90 BULLETIN OP THE BUREAU OF FISHERIES. 



early cleavage. Both eggs and young of all the species with pelagic eggs were taken 

 in the plankton. 



The embryology and early larval life of several species included in this paper were 

 early studied by Agassiz " and Agassiz and Whitman.'' The embryology of one species, 

 vdz, Tautogolabrus adspersus, is described and illustrated in great detail by these authors 

 in their fundamental work on the development of osseous fishes.* Their observations 

 on other species included in this paper are more or less fragmentary. The pelagic eggs 

 and larvae identified by them as Coitus grcenlandicus are doubtless Prionotus carolinus, 

 as a comparison of their figures with the figures here presented of the eggs and larvae 

 of the latter species will show. The eggs and larvae described by them as species alUed 

 to Motella are probably eggs and larvae of the butterfish. Eggs apparently identical 

 with the eggs described by them as those of the Sienna flounder were taken throughout 

 July and August. They were taken in greatest abundance ofif Gay Head on August 24. 

 These eggs were not identified by the present writers. Observations on the early devel- 

 opment of one species {Apeltes quadracus) included in this paper are recorded by Ryder." 



The observations recorded herein were made almost exclusively on Uving material. 

 It is not the purpose of this paper to discuss in detail the embryological development 

 of each species studied, but rather by means of illustrations and descriptions to afford a 

 ready means of identifying eggs or larval fishes at any time during embryonic or larval 

 life. With this purpose in view, the inclusion of several species upon which more or 

 less complete observations have been previously recorded seems justifiable. 



Acknowledgments are due Homer Wheelon for the preparation of the majority of 

 the illustrations and general assistance in the investigation and Vinal N. Edwards for 

 assiduous collecting of material. 



KEY TO EGGS OP CERTAIN FISHES. 



As an aid to the identification of eggs which may be met with in the Woods Hole 

 region during July and August, the following key is appended : 



I. Pelagic eggs. 

 a. Eggs without oil globules. 

 6. Eggs spherical. 

 c. Egg 0.7s to 0.S5 mm. in diameter, highly transparent; pigmentation appears in embryos of 10 

 to 15 somites in form of small black chromatophores distributed over dorsal surface. 



Tautogolabrus adspersus (cunner). 

 cc. Egg 0.9 to I mm. in diameter; in all other respects egg and pigmentation of developing em- 

 bryo resemble preceding Tautoga onitis (tautog). 



66. Eggs ellipsoidal, yolk cortex segmented. 



d. Major axis but little longer than minor axis, 0.65 to 0.75 mm. long, minor axis o.i to 0.3 



mm. less Anchovia mitchilli (anchovy). 



dd. Major axis considerably longer than minor axis. 

 e. Major axis 1.15 to 1.25 mm. and minor axis 0.55 to 0.8 mm. in length; developing embryo 



within egg unpigmented Anchovia argyrophana (anchovy). 



ee. Major axis 1.2 to 1.5 mm. and minor axis 0.84 to 0.86 mm. in length. 



Anchovia brownii (anchovy). 



« On the young stages of some osseous fishes (part m). Proceedings, American Academy of Arts and Sciences, vol. xvn, 

 1882. p. 271. 



*> The development of osseous fishes: i. The pelagic stages of young fishes, n. The pre.embryonic stages of development. 

 Memoirs, Museum of Comparative Zoology, Harvard College, vol. xiv. no. i. pt. I, p. i, 1S85; pt. n, p. 3, 1889. 



^ On the development of osseous fishes. * * * Annual Report, Commissioner of Fish and Fisheries, 1885, p. 489. 



