gradually, leaving at one end a region which the salt water did not cover, the lobsters might be so driven, by the influence of the light rays coming from the opposite end of the box, that, as a result of their negative reaction, they would be “stranded” so to speak, on the “shore.” Here they would invariably remain, and in this position they would have perished, rather than turn to face the light and travel into deeper REPORT OF COMMISSIONERS OF INLAND FISHERIES. 191 water, had they not been returned to the water at the end of each successive test. Contact-irritability.—In the preceding section we have considered merely the phototactic and the photopathic reactions, together with some points of their inter-relation. It may now be of interest to examine briefly that response of the lobsters to solid portions of their immediate physical environment which, for the present lack of a better term, we may call contact-irritability. It might reasonably be imagined that the loss of the swimming branches (exopodites) of the thoracic appendages, which takes place with the entrance to the fourth stage, would at once determine a very radical change in the habits of the lobster larve from that time. We might surmise that the larve would at once abandon their pelagic manner of existence and enter at once upon a more sedentary life among the rocks and weeds of the sea bottom. But this is by no means the case, for never in the life history of the lobster do we find them more able and persistent “swimmers” than in the fourth stage of their existence, and just after the loss of those very accessories, without which swimming would have been impos- sible for them in any of the earlier stages. This energetic surface swimming of the fourth-stage larve was evident from many obser- vations. One such case is especially noteworthy. In July a steam launch, of which the captain had lost control, rammed one of the floats which suspended six large hatching bags containing lobsters in various stages. As a result of this accident a very large number of fourth-stage larvee were suddenly liberated in the water about the hatchery. When order had been restored an attempt was made to recover the lost lobsters, and as a result, over five hundred, which were Swimming actively at the surface of the water (fortunately smooth), were picked up by means of scrim nets. When we come to examine the behavior of the fifth-stage lobster under natural conditions, we find very different action. When a number of fifth-stage larve were cast loose in the open water, it was a most interesting sight to observe them swim for a moment, 192 REFORT OF COMMISSIONERS OF INLAND FISHERIES. then, turning head down, disappear for good in:the deeper water,— a great contrast to the behavior of the fourth-stage larve under similar conditions. One other set: of observations may be mentioned, and these refer to the burrowing instinct of the larval lobsters. When early fourth- stage larvee were transferred to glass dishes, on the bottom of which a layer of sand or gravel and a few broken shells had been spread, the larve at first gave no heed to these conditions, but for some days continued to swim as persistently as ever. Finally, however (usually within two or three days after the larve had been placed in the dish), the lobsters began to plough through the sand, especi- ally near the rim of the container, and to construct burrows for themselves beneath shells, stones, or other objects. In the ease of the fifth-stage lobsters, on the other hand, when they were intro- duced into the dishes containing sand, gravel, and shells, they com- menced this burrowing at once; and when the burrows were com- pleted the lobsters showed a much greater tendency to remain therein than did the fourth-stage larve under similar conditions. The question now arises, what conditions or factors cause these various types of behavior which have been mentioned above: The energetic surface swimming of the fourth-stage larve, or the bottom- seeking and burrowing habit of the late fourth-stage and the fifth- stage lobsters? Are these reactions to be explained as phototropic reactions, geotropic reactions, response to contact, or do all three of these, and perhaps still other circumstances, unite in determining the final result? We are not yet prepared to venture an answer to these queries. Some experiments were performed, however, in which the choice between a clear and a sand-covered area was offered to lobsters in the fourth and fifth stages, and methods were intro- duced whereby the lobsters which had gathered in either of these regions could be imprisoned there until they were counted. The results of these tests made it apparent that the early fourth-stage lobsters showed but slight, if any, preference for the sanded area. But when this experiment was repeated with the late fourth-stage REPORT OF COMMISSIONERS OF INLAND FISHERIES. 193 larve it usually appeared that a greater number would remain in the sanded region. In the case of the fifth-stage lobsters, moreover, a very definite tendency to remain in contact with the sand, to burrow in it and not to be dislodged, was most clearly manifested. Reactions Determined by Hunger.—Many students of animal be- : havior have learned that the condition of hunger is able to greatly modify the reactions of organisms to many stimuli, especially to food. Generally speaking, it has been found that hunger prevents the manifestation of the normal type of reaction. The effect of hunger upon certain stages of Homarus is no exception to this rule. In this instance, however, the condition of hunger appears to be instru- mental in modifying the reactions of the lobster only in the fourth and later stages. To a certain degree this has an explanation in the fact that the larval lobsters of the first three stages are not able to direct their own activity in a definite direction, as toward food; and it is not until this fourth stage is reached that the lobster is at all the master of its own progress. It was learned in the early part of the investigations on the behavior of the fourth-stage lobsters that, if any study of their reactions to light was to be made, the lobsters must first be fed—and well fed. For, if such was not the case, the tendency to eat one another usually annihilated any possible mani- festation of a response to the influences of light. Even if the condi- tion of hunger did not excite these extreme cannibalistic instincts, it usually produced a manifestation of unrest which made any results, in the way of numerical counts, impossible. As has been shown, the fourth stage-period—at least in the early part—is the “swimming period”’ of the lobster’s existence. It is not until the latter part of the fourth stage-period that the lobster, under proper conditions of environment, goes to the bottom and begins to burrow in the sand or under the bits of shell. Now it was found that the condition of hunger appeared to have a very definite influence upon the time at which the “burrowing instinet”’ was first “liberated.” To ascertain more fully regarding this point several experiments were performed, of which the following is a fair example of all: 25 194 REPORT OF COMMISSIONERS OF INLAND FISHERIES. Influence of Hunger in “ Burrowing”’.—On August 5, about thirty early fourth-stage larvee were taken from one of the confinement bags. They did not show much evidence of hunger, and were there- fore isolated for forty-eight hours without food. At the expiration of this time they all proved to be very hungry. Now two groups of five lobsters each were taken from this lot and each group was placed in a 14 centimeter crystallization dish, the bottom of which was covered with sand, gravel, and shells. Immediately after this one group of lobsters was fed with chopped clam meat, while the other group was left hungry. The dishes were placed on the labora- tory table, and records were taken frequently to determine when the burrowing would be first manifested, and in which group. For some little time both groups swam more or less constantly near the surface. Further records may be presented as follows: TIME. | Grovp Fep. | Group UNFED. | - Aug. 7, 10 TAC EM retatre ore care 1 larva burrowed....:..... | 5 larve swimming or crawling. 7 AAGSO A. Meo te054. cae) ealameee: DNeeR Poe reeleee fore Sat 7h sOsae Ou Saal) emia aimicha, aglhice | cs BP ord. Ne (cs) ; Se Qa Dia) TAM BRE? SINR Soe ox ct eraee eee | 5 9, 9 [hal iO Oeace3|j) Ze) ve a Ne eS ae eb UETOMmed st a6. Get 2? Mi i URNS er a8 | 4 | *At this point one of the five lobsters was killed and eaten by the others, three of which immediately burrowed. These results appear to show that while hunger may postpone the liberation of the burrowing instinct, satiety appears to favor its early appearance. One other experiment, the converse of the pre- vious case, may be introduced: Influence of Food Stimulus upon Surface Swimming in the Fourth- stage Larve.—In this case about twenty larve in the middle and late fourth stage were placed ina 25 centimeter glass jar filled with salt water to a depth of four inches. These lobsters were kept without food until they showed evident signs of hunger. All the larve re- REPORT OF COMMISSIONERS OF INLAND FISHERIES. 