88 Psyche [June 



occupy a position strictly comparable to that of the paragnaths, 

 unless it be true that the so-called second antennge of trilobites, 

 are in reality the representatives of the mandibular appendages 

 of other arthropods. In certain trilobites there is a rather deep 

 median incision, or emargination in the metastoma, thus suggest- 

 ing that this organ may have been formed by the union of two 

 lobes like the paragnaths; but this cannot be demonstrated from 

 the material at present available. The suggestion that the metas- 

 toma of trilobites may represent the united paragnathal lobes of 

 Crustacea, is thus merely a speculation, and has no particular bear- 

 ing upon the subject of the origin and development of the parag- 

 naths in Crustacea and insects. 



I imagine that there are still some individuals who will vigor- 

 ously maintain that the "superlingua^" of insects must represent 

 the maxillulge (first maxillae) of Crustacea, on the gi'ound that 

 Folsom, 1900, has described in a collembolan embryo a supposed 

 "superlingual" segment, or neuromere, which he claims is the rep- 

 resentative of the first maxillary segment of Crustacea; and he 

 further claims that since the "superlinguje" are supposedly the 

 ajjpendages of this alleged "superlingual'' segment, they must there- 

 fore represent the maxillulae, or appendages of the corresponding 

 first maxillary segment, in Crustacea. 



In reply to this argument, it is sufficient merely to call atten- 

 tion to the fact that Philiptschenko, 1912 (Zeitschr. Wiss. Zoologie, 

 Bd. CIII), who has made an exceptionally careful and thorough 

 study of colleml)olan embryology, and has attempted to verify Fol- 

 som's work on these, insects (Bull. Harvard Mus. Comp. Zoology, 

 1900, Vol. 36, No. 5), has demonstrated that the supposed "super- 

 lingual" neuromere, or embryonic segment, described by Folsom, 

 exists only in its author's imagination; and recent writers who 

 quote Folsom's mistaken observations as though they were estab- 

 lished facts, are ajoparently wholly ignorant of Philiptschenko's 

 work, and know even less of the anatomy and embryological devel- 

 opment of the structures of Crustacea with which they seek to 

 compare the structure of insects. If there were no other reasons 

 for discrediting the statement that the "superlinguse' represent tho 

 maxillulae of Crustacea, the fact that the paragnaths (not the 



