Parker. — Anatomy and Embryology of Scynmus licliia. 223 



"Family SPINACIIX2E. 



" No membrana uictitans : two dorsal fins, no anal : mouth but slightly 

 arched : a long deep straight oblique groove on each side of the mouth : 

 spiracles present : gill openings narrow : pectoral fins not notched at their 

 origin. 



" Genus Scymrms. 



" Two short dorsal fins without spine, the first at a considerable 

 distance from the ventrals ; dermal productions uniformly small ; nostrils 

 at extremity of snout ; upper teeth small, pointed ; lower much larger, 

 dilated, erect, triangular, not very numerous : spiracles wide." 



Only species, S. licliia. 



1. External characters (fig. 15). 



The colour of the specimen is uniform dark brown and has been quite 

 unaltered by the preparation of the skin for stuffing. 



The head is flattened and the snout very blunt, with the nostrils (no) 

 near but not at its extremity : each nostril is guarded by a cutaneous flap 

 on its inner side. The eyes (e) are large, and when fresh were remarkably 

 beautiful, owing to the fact that the pupil was greatly dilated, allowing the 

 silvery tapetum to be seen through the humours, producing a delicate 

 greenish shimmer. There are 19 lower teeth. 



The body is markedly constricted a little behind the mouth, producing a 

 sort of imperfect neck ; there is then a great increase of girth in the region 

 of the shoulder-girdle, from the pectoral (pc) to the pelvic (pv) fins the 

 circumference is tolerably uniform. 



As to the fins, the small size of the pectorals is noticeable, and the 

 pelvics present a character, apparently not heretofore noticed, which appears 

 to me of some morphological importance. This is a low ridge (l.r) extending 

 forwards for some 6 or 8 inches from the anterior border of each pelvic fin, 

 ascending somewhat as it goes. I think there can be no doubt that this is 

 to be looked upon as a retention in the adult of the ridge which, as Balfour 

 has shown, connects the pectoral and pelvic fins in the selachian embryo. 

 On the lateral fin theory of the limbs, this ridge must therefore be considered 

 as a rudimentary structure of considerable interest. 



Within the lips of the cloaca is a well-marked pair of abdominal pores 

 (fig. 1, ab.p), which communicate with the abdominal cavity. The lateral 

 line (fig. 15, 1. 1) is very obvious. 



2. Alimentary organs. 



The stomach consists, as usual in Selachians, of a wide cardiac portion 

 (fig. 1-3, cd. st) of but slightly greater diameter than the gullet, and of a 

 small tubular recurrent pyloric portion (py. st) ; the latter is unusually 

 short, so that the anterior end of the intestine projects but slightly in front 



