353 JOURNAL, BOMBA Y NA TCRAL HISTORY SOCIETY, Vol XVIIL 



four walking legs, it is obvious they belong to the last four thoraoio 

 segments. They are called the side-gills or i>leuro!>ranchue (Greek 

 pleuron side). 



The remaining gills are eleven in number. The most anterior is 

 attached to the membrane which joins the second maxilliped to the 

 thorax. The other ten are attached in pairs to the inter-articular 

 membranes of the last maxilliped and of the first four walking legs. 

 From their attachment they receive the name of "joint-gills'" or 

 arthrobranchice (Greek arlhros, a joint). 



Remove the thoracic limbs one by one beginning with the hind- 

 most. With fie point of a knife cut the articular membrane close to 

 the basal piece of the limb so as not to remove the arthrobranch ; 

 but be careful to remove the foot gill and leaf-like flap. When the 

 articular membrane has been cut all round, a gentle wrench will 

 disengage the two little pegs and sockets by which the limb is hinged. 



Number the limbs with a coloured pencil so that you can recognise 

 to which segment each belongs. 



The second maxilliped is perhaps the most complete of the limbs 

 and you had better study it first as a type of the whole series. 



Enq- 



Fig 5 - SECOND Maxillipbo. 

 B = Basipnriite j Pi. = Protopo- , P = Propodite. 



G = Coxopodjie I due. 



En = Eu-lopr^iite 



J = IschiO|<dite. 



M = Mern] odite. 



Cn = Carpopoaita. 



X = BxojioJite. 



G = (ill. 



E.j — Epipfidite. 



L = l.arueila or leaf. 



D = D ictylopcdlc 



Like the swimming limbs, it is madt up of a proximal stem, the 

 protopodite, consisting of coxopodite and basipodi L e to the latter of 

 which are attached two terminal divisions, the endonodite and exopo- 

 dite. Attached to the outer surface of the coxopodi'e we find a new 

 structure, a lateral development which runs up into the pll chamber 

 and bears at its extremity a gill in front and a thin membranous 

 lamella behind. 



