168 ME. GEOFFREY SMITH ON THE 



Parachceraps. My identification of the New Guinea form with 

 Von Martens's Chceraps quadricarinatiis appears to me certain 

 from his description of the keels, tail-fan, and chelipeds of hi.s 

 Cape York specimens. 



Since the above was written, Dr. Jean Roux, of Basle, has 

 described certain specimens belonging to the genus Chceraps 

 which are evidently closely allied to Chceraps quadricarinatus. 

 He has also re-examined the specimen described by Nobili as 

 Astaconephrops alhertisii, and comes to the same conclusion as 

 myself that this specimen is an undoubted Chceraps, practically 

 identical Avith C. quadricarinatus. Dr. Roux remarks, however, 

 that Nobili's specimen has three serrations on the rostrum, 

 Avhereas C. quadricarinatus only possesses two, and he therefoi'e 

 proposes to keep Nobiji's species as valid. Since no other 

 differences are to be observed, it seems to me desirable to examine 

 many more specimens of both varieties before accepting ISTobili's 

 species on this single difference. 



Dr. Roux also creates two new species, separate from quadri- 

 carinatus, for his specimens from the Aru Islands and for those 

 from other localities in New Guinea; Here, again, he admits the 

 practical identity of his forhis with quadricarinatus, but calls 

 attention to certain differences in the proportions of the cheliped, 

 especially in the male. He also finds in the males of his 

 C. aruarius and C. lorentzi that the iliternal border of the carpus 

 of the clieliped in the male possesses smooth soft areas, which 

 have not been obsei'vfed in C. quadricarinatus or albertisii. It 

 seems possible that these are^s may be olily developed periodically, 

 as Calmali Suggests, and thkt they do not represent specific 

 characters. Without ventuHng to doginatise on the subject, it 

 seems premature to accord thesfe varieties of C. quach-icarinatus 

 more than subspecific rank, especially as the variability of the 

 cheliped in the Crayfish according to age hnd individuality is 

 notorious. (Sfee Dr. Jean Roux (15, l6), Zoologischer Anzeiger, 

 Bd. xxxvii. Nr. 5, pt 104, Feb. 1911, and Notes from the Leyden 

 Museum, vol. xxi;iii. p. 81, 1911:) Caltnan (17) has examined a 

 number of specimfehs from the Mimika River, New Guinea, and 

 has observed soft areas bh the claws of the male identical with 

 those obsferved by tloux^ and he also notices variations in the 

 proportions of the chela, which, howeVer, graduate intb bne another. 

 He is emphatically of thfe same bpinion as myself that all these 

 specimens from New Guinea and the adjacent islands hitherto 

 described ai'fe not sufficiently distihct to warrant thfeir sepiaration 

 into more than One spfecies. 



I am therefore all the morfe ihclined for thfe prefeeilt tb preserve 

 the name qtiadricajrinatiis for all thfese forms. 



Ch^Kaps ixtermedius,- sp. n. {Ph. XXIV. fig. 2 ; XXVlI. 

 fig. 34.) 



The rosti'um i§r fiat and (|tiite unexrtnated, without any lateral 