195 mained on the clean bottom of the jar, over which they crawled or lightly swam. Occasionally one would come to the surface, only to leave it again for the bottom of the jar. Now a long pipette was partly filled with fresh clam juice,and the outside of it carefully washed to remove all possible trace of clam odor from the surface of the tube. When the lobsters were resting quietly the point of the pipette was slowly lowered to the very bottom of the jar, where a few drops of clam juice were liberated in the vicinity of the resting fourth- stage lobsters. Within afew seconds all the larve in that region rose to the surface of the water,and swam wildly about for a variable length of time. Then they again went to the bottom of the jar. Here they either rested permanently, or, if a sufficient amount of the clam juice remained near the bottom of the jar, the larve, apparently restimu- lated, displayed further surface swimming. These same tests were tried on the fifth-stage lobsters, but, although the clam juice might excite them to more active crawling over the bottom of the jar, it never produced the active surface swimming characteristic of the fourth-stage lobsters under.similar conditions of stimulation. These observations have received further support from facts which the writer has learned from ¥.E.Emmel. It appeared in his experi- ments that the hungry lobsters, when stimulated by a piece of clam meat dropped into their confinement bottles, would not remain on the bottom to enjoy the morsel, but would rise to the surface and manifest active swimming for some moments. These few observa- tions demonstrate clearly that the lobsters, at least of a certain age, respond very definitely to certain kinds of food stimuli. To what extent this kind of reaction may be responsible for the surface swim- ming so characteristic of the early fourth-stage lobster under natural conditions, it is difficult to say. It is not improbable, however, that, after the fast that usually accompanies the approach of the third molting process, the sense of hunger which characterizes the early fourth-stage lobster may be in part the cause of the surface swim- ming, although as has been shown in previous pages the reaction to light is no doubt an influential factor. 196 REPORT OF COMMISSIONERS OF INLAND FISHERIES. Reactions to the Electric Current.*—The study of the reactions of the lobster larve to the electric current was a point of incidental interest during the progress of the experiments on the reactions to light. The current used was that from two to four dry cells, and the exact strength, in the circuit, was never known. The long-applied constant current was not employed, but a more or less interrupted current, the flow of which was seldom permitted for more than four to six seconds. The results are therefore qualitative rather than quantitative. The larve were imprisoned between two glass slides placed vertically, parallel to each other, and about 2.5 centimeters apart in a crystallization dish 10 centimeters in diameter. They were thus confined in a rectangular area formed by the glass slides and the sides of the dish, and between the two electrodes. These were made of zine strips wound with cotton and were hung over the rim of the dish so that they dipped about 1.5 centimeters into the salt water. The current was made, broken, or reversed by a rocking key. Usu- 3 ally the reactions of one larva were tested at a time. The results of the experiments may be briefly stated as follows: (1) The larval lobsters of all ages reacted very definitely to the electric current by gathering at the an8de. (2) Reaction to the current took place only when the tail was directed to the anode, or when the head was directed to the cathode and the back obliquely to the anode. (3) The reaction took place as a result of rapid con- traction and expansions of the abdomen. By this movement the larvee were impelled backward to the anode. This method differed from the mechanics of the reaction to light. (4) Although the ascending electric current, as used, caused a progressive orientation to the anode if the longitudinal axis of the larva came into proper relation with the lines of the current, no current was apparently ever itself instrumental in producing body orientation. (5) The excitations arose and were strongest at the anode. Therefore, the reaction of the lobster larve to the galvanic current does not appear *The writer expects to publish soon the detailed results of his observations on the galvano- tatic reactions of the larval lobsters. REPORT OF COMMISSIONERS OF INLAND FISHERIES. 197 to conform to the main requirements of Pfluger’s law of polar stimu- lation and contraction. Il. Tue MEcHANISM OF REACTION. We now come to a consideration of the mechanism of reaction on the part of the lobster larvee; and we may express the point of our inquiry in the following terms: By what means, or by what movements of the larve are the positive or negative orientations accomplished ? In our effort to answer this question we shall for the present attempt to avoid, so far as possible, all those considerations which deal directly with the ultimate causes of orientation; in other words, we shall limit ourselves to the observation of the actual movement of, the body, or of certain parts of the body, of individual larve; and attempt to show what relation exists between these movements and the internal or external factors which appear to determine them. Thus it is merely a matter of convenience that we divide these con- ditions which may determine or modify the behavior of the larve into the internal and the external factors. Among the former we may include the cumulative effect of all previously acting stimuli; among the latter we may consider the conditions of environment which act directly upon the organism to cause an immediate response. It is the effect of the latter in producing certain kinds of movements of the larve as a whole, or of their parts, that we are now ready to consider. First, however, we must establish some points regarding the natural behavior of the larve when the reaction to the external stimuli is at the minimum. The Normal Behavior of the Larve.—Obviously enough we should not be able to recognize certain forms of reaction in the lobster larve, did we not first have some knowledge regarding what we may call the normal type of behavior. There will be recognized a certain point of difficulty in establishing this basis. What do we mean by natural or normal behavior? Whatever answer may be given to this question where the higher animals or man are concerned, for our 198 REPORT OF COMMISSIONERS OF INLAND FISHERIES. present purpose we may conceive of normal behavior as that type of action which is present when the response to exaggerated or unusual conditions of stimulation is at its minimum. In view of the fact that swimming constitutes the chief activity of the larval lobsters, our question resolves itself into the following: What is the nature oj the normal swimming? When one first observes the behavior of individual larve among the thousands contained in the large hatching bags, no difference is evident in the swimming of those in the first three stages. In all instances the back of the larva is, for the most part, uppermost, the abdomen bent under and downward at an angle of about 60 degrees from the longitudinal axis of the cephalo-thorax, which in turn is inclined at about 30 degrees from the horizontal plane. In daylight this position may occasionally be maintained without modification for several minutes, but the equilibrium is frequently disturbed by other body movements, which, upon superficial observation, appear to be of a most diverse and ill-ordered nature. There are leanings, turnings, fallings, somersaults, revolutions, and rotations, which follow one another in no apparently definite sequence, and which disturb the general equilibrium either greatly or slightly as the case may be. Whether the balanced equilibrium, the devious rotations, or other activities, be in effect, the exopodites, or swimming attachments of the thoracic appendages, beat the water more or less constantly with short vibratory strokes, sometimes lifting the larve high, toward the surface, and again allowing them to sink to the bottom where they may frequently lie for some moments almost motionless, only to resume again immediately their varied activity. Now they swim forward, now backward, now they lurch to the side, now to the rear, always maintaining more or less energetically this series of apparently aimless activities. Such is the nature of the swimming in daylight or other brilliant illumination; and for our purpose it can not be called the normal swimming of the lobster larve. It is only under special conditions that the latter may be observed; and, in view of REPORT OF COMMISSIONERS OF INLAND FISHERIES. 