64 MR. L. A. BORRADAILE ON THE 



There are two openings to the lip-chamber — a narrow median 

 slit between the lobes (paragnatha) of the metastoma and a wider 

 transverse gap between the metastoma and the labrum. The 

 incisor processes close the transverse opening, meeting in the 

 middle line. The molar processes meet deeper in the chamber, 

 just under the opening of the gullet. 



3. In the maxillule (text-fig. 46), the inner lacinia, which is 

 usually the narrower of the two, curves towards the outer and 

 is provided with relatively feeble bristles. The outer lacinia has 

 very stout, yellow bristles and is probably the only structure, 

 other than the mandible, which is capable of tearing the food. 

 The endopodite is bifid at the tip, the proximal branch, which 

 possibly represents an endite, being curved in a short spiral, the 

 distal branch nearly straight. The maxillules stand close against 

 the paragnatha (text-fig. 44), the lacinise of each opposed to those 

 of the other across the median line, but not quite meeting them. 



Text-figure 46. 



Maxillule oi Ijeander serraius. 

 For lettering see p. 71. 



The inner laciniae are just behind the cleft of tlie metastoma, 

 the outer stand beside the cleft. The endopodite is directed 

 outwards and hooks its curved process around the outer edge of 

 the paragnathum, which has a notch to receive it. Probably 

 this gives a purchase for the action of the limb. 



4. In the maxilla (text-fig. 47), the first dovible lobe has 

 disappeared and is represented only by a slight swelling of the 

 edge of the limb. The second lobe is of good length, but tends 

 to become simple in the Pontoniinse. In this respect it is very 

 variable, the maxillpe of the two sides sometimes differing in an 

 individual. From the frequent occiuu^ence of reduction in the 

 lobes of this limb in the Carides, it would seem that they are 

 structures of no great physiological importance. The endopodite 

 is of simple shape, ta.pering distally, and the exopodite (scapho- 

 gnathite) varies in shape and width with the gill-chaiTiber, and 



