LIFE HISTORY OF THE BLUE CRAB. IOI 
TaBLe C. 
Intervals 
Stage. Width. Increase. between 
molts. 
Inches. Inches. Per cent. Days. 
SIE aE Nea ara tenia sn reir oinss sets nde le vonetec ere fafa param base as oa ics urease ei AI arpa puta rasarati cal nsucattcamnv wae ora tarbrac wiaco cats 
ESMRSECEA Hotere ctrcre cisto(cpieeice tt nrc eiaside sires ciewavaiciaas tists ciearcatince aiapae emaceh -128 0. 088 FEW a essa taeitis 
SSEASISIEPRMORELLD 01, CIRM aie alc eee E vie <nin hs Sie esaie oud wie Ses ee tre Blea eee eee +196 +068 53 8 
SD SRER RTE tees crac ae bwin haronrnie nish» earner aaitiais ada G awn aa aerate yas Dee +260 +064 32 5 
OUKEIMCTA DS free cre ce hc ee cocoa ian Ue dnict chet nae aioe ce etc ameneeenane +348 +088 33 6 
RSTO OTA See ah eek oes Ege ocleeoee ene Salincny diaeee ns Wamemmen cena +437 +089 25 6 
SSTRUL CHAD Ca athsies side cist ae eho e Retna eae oro akian shina ceice te dee toadanmancoans +562 «125 28 17 
BOWEN E CER cries 5 simian Ses Ste Pood al asin aby eectigialabe siBinral las coer gale seas aeiiee'esa +812 +250 44 II 
eit thy Crag oo wis vic «sg ie RRR a cia oie Gwaun mae usleic sila da Seas emma ccieidmeree 1.062 +250 go 13 
Nari CHa Cred Es eather crisie s olcsooefols s QUE INS sclu nie Salsa aialeiaiers) ales Warmedastesrelsetela nsec are eg aecnre 1-375 +313 29 10 
Pertti crabs. atgeeess sete eek haan tae isla elaasiasa]estetalaes hole, eter peat chele sloledtey lg 1. 687 +312 22 15 
MOTI Le Gomeeoesece sagt 4 BEE acer es SED ACE en cOe oo Benne Dome Der eset 2.250 +563 33 16 
PE eveN eh CRED a alo cra Siale SEM RE MR tele cient cia chaise ates acini nner ies clobaaielaiate 3-125 -875 38 20 
Mirte|nth crab a ..oces 3 dies tae Wis rales aisle acme s anicsviscdie sinjeisypasiejs. en gsoieserciseceichereinns 4-312 1.187 37 aI 
aigrecetMer toes Song un Wa SLaeBo oct CoUeMotc: Doel obo caae San eone SeeanEe: 5-500 1. 188 27 @ 25 
Rast Peerat hy Cla bape tee «iciein sic clea ae ibe s' Tesbreteten bins, foie asapseateiaieress ats eictescheleueinie stovenatareigis 7000 I. 500 27 2 35 
Average increase (first to fifteenth 'crabstages) oc o5.c 00. scscnc rabinecce|vowcericdsovcledeecscevue 32.71 b 14.85 
a Estimated. > Total time, 208 days, or 6.9 months. 
It will be seen that, according to this table, 15 moltings occur. It is probable that 
the number is not absolutely fixed, but that it varies somewhat with the individual 
crab, usually being about 15. The size and rate of growth of individual crabs vary so 
that not all reach the width of 7 inches. No doubt, however, as many moltings 
occur, on the whole, in the smaller specimens as in the larger, the individual being 
smaller at the start and the actual increase in size at each molting being less. Various 
factors, such as temperature, food, etc., certainly affect the growth rate. Ninety-six 
adult female crabs were measured, and the average width was found to be 6.117 inches. 
No similar records are available for the male, but the average width is probably about 
6.5 inches at least. Individual specimens of males are found which are much greater 
in width than this. Two exceptionally large specimens were measured, one of which 
proved to be 8 inches in width and 20 inches from tip to tip of the extended claws, and 
the other 8.5 inches in width and 1.25 pounds in weight. Specimens of females 7 inches 
in width are occasionally seen. 
The average increase in width at each molting is 32.71 per cent, or about one-third. 
This does not include the change from the last megalops to the first crab stage, at which 
time the increase in width is over 200 per cent, owing to a material change in the form 
of the animal. The increase from the first crab stage to the second is over 50 per cent. 
At the subsequent moltings the increase varies from 22 to 44 per cent, usually being 
about 33%. 
The time elapsing between molts is less in the early stages than in the later, averag- 
ing 6 days during the first 4 stages, 13 during the next 6, and 25 during the last 4. The 
average for all the stages is nearly 15 days. 
The results above set forth are confirmed by data obtained from some unpublished 
notes which were kindly placed at the disposal of the author by Prof. Hay. Hay 
