SCANDINAVIAN KIMIKS. 



l)och', <iLNTiiEu's MarnirKs rrnsfiiceps" tVoin the duci)- 

 sea fauna of Australiii. 



In 1884 Professor Lkche took a specimen of a Kroliin'iin-lunn at 

 Uic surfiice off Messina. This specimen (fig. 138) lias advanced so 

 far in development tliat we need not liesitale in referring it at least 

 to llie genua Macmrus. Including the very fine tip of the tail the 

 specimen measures 92 mm., the forepart of the body being 12 mm. 

 long. 'J mm. deeji, (> mm. broad, clumsy, and almost spherical, while 

 behind tliis point tlic strongly compressed tail begins with a depth of 

 4'/.2 nim. and very gradually tapers to a filamentous, narrow but com- 

 pressed, and menibvanous appendage. This appendage, which is IS'/j 

 mm. long, forms a slight break at its insertion in the tip of the tail 

 and .iilvances straight back, marked with dark reddish brown spots of 

 pigment, small, but dense, and set in two rows at the base of the 

 appendage, in one row, more scattered, and larger (finally occupying 

 the entire breadth of the appendage) towards its tip, which is, how- 

 ever, colourless. The head does not measure even half of the bulky 

 forepart, though its length, measured as usual from the tip of the 

 snout to the hind margin of the gill-cover (oldiquely against the lon- 

 gitudinal axis of the body), is 6-/3 nim. From the same cause the 

 .length of the snout becomes fairly great, measuring l'-, mm., although 

 the round eyes, with a longitudinal diameter of 2 mm., and set at a 

 distance of about 2 mm. from eacli other, evidently lie far forward. 

 The postorbital part occupies about half the length of the liead, or S'/s 



JSSr 



Fig. 1?>8. Krolmiiis fikunenlosiis, natural size. From Messina, Feb., 1884, 

 V. Leche. Original in the possession of the High School of Stockliohii. 



mm. The moulh is both terminal and lateral, with sharply ascending 

 cleft. The maxillary bones end almost below the middle of the eyes. 

 Below the chin there hangs a barbel about equal in length to the 

 diameter of tlie eye. The nostrils are set on each side at the upper 

 .■Ulterior corner of the eye, in a common opening, divided into two 

 ])arts liy a thin partition-wall. The first dorsal fin begins at a distance 

 of 7 mm. from the tip of the snout, or a little behind the head. It 

 is high — the longest ray measuring about 7^/2 mm. — and pointed, 

 almost falciform; but the anterior rays (except the first, which is 

 rudimentary) are elongated into filaments. Tlie fin contains one rudi- 

 mentary ray aud nine perfect, but simple rays. The length of its 

 base is 2'., mm., or somewhat more than the longitudinal diameter of 

 the eyes. Behind this fin the dorsal edge still retains a low dermal 

 flap, a remnant of llie enibrj'onic vertical fin, and distinguishable not 

 (piite to the end of (lie bulky forepart. At this point the flap dis- 

 appears, but soon returns again, though at first scarcely distinguishable, 

 at about the end of the swollen forepart of the body, now with true 

 rays and in the form of a second dorsal fin, which is remarkably low 

 and follows the dorsal edge back to the base of the caudal filament. 

 The anal fiu begins at a distance of 11 "5 mm. from the tip of 

 the snout, on the posterior part of llirit which we have termed the 



swollen forejjart of the body, lis base thus follows the ventral margin 

 backwards and upwards, then passing in a rounded obtuse angle to 

 the ventral margin of the caudal part, and following the latter to its 

 termination. The rays of the anal fin, which, like those of the dorsal 

 fins, are all simple, first increase in length uniformly but sharply, the 

 length of the rays at the beginning of the tail being about equal to 

 the depth of the latter. Thus the margin of the anal fin is fairly 

 straight, in spite of the sinus in the margin of the body at this spot. 

 From this point the rays gradually decrease in length, until at the 

 beginning of tlie posterior half of the tail their length increases some- 

 what, the height of the anal fin being here greater than the depth 

 of the tail; bnt towards the tip of the tail the length of the rays 

 again decreases. At the base of each ray of the anal fin we find a 

 dark-brown, pigmental spot. The pectoral fins are perhaps the most 

 characteristic peculiarities of this larva. They are almost semicircular 

 disks, for the greater part free, attached to the shoulder-girdle only 

 at the top by a narrow shaft, which is inserted on about a level with 

 the middle of the eye. The outer part of these disks is extremely 

 thin and membranous, but with rudiments of the future pectoral rays: 

 the inner piart is somewhat thicker, in the specimen preserved in spi- 

 rits opaque, and is of an almost regular, but flattened kidney-shape, the 

 upper corner of which, situated about one-third of the way up the 

 pectoral fins, forms the point of origin for the said shaft. If we com- 

 pare this form of tlie pectoral fins with their arrangement in certain 

 Codfishes, where the internal structure is known', it appears extremely 

 probable that the shaft corresponds to the rudiments of the proximal 

 parts of the shoulder-blade and the coracoid bone, wliile the distal parts 

 of these bones and the basal bones of the pectoral rays are developed 

 in the kidney-shaped part of the base of the pectoral disk. Shafted 

 (lobate) pectoral fins are indeed bj- no means rare in the fry of other 

 species'; but a shaft so long and so narrow as in this larva — remind- 

 ing us of the elongation of the basn! bones in Lophius — is unparal- 

 leled within our experience. The ventral fius are set vertically below 

 the insertion of the pectoral fins, somewhat in front of the middle 

 ]ioint between the tip of the snout and the anal fin — the foremost 

 point of their insertion lies at a distance of G mm. from the beginning 

 of the anal fiu — aud are remarkable for the great elongation of the 

 six middle rays. Tlie first ray is not short, its length being very 

 nearly as great as that of the head: bnt the next 6 rays attain a length 

 of as much as 30 mm., are pigmented in the outer part in the same 

 way as the caudal filament, and are also flattened throughout their 

 length like this filament. The innermost two rays are short, the inner- 

 most ray the shortest of all. The anal aperture lies about half-way 

 between the insertions of the ventral fins and the beginning of the 

 anal fin; it has a pointed anal papilla behind it. Half-way between 

 the ventral fins and the isthmus we find a round depression in the 

 ventral wall, coasted in front by a semicircular, membranous, dermal 

 swelling, the two ends of which are continued each bj- a dermal ridge 

 which disappears behind. This structure evidently bears the appearance 

 of having served as an adhesive apparatus by means of which the larva 

 has been enabled to attach itself to floating objects, and is probably 

 of importance as an explanation of the bare (scaleles.s) spot which in 

 adult examples of some species of the genus occurs on this part of 

 the body. On the upjicr portion of the abdominal sides the scales have 

 apparently begun to develop; but the rest of the body is naked. 



It is ditiicult as yet with certainty to determine the species of 

 this larva. Among the four Mediterranean species of the genus given 

 by GiGLiOLi'', it can hardly be referred to any other than Macrurus 

 litvi.f. This opinion is borne out botli by the number of rays in the 



" Deep Sea Fish., Chall. Exp., p. 143, pi 



' See for example Emery, Fierris/er in Fau 



' Cf. above, fig. 77, p. 311. 



" Espos. Intern, di Pcsca, Berlino 1880, Sez. Ital. Cat., p. 98 



XXXVll. 



. nnd Flora des Golfes von Neapel, II Monogr., p. 29. taf. IV, fig. 40. 



