424 UNDESCEIBED FORM OF GASTEROrOD MOLLUSK. 



descriptions and drawings of Diphyllidia, that I had no 

 hesitation in referring it to a new genus, which I had pro- 

 posed to denominate Cryptophylloma. Professors Jameson, 

 Allman, and Huxley all agreed with me as to the novelty of 

 the form. Within the last few days, however, I have again 

 carefully examined the specimen, and have discovered the 

 oblique dotted markings under the margin of the cloak. 



I am now inclined to believe that it is merely a new 

 species of Diphyllidia, with its posterior branchial laminae 

 removed or torn off. I am the more inclined to believe 

 that this is the case from the examination of Mr. Albany 

 Hancock's drawing in the first volume of Forbes and 

 Hanley's British Molhisca, and from a reperusal of Otto's 

 description (J), liniata) in the tenth volume of the Nova Acta. 

 Otto states that " the branchiae, where they terminate under 

 the curved anterior border of the mantle, become suddenly 

 broader, and form a process which passes into a hollow in the 

 form of a blind sac, so that the right and left branchiae 

 nearly touch one another between the body and the mantle." 

 If my supposition be correct, the existing descriptions of the 

 branchiae of Diphyllidia are insufficient. I have no doubt 

 that each portion of the branchial laminie in that genus will 

 be found to depend obliquely from behind forwards and 

 inwards from the lower surface of the free margin of the 

 mantle, and that the anterior ones become crowded together 

 as a transverse series of large longitudinal plates in the pit or 

 ciypt in which the lateral groove terminates under the 

 lateral angle of the mantle. As I have only discovered the 

 markings under the margin of the mantle within the last few 

 days, I have not yet had time to communicate with Mr. 

 Hancock. At a subsequent meeting of the Society I hope 

 to be enabled to submit the result of additional inquiries 

 regarding this form of mollusk. 



