PLANKTOX OF THE WOODS HOLE REGION 
159 
The following Macrura were taken in the surface collections for 1922-23: 
Homarus americanus, Milne-Edwards. 
Emerita talpoida (Say). 
Upogebia afFmis (Say) . 
Crago septemspinosus (Say). 
Palsemonetes vulgaris (Say). 
Hippolyte zostericola (Smith). 
Naushonia crangonoides, Kinglsey. 
Callianassa stimpsoni. Smith. 
Pagurus sp. 
BRACHTUKA 
Larval crabs are always present in the su mm er plankton in large numbers and 
form very important food for many fish. As few of the zoeas had been worked out, 
they were a source of much trouble until the many forms were finally identified. 
The development of the various species will be taken up in a later paper. 
All the crabs of this region have free-swimming larval stages, although certain 
species are seldom taken in surface collections. The megalops are found in smaller 
numbers than the zoeae. Investigation showed that in this stage the young crab 
is usually found among the eelgrass and ^ 
Fucus. It can swim as well as the zoea 
but remains closer to the bottom. 
After hard winds large numbers were 
PinD9thcr«s ettrtua (Say) 
Pinnln MTU* Stlapcen 
Cancer borcalls Stlaps«B 
Surypaneptus deprtscus (Saith) 
OnJlpes ootllAtus (Ucrbst) 
CaralaUcs aMoas (Llanaeus) 
Plaatt Biautut (LinutuB) 
Doa pupnx (Saith) 
Dm pusUater (fioso) 
Fig. 58.— Brachyura occurring rarely in surface 
collections of 1922. Eggs of Planes minutes 
(Linnaeus) from an adult taken in the tow 
were hatched in the laboratory 
«cac«r Irraratas 
Caneer borealis 
Orallpes oaellatns 
Calllneotes sapidxis 
(Carcinldes n&n&s 
Xlblnla sp. 
Eeteroorypta erasalata 
Pelia nut lea 
Heopsnope tezasa sayi 
PolyoDTX maarooheles 
Plnniza «lb£^tapt«raaa 
Pimilsa saTaoa 
Pinnotheres maoolatiu 
Ooa sp> 
Bfas ooarotatos Leach 
Fig. 59.— Occurrence of larval forms of Brachyura in surface 
collections of 1923. No observations were made from 
August 22 to September 18. Megalops of Hyas coarctatus 
Leach were obtained from Muskeget Channel on August 25 
often taken in the nets. The megalops transforms into the "young crab " stage in a 
single molt. The "young crabs" are very rarely found swimming, except in the 
species Pinnixa chsetopterana and P. sayana. These have no megalops stage but 
change directly from the zoea into a young crab, which may be compared with 
the megalops of other species, for they swim about in much the same manner and are 
often very abundant in the plankton. 
The zoese of Uca were rarely taken at the surface. Megalops appeared on only 
two occasions, after storms. This seems very strange, because Uca is probably the 
most abimdant crab found in this region. Hymen reports the zoe?e as being very 
abundant in the siu-face collections at Beaufort, N. C, at all times during the 
summer. I believe that the fiddler crabs of this region have a very short larval 
period in which the zoese as well as the megalops remain at or near the bottom. 
Carcinides msenas larvte may have similar habits, in this locality at least, for zoese 
were taken on only three days in October, 1922, and on one occasion in 1923 (figs. 
58 and 59). 