199 the fact that it is the conditions of light which influence, more strongly than any other factors, the behavior of the larve, it is under certain light conditions that we may expect to find manifested what we may call the characteristic or normal swimming. It is the twilight, or nocturnal, swimming of the larval lobsters which invariably presents the fairest example of natural behavior. It is at such times alone, or when the larve are submitted to arti- ficially produced twilight, that the multiplicity of conflicting cross- light influences are most nearly eliminated from the amphitheatre; and whatever sort of swimming or other reactions are then mani- fested can be said to represent most truly and most exclusively those influences which arise from the physiological states themselves, independent of stimulation from without. In many instances, when the twilight was so dim that the activities of the larve could with difficulty be discerned, the writer thas observed that the swimming was delicate and regular. The young larve would mount up, bird- like, to the surface water, and often hover for many seconds in a single position, or swim backward or forward with equal ease— perfect masters of their own activity. In case, at such times, even a lighted match should be brought near the side of the jar in which the larve were confined, the same restless and uncertain swimming, characteristic of the diurnal activities, would again be manifested, with the accompanying leanings and rotations. From these facts we may assume that the twilight swimming of the larve probably represents most accurately the natural behavior; and that the peculiar antics, characteristic of the daylight swimming, represent an unusual type of behavior, due to the action of conflicting external stimuli. The question now naturally arises, do the various turnings and rotations, leanings, and fallings, which constitute the apparent hap- hazard behavior of the larval lobsters swimming in daylight or other brilliant illumination, give any indication of a method which may underlie this seemingly random activity? Our previous observa- tions have at least given us a suggestion as to a means whereby we 200 REPORT OF COMMISSIONERS OF INLAND FISHERIES. may attempt to ascertain the value of certain light conditions in determining the enaction of these peculiar gymnastics.* If larval lobsters of any of the first three stages are submitted to such conditions of light that the stimulus comes from one direction, as from the side, the first fact observable in the reaction is that the larvee undergo a certain body orientation; they turn their heads away from the light and bring the longitudinal axis of the body to lie parallel to the direction of the rays of light. The second fact which may be noticed is, that the larve, having assumed this body orientation, move in the direction of the light rays, either toward or from the source of illumination. A third fact, which is of maximum importance and which involves the considerations stated above, is that, no matter whether the progressive orientation (motion) of the larve is towards or away from the source of light, the orientation of the body (head away from the sdurce of light) remains unchanged. To state the matter briefly we may say that, whatever the nature of the progressive orientation of the larve, the body orientation is at all times, and under all conditions, negative. Bohn} has clearly pointed out this fact for the larve of the European lobster. In this regard Bohn says: En général, les larves de homard se placent dans le sense négatif; meme, dans les eeres heures aprés l’éclosion, alors qu’elles se groupent vis-a-vis des lampes leur tete se tourne du cété opposé, et les larves s’approchent de la lumiére en regardant l’obscurité, c’est-a-dire en reculant. Ainsi, aprés l’éclosion, |’- orientation a lieu dans le sens négatif, mais le déplacement se fait dans le sens positif. Dans la suite, si le sens de l’orientation reste le meme, le,sens du déplace- ment peut changer. Quite recently Lyont has recorded a similar observation for cer- tain larval stages of Palemon. The condition of affairs here noted is *Many of the observations which follow were made previous to the writer’s knowledge of the excellent work of Georges Bohn, of Paris, along similar lines, but involving observations upon the larvee of the European lobster, Homarus vulgaris. The writer would acknowledge his great indebtedness to this investigator, whose work has proved suggestive in the highest degree; and whose observations on the mechanics of behavior the writer has been able, in the majority of instances, to verify and add to. +Impulsions Motrices D’Origine Oculaire chez les Crustacés. Institut Général Psychologique, Extrait du Bulletin no 6-5 e annee. 1905 y tBiol. Bulletin, 1906, Vol. XII, p. 23. REPORT OF COMMISSIONERS OF INLAND FISHERIES. 201 somewhat at variance with the majority of observations on the phototactie reactions of most animals, as it is contrary to the condi- tions of body orientation which we find in the fourth larval stage of the lobster itself; forin this stage we find, at least in the phototactic reactions, that the body orientation brings the head toward the source of illumination rather than away from it, as is invariably the case in the first three larval stages. A question at once arises as to what we may mean by a positive photatactie reaction, for in the case of the lobster the fact is clear that we may very frequently have a negative body orientation coupled with a positive progressive orientation. Loeb* states: “ Positively heliotropie animals are compelled to turn their oral pole toward the source of light and to move in the direction of the rays to its source.” The instance of the lobster larve, and of other forms mentioned above, are certainly notable exceptions to this general rule. Until we know more regarding these differences and regarding the rela tions between body orientation and progressive orientation, it may be considered safe to say that the direction of the progressive movement, with respect to the source of illumination, may be held as the surest criterion for the nature of the phototactic response of animals in general. ; On the other hand, the point has been made clear by some writers, that the body orientation of the organisms, the definite relation of the longitudinal body axis to the lines of active force of the stimulus, is the primary consideration for all deeper problems dealing with progressive orientation. However this may be, we have before us at least one instance wherein (although the relation of the body axis to the lines of force is an important consideration) the body orienta- tion per se has little or nothing to do with the question oj the positive or negative progressive orientation of the organism; for the same condi- tions which invariably determine a negative body orientation may also determine either a positive or negative progressive orientation, as other circumstances demand. We will therefore first concern ourselves *Studies in General Physiology. Decennial Reports of the Univ. of Chicago,Vol. XX, p. 30. 26 Le) 02 REPORT OF COMMISSIONERS OF INLAND FISHERIES. with the mechanics of progressive orientation, and then turn with better understanding to the mechanics of body orientation; for these two are presumably dependent upon quite different circumstances. . THE MECHANICS OF PROGRESSIVE ORIENTATION. , As we have already observed, the only means of locomotion pos- sessed by the larve of the first three stages are the exopodites of the thoracic appendages, and the strong flexible abdomen with its broad terminal fan. It is but seldom that the latter is used, however, and never when it is a question of progressive orientation to light. We are then confronted with the problem: How, with the action of the thoracic exopodites alone, is the larval lobster able to execute those movements which shall determine his motion either toward the source of illumination or away from it? The superficial expla- nation of this phenomenon is simple enough; and it is probably due to its very simplicity that it has remained so long a time unde- termined. If the larval lobsters in any of the first three stages be put in a glass jar which is surrounded by black paper and placed in subdued daylight, their swimming activities may be studied to the greatest advantage. The short vibratory strokes of the exopodites may be readily observed. At one time, certain individuals may be seen to swim rapidly backward, and again forward, without any apparent change in the position of the body or in the direction of the stroke of the exopodites. If, however, the thoracic appendages themselves be carefully watched, one can observe that, from time to time, these limbs undergo either a forward shifting (extension) or a backward shifting (contraction). These changes from the “anterior” position to the “posterior”? position may occur successively and at short intervals; the “forward” or the “backward” position may persist for some seconds, or again, there may be a successive alteration, with periods of longer durationin either one or the other of these positions. <= CC REPORT OF COMMISSIONERS OF INLAND FISHERIES. 