given in table 3. Body robust, caudal axis not 

 elevated; head broad; snout broadly rounded, 

 short ; nasal flaps rather large, each with a central 

 swelling dividing each flap into two portions which 

 cover the two parts of each nasal aperture, sepa- 

 rated from one another in the midline, nearly 

 reaching mouth, no groove connecting nasal aper- 

 tures with mouth; mouth broad, moderately 

 arched; well-developed labial folds extending a 

 short distance along the inner sides of lower jaws, 

 no labial folds along outer margin of upper jaws; 

 orbital opening elongate, slitlike, a well-developed 

 fold below eye, not touching eyeball; spiracle 

 small, located short distance from rear corner of 

 eye, about same level as eye ; fourth and fifth gill 

 slits over pectoral base; first dorsal origin over 

 end of base of pelvics, its area about twice that of 

 second dorsal ; second dorsal origin slightly in ad- 

 vance of posterior end of anal fin base; anal fin 

 origin very slightly posterior to free tip of first 

 dorsal, its free tip reaching end of base of second 

 dorsal ; caudal fin less than one- fourth total length ; 

 pectoral fins broad, short, their distal margins 

 nearly straight ; pelvic fins united along their inner 

 margins about half the distance from anus to fin 

 tips. 



Denticles, three-ridged, imbricate, with a single 

 strong apical (posterior) point with a weak lateral 

 point on each side, denticle size not uniform, some 

 twice as large as others. 



Teeth similar in upper and lower jaws, small, 

 in 24 + + 24/22 + 2 + 22 rows; each tooth with 3 

 or more smooth-edged cusps, the central cusp long- 

 est, most teeth with two pairs of lateral cusps, the 

 outer pair very small. 



Color pattern of type approximately as illus- 

 trated for specimen shown in figure 15B. 



Schroederichthys new genus 

 Type species — Schroederichthys maculatus n. sp. 



Members of this genus differ from nearly all 

 other sharks in having the posfpelvic trunk region 

 in advance of the caudal fin greatly elongated, the 

 distance from the origin of the pelvics to the origin 

 <>f the caudal fin lobes about one and three-fourths 

 times the distance from the tip of the snout to the 

 origin of the pelvics. In this character of body 

 proportions, members of the genus St-hrorderirh 

 thys show a parallel development with some Aus- 

 tralian sharks of the family Orectolobidae. 



particularly Hemiscyllium. These orectolobids, 

 however, have quite different arrangements of 

 parts near the mouth and have nasoral grooves 

 and barbellike structures. In Schroederichthys 

 also the anal fin is separated from the lower caudal 

 lobe by a considerable distance (a distance equal 

 to about two times the length of the base of the 

 anal), whereas in some orectolobids (Hemiscyl- 

 r/uw- and related genera) only a notch separates 

 the anal from the lower caudal lobe. 



Schroederichthys differs from ScyJiorhinus in 

 having definite though short labial grooves along 

 both upper and lower jaws at the corners of the 

 mouth. It is similar to the two Chilean-Patago- 

 nian species provisionally referred to the genus 

 Halaelurus in having upper labial grooves or folds. 

 Schroederichthys differs from these species in 

 having a somewhat longer postpelvic trunk, 

 shorter labial grooves, and consistently (at all 

 ages in S. maculatus) multicusped teeth in both 

 jaws. 



Generic description. — Small slender sharks of 

 the family Scyliorhinidae having greatlv elon- 

 gated caudal regions with relatively short caudal 

 fins; distance from tip of snout to vent about half 

 the distance from vent to tip of tail; caudal axis 

 little elevated, lower caudal fin not produced as a 

 lobe; two dorsal fins, second dorsal slightly larger 

 than first and similar in shape, first originating 

 behind posterior end of pelvic base; anal fin rela- 

 tively low, its base longer than base of either dor-' 

 sal fin; pectoral fins relatively broad, their distal 

 margins straight or very slightly convex, their 

 outer corners rounded; pelvic fins with their in- 

 ner-posterior comers somewhat produced and 

 their distal margins oblique, pelvics of males 

 united at bases for a very short distance, not form- 

 ing an apron. 



Snout only moderately rounded; nasal flaps 

 small but extending across the nasal apertures; 

 nostrils not united with mouth by a groove and 

 separated from mouth by a distance as great as or 

 greater than width of nasal flap; mouth strongly 

 arched; labial grooves short but extending around 

 corners of mouth; eye elongate, with well-marked 

 fold below, not in contact with eye; spiracle small, 

 on level of eye and close behind it; gill slits five, 

 anterior longest, two posterior slits over pectoral 

 base: no ridges or keels in skin, no precaudal pits, 

 a shallow groove on midventra] line posterior to 



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