864 



SCASDINAVIAX FISIIKfS. 



least ;i trace of canine tbrniation; Ijut the maxillarj- 

 teeth are still smaller, set closer together, at least in 

 places, and rather blunt. The tongue is boat-shaped, 

 with fleshy lateral margins and bears at the tip one or 

 two large canines and on each side of the true hyoid 

 bone (os linguale), within tlie said margins, a row of 

 somewhat smaller, similar teeth or only one or two, 

 in the latter case large canines. The copular part of 

 the hyoid bone is armed with smaller teeth, of about 

 the same size as the intermaxillav}- teeth, the largest 

 in a row along each of the edges, the others (the inner 

 ones) irregularly distributed in two rows. The pharyn- 

 geal teeth are about equal in size to those on the co- 

 pular part. Among the upper pharyngeals of the Scan- 

 dinavian Smelt only the two hind pairs are furnished 

 with teeth, the hindmost with several (3 — 4) rows, 

 the penultimate with one row. On the elongated lower 

 pharyngeals the teeth are set in two rows. These 

 numerous teeth of different form show that the Smelt, 

 in proportion to its size, is a voracious iish-of-prey. 

 The intestinal canal is short. The a?sophagus 

 with its longitudinal inner folds passes uniformly into 

 the thick-walled stomach, which resemliles a ctecum, 

 and the bottom of which sometimes does not even 

 extend to a line with the tips of the pectoral tins, but 

 sometimes reaches to the anterior extremity of the 

 pelvic bones. On its under surface and in about a 

 line with the middle of the pectoral tins, the pyloric 

 part originates, running forwards at an acute angle, 

 and extending almost to the diaplu-agm, where it bends 

 abrupt!)" back at the transition to the intestine, \\hich 

 is here furnished with a few" comparatively short, but 

 thick pyloric appendages. The intestine runs straight 

 back to the vent. The liver is short and lies almost 

 entirely to the left of the oesophagus and stomach; it 

 extends back to about a line \vitli tlie pyloric angle. 

 On the right, Ijetween tlie uesophagus and the small 

 lobe which the li\'er sends out on this side, lie the 

 gall-bladder and, a. little further liack, the spleen, which 

 in a healthy state is ver\' dark, nearly black, and 

 elli})soidal, more or less flattened''. In the structure 

 of the generative organs we have above remarked a 

 pecidiarity characteristic of the Smelts: behind the 

 ovaries or, when they are fully ripe (in the spawning- 



season), beside their posterior part, tlie mesoarium joins 

 its ventral margin, which in the preceding genus hangs H 

 free in the abdominal cavity, to the lateral wall of the 

 said cavity, thus forming an oviduct open in front 

 (fig. I'ns, p. 828). The left ovary is the larger and 

 lies uKjre to the front. In the sp.iwning-season it 

 occupies almost the whole length of the alxlominal 

 cavity, all the way from the diaphragm. The right 

 ovary lies in the posterior part of the abdominal ca- 

 vity, and extends forward only a little beyond the in- 

 sertion of the ventral tins. The testes occupj' the same 

 position with relation to each other, and the left testis 

 is also the larger; but the difference in their size is 

 not so great as in the case of the ovaries. The air- 

 bladder is simple, long, and united throughout its length 

 to the dorsal side of the abdominal cavity, l)ut does 

 not extend forward to the diaphragm or back quite to 

 the end of the cavity. Fr(_im the lower part of its 

 anterior extremity the pneumatic duct runs to the 

 oesophagus. 



The skull is weakly ossifled, more elongated and 

 shallower than in the Salmons, and without the cur- 

 vature characteristic of the latter in the sphenoid re- 

 gion. Nor does the parasphenoid bone extend so far 

 back as in the preceding genus: its hind extremity 

 lies outside (under) the front portion of the basilar 

 part of the occipital bone, which jiart behind this point 

 is tumid on each side, whereas the Salmons here have 

 only a longitudinal, terete carina. This swelling, the 

 anterior part of which belongs to the temporal region, 

 includes the saccuJus of the labyrinth, with the flat, 

 but long, heart-shaped otolith, which in a Smelt mea- 

 suring 177 nnn. is 5 mm. long. The posterior oculo- 

 muscular canal extends about as far back as the para- 

 sj)henoid lioiie, and thus belongs to the sphenoid and 

 temporal regions. The basisphenoid bone is wanting, 

 and the \vall between the orl)its is reduced to a car- 

 tilaginous ridge, ascending in front and belonging to 

 the hind part of the ethmoidal cartilage. The maxil- 

 laries with their os supplcmenfarc {Jut/ale), the inter- 

 inaxillaries, the palatines, the vomer, and the pterygoid 

 bones, are arranged as in the Salmons; but the reduc- 

 tion of the vomer and the dentition of the mesopte- 

 rygoid bones we have already noticed. The Ijran- 



" According to Kroyeii 3, 1o Day sometimes as many as 7; we Iiave most often found 5. 



'' In a male Smelt 133 mm. long tlie spleen was mm. long dining the spawning-season, in two females measuring 139 and 177 

 mm. the spleen was respectively 5 and 7*8 mm. in length. 



