PCEOILOSTOMA. 29 



2-braDclied maxilla, and a stout proboscidiform suc- 

 torial mouth (PI. LXXXIX, figs. 4, 5, 6). And it can 

 scarcely be doubted that the two-branched organ 

 shown in Plate LXXXYII, fig. 10 (Acontiojphorus 

 armatus), is homologous with the mandible and palp 

 of Gyclojpicera nigripes represented in Plate LXXXIX, 

 fig. 4, and of G. gracilicauda (Plate LXXXIII, fig. 3). 

 To recur to the genus Lichomolgus. If we examine 

 again the disputed organ (PI. LXXXV, figs. 4, 12, 

 PI. LXXXYII, fig. 3, PI. LXXXYIII, fig. 11) we shall 

 find that it bears a very strong structural resemblance 

 to those appendages of siphonostomous genera which 

 have just occupied our attention, and the mandibular 

 nature of which is, I think, pretty conclusively shown. 

 I have therefore little doubt that this organ in Licho- 

 molgus ought to pass for a mandible, and inasmuch as 

 the mandibular palp amongst the Siphonostoma is 

 sometimes nearly or quite suppressed, but the maxilla 

 never, and, moreover, as when the mandible-palp does 

 exist it assumes a form totally diff'erent from the palp- 

 like appendage of the mandible of Lichomolgus; for 

 these reasons I am disposed to regard this appendage 

 as a rudimentary maxilla. The opinion is confirmed 

 by a comparison of the maxilla of Gorycceus, which is 

 connected with the mandible in a manner very like 

 that of the supposed maxilla of Lichomolgus to its 

 mandible (see Plate LXXXIY, fig. 10). 



