SANGUINOLITES. 363 



M'Coy originally described fifteen species as belonging to Sanguinolites. Of 

 these, only four should in my opinion be removed from the genus, — S. arcuatus, 

 Pbill., sp. {Edmondia), S. cosfellatus (1844), and 8. radiatus {Soleiwnij/a), and 8. 

 iiulcatus, Phill., sp. {Edmondia). 



In a later work, however {op. supra cit.), 1855, M'Coj unfortunately enlarged 

 the genus, and included Allorisma, King, referring to the genus at the same time 

 certain shells from the Upper Ludlow series and Carboniferous beds, which 

 should not be included in the genus. He described eight species from Carboniferous 

 and Permian rocks, three of which, 8. clava, 8. sulcatits, and 8. lunulatus, can be 

 no longer included, as they possess a sinuated pallial sinus, and no angular ridges 

 externally, although in hinge characters they have a certain resemblance to typical 

 species of the genus. The genus SangainolUe!^, however, hardly deserves the 

 criticisms with which de Koninck, Hall, and others have assailed it. 



Salter thought that Orthonota should include the Carboniferous forms 

 described as 8anguiaolites and Allorisma, and there is no doubt that there is a 

 close relationship between that genus and certain compressed elongated species, 

 e. g. 8. plicatus ; but Hall shows that Orthonota also has been much misunder- 

 stood {op. cit., p. xlv), and says, " The species of this genus are always elongate, 

 extremely inequilateral, without external ligamental cicatrix or lunule, which 

 are always marked features in the Gh'ammysiidie.'''' The absence of lunule and 

 escutcheon at once separates Orthonota, Conrad, from 8anguinoUtes, M'Coy. 



I have pointed out at p. 228 the unsatisfactory character of Leptodomits, 

 M'Coy, and that the shells included in the emended description were totally 

 different from those included in the first. Leptodomus costellatus should un- 

 doubtedly be included in 8angidnolites, and it is astonishing that M'Coy should 

 refer shells so similar in character as those he describes as 8. variabilis, ovate 

 variety, and Leptodomus costellatus, to different genera. 



The genus 8phenotus, Hall, appears to me to be probably unnecessary, as the 

 general characters of the genus are identical with 8anguinolites ; but Hall 

 describes the hinge as possessing " two short, narrow cardinal teeth beneath the 

 beak of the right valve, and with one or two extremely slender lateral teeth." 

 Only one figure of the hinge is given, and that is shown to be edentulous. 



Cimitaria is another genus which I think should be included in 8anguinolites. 

 It possesses, as stated in the original diagnosis, no character which can be 

 pointed out as of diagnostic value in separating these two genera ; and shells 

 referred to Cimitaria possess the curved hinge-line, with its concavity upwards, 

 which is seen in 8. angustatus, the type of the genus, and in others. In addition, 

 Cimitaria has the tuberculated periostracum seen in many of the species of 

 Sanguinolites. 



