''SLIPPER LIMPET" OB ''BOAT SHELLS' 413 



further enters into the sex relations of the chains by tabular 

 data and otherwise. As above indicated, the females are at 

 bottom, the hermaphrodites in middle, and males atop, their 

 size decreasing upwards. 



From his examination of the gonad, it looks doubtful whether 

 pure males with only sperm in them are ever found in C. forni- 

 cata (?). The youngest forms are doubtless males as regards 

 function, and the oldest exclusively females. He infers : " There 

 is no doubt that all the individuals of this species are horn males, 

 and change in the course of their life -history into females.^' He 

 suggests that chain formation and hermaphroditism are in some 

 way casually connected. They would seem to have arisen along 

 with, and favoured the acquisition of, Protandric Hermaphro- 

 ditism. Thus Crepidula fornicata appears to have become > 

 adapted to a sedentary life without losing any of the pro- 

 creative advantages of a free-living habit. 



After some remarks on dwarf females, Orton concludes with 

 memoranda on sex phenomena in allied species, and in those of 

 the Limpet genus, Calyptrcsa. 



To Prof. Conklin, all the same, is due the credit of first 

 promulgating the idea of conversion of the sexes in Crepidula, 

 which Orton has afterwards worked out in a creditable manner. 

 The theoretical or speculative views of both authors, notwith- 

 standing, leave still a gap in application to Fisheries' practical 

 interests other than explanatory of the prolific nature of the 

 parasitical " Limpet." 



We can corroborate Orton's allusion to West Mersea chains 

 being larger and more numerous than outer coast ones, and 

 his anatomical diagrams fairly representative. (Compare our 

 figs. 11, 12, 13, 14, and 15 in Plate VI.) He makes a few 

 introductory remarks on its American origin and distribution, 

 with Dodd's hint of 1880 introduction and favourable propaga- 

 tion in Essex. 



We may here emend the paragraph {ante, p. 405) by men- 

 tioning that since it was in type we have had the good fortune 

 of receiving from a shrimper specimens of Hermit Crab-shells 

 with numerous small " Slipper Limpets " attached to them. 

 Nay, more, a young Shore Crab {Carcinus mcenas) with several 

 on its back. These were got in the trawl-net, Sea Eeach, 