203 It will be observed, further, that, when the thoracic appendages take the “anterior” position, the direction of the strokes of the exopodites becomes somewhat forward, as well as downward; and the resulting motion of the larvee becomes upward and backward. When, on the other hand, the thoracic appendages assume the “nosterior’’ position, the stroke of the exopodites becomes backward and downward; and the resulting motion of the larve becomes forward and upward. During a great part of the time the upward movement of the larve, as the result of the outward and downward stroke of the exopodites, does little more than compensate for the natural tendency to sink toward the bottom. For this reason, the progression of the larve may be often directly forward or directly baekward, with but slight deviation from the horizontal plane; while at other times, when the stroke of the exopodites is directly outward and downward (exclusive of either the “forward” or “backward” factor), the larve may mount to the surface in nearly vertical lines. Obviously enough, however, there may be many different directions of swimming, as determined by the degree of extension or contraction of the thoracic appendages. It thus becomes evident that the progression of the larve, back- ward or forward, upward or downward, is largely determined by the position (the state of extension or contraction) of the thoracie appendages. In other words, if, for the greater part of the time, cc these appendages are in the ‘“‘anterior”’ position, the reaction of the larva is positive; but if the thoracic appendages are more frequently in the “posterior” position, then the consequent reaction of the larva is negative. Naturally, the next important question which arises is: What conditions determine the “anterior” or the ‘“ posterior” positions of these thoracic appendages? It can not be questioned that these changes are directly due to certain variations in the intensity of the illumination, and are also modified by the ‘“ physio- logical state”’ of the larve themselves; that, furthermore, the state of extension or contraction of the thoracic appendages (and conse- quently the direction of the stroke of the exopodites,) is regulated ? 204 REPORT OF COMMISSIONERS OF INLAND FISHERIES. to a great degree through the medium of the eyes and the nervous systems of the larve. But in what way this regulation is brought about we are not able at the present time to state. Obviously enough there here lies a problem, the solution of which would clear up many perplexing questions in the field of animal behavior. THE MECHANICS OF BODY ORIENTATION, Under the present heading we shall undertake a consideration of the nature of those peculiar movements which the lobster larve undergo when they. are placed under diverse and changing conditions of stimulation; to explain the cause of these actions, and to show their relation to certain definite laws which may be said to regulate, to a great degree, the body orientation of the larve. The Effects of Direct Lighting and Shading.—This section deals, first, with the directive influence of ight rays so introduced as to strike the larvee from different directions relative to the longitudi- nal body axis: from before, from behind, from the side, from above, from below, or at various oblique angles to the body axis, as the case may be. The larve upon which observations were to be made were placed either in a cylindrical glass jar or in the rectangular glass box already described. Both of these receptacles might be easily placed in the dark box where the direction and the intensity of the light could be regulated by mirrors and by screens. To regu- late the intensity, colored slides of glass were used, while, to change the direction of the rays, a series of mirrors was also employed. In certain instances, when a bottom-light was required, the receptacle containing the larvee was placed upon a glass plate which was raised to such a distance above the bottom of the box that a mirror could be introduced below. In still other instances the direction or the intensity of the light was modified by the use of light-absorbing (black) or light-scattering (white) backgrounds. These were used more frequently when the observations were made in diffused and almost homogeneous daylight, the subdued light coming to the glass REPORT OF COMMISSIONERS OF INLAND FISHERIES. 205 containers from many different directions and thus eliminating, to a ereat degree, the directive influence. Still other experiments were performed to ascertain the effects of suddenly blocking the illumina- tion by which the larvee were being stimulated. In these cases the ‘cut-off’? was made by closing the window through which the light entered, thus leaving the larve in the sub- dued and diffuse light fromthe room. Inasmuch as the body orien- tation of the larve to the directive influence of the light is always the same, obviously enough there, could not be very many different varieties of orientation to which the change in the conditions of light could be applied. The resumé of these experiments may be pre- sented as follows: Résumé of Experiments on the Effect of (A) Direct Lighting and (B) Shadowing.—(A) The effect of suddenly submitting the larval lobsters to a light which has a single directive influence is to cause the larvee to orient themselves in such a manner that the longitudinal axis of the body assumes a certain definite relation to the direction of the light rays; and this orientation is a position with the longitudinal axis of the body parallel to the light rays, and with the head turned away from the source of light. (B) The effect of suddenly blocking the light to which the larve are reacting phototactically, is to cause a new body orientation wherein the head is usually brought to face the direction from which the light had previously come. In either of the cases mentioned above, the body orientation is brought about by a series of motor reflexes some of which Bohn* has deseribed for Homarus vulgaris. 1. Forward or Backward Rotations or Somersaults.—These are usually rotations in an are of few degrees which directly determine anew swimming position. The head is raised or lowered, depending upon the direction from which the light or shadow has been intro- duced. In other cases these rotations may take the form of a variable number of complete rotations through 360 degrees, either backward *DLoc. cit. 206 REPORT OF COMMISSIONERS OF INLAND FISHERIES. or forward, in which the body of the larva forms a constant part of the circumference of the circle of rotation. 2. Revolutions on the Longitudinal Axis of the Body or “ Rollings.”— The revolutions or rollings may take place either to the right or left, but usually in such direction that the back of the larva becomes directed more or less toward the light. They may be through a few degrees or they may exceed 90 degrees, in which case the larva falls to the bottom. In the case of larve which have suffered injury to one eye, these revolutions may take place very rapidly—often at the rate of one hundred and fifty per minute—and always in a deter- mined direction. 3. Swingings of the Longitudinal Axis of the Body.—These are in such direction that the head is brought to face the dark, and the tail to point toward the light. The swing is always of such a nature that the head is brought, by the shortest path, to face the dark. 4. Rotations in the Radii of a Circle.—In these the longitudinal axis of the larva forms a radius and, with either the head or the tail at the center, the larva rotates about a fixed point. This type of reac- tion is uncommon and, as yet, unexplainable. These four types of movement seldom occur separately, except under especially devised experiment. Two or more of these types usually are found blended to form composite types of action. To these previously mentioned simple componets, all the movements of the larval lobsters may be reduced. The Effects of Screens and Backgrounds.—Generally speak- ing, it is fairly probable that the reactions to light, which are brought about through the use of backgrounds, are dependent upon the same factors and conditions of illumination which may be produced by the employment of light-absorbing or light-scattering screens. For this reason we might consider the effects of screens and backgrounds together, were it not for the fact that the nature of the experiments makes it more advantageous to treat the two subjects separately: first, the effect of screening upon the body orientation of the larve. — REPORT OF COMMISSIONERS OF INLAND FISHERIES. 207 In these investigations were used screens of black and white, and of such size that they could readily be brought close to the sides of the glass containers in which the larve were placed. Bohn has made a special study of the reactions of crustacea to the influence of such screens, and in several instances the observations of the writer upon the larve of Homarus americanus are but confirmations of certain phases of Bohn’s work. In many cases, however, new facts have been added. Generally speaking, it may be said that the use of the white screen gave much the same sort of results as those obtained by the sudden introduction of direct light; and the black screen, the same results - obtained by-“ cutting off” the ight. For this reason it will not be considered necessary to go into extensive details to show the nature and the result of each experiment. Let it suffice to state the results in a general way, and to contrast the results with those obtained in the case of direct lighting and shading. Resumé of Experiments on the Effect of Black and White Screens.