1853] 



PROF. AGA8SIZ ON EXTRAORDINARY FISHES FROM CALIFORNIA. 



89 



latter, in which the scales present a very uniform ctenoid type. 

 The thick lips might remind one of the Labroids, but the scales 

 of the Embiotoea are neither elongated, nor provided with the 

 characteristic branching tubes of that family. 



One long dorsal fin, the anterior portion of which is supported 

 by spinous rays, and the posterior by numerous articulated branch- 

 ing rays, which are sheathed at the base by two or three rows of 

 scales, separated from those of the body by a rather broad and 

 deep scaleless furrow. This last peculiarity has not yet been ob- 

 served in any fish, as far as I know. There is indeed a distinct 

 longitudinal space parallel to the soft portion of the dorsal, nearly 

 of the width of a single row of scales, which is entirely naked 

 and well defined, forming as it were, a furrow between the scales 

 of the back, and those which rest against the base of the fin rays. 

 Though protected in this way by a kind of sheath, the anterior 

 part of the dorsal fin alone can be folded backwards and entirely 

 concealed between these scales, as in many Sparoids ; the poste- 

 rior part only partially so. Moreover, the scales of the sheath are 

 separated by a furrow from those of the back, only along the base 

 of the soft part of the dorsal fin. The first rays of the anal fin 

 are short, comparatively small and spinous. The base, of this fin 

 is strangely arched, and sheathed between scales, in the same 

 manner as the dorsal ; the spinous rays wdien folded back being 

 more fully concealed in the sheath than the soft rays. 



The ventrals' are subthoraeic as in the Sparoids, and provided 

 with a strong spinous and five soft rays. 



Four branchial arches, supporting four complete branchiae with 

 £wo rows of lamella? in each. The opening behind the last arch 

 is very small and entirely above the base of the pectoral fins. 

 Pseudobranehia very large, and composed of sixteen or seventeen 

 5amelloa. The alimentary canal is remarkably uniform in width 

 for its whole length. It extends first on the left side as far back 

 as the ventrals, turns forwards and upwards to the right, then 

 follows the middle line along the large air bladder, to the second 

 ihird of the abdominal cavity, then bends along the right side 

 downward and slightly forwards almost to meet the first bend, 

 when it turns backwards again, and ends in a straight course at 

 the anus. The stomach can not at all be distinguished externally 

 front the small intestine by its size and form. There are no 

 coecal appendages at all in any part of the intestine. The wdiole 

 alimentary canal contained large numbers of shelL fragments of 

 small Mytili. Th.3 liver has two lobes, a short one on the left 

 aide, and a long one along the middle line of the body. 



The female genital apparatus, in the state of pregnancy, con- 

 sists of a large bag, the appearance of which in the living animal 

 has been described by Mr. Jackson; upon the surface of it large 

 vascular ramifications are seen, and it is subdivided internally into 

 a number of distinct pouches, opening by wide slits into the lower 

 part of the sact This sack seems to be nothing but the widened 

 lower end of the ovary, and the pouches within it to be formed 

 by the folds of the ovary itself. In each of these pouches a young 

 is wrapped up as in a sheet, and all are packed in the most 

 economical manner as far as saving space is concerned, some 

 having their head turned forwards, and others backwards. This 

 is therefore a normal ovarian gestation. The external genital 

 opening is situated behind the anus, upon the summit and in the 

 centre of a conical protuberance formed by a powerful sphincter, 

 kept in its place by two strong transverse muscles attached to the 

 abdominal walls. The number of young contained in this sack 

 seems to vary. Mr. Jackson counted nineteen ; I have seen only 

 eight or nine in the specimens sent by Mr. Cary, but since the;e 

 were open when received, it is possible that rorne had been taken 

 Tiuf. However, their size is most remarkable in proportion to the 

 mother. In a specimen of Emb. Jaeksoni, lOi- inches long, and 

 H 



4 \ high, the young were nearly three inches long and one inch 

 high; and in an Emb. Caryi, eight inches long, and Sj high, the 

 young were 2-f inches long, and $ths of an inch high. Judging 

 from their size, I suspected for some time that the young could 

 move in and out of this sack like young opossums, but on care- 

 fully examining the position of the young in the pouches, and 

 also the contracted condition of the sphincter at the external ori- 

 fice of the sexual organs, I remained satisfied that this could not 

 be the case, and that the young Mr Jackson found so lively after 

 putting them in a bucket of salt water, had then for the first time 

 come into free contact with the element in which they were soon 

 to live; but, at the same time, it can hardly be doubted that the 

 water penetrates into the marsupial sack, since these young have 

 fully developed gills. The size of the young compared with that 

 of the mother is very remarkable, being full one-third its length 

 in the one, and nearly so in the other species. Indeed these 

 yoimg Embiotoea?, not yet hatched, are three or four times larger 

 than the young of a Pomotis (of the same size) a fidl year old. 

 In this respect these fishes differ from all the other viviparous 

 species known to us. There is another feature about them of 

 considerable interest, that while the two adult differ markedly in 

 coloration, the young have the same dress, light yellowish olive 

 with deeper and brighter transverse bands, something like the 

 young trouts and salmons in their Parr dress. The traverselv 

 banded species may therefore be considered as inferior to the 

 other, since it preserves through life the system of coloration of 

 the embryo. 



It will be a matter of deep interest to trace the eady stages of 

 growth of these fishes, to examine the structure of the ovary and 

 the eggs before fecundation takes place, etc., etc. The state of 

 preservation of the specimens in my hands, precluded every such 

 investigation. 



Though I know thus far only one single genus of this type, I 

 do not think it right to combine the generic characters with those 

 of the family, as is generally clone in such cases, as I would ako 

 object to the practice of omitting any specific characteristics where 

 only one species is known of a genus. This shows an entire mis- 

 apprehension of the relative value and subordination of the char- 

 acters of animals. I would therefore characterize as follows the 

 genus 



EMBIOTOCA, AGASS. 



Body much compressed and elevated. Head small, with scales 

 only on the cheeks and opercular pieces. Teeth in both jaws, 

 short, conical, arranged in one row, and slightly recurved. Tie 

 pharyngeal teeth much shorter and blunter than those of the 

 jaws, and arranged like pavement. Dorsal fin with nine or more 

 spinous rays. The first three rays of the anal fin, spinous, and 

 much shorter than the following articulated rays, which are 

 always finer and more numerous than the corresponding rays of 

 the dorsal fin. The lateral line is continuous to the base of the 

 caudal fin. Whether the peculiar mode of reproduction is a 

 family or a generic character, remains to be ascertained by further 

 investigations. It is however probable that with some slight 

 modifications it will be found the same in all the members of the 

 family. 



f Some differences between the two species observed, might ren- 

 der it doubtful whether they ought to be considered as belonging 

 to as many distinct genera or not, But we know that in genera 

 differincr greatly from others, the range of the specific differences 

 is also wider than in genera with many species; so until I am 

 tauo-ht differently by new discoveries, I would refer them both to 

 one and the same genus. Such doubts could scarcely be enter- 

 tained respecting families, with many genera, where a standard to 

 estimate spermine generic differences is easilv obtained. 



