14 c. BOVALLIUS, NOTES ON PTERYGOCERA ARENARIA, SLABBER. 



small upper-lip, a little swollen and triangulär, at the hinder 

 part a slender and siipple under-lip. After this follows one 

 of mandibles, two pairs of maxillse and the maxillipeds. 



The mandibles (Pl. III, fig. 30) are irregularly quadran- 

 gular with the hinder outer angle produced and thickened, 

 with a strong ridge of chitine for attachment of the muscles, 

 the hinder börder is strongly, the foremost one a little less 

 concave. The inner börder, directed towards the correspon- 

 ding mandible, swells at the lower börder into a strong molar 

 tubercle (tuberculum molare) ; it is crossbent at the point, 

 feebly concave, close beset with finely denticulated ridges, 

 forming a strong molar or grinding surface ; above this it car- 

 ries a range of strong sawlike spines, bent at the point (Pl. 

 III, fig, 33). The foremost part of this side shows two tooth- 

 like prominences, and behind these a range of straight spines. 

 In the foremost outer angle the mandibular palpe is attached; 

 it is three-jointed, scarcely twice as long as the mandible it- 

 self. The first joint is very small, without hairs or bristles, 

 the second the biggest of the three, swollen and dilated an- 

 teriorly, on the inner and outer sides provided with straight, 

 unciliated bristles of different length and feebly bent at the 

 top. The last joint is a little shorter than the preceding, 

 rounded at the end. The outer side, about the middle of 

 the joint, presents a range of about eighteen short spines, broad 

 at the base (Pl. III, fig. 35); towards the point they are finely 

 ciliated. They contain a finely granular substance and to 

 their common base goes a thin nerve; possibly they are 

 organs of taste. At its end and on the inner side the joint 

 carries a certain number, mostly about twelve tactile bristles, 

 bent at the top, a little swollen and transversally bifid. (Pl. 

 III, fig. 48). 



The first pair of maxilla; (Pl. I, fig. 5) consists of a broad 

 basal-joint, slightly rounded in the lower angles, two extended 

 lamin?e, one inner and one outer, and a palpus. The basal-joint 

 carries on its lower margin a broad fringe of long, fine hairs; 

 at its upper inner angle the inner lamina (lamina interna) is 

 attached. This lamina is small, of an elliptical shape, on the 

 inner margin provided with 11 — 12 long hairs, bent at the 

 point and thinly ciliated below it (Pl. III, fig. 40). The outer 

 lamina is considerably larger than the inner one and terminates 

 anteriorly, at its inner end, whith a broad, short, truncated. 