— When black or white screens are made to approach lobster larve of any one of the first three stages, diversely oriented, the larve may present two forms of response: First a motor reflex which tends to place the longitudinal axis of the larve in a certain relation to the plane of the screen; secondly (and subsequent to the first response), a progressive orientation, toward or away from the screen, as the color of the screen and other conditions of the case determine. (1) When the white screen is employed the larvee become oriented with the head, in general, directed away from the screen. With the use of black screens, however, the head comes to be directed toward the screen, and the back more or less away from it. (2) After these body orientations have taken place, the larve may approach or recede from the black or the white screen, according as they are ‘reacting positively or negatively to the directive influence of the light. The types of reaction upon which the body orientation to the influence of screens was found to depend, agree, for the greater part, / 208 REPORT OF COMMISSIONERS OF INLAND FISHERIES. with the types of reaction to black screens which have been reported by Bohn for the European lobster. We have now examined rather briefly the effects of sudden illu- mination and of sudden shadow, the effects of white screens and of black; and if we now compare the detailed results of these studies, we note that the effects produced by introducing a white sereen are very comparable to those obtained by suddenly admitting illumina- tion, while the effects brought about by black screens are comparable to those determined by suddenly cutting off the light. In other words, it becomes clear that the larve respond to the influence of screens of black and white by reactions which are dependent upon the same simple types of behavior that have been previously described. In view of this correspondence in the nature of reaction to direct lighting and to screens of black and white, it may be considered most probable that the screens are instrumental in determining the behavior of the larve, only in so far as they are themselves the source of (reflected) illumination, or, in the case of the black background, a light-absorbing agent. Therefore, when the black background causes a swing of the larva, as a result of which he comes to face the screen, we cannot say that the primary factor is the blackness of the screen; but rather, that the total light absorption and consequent non- reflection of light rays from a particular direction allow rays of light from other directions to be particularly effective; and we know from our previous experiments that the final orientation of the larva is determined by the relative intensities of light striking the eyes from different directions. Therefore, the larva “heads” to the black sereen because his eyes encounter no light rays coming from this direction; and he “heads”? away from the white screen because his eyes do encounter a stronger reflected light from this than from any other direction. The Effect of Backgrounds.—The question of the influence of back- grounds in determining the orientation of some crustacean larvee has been ably brought forward by Keeble and Gamble.* The whole *The Color Physiology of Higher Crustacea. Philosophical Transactions, Royal Society of London, Series B, Vol. CXCVI, p. 295-388. REPORT OF COMMISSIONERS OF INLAND FISHERIES. 209 question of screening which we have discussed in the preceding section is probably but a single phase of this problem of backgrounds. By the term background, as it is used in the present case, is meant the permanent color-tone of the surrounding walls (as a whole or part) which confine the young larve. This condition was somewhat different from that determined by the use of screens that were mov- able and could be placed at any angle with reference to the body axes of the larve. In the present treatment, backgrounds were employed in several different ways. They were sometimes repre- sented by the black or white lining of the reaction boxes; again by the ground upon which the glass dishes or tubes rested, or in still other cases by the outer covering of these dishes or tubes. The ques- tion of the effect of background may be considered under two heads: (1) the effect of backgrounds in connection with the purely photo- pathic responses; (2) their effect in determining the “choice”’ of a region of particular light intensity when phototaxis is also operative. From the result of experiments on the effect of backgrounds in connection with purely photopathic responses, it appeared that the nature of the background had no important influence upon the sign of the photopathic response of the early stage larve of the lobster, although the intensity of the light did appear to have been of value in determining the nature of the reaction. On the other hand, we note from other experiments that larve which were positive on a white background were negative (under the same conditions of light) when upon a black background. It is true that, when these experi- ments were performed, the value of knowing the exact age and history of the larve under observation was not fully appreciated by the writer. But these experiments were nevertheless suggestive of a certain effect of background in modifying the sign of the photopathic reaction. A study of the effect of background in connection with both the phototactic and photopathic response received greater attention. Under this head we may consider those conditions of experiment which, although they are no doubt chiefly productive of phototactic 27 210 REPORT OF COMMISSIONERS OF INLAND FISHERIES. reactions, nevertheless do not eliminate the possibility of a response to the intensity of the light. These conditions were secured by the use of the Y-tubes, already mentioned. The experiments therewith serve to demonstrate why the tendency to gather in the brighter areas (assumed positive photopathy) is usually associated with positive phototaxis; and why a tendency to gather in the darker areas (assumed negative photopathy) is usually associated with negative phototaxis. The citation of a few experiments will serve to illustrate both technique and results. In the diagrams of the accompanying plate are represented the Y-tubes as set up for experiment. Those whose horns are above were arranged for experiment with larve having positive phototactic reaction; those whose horns are below, for larve having a negative phototactie reaction. In tubes A and B, one side of one horn (c) was fitted with a band of black paper which extended half over the cir- cumference of the horn, and reached a very short distance down each stem. In tubes © and D the same arrangement existed, save that white instead of black paper was used. In every case the light rays came from the window in the direction indicated by the arrows. In all cases of larvee manifesting a negative reaction, the start was made at the end of the tube (lying horizontally on the table) nearer the window. In the case of positively reacting larve, on the other hand, the start was made from the end of the tube farther from the window. The end designated a, was in every instance the end from which the larve moved. The point of the experiment was to determine in which horn of the Y-tube the larve would eventually congregate. Case 1. In this instance the tube was arranged as in Fig. A. Ten posi- tively reacting, first-stage larve were placed in the Y-tube and, by certain manipulations of the light and by virtue of their positive reaction, were made to congregate in region a. Then suddenly the direction of the light was changed so as to come in the direction of “REPORT OF COMMISSIONERS OF INLAND FISHERIES. Pall the arrow. Immediately the larve would orient themselves with their heads toward the end, a, and pass through the tube toward the light. As soon as they approached the region marked x, they would come under the influence of the dark background bounding the side of the tube. Immediately, as we have seen to be the case in previous instances, the larvee would undergo a swing of the longi- tudinal body axis so that the head would come to face more or less obliquely the dark background. The directive influence of the rays, however, continued to draw the larve on, but since they must travel in the direction in which the tail was directed, they entered the horn of the tube, b, and continued until further progress was prevented by their reaching the end of the horn. Space will not be taken to show the numerical counts resulting from the actual experiments. Suffice it to state that nearly all of the positively reacting larve, of whatever stage or age, when submitted to these conditions of experiment, reacted as has been described above. This experiment was modified by so placing the Y-tube that the horn, b, overlay a piece of black paper. The results were invariably the same: the majority of larve entered that horn of the tube not overlying the black backgronnd. Case 2. In this case the conditions of the experiments were further modi- fied by so reversing the Y-tube that the horns pointed away from the window. In this instance larve which were manifesting a negative reaction were employed, and were first placed in the end, a, nearer the window. When the light was admitted, the larve at once oriented with their heads directed away from the light, and began a progression away from the window. When they had reached the point designated x, they immediately underwent a swing of the longitudinal axis, as in previous cases, so that the head became directed toward the black ground bounding the outer surface of the horn, c. In this direction they continued to advance until the 212 REPORT OF COMMISSIONERS OF INLAND FISHERIES. majority of the larve had gathered in this horn of the tube. In this instance, however, instead of moving to either end of the horn, the larve frequently rested between x and ec. Case<3: In this instance the black background bounding the outer side of one horn was exchanged for a white ground of the same size, and having the