364 CARBONIFEROUS LAMELLIBRANCHIATA. 



Some of tlie species of Saugninolltes found in Scotland have been referred to 

 Ci/pricardia, following de Koninck's earlier work. 



De Koninck adopted M'Coy's genus Sanguinolites in his larger work, and 

 referred to it no less than fifty-three species. Of these twenty-eight were new, 

 but certain shells, notably Paralhlodon squamosus, Phill., sp., which does not belong 

 to the genus, were included ; and also a group of very strongly carinate wedge- 

 shaped shells, which I have separated under the genus Miitllomovplia, with 

 M. rhomhea as the type. Probably many of the species will be found to be the 

 young or varietal forms of others, as several are founded on a very slender 

 amount of evidence. 



De Koninck has, however, separated a group of shells under the genus 

 Chxnomya, Meek, which I replace in Sanguinolites. In the first place, it is not 

 easy to understand why de Koninck referred his shells to this genus, for 

 Cha'nomj/a is stated by Meek to have a " pallial line with a broad, shallow 

 sinus;" and de Koninck correctly states that his shells have an entire pallial 

 line, and on that account I think that they cannot be placed in Ghsenomya. 

 Further, de Koninck is in error in stating that his shells gape. This idea was 

 apparently due to the incomplete filling of the interior of the shell with matrix, 

 or its fracture, for when specimens are obtained whole the shells are seen to be 

 close all round. Five species are referred to Ghsenomya by de Koninck, three of 

 v/hich, C. jucimda, C. Walciodorensis, and C. Omaliana, occur in Great Britain ; 

 and the two latter form a group of the genus Sanguinolites which comes midway 

 between the group of which S. angustatus and S. costeUatus are the types. 

 C. jucunda should be referred to the genus Tellinomorpha , de Koninck; Ghsenomya 

 Vaulxiana is, I should judge from the figure, probably an Edmondia. De Koninck 

 considers that S. discors is the type of the genus Sanguinolites ; but if on the 

 ground of priority, it is diflScult to understand, as this species was sixth in the 

 list of those described by M'Coy. As a matter of fact, this species is un- 

 doubtedly a synonym of S. angustatus, which is the first species described under 

 the genus, and therefore the published type. De Koninck subdivided Sanguino- 

 lites into three groups, distinguished by the number or strength of the radiating 

 lines or folds on the dorsal slope. This subdivision I hesitate to adopt, as I find 

 in some species the number or strength of these lines varies in individuals. 

 Tornquist, in discussing the affinities of the genus, largely follows de Koninck, 

 but seems doubtful of the real position of the genus and of some of its characters. 

 He states, p. 122, that there is some difficulty in discriminating between certain 

 species of Edmondia and Sanguinolites ; but this observation must be based on a 

 misunderstanding of the characters of the genera. The total absence of 

 lunule and escutcheon in the former is quite sufficient to at once distinguish 

 the one genus from the other. 



