454 Edward Phelps AUîs jr., 



ossicles on tliat side and a third one that is apparently median in 

 position. In Salmo salar, Parker says there are no "conspicuous 

 supratemp orals", but Schleip says that these bones are represented, 

 in embryos of this same fish, by a large number of disconnected little 

 plates. Extrascapular bones accordingly undoubtedly exist in the adult 

 Salmo salar exactly as in Salmo namaycush. Parker describes, as a 

 supratemporal that is "worth description", a bone that belongs to the 

 preopercular series. 



Posterior to the lateral extrascapular ossicle, the main infraorbital 

 canal traverses the suprascapular and then the supraclavicular. 



Nothing in any way resembling the system of "drain-pipe-like 

 canal-bones" of Collinge's [30] descriptions of Salmo salar were found, 

 and I can not but believe that that authors descriptions are, in this 

 respect, wholly erroneous. 



Coregonus clupeiformis (J. and E.). The drawings of this fish 

 were made in 1887 — 88. Fig. 27 shows the latero-sensory canals 

 and their related bones, and both the canals and the bones agree so 

 closely with those of Salmo that no detailed description is needed. 



The supraorbital canal has anastomosed with the main infraorbital 

 by what is apparently its penultimate tube. The postfrontal bone 

 is somewhat detached from the more anterior bones of the postorbital 

 series. The squamosal apparently lodges a post-preopercular sense 

 organ. The extrascapular, on each side, is represented by two bones, 

 a lateral and a mesial one; the lateral bone apparently lodging one 

 sense organ of the main infraorbital line and also one belonging to 

 the supratemporal canal, 



Alosa sapidissima (J. and E.). The drawings of this fish were 

 made in 1887 — 88, and are reproduced in fig. 28. 



The postfrontal is apparently represented in a small ossicle that forms 

 the dorsal one of the postorbital series. The extrascapular is a single, 

 triangular or V-shaped bone, and it apparently lodges one sense organ 

 of the main infraorbital line and one of the supratemporal line, thus 

 apparently here agreeing exactly with what I have described in Esox. 



Heterotis Ehrenhergi. In this fish the supraorbital and infra- 

 orbital canals anastomose, according to Hyrtl's [50] desciiptions, be- 



