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Show 1888.] VEINS IN THE ANUROUS AMPHIBIA. 125 Hochstetter has examined Bombinator, Hyla, Rana, and Bufo, and in none but the former has he found a persistence of the vessels above named. He was not in a position to discuss the morphological significance of the fact, as a guide to affinity. The researches of Cope1, Boulenger2, and others point to the conclusion that the Discoglossidae, rather than the Aglossa, are to be regarded as the least modified of all living Anura. Boulenger writes3, "in the presence of ribs and opisthoccelian vertebrae the members of this very natural family closely approach the higher tailed Batrachians." The retention of the posterior cardinal (azvgos) vein in Bombinator can only be regarded as a sign of low affinity, and, mindful of the well-known osteological and other characters of this family, I have been led to examine other genera thereof, with the view of ascertaining if this retention is common to all its members. I find the veins of both sides well developed in two specimens ( 3 and $ ) of Bombinator bombinus. Of five Alytes obstetricans examined (three 3 , two 2 )> f°ur showed no traces; in the fifth, however (a $ ), both veins were fully represented, but small. This was also the case in a 3 of Discoglossus pictus. From this it must be assumed that the character is fairly distinctive of the Discoglossidae. Thanks to Prof. Huxley, I have had the opportunity of examining adults of Pipa (3) and Dactylethra ( $ ). In neither of these could I observe a trace of the vessels in question ; the specimens had been previously very much dissected, but should subsequent investigation upon fresh material (which I hope to carry out) substantiate this, the deductions of the afore-named authors as to the lowliness of the Discoglossidae will receive striking confirmation. These facts are, in themselves, sufficient to invest any Anura with a fresh interest, whose affinities with the Discoglossidae have been suggested or called into question. Conspicuous among such is Pelodytes; and for an opportunity of examining this and other genera m y best thanks are due to Mr. Boulenger, who has, with his customary generosity, afforded me unstinted aid. Pelodytes is held by Giinther and Mivart4 to be allied to the Discoglossidae, and by others (Cope, Lataste, Boulenger) to the Pelobatidse5. As I am unable to find any traces of the vein in two adult males of Pelodytes and one of Pelobates, I can but give my support to the latter view. Finally, Hochstetter, in his earlier paper, describes an anastomosis between the hepatic sinus and the posterior cardinal veins in Elas-mobranchs6, which he holds to he tantamount to the formation of a vena cava inferior. This deduction is far too revolutionary to merit immediate adoption ; tlie probability of its accuracy is, however, cer- 1 Nat. Hist. Eeview, 1865 ; also Journ. of Acad. Nat. Sci. Philadelphia, vol. vi. 1866, p. 67. 2 Catalogue of Batrachia Salientia, British Museum, 1882. 3 Ibid. p. 444. 4 P. Z. S. 1869, p. 280 et seq. 5 For references, see Cat. Batr. Salientia. 6 Cf. Jourdain, Ann. des Sci. Nat. 1859, series 4, vol. xii. Also quoted by Parker, of whose papers Hochstetter does not appear to have been cognizant. This is to be regretted, as the two differ on joints of considerable interest. |
