450 JOHN BEARD, 



my friend, F. J. Cole (1898). While in some and very minor points 

 agreeing with Cole, I believe him in the main ones to be simply 

 begging the question ^). The dorsal series of sense organs in the 

 ammocoete broadly corresponds — and Cole does not appear willing 

 to admit this, to do so would destroy his whole case — to the "lateral" 

 sense organs of the head of ordinary fishes, minus the hyoid group. 

 To them and to the ventral sense organs Cole would deny the right 

 to classification as lateral sense organs, holding, that possibly they 

 correspond to the terminal buds of other fishes. 



So far as I am aware, there is no cogent reason why the lamprey, 

 a very aberrant and low vertebrate, should be compelled to conform 

 to the conditions seen in other fishes, such as skate and cod. In 

 other respects in its organisation it egregiously fails to do this. But 

 the crux of the matter is doubtless contained in the answers to the 

 following questions, which may now be put. 



1) If some of the dorsal series be lateral sense organs, in what 

 points of minute anatomy do the ventral sense organs difier from them? 



2) If the ventral series be not true lateral sense organs, where in 

 the lamprey do the hyomandibular nerve and its sense organs, as they 

 exist in other fishes, come in? 



3) In what way are the facts of the development, described by 

 von Kupffer, to be explained ? 



In minute structure dorsal and ventral series apparently agree, and 

 the mode of development in the hyoid segment of both series is the same 

 in the lamprey as it is in the skate 2). It follows, I think, with a 

 fair degree of certainty, that the system of the lateral sense organs in 



1) E. P. Allis, an observer with a very extensive and minute 

 practical acquaintance with the lateral sense organs and cranial nerves 

 of fishes, describes Miss Alcock's work as "a valuable contribution to 

 our knowledge of the lateral sensory system, differing radically in this 

 with Cole" (in: Anat. Anz., V. 15, 1898—99, p. 376). 



2) In his "Reflections on the cranial nerves and sense organs of 

 fishes" (in: Trans. Liverpool biol. Soc, V. 12, 1898) Cole writes: 

 "Further, there is more than a suspicion that embryologists have hitherto 

 been following a Will-'o-the "Wisp, and that the sense organs they 

 have been tracing do n o t become the lateral sense organs of the adult" 

 (p. 239 — 240). Is this another variety of the Ayers-Goronowitsch 

 myth? From an embrj'ological acquaintance with these structures and 

 with Elasmobranch embryos of all periods of development extending 

 over nearly 20 years, I can assure Cole, that there is not a particle 

 of fact in his suggestion. I quote his words here, because they clearly 



