152 DISCOVERY REPORTS 



The maxillula (Text-fig. ^d), for example, was first described by Stebbing (1900, p. 54). He stated 

 there were ' six strongly plumose setae on the narrow inner plate ' ; in a subsequent paper, published 

 in 1902, he altered this number to five. Nierstrasz (1917, p. 113), discussing this point, said that in his 

 specimens the number of plumose setae varied, some specimens having four and others five. Collinge 

 (1918), not having seen Nierstrasz's paper, disagreed with Stebbing and said (p. 82) that the inner 

 lobe has ' four stout setose spines terminally, and a small setule on the middle of the ventral surface 

 close to the anterior margin ' ; further, he stated that all his nine specimens were alike in this respect. 

 It is unfortunate that Collinge gave no indication of the size of his specimens ; those of Stebbings 

 measured 51 mm. and 48 mm. in length. 



Text-fig. 4. Paridotea ungulata. (a) First brood lamella (left) of breeding female, x 18. a./, anterior lobe; /)./. posterior lobe; 

 /, fold;/./), finger-like projection, {b) Left maxilliped, .3, ventral view, x 18. (c) Base of right maxilliped (breeding?), 

 dorsal view, x 18. (J) Maxillula (right), X2i. (e) Maxilla (left), X2i. 



In the Discovery collections the specimens vary considerably in size, and an examination of the 

 maxillula of a large, a medium and a small individual shows that the number of setae is definitely 

 correlated with the size of the individual : 



Large specimen: body length 52 mm. Number of spines 5. 

 Medium specimen: body length 22-5 mm. Number of spines 4. 

 Small specimen: body length 10 mm. Number of spines 3. 



