76 Memoir Sears Foundation for Marine Research 



radiating out from the primary ring and which may or may not invade the four primary 

 uncalcined areas that radiate out to the bases of the neural and haemal spines." 



Jordan and Evermann," for example, followed in 1930 by Jordan, Evermann and 

 Clark," classed all sharks, other than the notidanoids, in two orders, Asterospondyli (cor- 

 responding to our Galeoidea and Heterodontoidea) and Cyclospondyli (including the 

 squaloids, pristiophoroids and squatinoids) ." The sharks have also been subdivided accord- 

 ing to the external or the skeletal structure of the male copulatory organs. However, this 

 results in grouping the notidanoids with the squaloids, and the squatinoids with the Batoi- 

 dei in one case,"' or Chlamydoselachus with the Holocephali in another.^' 



The majority of modern authors'" have given primary consideration to characters 

 that are visible externally in both sexes, such as the number of gill openings, the presence 

 or absence of the anal fin, number of dorsal fins and the dentition. 



White" classed the Selachii ("Antacea") as a superorder with four orders — Hexan- 

 chea, Heterodontea, Squalida and Galea, dividing the Squalida into the suborders Squalida 

 and Rhinida, the Galea into the suborders Isurida and Carcharinida. Still more recently, 

 Bertin'" classed the skates and rays with the sharks as four suborders under the order 

 Euselachii, and distributed among three suborders (Scylliformes, Musteliformes and 

 Lamniformes) the assemblage of families that are united here as the suborder Galeoidea 

 (White's order Galea). 



In our opinion, however, the characters on which these subdivisions of the galeoid 

 sharks are based — the presence or absence of a nictitating fold or membrane, the position 

 of first dorsal relative to pelvics, the details of vertebral calcification and the morphology of 

 the spiral valve — are of a lower taxonomic grade than are those by which the notidanoids, 

 heterodontoids, squaloids, pristiophoroids and squatinoids can be defined."' 



Apart from the names employed, the subordinal classification used in the present 

 paper follows that of Rey," which in turn is based in its essentials on Garman's" system, 



24. Hasse (Nat. Syst. Elasm. Algem. Theil, 1879) proposed the names "cyclospondylic" for the vertebral type 

 with primary annular calcification only, "tectospondylic" for that with secondary concentric rings of sec- 

 ondary calcification, and "asterospondylic" for that with radiating bars in addition to the primary ring. Regan 

 (Proc. zool. Soc. Lond., 1906: 737), however, has more recently limited "asterospondylic" to the type with four 

 radial bars only, which do not invade the four primary uncalcified areas, and has expanded "tectospondylic" to 

 include all types that are not either "asterospondylic" as so limited, or "cyclospondylic," an emendation that has 

 caused some confusion in nomenclature. 



25. Bull. U.S. nat. Mus., 47 (1), 1896. 26. Rep. U.S. Comm. Fish. (1928), 2, 1930. 



27. In the interim, Jordan (Class. Fish., Stanford Univ. Publ. Biol., 3 [2], 1923) had recognized five orders of 

 sharks and employed the term "Tectospondyli" in place of "Cyclospondyli" for the order including squaloids, 

 plus squatinoids. 



28. Huber, Z. Wiss. Zool., 70, 1901 : 671. 29. Leigh-Sharpe, J. Morph., ^2, 1926 : 336. 



JO. Notably Regan (Proc. zool. Soc. Lond., 1906: 722), Garman (Mem. Harv. Mus. comp. Zool., 5«, 1913), 

 Rey (Fauna Iberica Peces, r, 1928), White (Bull. Amer. Mus. nat. Hist., 74 [2], 1937) and Bertin (Bull. Inst. 

 oceanogr. Monaco, 775, 1939). 



31. Bull. Amer. Mus. nat. Hist., 74, 1937: 100, loi. 32. Bull. Inst, oceanogr. Monaco, 775, 1939. 



33. For a recent discussion of inter-relationships of modern sharks, with resultant proposals as to classification, see 

 Bertin (Bull. Inst, oceanogr. Monaco, 775, 1939). 



34. Fauna Iberica Peces, /, 1928: 280. 35. Mem. Harv. Mus. comp. Zool., 36, 191 3. 