same position shown in Fig. C. In this ease, third-stage larve giving a positive reaction were employed for the experiment, and were started in the end of the tube, a. When the light was ad- mitted, the usual body orientation resulted, and the larve began their progression through the tube toward the window. When they had arrived at the point x, they would come under the influence of the white ground and turn their heads away from this side. Progressive orientation would continue and the larvee would eventually become grouped in the horn of the tube marked c. Similar results were obtained when this arm of the tube was laid over a sheet of white paper. Case 4. The previous experiment was further modified by reversing the Y-tube so that the-horns were directed away from the window, Fig. D. In this instance, larve which were giving a negative reaction were employed. They were placed in the end, a, and the light was admitted. After the usual body orientation, the progres- sion away from the window began to take place. When the larve reached the point x, and had come under the influence of the white ground bounding the side of the tube, they would swing their heads toward the left and continue their progress until all were gathered in horn,¢. This was somewhat unexpected. It eventually trans- spired, however, that the white ground bordering the outer surface of the tube did not act as a reflector or intensifier of the rays, but as an opaque shield, cutting off the rays which would have otherwise REPORT OF COMMISSIONERS OF INLAND FISHERIES. Ze entered the horn, ec. Thus, as in ease B, the negatively reacting larve had merely grouped themselves in the horn where the light was least bright. When the Y-tube was so placed that the arm, ¢, overlay a sheet of white paper the result was different. The larve congregated in horn, b, which was, under these conditions, the region of least light intensity. | The four cases mentioned above were supplemented by other experiments involving the use of colored glass plates, which were placed over the horns of the Y-tube in such a manner as to create a _/ ZY S AW Ss AX S Cc) Showing the ues of the Y-tubes. difference in the intensity of light in the two horns, as shown in Fig. 1, E, F; or sometimes the light striking one horn would merely be intercepted by interposing a red, orange, or yellow glass plate between 214 REPORT OF COMMISSIONERS OF INLAND FISHERIES. that horn and the source of illumination. In these cases the same general results which we have seen in the four previous cases ap- peared: The positively reacting larvee would gather in the horn where the light intensity was greater, while the negatively reacting larve would group themselves in the horn where the light was less bright. When one horn of the tube was covered with red glass, the other with orange, the positively reacting larvee would gather in the orange horn, while, if the experiment was modified for negatively reacting larvee, they would congregate in the red horn. As a rule, larve of the eariler stage appeared to be more susceptible than the others to slight differences in the intensity of light at the entrance to the horns, and would react readily to such a slight difference of intensity as that between red and “ruby” glass. (Unfortunately no means of accurately measuring the entensities of light in which certain reactions took place, was at hand.) Thus we have explained the general tendency for positively reacting larve to gather in regions of greater light intensity; and, on the other hand, the tendency for negatively reacting larve to congregate in the regions of lesser light intensity. CONCLUSIONS. It is not to be doubted that the types of reaction which have been described in the previous pages are influential in determining, in a large measure, the behavior of the lobsters under natural conditions of environment. But when one attempts to interpret the daily behavior of the larve in terms of these tropisms, the results begin to flavor of speculation. For instance, we know that under experi- mental conditions the fourth-stage larve, when submitted to food stimuli, will rise at once to the surface of the water and swim about excitedly for some moments. We know also that the early fourth- stage larve, under experimental conditions, will leave a region of low light intensity, and remain in a region of greater light intensity. REPORT OF COMMISSIONERS OF INLAND FISHERIES. OWS We have learned, furthermore, that these same fourth-stage larvee of all ages, under experimental conditions, will usually shun the light when it has a single directive influence, and travel in the direction of the rays away from their source. Finally, we have observed that the fourth-stage larve, except those in the latter part of the stage period, show a very definite tendency to remain at the surface of the water, where they swim actively during a large part of the fourth stage-period. The question now arises: What is the cause of this surface swimming of the fourth-stage lobsters, under normal condi- tions? Is it a response to intensity of light, to the directive influence of light, to hunger, or is it perhaps a form of geotaxis? Although we know something of the individual workings of several of these reaction factors, we need to be cautious in deciding upon their indi- vidual instrumentalities when they have opportunity to work in combination. If we can discover, however, any parallel between a certain type of reaction under experimental conditions and a certain mode of behavior under natural conditions, and find that, as one is modified or lost, so is the other,—then, and then only, are we justified in believing that we know the determining cause of the particular type of natural behavior in question. We have such a parallel between the photopathie reactions and the surface-swimming ten- dency of the fourth-stage lobsters. As the former becomes modified and is eventually replaced by the negative reaction, so the latter is changed, and finally gives way to the bottom-seeking tendency, as the lobsters pass on through the fourth stage-period. With such a parallel before us, it can not be doubted that there exists a certain causal relation between the positive photopathic reaction and the surface-swimming tendency on the one hand, and the negative photopathic reaction and the bottom-seeking tendency on the other. This view is further supported by the fact that the early fourth- stage larve could, at night, be drawn into a region illuminated by means of acetylene lanterns. Late fourth-stage larve would never manifest this reaction so clearly, and often appeared even to be repelled by the influence of the light. | 216 REPORT OF COMMISSIONERS OF INLAND FISHERIES. But the photopathie reaction may not alone be responsible for the surface-swimming tendency on the part of the fourth-stage larve. As has been shown, the presence of food particles in the water excites them strongly and causes them, when in the museum jars, to swim excitedly at the surface of the water. This tendency was never manifested by the fifth-stage lobsters. It therefore appears quite within the bounds of possibility that hunger and the stimulation by food particles in the water may also play a certain part in determining the surface-swimming characteristic of the fourth larval stage. There is little advantage to be gained by attempting to explain the natural behavior of the lobster larve of early stages, on a basis of the tropisms. It is true that they usually do select the regions of greater light intensity. On the other hand, the directive influence of the light rays may determine at one time a positive reaction, at another, a negative; and these reactions may follow each other in such rapid succession (depending on the intensity of the light and the age or stage of the larve) that the general reactions of groups of lobster larvee, or of isolated individuals in question, could in no way be readily predicted. One exception to this may be stated: The first-stage larve, directly after hatching, would be strongly drawn to the surface of the water by virtue of not only their positive phototactic, but also their positive photopathic reaction. After the first day or two, however, begins that modification and variation in the reactions which, for groups of uncertain age, makes an accurate prediction of their movements impossible. The explanation of the behavior of lobsters in the fifth and in all later stages, on a basis of the tropisms, is a far different matter. We have observed that the fifth-stage lobsters invariably manifest both a negative phototactie and a negative photopathic reaction. This circumstance explains well enough the fact that lobsters of the fifth and all later stages shun the light at all times.