28 :Mr. W. T. Caiman on 



the first pair of perseopods a very minute chela in place of 

 the styliform termination usually ascribed to thi-s appendage. 

 In calling attention to this character M. CauUery says : — 

 " En comparant i\ la fig. 12 certains dessins des auteurs, on 

 se dcmande si cette j)ince n'a pas ^ehappd quelquefois aux 

 obscrvateurs dans d'autres formes, et il serait desirable puisque 

 maintenant son existence est reconnue dans un cas, de la 

 recherchcr dans les autres Pandalidaj." So far as concerns 

 the British species, at any rate, I am able to confirm this 

 suggestion of M. Caullery. A microscopic but perfectly 

 formed chela is found on the first perajopods of all of them, 

 including the familiar type of the genus, P. Montagui 

 (PI. I. fig. l,f), which for more than three quarters of a 

 century has been described as having the first legs " simple." 

 Even under the microscope the chelate termination may 

 easily escape notice, on account of the brush of setae among 

 which it is partly hidden. Closer examination, however, 

 reveals the minute dactylus, separated from the propodus by 

 a distinct articulation and, as it is easy to convince oneself by 

 touching with a needle, freely movable, 1 am unable to say 

 whether muscles for opening and shutting the chela are 

 present. Both the fingers are slightly curved, and a tuft of 

 long curved setae springs from the inner margin of each. 

 The fingers are from one-twelfth to one-tenth of the whole 

 length of the propodus in adult specimens of P. ^[ontagui, 

 and proportionately a little longer in young individuals. No 

 differences worthy of note are observable in the other British 

 species. 



Further research is required to show whether the subgenus 

 Dichelojjandahis which M. Caullery has based upon this 

 character may not be co-extensive with the genus Pandalus 

 itself. The collection of Crustacea in the Museum of 

 University College, Dundee, contains only three species of the 

 genus, in addition to those already named; but all of them, 

 viz. P. borealis, Kroy., P. leptoeerus, S. Sm., and P. Dance, 

 Stps., agree in this respect with the type species. As regards 

 the other genera of the family, M. Caullery has shown {l. c. 

 p. 379) that no chela is formed in Plesionika martia, A. M.-E., 

 though a minute dactylus appears to be present. I find, on 

 the other hand, that the first pera^opod of Ileterocai-pus gib- 

 bosziSj Sp. Bate, carries a chela similar to that of Pandalus. 

 I have below given reasons for believing that M. Caullery's 

 DichelopaJidalus Bonnieri is identical with the P. lepto- 

 rhynchus of Sars and that the former specific name must be 

 retained for it. 



As regards the generic position of the forms hero discussed, 



