of Recent Species o/*Limulu3. 257 



admlraljle and unmistakable diagnosis of the genus and 

 c'w'ing pt)h/p/iemus as a representative of it, though by refer- 

 ence and number, not actually by name*. 



Miiller, like Linnaeus, mixed up the Molnccan and American 

 ppecies under the name Limnlus gigas (Entomostr. p. 12f), 

 178o). Following him came Faljricius (Fnt. Syst. ii. p. 487, 

 17y3), who restricted the name Limnlus to the genus typified 

 by gigas, or, as he called it, polyphemus, and thus antici- 

 pated by eight years Lamarck's proposal to call the same 

 genus Pohjphemus (Syst. Anim. sans V-'ert. i. p. 168, 1801). 

 Kightly, 1 think, have these genera been regarded by common 

 consent as synonyms ; and whether we call the genus Xipho- 

 sura or Limu^us, its type is polyphemus as limited in the 

 catalogue of the Mus. Ludov. Ulr. 1764. The only other 

 genus introduced into this family is Tachgp^eus^ founded by 

 Leach upon a character peculiar to the male sex and noticed 

 by him in a specimen of one of the eastern species. There is 

 no reason to doubt that this species is the one that Latreille 

 described as heterodaclylus and moluccanus \ and since Leach 

 cites heterodactyJus as belonging to his genus Tachypleits, we 

 may take that species as its type. 



Although TachjpAeus was constituted on insuflScient data, 

 the name must be reserved for the group of king-crabs con- 

 taining gigas { = moluccanus) and tridentatus {^■=iongispina)j 

 to which 1 have here given generic rank. 



Into the specific nomenclature only two changes have to be 

 introduced : this is the restoration of the name gigas for the 

 Moluccan species and the substitution of tridentatus for longi' 

 spina in the case of the Chinese species. 



Part IL — Material. 



The material worked upon is that preserved in the Briti.sh 

 Museum. Although the collection contains the young aiid 

 adults of both sexes of all the usually recognized species, it is 

 scanty enough. Considering the quantities of specimens of 



* Latreille admitted the claims of Xiphosura t<i peneiic recojmition 

 and deprecated the action of Miiller and Fabricius in renaming the same 

 genus Limulus. In his unwillingness to side altogether with these authors 

 in ignoring the work of Gronovius, he eti'ected a compromise, retaining 

 Limulws fur the genus and erecting Xiphosurn to ordinal rank. It 

 appears to me, however, that (Jronovius's name should be recognized for 

 the genus, although he cite# no species by its technical name as the type. 

 His genera rest on exactly the same basis and have the same right to 

 recognition as Brisson's genera of mammals (see on this point JeHrey 

 Bell's vindication of Gronovius in Ann. & Mag. Nat. Hist. (6) xix. p. 239, 

 1897). I cannot tind in the work of Gronovius any reference to '' Xipho- 

 theca, Grouovii," quoted by Leach in Diet. So. Nat. xiv, p. 536 (1819), 