* *The object*of the present paper has been to present briefly the results of an investigation, the complete details of which will be published at a later date. REPORT OF COMMISSIONERS OF INLAND FISHERIES. Dg X. THE PREPARATION OF AN EXHIBIT ILLUSTRATIVE OF SEA FarRM— ING, INCLUDING LivE FIsHES IN Sat WATER AQUARIA, FOR THE WASHINGTON County Fair, FOR THE PURPOSE OF INTERESTING THE PEOPLE OF THE STATE IN THE MAGNIFICENT POSSIBILITIES OF ‘SEA FARMING.” For the third time your Commission has coéperated with the Washington County Agriculture Association in arranging an exhibit of “Sea Farming.” The feature of the exhibit which was particularly noteworthy of this occasion was the collection of live salt and fresh water fishes. The authorities in charge of the affair installed, under the direction of your Commission, a system of filters, storage tanks, and pumps, by means of which salt water could be used over and over again, after passing through the filter. The water was cooled by means of ice underneath the aquarium. The results were, in general, very satisfactory and most of the fish shipped from Wickford remained alive in the tanks during the several days of the fair. Exhibits of trout, from the Carolina hatch- ery and various forms of shell fish, including the scallop, clam, lobster, ete., and exhibits of various kinds of fishing tackle and other contrivances of catching fish were made. The object of the exhibit from the point of view of the Commissioners was to interest the people of the State in the fisheries, and indirectly in the possibility of developing the fish industries. A very large number of people examined the exhibit, and the interest manifested was especially gratifying. Your Commission expects to continue this work next year. 218 REPORT OF COMMISSIONERS OF INLAND FISHERIES, XI. THe PREPARATION OF AN EXHIBIT FOR THE INTERNATIONAL EXHIBITION AT JAMESTOWN. Your Commission was invited by the United States Bureau of Fisheries to collaborate with them in arranging an exhibition of fisheries at the Jamestown Exposition; accordingly a considerable part of the exhibit which was used at the Louisana Purchase Exposi- tion was forwarded to Jamestown, and placed under the direction of the government authorities. This was the third international exposition in which your Commis- sion has taken part; two of them in collaboration with the Fisheries Bureau of the United States. APPENDIX A. STATE FISHERIES AUTHORITIES. (List based upon most recent information at hand, date of which is given for each state.) ALABAMA. State Game and Fish Commissioner, (1907). JT sleiin Tose (CII E88 OA cies eg eR an PR Montgomery. ARIZONA. Fish and Game Commission (1905). Te Be BSTERY Cl 0) Seer eae ed oak eae eg a Safford. Bageene VANNS OM) G3 22.6 ¥ cs ae aes oe bee Se Mtoe ee es Jerome. Wee AEH iiy MOECEE GAL Y's 5 fa Sects 5 fuib.oe. «re epeie, Wo auc eee a Phoenix. CALIFORNIA. California Fish Commission (December, 1906). Wretvise\aneArsdale “President. sacrnscteeiat set mann eee San Francisco. SNORE (Crt STN ee oie Ce aie eg eee ae Rn aa ne es Sacramento. Mfume erin emennr), Ass.) 2c crakear oe aoe Sen ay Pinole. Charles A. Vogelsang, Chief Deputy.......................San Francisco. CoLoRADO. Department of Game and Fisheries (December 1906). J. M. Woodard, Commissioner............ Capitol Building, Denver. 220 REPORT OF COMMISSIONERS OF INLAND FISHERIES. CONNECTICUT. Department of Fish and Game (December, 1906). George: I. Mathewson, President... 0.040% .2.5 Saas, see e Thompsonville. RoberiiGe Pike =.nc aes ot sein ih eee cee ae eee Middletown. Ee Hart Geer; Seceretiinyn.: he fe et eo eae se eee ee aes Hadlyme. Connecticut Shellfish Commission (1906). (Ge ORGer W uNVial Os teen etre oe ale pilin ¢ PRO eatery eee Sinead Bridgeport. Christianischwantz ease ct 28 ache cae Sees fe eee South Norwalk. Waillivenraa MU emA Wate In cc cost eect ae seen wtp pete Ncu ge siets ts aac meee te New Haven. FLoripa. Florida Fish Commission (1907)*. John Y. Detwiler, Honorary Commissioner................ New Smyrna. Jonny GwRucesSecretany. 55.0 see een = eect ee Appalachicola. CR seWiallkere asc, «24a eae en NL ee a Ae Sanford. GEORGIA. Superintendent of Fisheries (December, 1906). PAC, NSS bas vos. 5 2'1a nga ee RO LS eae, Se ie Pe La Grange. IDAHO. WSNet Stephens. 2S o..5 2S ee ates pacar ab eee Rexburg. ILLINOIs. Board of State Fish Commissioners (1907). Nat. she Cohen* President... -. 2...................-. St. Paul. John H. Grill, Second Vice-president OR Rte AM ar ae 8 cel PN St. Paul. BG Smith .Seerevary yc: < Sales whl, we aes enter eee eee eee St. Paul. 8. F. Fullerton, Executive Agent.:......... otc oi Nts ov aaa Oe Duluth. MISSOURI. Missouri State Fish Commission (March, 1907). Ruichardyeorter: EresiGen... ...\ cers eioien mad Caetano rae ee Paris. Wier Elughes: Vice-president." ..2.- 5. difeue hot mtmels aie inn bere St. Louis. Je iasnecinl Secretary... .. ...\. senate koeeee Mee ona St. Louis. RG aC orn: 2 2%, vic. Shak, sis 5 s.<\ oo oe Se eR Reet ae ee Browning. ep AV AMON GEA, fo. ss wos ale a ei SRV OR Se ee oe ee St. Joseph. MONTANA. State Game and Fish Warden (December, 1906). NV eee S COUU sir ee ict tara eio ce cia clnas Reais omaO RIT GmucE Teron Ree Helena. NEBRASKA. (December, 1906). Governor, Commissioner ¢4¢-0/fieta 2. 08. on ot seo « Lincoln. Georve LL -Carter. Ohiek Wardena t= 95, nc.tgs Saree cece eee Lincoln. W. J. O’Brien, Superintendent of Hatcheries............... Gretna. APPENDIX. New HampsHIre. Fish and Game Commission (1906). bo Nathaniele Wentworth Ghaimmaneoel= <.... cn. nats eee Hudson Center. Chanews. Clark Financial Agent. oo 5.,6 case Sens Gate Concord. Plerrille Sinirtlet, Seerenaryeecs oS eSe oc ox 25S ks a eee Lancaster. New JERSEY. Fish and Game Commission (1907). Eee RE LIS Eire 20 Sn Bh os hed hee ye ee ELT Long Branch. Eee em em 2 ene gs 3 ass et eo Camden. pee Vie Cle liieimey creates oes. A ects atc kee Se I ee Morristown. per lemelenanesorrerteis eee "s Sah Salk 5 Sea aia hee Bloomfield. J..M. Stratton, Fish and Game Protector. :........0s.4...5 Long Branch. State Oyster Commission (1904). PuMinnmieyeren mmr SS os FS Se am el ee eee Newport. PPR eo RIGS an) ene ns ne a SRN Soties o ee eee Fort Norris. ~ SEPSED A ab) 5 OG Cie a ar ec hc Bridgeport. Vin dies LOVES GS) 1 ae cee eee See aoe ee eS Ixeyport. A. T. Bacon, Superintendent of Hatcheries................ Mauricetown, New York. Forest, Fish and Game Commission (1907). Faso Sen apple, Commissioner :'scs:.%s ions aids oa ete eae Albany. J. Duncan Lawrence, Deputy Commissioner............... Albany. Jonmee Wihhish, Secretary i:i2.5 5+.0i bes Sen ees eee Albany. Dr. T. H. Bean, State Fish Culturist.....1 Madison Avenue,New York. B. Frank Wood, Superintendent of Shell Fisheries.......... Jamaica. Wm. F. Fox, Superintendent of Forests....:.............. Albany. NEVADA. State Fish Commissioners, 1907. eorce vl S x. sets A eee ne Cee eee ee et ack Carson. dBi B/S Ne UT 0°01 Ve pe eee Ne a SB Se oO a ee Carson. TEAC ore hae Me eS en hel DANSE ese Meh a wn Fe ows Nh Wells. 224 REPORT OF COMMISSIONERS OF INLAND FISHERIES. NortH CAROLINA. State Fish Commissioner (1907). Theodore: Ovecleins. 20 fea) teat oer eae fox eee ee ee: Manteo. Shellfish Commissioner (1907). WAM “Web DE 8c ee eR Age oie NC roped Deore Morehead City. NortH Dakota. Game Wardens (1905). Were hlechiter: 2 perme Mier ant titty. ee ee ane oe Fessenden. Warr eIGICGa Tiga Bee) Stee hs ie ere SU Ne ak as Se obey ree yy ete Sanborn. OHIO. Fish and Game Commission (1906). RaullNorth) residents, (2. s0 ae ee ee ace ee eae eee Cleveland. PAT TBS) Rr s <0) 0 Ree 9 NR cE eee eT Cincinnati. AWW REGHEGIT ity E88 802s accnci are. aus, arta A Sem ones ee Dayton. Georce MeCookaite 1. a! my aaa Rk Ses td ae cote age Steubenville. CARON aT Te Bp! oo eis, ues sds eg ae eo ie eae meat ee South Charleston- OKLAHOMA. Territorial Game and Fish Warden (1907). Bene VV AEROS. <2 clays eee Nelpepe i oe ee eee Enid. OREGON. Board of Fish Commissioners. (SOR WETTA ORS «ee ae RES EA age Rinne ERI ea Bes te Salem. BeELelanigGirOudbe.f ja nee a0 <1h.-ue- On cc by Sedge eee Salem. SNS MESES Oe AP Al en crt ontaia wo Salem. Master Fish Warden (1907). i Geman @lOUSCI I. hs Shige dl oases oh eee, Eten eee Astoria. PENNSYLVANIA. Department of Fisheries (1907). W. E. Meehan, Commissioner... . Jobnylambercerae ass ce ye oes I eae ee Erie. APPENDIX. PAD) PORT OU OGY oe ea eM BA hs OO eS Wellsboro. PATI Walt RV VIDUD ACT Merwe pare o nate ene ecm tS Phoenixville. VS uated LGYTSTEy OTs kat ea cate Ries Ee SN eee a ae tte Mauch Chunk. RuopeE ISLAND. Commisisoners of Inland Fisheries (1907). Henry T. Root, President, Treasurer and Auditor..........Providence. eve Ke. Southwick, Vice-presidents: 2 eo. 0.0% bee Newport. SereaeleraN ti: SWAN (ohh aie ode 3 tale eigenen Peet Lee ... Westerly. 2\c De URN UIE sree a re eS Brown University, Providence. Wer. Mortons secretary. ... 2... 0.002 ee .-P. O. Box 966, Providence. ANrokelllsyereie 1D) 1860) Sexe See eee ere Re a -P. O. Box 264, Woonsocket. VTLS Tei) SI Boe ric 602 ee eso nL Central Falls. Commissioners of Shell Fisheries (1907). TPUNEUATD Ad La Sly eT esi 2. a a ela i aa Paes Sh 0h Little Compton. ame eNom Pe MGre an ac ae VES hk NS Poe ts ee eee Clayville. John H. Northup....... 2 hed Cnn CPM Te AR A pponaug. eEDEM eMLIO NEE FS cowie ace 2s Socks alee 2 here as hee Shannock. TE ee) Seay tsi Teh G21 NI (= eae re Barrington. SoutH CAROLINA. State Board of Fisheries, (1907.) Janeaversy lool ed aces rire, (Cihventia sch dye epee ee, 2d Caen ee Neca, 2 Beaufort. Tbs INES CRRCIIES ao ee ee Gta ee ate ee eet, oS eh Marion. See ERS UOT oe e305, agers ee ale ¢ onde noe bi Soke ee Newberry. TENNESSEE. State Game and Fish Warden (1906). - (DESI WL 5 io Cl cel PS ean mae Re MN ap al bode Me ee Nashville. State Fish and Oyster Commissioner (1907). Ila SE SGT ot Yee a eae a ection Pence, Riles 4 bayer oer Pees ete Port Lavaca. Uran. State Fish and Game Commissioner (1905). ESV EVCMSI NIG 3 Oh Scope oo! Ae ae ar ak EO Ry i ogee ae -. Salt Lake City. 29 i) i) op) REPORT OF COMMISSIONERS OF INLAND FISHERIES. VERMONT. Commissioner oj Fisheries and Game (1907). HentyeGren) Nomar... a eds ee ere acre Stowe. VIRGINIA. State Board of Fisheries (1905). J: W. Bowdoin Chamman 42... oe wees oe ce Bloxam. Sido iMillensiSeere tain... edo hte 9 Nas sais aot ee eae toate Foster. Georce Bedseezelliia co tes fe tas no ee ee en ag te Keezletown. ERE Mes Daler sths Ate Re ee AER, cet d ae hotel ait ae ee Richmond. 1 RES OF) ca) oe em Rect Pa pepe ere Near tee ft eMac Franklin. WASHINGTON. Department of Fisheries and Game. Board oj Fish Commissioners. GOUEENOE NG AU Bae Rs 2 Dee AO eR oe AS oun a oe eae Olympia. State Dreasnrery 24. 255 ee Ae Ore eae rates Sie eee Olympia. State Fish Commissioner and Game Warden. Jolie sso... 4 ace ee aati es Seat ak ene ee er thas Bellingham. West VIRGINIA. State Game and Fish Warden (1905). SJ Sede MAT CUM iy a2, 2cts, ons hs. oe eee Cae or aaa nea ete Meenas Huntington. WISCONSIN. Commissioner of Fisheries (1907). PERO OM EENOR yc. 5.5 cath o:s ne ee OAS ee ee eee eRe Madison. Oalvert opetisiey, Presidents. 2.2... 25 sce Sse ee ee Mineral Point. James*J.nkogan, "Vice-president... 2. 2.12.5 Su. Feo anaes tes La Crosse. Bip Ase EMEC Cs CCEEUAIY 6A 6 2 bias Sip. 1s Selon Ae Ae Bee EE Madison. WWicllinamedes Stamens =e cen eee eae = oi ae earch ner ge Eau Claire. kenny: Dna ae tae Fhe acme ol a8 - chat nit Seba. oe Oe Appleton. JabevAVord: 2. o% x eRe t es ak HOE s 2G TE ae. ee Madison. INT SNC ne

