108 WINCHELL AND MARCY ON FOSSILS FROM THE 



2. The following eleven species are quoted only from Bridgeport. 



IcMlvjocrinus subangukris, Illcenus annatus, Acidaspis Damn, Lichas breviccps (?), Ambonychia 

 acutirostris, Pterinea Brim, Cypricardites (?) qaadrilutera, Pleurotomaria Axion, Tremanotus Alpheus, 

 Cyrtoceras Fosteri, Gomphoceras scriniiim. 



3. The following three species, quoted from Bridgeport, have not yet been seen there by us. 

 Sphcerexochus minis Beyr., Modiolopsis Dictccus, Cypricardites (?) quadrilatera. 



4. The following five species, described by us as new, have been identified by Hall with 

 old species. 



(a) IcMhyocrinus corbis W. and M., with I. subangidaris Hall. Besides the uniform want of 

 angularity of this species, it differs in the perfectly straight bounding lines of the upper 

 and lower sides of the secondary and tertiary radials, which, in I. subanguturis, are bounded 

 by a double curvature, as in I. Icevis. We are not in possession of specimens of I. suban- 

 gidaris showing the form of the primary radials, but Hall states that " the centres of the 

 upper margins are depressed or emarginate, and their lower margins produced." Scores 

 of specimens of I. corbis show a uniform difference in this respect, not to speak of the 

 supposed difference of basal structure. 



(b) Lichas pugnax W. and M., with L. breviccps? Hall. The glabella is extremely similar 

 to that of L. breviceps, but the pygidium has its axis much narrower anteriorly, and it 

 continually tapers backwards instead of widening. The plurae also differ. 



(c) Pterinea volans W. and M., with Avicula emacerata Conrad. Had Prof. Hall seen the 

 full-grown and perfect specimens in our possession, it is doubtful whether this identification 

 would have been made. 



(d) Sttbidiies brevis W. and M., with S. ventricosus Hall. We are not confident in our opinion 

 in this case, but, besides the contrast in proportions, already pointed out, it may be stated 

 that all the specimens in our possession (as well as Prof. Hall's) have the upper part of the 

 spire turned to one side. 



5. The following six new genera and species, described by Prof. Hall, have been iden- 

 tified by us with established forms. 



(a) Ambonychia Aphcea, with A. myiiloidca Hall. Prof. Hall has cited also A. acidirostra Hall, 

 from Bridgeport, and refers to his Ann. Pep. of Progress of Geol. Surv. of Wisconsin for 1880. 

 Our copy of that Report (embracing a manuscript copy of a "galley" of matter not bound 

 up with the Report), contains no mention of A. acidirostra, or any other Niagara species of 

 that genus, except A. myiiloidca. The same is true of the final Report for 1862. Both A. 

 Aphcea, and A. acidirostra must be extremely near to A. mytiloidea, — judging from the 

 descriptions ; and it is probable that our identifications, however correct, have embraced 

 both the forms separated by Prof. Hall. 



(b) Pterinea brisa Hall, is undoubtedly Ambonychia stricccosta McChesney, or Pterinea 

 stricccosta W. and M. 



(c) Amphiccelia Lcidyi Hall, is Ambonychia ncglccta McChesney, or Pterinea neglecta W. and M. 

 This new sub-genus (of Lcptodomus, as supposed) will hardly stand, as our abundant materials 

 have shown that the species on which it is founded possesses a long, broad striated carti- 

 lage plate, — an important character not seen by Prof. Hall, and one which, with the 

 cardinal teeth, make it a proper Pterinea. At least, it cannot stand as a subgenus of Lcp- 

 todomus. At the same time the general form departs considerably from the type of Pterinea 

 (P. Icevis Goldf.) in being less modified by the anterior and posterior relations. The deep 

 triangular pit beneath the break in each valve, and the duplex, crescentic posterior muscu- 



