. The Cambridge natural history. Zoology. Fio. 268. — Proboscis and chelophores of Oordylochele longi- collis, (After Sars.) these the terminal portion or " hand " forms a forcipate " chela," of which the ultimate joint forms the " movable ; In some species of Nymphon the chela is greatly produced and attenuated, and armed with formidable serrate teeth on its opposing edges ; in others it is shortened, with blunter teeth ; in Boreonymphon robustum the claws are greatly curved, with a wide gape between. In tins last, and in PhoxicJiilidium, the oppos-
. The Cambridge natural history. Zoology. Fio. 268. — Proboscis and chelophores of Oordylochele longi- collis, (After Sars.) these the terminal portion or " hand " forms a forcipate " chela," of which the ultimate joint forms the " movable ; In some species of Nymphon the chela is greatly produced and attenuated, and armed with formidable serrate teeth on its opposing edges ; in others it is shortened, with blunter teeth ; in Boreonymphon robustum the claws are greatly curved, with a wide gape between. In tins last, and in PhoxicJiilidium, the oppos- ing edges are smooth and toothless. In Oordy- lochele the hand is almost globular, the movable finger being shortened down, and half enclosed by the other. Palpi.—The second pair of appendages, or palps, are absent, or all but absent, in the adult Pycnogonum, Phoxichilus, Plioxi- chilidium, Pallene, and their allies. In certain of these cases, Phoxichilidnim, a knob remains to mark their place; in others, Pallenopsis, a single joint remains; in a few Pallenidae a sexual difference is manifested, reduction of the appendage being carried further in the female than in the male. The composition of the palps varies in the genera that possess them. In Xymphon there are five joints, and their relative lengths (especially of the terminal ones) are much used by Sars in defining the many species of the genus. The recently described Paranymphon, Caullerj', has palps of six or seven joints. In the Ammotheidae the number of joints ranges from five or six in Tanystylum to nine (as a rule) in Ammothea and Oorhynchus, or ten, according to Dohrn, in certain species of Ammothea. Colossendeis and the Eury- cididae have a ten-jointed palp, which in this last family is very long and bent in zigzag fashion, as it is, by the way, also in Ammothea. The terminal joints of the palp are in all cases more or less setose, and their function is conjecturally tactile. Ovigerous Legs.—Custom
Size: 1162px × 2151px
Photo credit: © The Book Worm / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1800, bookdecade1890, booksubjectzoology, bookyear1895
