VI.—On the Lateral Sense Organs of Elasmobranchs. II. The Sensory Canals of the Common Skate (Raia batis)

Abstract

In the paper on the sensory canals of Læmargus, communicated to the Royal Society in July last, it was pointed out that the arrangement of the sensory canals differed considerably in the Batoidei from that in Selachoidei, and it was mentioned that the sensory canals of the skate would be next described.The skate has been selected chiefly because the sensory canals are more typical than in the torpedoes and the whip and sting rays. In the torpedoes some of the canals are in a vestigial condition; while in the rays proper they have in most species undergone great specialisation. But another reason is, that an account of the development of the lateral sense organs in the skate is likely ere long to be published; and, further, the skate will be more easily obtained and kept under observation than the rays, when physiologists eventually direct their attention to the lateral sense organs of Elasmobranchs.

A taxonomic and morphological redescription of Potamotrygon falkneri Castex & Maciel, 1963 (Chondrichthyes: Myliobatiformes: Potamotrygonidae)

“…X-ray radiographs were taken on Kodak mammography film (Min-R2000). Terminology for skeletal structures follows Nishida (1990) and Carvalho et al (2004), for dermal denticles Deynat & Séret (1996), for internal and external clasper components Taniuchi & Ishihara (1990), for dentition Compagno (1973), and for lateral-line canals Garman (1888), Ewart & Mitchell (1892), and Chu & Wen (1979).…”

The Lateralis Components of the Acoustico-Lateralis System in the Sunfish Family Centrarchidae

“…According to several authors, among them Ewart (1895), the fir st observations recorded on the lateral line were made by Stenonis in 1664 and 1669 on skates and sharks. The tubular structures were assumed by him and later workers to be slime canals (Schleimkanales) and the term is still occasionally seen in the literature.…”

“…The system has often been credited with a "sixth sense" function (Parker, 1905;Ewart, 1895; Knox, 1925) but more often it is referred to as an accessory auditory organ (Pumphrey a 1950) or "Akzessori sches Gehororgan" by several German workers (Dij kgraaf, 1952) ; a true external labyrinth Cun vlritable labyrinthe externe) (Piveteau, 1935) , and a "poor relation to the auditory organ" (Hillier,19~1). Other workers, notably DeSld~ (1884), have implicated the series of or-• gans as being very sensitive touch receptors. In general, the idea that the lateral-line system-is auditory in function has not met very wide acceptance by physiologists and behaviorists.…”

Description of two extraordinary new species of freshwater stingrays of the genus Potamotrygon endemic to the rio Tapajós basin, Brazil (Chondrichthyes: Potamotrygonidae), with notes on other Tapajós stingrays

“…Ventral lateral-line canals were observed after superficial dissection of the skin. Anatomical terminology is as follows : Carvalho et al (2004) for skeletal structures, Deynat & Séret (1996) for dermal denticles, Taniuchi & Ishihara (1990) for clasper structures, and Garman (1888), Ewart & Mitchell (1892), and Chu & Wen (1979) for ventral lateral-line canals. Specimens were captured in the field with the aid of hand nets, by hook and line, and/or long-lines placed during the night and checked a few times before sunrise, baited with bony fishes (usually characiforms).…”