o> con We Gc Se NE ae Ree Greco one eae 1 1901 18 1897 21 UME GOCEEOR OLATISH scenic... vote ea re eee nine = Sos mas | 1898 55 : 1901 18 Avg, EFTTA Eas AVG TT eR 20) 0G Cea ios Or or eae ee rt | 1902 24 ie TERE STIRS 4 aNd oS a ee ae a ee eC 1900 10 bo On bo es) & tae] © ty ca] (e) se 9] (| © = s Lal Mm (op) e (e) a & ty mn je) x _ A sol po Fa 9 ty Low mM jan) & t=0) = rep ie Physical Examination of Narragansett Bay.................. (See Dredging.) AGP OInt SUCIEN SEONG Eee Ate ece mene Nie ht ae rn nO a OM OG are hewn eee os deste es RL Mn ae ay sc te fel RUS eR ER aR ee en RE ae Providence River, Physical and Biological Conditions of......... TLERO PILE SUECUTE SSW stor, oe en) ee am heal ae Patter, miGoth. oo io: <4. eee PSU RU EN HIRS Weer ore eit tee tal OS Rei ate PUE-NOREM JSANRER Fce.n-: <=. 5 ci ARINC NL ea RLS tM en eI eee Habits and Life History of the Quahog.—Paper by A. K. TSG AUI SG 56s eee Sore cae ge ee ee ee RuresbishessLakenin 1906. 120 wo. Stee Al ee ea ee Red mWatereblaruG:s 2 fo. cio. bo. so oa es Re eee Regenerationtin: the diobsters le .v.is a. uo a ee Relation to the Moulting Process....-..........:..:2+.+: Regenerated: Appendages: 25). cies ssa ac we ee eee ee Reliet Matyi aio Salen Ar an ale Wee) a ar 49 258 101 APPENDIX. Scallop—Habits and Life History of the Scallop—Paper by SIMETADEISLEE SEL ISSOT 15 25° oe 2. 34,4 0 oie ek Sere etic SSS Sian, Siar. 2 ook ee ee Te EERO eR re. Sete We SAE DGUTUG 5 55a ee ay em ce! SNES EE cals ar re armen on clin 6 ot 5 SEES DEG Se a en Eee rae ie 12 SpammmimmGround Ol Hishes.. 3... ..... 255-2 << see mete BRE errr e eee ako Se... fs ahaa Wes ee tape aera 254 REPORT OF COMMISSIONERS OF INLAND FISHERIES. Report for the Year. Page. Starfish— ; 1897 14 Distrib wtOnMe ss Ae. + tek Pe ee ae ee 1898 34 1898 38 ‘ 1897 25 IPMEMICS As A eee ae Or ee oe ee, ia ee ee 1898 68 1897 19 OO CEs Fs See te ee tet 8 nae a ey ae 1898 42 1898 55 , | 189 19 HECOMIG TEL ADIIS 2 os ecu 8. eah 5 ee a Sree ua rine , i 43 1897 25 arvaleReniodeesi >t sey tot a ee eee ae ae 1898 47 1898 53 : 1897 28 Methodsror Destruction..4.ce- heck eee een eee 1 1898 74 189 1 Ride ot hate tx oa, Ys eee ok ee Crane oh eee ee ; ee a 1 2! RateiomGrowbhescs5o ee ee ee Eee eeras / ee a 189 2 REP ORG ATEON 2.4: io: | pelerteners (cfaetehete Some RISEEP eee | eae - 5 189 25 UZ OVATRO PANE oo Te ee As onthe ga te ey uc ee eae ere ea / ioe a : f ( 1897 24. SPAWNS SEASON -.:.2. ste eee hy ee eee ee ree ee i 1898 44 Pans 1897 14 SPRCIGES ea... sss Hes te aie bn et eer ee 1898 38 ROU seen ie oo x. Pe ee Rn i eae 1898 47 { 1897 24 ; | 1898 47 BEADIGS OL... ca... 2 Site ew ps ee a See ee 4 1898 50) | 1898 53 f 1897 i | 1898 7 1899 10 1900 10 Peek ¢ : : ; 1901 11 Statistics of the Commercial Fisheries..................... { 1902 16 1903 14 1904 12, } 1905 15 L 1906 20 APPENDIX. ELV aM CHER CEM LOOT els-.. save ty sey arene MIG, a Sei ees 54 SUT 128 ots De a Re EOE ae ama een Ae ae SHITE COMP D eh. one eS hike oe 8 SVU aE adh Uenie’ nih See aaa ERE SWVORGBE Shien Phe wie ed, ie A te a Rae Temperature of Water, (see Physical Examination.) VOTE TNYGINS O05 As eh i ernie it Mina caries: tee eer CULE TEES hee 2 0 00 OLAS a ee ease G5 Times of Arrival and Departure of Food Fishes............... LORESE OG EH NS ETOYS are ae a PS rec ke oa TMS cess cue 5 2 tS COS Re a ea Pe PLS Gs oc one irapsemmmuence of, on Line Pishing.. .... 2... 6+ asa. s 322s PE SIO GAON SOLS S82 op 5.8 «0 civ ince 21s Ohh esee ale RNR ree ee Sie ee RBLIS npr A to a ks aes hes eee ee WS tigate { 1897 | 1898 } 1900 1901 1904 | 1908 1906 { 1898 | 1899 | 1900 1905 1899 1900 ( 1898 | « } 1903 | 1904 | 1905 ( 1899 V 1900 ( 1898 pe 1900 | 1901 { 1902 1903 1904 1905 | 1906 1906 256 REPORT OF COMMISSIONERS OF INLAND FISHERIES. PriplesVaMls Aw ae eck. ». yhaes tse Reha l ates Some apres eee Ve ViGIer SCLUDITAISES 2.0.0 cook ema ca Nena cele Deere eee oes aero ee 1906 67 APPENDIX D. TITLES OF SPECIAL PAPERS PUBLISHED IN THE ANNUAL REPORTS OF THE COMMISSIONERS OF INLAND FISH- ERIES OF THE STATE OF RHODE ISLAND. 1. Meap, A.D. The Starfish. (First paper.) Twenty-eighth Annual Report. 1898. 2. Meap, A.D. The Starfish. (Second paper.) Twenty-ninth Annual Report. 1899. 3. Tower, R. W. Improvements in the Methods of Preparation of Fish for Shippment. Twenty-ninth Annual Report. 1899. 4. Bumpus, H.C. The Extension of the Commercial Fisheries of the State.’ Twenty-ninth Annual Report. 1899. 5. Kexioee, J. L. The Life History of the Common Clam. Twenty-ninth Annual Report. 1899. 6. Mason, N.R. A List of the Diatoms Found in the Water over the Clam, Mussel, and Oyster Beds in Narragansett Bay. Thirtieth Annual Report. 1900. 7. Merap, A.D. Observations on the Soft-shell Clam. Thirtieth Annual Report. 1900. 8. Merap, A. D. Observations on the Soft-shell Clam. (Second paper.) Thirty-first An- nual Report. 1901. 9. Risser, J. R.H abits and Life History of the Scallop. Thirty-first Annual Report. 1901. 10. Merap, A.D. Habits and Growth of Young Lobsters and Experiments in Lobster Cul- ture. Thirty-first Annual Report. 1901. 1i. Merap, A.D. Observations on the Soft-shell Clam. (Third paper.) Thirty-second An- nual Report. 1902. 12. Merav, A. D. Habits and Growth of Young Lobsters and Experiments in Lobster Culture. (Second paper.) Thirty-second Annual Report. 1902. 13. Mean, A. D. and Wittiams, L. W. Habits and Growth of the Lobster and Experiments in Lobster Culture. (Third paper.) Thirty-third Annual Report. 1903. 14. Merman, A. D. and Barnes, E. W. Observations on the Soft-shell Clam. (Fourth paper. ) Thirty-third Annual Report. 1903. 15. Mean, A. D. and Barnes, E. W. Observations on the Soft-shell Clam. (Fifth paper.) Thirty-fourth Annual Report. 1904. 33 258 16. 18. 19. 20. 29. 30. 31. 32. 33. 34. REPORT OF COMMISSIONERS OF INLAND FISHERIES. Barnes, E. W. Preliminary Inquiry into the Natural History of the Paddler Crab (Calli- nectes hastatus) with Remarks on the Soft-shell Crab Industry of Rhode Island. Thirty-fourth Annual Report. 1904. Meap, A. D. Experiments in Lobster Culture. (Fourth paper.) Thirty-fourth Annual Report. 1904. Meap, A. D. Experiments in Lobster Culture. (Fifth paper.) Thirty-fifth Annual Report. 1905. ; Haptey, P. B. Changes in Form and Color in Successive Stages of the American Lobster. Thirty-fifth Annual Report. 1905. Emmet, V. E. The Regeneration of Lost Parts in the Lobster. Thirty-fifth Annual Report. 1905. Tracy, H.C. A List of the Fishes of Rhode Island. PlatesI-XII. Thirty-sixth Annual Report. 1906. Tracy, H.C. The Common Fishes of the Herring Family. Plates VII-XII. Thirty- sixth Annual Report. 1906. i Barnes, E. W. Methods of Protecting and Propagating the Lobster, with a Brief Out- line of its Natural History. Plates XIII-XXVI and XXVIII, XXXI, XXXII, XXXVI. Thirty-sixth Annual Report. 1906. Hapuey, P. B. Regarding the Rate of Growth of the American Lobster. Plates XX VI-— XXXVII, and XL. Thirty-sixth Annual Report. 1906. Haputey, P. B. Observations on Some Influences of Light upon the Larval and Early Adolescent Stages of Homarus Americanus. Plates XX XVITI-XL. Thirty-sixth Annual Report. 1906. Emmet, V. E. The Relation of Regeneration to the Molting Process in the Lobster. Plates XL-XLI. Thirty-sixth Annual Report. 1906. Tracy, H.C. The Fishes of Rhode Island, III: The Fishes of the Mackerel Family. Thirty-seventh Annual Report. Tracy, H.C. A List of Rare Fishes taken in Rhode’ Island in the year 1906. Thirty- seventh Annual Report. Witutams, Dr. Leonarp W. List of the Rhode Island Copepoda, Phyllopoda, and Os- tracoda, with new species of Copepoda. Thirty-seventh Annua: Report. Emmet, V. E. Regenerated and Abnormal Appendages in the Lobster. Thirty-seventh Annual Report. Wiuurams, L. W. The Stomach of the Lobster and the Food of Larval Lobsters. Thirty-seventh Annual Report. Hapuey, P. B. Regarding the Behavior of the Larval and Early Adolescent Stages of the American Lobster. Thirty-seventh Annual Keport. Barnes, E. W. Lobster Culture at Wickford, Rhode Island, in 1906. 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