On the Morphology and Classification of the Saleriiidse, 117 neck ; posteriorly the thin edges are turned over the back. Creamy white in colour. The posterior is twice as large as the anterior sucker, is quite circular, prominent, 1 inillim, in diameter J it is placed just anteriorly to the middle of the ventral surface. The pharynx is large, and cseca are developed from the hinder halves only of the two branches of the intestine. The eggs are scattered abundantly through all but the anterior region of the body, and call to mind the figure given by Olfers of Distomwn folium^ from which species (found in the urinary bladder oi Esox lucius) this may be at once distin-guished by the absence of a neck; the eggs measure 0*1065 millim. in length, and '07 millim. in breadth. The length of the whole body is 5*5 millim., and its greatest breadth 3 millim. The specimen of Halosaurus from which this fluke was taken was dredged off Cape St. Vincent at a depth of 1090 fathoms. XV. — On some Points in the Morphology and Classification of the Saleniidge, Agassiz. By Prof. P. Maetin Duncan, M.B., F.R.S., F.L.S., and W. Percy Sladen, F.G.S., Sec. L.S. Contents. The Sur-anal or Dorso-central Plate and its Homologies ; the Periproctal Plates. Some new Points about the Genera Acrosalenia, Peltastes, and Salenia, and a reconsideration of the Classificatory Value of the Genera Fseudosalenia, Hyposalenia, Ooniophorus, and Heterosalenia. I. The Sur-anal Plate. When the genus Salenia is mentioned, or the family of the Saleniidse, to which it belongs, one of the most important structures inevitably arises in the mind — the sur-anal plate, with its many synonyms. The term has been an unfortunate one, although nothing could have been clearer than the meaning which its author desired to give it. L. Agassiz wrote, in his Monogr. d'fichinod. Viv. et Foss., 1838, livr. i. p. 6 : — " The genus Salenia^ restricted within the limits now assigned, is characterized by an odd plate placed in the midst of the oviducal apparatus, which I shall call the sur-anal, which, consequent on its position vis-a-vis to the anal aperture, always renders the anus excentric."
BioStor
